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big six max rpm

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67chrrybucket
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big six max rpm

Post #1 by 67chrrybucket » Wed Nov 06, 2013 5:56 am

I have a 75 300 im building it for my 67 comet i was planning on running it on the street what is the max rpm to safely spin these and what do i do to the bottom end for insurance besides forged crank :) the plan is to fully port and polish head 10/1 compression hyper or forged pistons,custom cam and proffesional products fuel injection with offy c intake and hd 300 exhaust manifold, any other suggestions appreciated and do they make stainless steel valves for the big sixes?
67 mercury comet 202 (new project )
03 silverado (hoped up daily driver)

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Re: big six max rpm

Post #2 by pmuller9 » Wed Nov 06, 2013 12:52 pm

If you have a forged crank that's fine otherwise the iron crank will work for what you are doing.
I'd save the forged crank for a 600 hp turbo build.

I'm doing a similar build with peak horsepower at 5500 rpm. Rev limiter set @ 6000 rpm
I'm using the early 240 rods that are 6.8" in length and do not have the oiling holes in the big end of the rod.
The longer rod allows for a custom piston that is shorter and weighs a lot less than stock.
Compression ratio also 10:1

Use ARP rod bolts, main stud kit and head stud kit.
ARP 152-6001
ARP 152-5401
ARP 152-4201

The ported head uses Chevy small block 2.02" intake and 1.60"
7/16" screw-in studs are installed for Chevy big block roller rockers

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Re: big six max rpm

Post #3 by CNC-Dude » Wed Nov 06, 2013 1:10 pm

Sounds like you each have a good build started. The main limitation being the cylinder head, so trying to spin the engine excessively isn't necessary or going to gain much above a certain point. A 5500-6000 RPM limit should be where you aim as a stopping point.
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Re: big six max rpm

Post #4 by worken2much » Wed Nov 06, 2013 10:06 pm

67,

There is a company called Si out of California that makes stainless 1.94 & 1.6 valves in Ford length. You will also want the Felpro 1024 head gasket. It is far superior for higher compression builds. Also, there is a Mr. Gasket intake / exhaust gasket that is worth getting. Can't remember the part number. It gives a much better fit than the Felpro gasket. No vacum leaks, no gasket protruding out into the port(s). A little search work on this site should turn up the Mr. Gasket intake / exhaust gasket number.

Myself and other circle burners turn 5,500 - 6,000 frequently with no ill effects. Arp rod bolts, high volume oil pumps & bearing clearances at .002 to .0025. The 240 rods with the shorter, lighter pistons would be the slick deal. Hypers will be less money & plenty strong. You'll need good fuel, 105 octane or better, to keep detonation away.

Your buds with the v-8's won't like getting dusted by your old six cylinder.


Good luck,
Worken2much
Rule #1. Six Cylinder Racers Have Longer Cranks.
Rule #2. Unless your given name is Richard...don't be a dick.

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Re: big six max rpm

Post #5 by 67chrrybucket » Thu Nov 07, 2013 1:13 am

The station up the road has 105 octane race fuel which is leaded should that be a concern i was also thinking of using e85? Ive seen the posts on bbc rockers but i also saw a couple of options on summits website any advantage or disadvantage to either of these? And with the carb style efi should i still run intake heat?
67 mercury comet 202 (new project )
03 silverado (hoped up daily driver)

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Re: big six max rpm

Post #6 by pmuller9 » Thu Nov 07, 2013 1:28 am

With a long duration camshaft I would hope premium pump gas will work with a 10:1 compression ratio.
The cam for my engine is a 288/288 seat duration, 232/232 .050" duration on a 112 LSA.
Valve lift is .534" with a 1.6 ratio rocker.

Using the 288 degree seat duration for calculations with the cam sitting straight up,
the Dynamic compression ratio figures to be 7.25:1 which shouldn't be a problem on pump gas.

I prefer using steel roller rockers for longevity although many use the aluminum without a problem.
The aluminum roller rockers usually hit the stock valve cover so either use a spacer or a taller valve cover.

The heated intake manifold is to keep the fuel droplets suspended and not needed for a dry manifold.

Worken2much
Thanks for all the tips. Much appreciated
Found Mr. gasket 260 for the intake/exhaust manifold gasket

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Re: big six max rpm

Post #7 by motzingg » Thu Nov 07, 2013 9:43 am

i think he means he's going to use TBI style injection, so the manifold will still be 'wet'

i'm not sure how the heat affects operation with TBI though, it obviously will have some kind of cold enrichment open-loop phase, but you are still dumping fuel onto a cold manifold the same as a carb and risking fuel separation.

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Re: big six max rpm

Post #8 by THE FRENCHTOWN FLYER » Thu Nov 07, 2013 4:23 pm

motzingg wrote:i think he means he's going to use TBI style injection, so the manifold will still be 'wet'

i'm not sure how the heat affects operation with TBI though, it obviously will have some kind of cold enrichment open-loop phase, but you are still dumping fuel onto a cold manifold the same as a carb and risking fuel separation.



I'm no fan of TBI, but I think the droplet size coming from an injector is much finer than the globs of fuel that come from a carb booster, so the need for manifold heat is probably minimized.

TBI has other issues though, most notably fuel distribution arising from the fact that fuel is coming from a pouint source above the throttle plates. I've mentioned this before in other posts so I'll shut up now.
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Re: big six max rpm

Post #9 by MechRick » Thu Nov 07, 2013 9:26 pm

Not to mention the fuel is hitting the throttle plate at low throttle settings.

I remember the switch from Motorcraft VV carbs to TBI. Power was about the same, but fuel economy went down a bit. I've always wondered if the miniscule amount of fuel entering below the throttle plate (idle and transfer slot) made the difference.

I would like to try a dual setup with tbi injectors above port ones. I want to size the tbi to supply just enough fuel for lean cruise, and then use the port injectors to supply accelerator enrichment and wot fuel. Should be the best of both worlds.
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

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Re: big six max rpm

Post #10 by 67chrrybucket » Fri Nov 08, 2013 4:03 am

So frenchtown your saying that the efi injection systems are no good for the big six i was looking at a msd or fast efi and the proffesional products efi but if i could save myself some money and go with a carb mabe a street demon from demon carbs?
67 mercury comet 202 (new project )
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Re: big six max rpm

Post #11 by motzingg » Fri Nov 08, 2013 8:53 am

Rick, that sounds like a terrible/crazy/awesome idea that my buddy is currently working on. He has a built 383 SBC with two huge T3/T4 hybrid turbochargers, one on each bank. He is using a blow through Holley with a carb hat and he has added 2 TBI injectors (305 style but modified for high flow) above the carb. He is actually using a embedded computer that was originally supposed to be used to control a hydraulic system, but has custom code to control the TBI injectors to come on when the boost kicks in. Since the turbos are so large, the system is almost unaffected until 3000 rpm, then the fuel consumption goes off a cliff hard and hp. triples from 3-4000 rpm. At least that is what the numbers say.

I haven't talked to him for a couple months but last i heard he was pretty close to getting it working.

When he first came up with the idea i thought he was nuts, but seeing it come together has been pretty awesome.


I think as we discussed in that other thread a big part of the reason for the fuel economy drop going from carb to EFI was the stricter control of AFR at cruising speeds, EFI preventing AFR from going too lean which a carb will allow.

I think the 'closed loop' modes on EFI dump more fuel as well, and on those early systems they were probably less precise and the vehicles spent more time in closed loop, than they do now.

I had a '89 VW GTI with KE-Jetronic, that thing ran closed loop like 90% of the time and would only run open loop when the planets aligned, temp was perfect, throttle position was perfect, etc. The cold start injector ran all the way up to like 180 degrees which was basically my entire commute in the winter. My '95 escort idles about 1200 rpm (probably running in cold start routine) for at least 5-6 minutes after i leave the house in the morning.

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Re: big six max rpm

Post #12 by MechRick » Fri Nov 08, 2013 12:30 pm

It sounds like what he is doing is similar to the seventh injector trick the Grand National turbo guys use.

I'm talking about the tbi injectors supplying a fixed rate of fuel (by MAF or something similar). About 16:1 air/fuel ratio. All of the enrichment (cold start, accel, wot, etc.) would be supplied by the port injectors. Ideally, the tbi injectors would be just under the throttle plate.

motzingg wrote:I think as we discussed in that other thread a big part of the reason for the fuel economy drop going from carb to EFI was the stricter control of AFR at cruising speeds, EFI preventing AFR from going too lean which a carb will allow.


If a carb is jetted right, they will never be leaner than about 13.5:1. Dumb air/fuel mixers require the richer settings to prevent them from going lean and producing nasty driveability, say, when driving in Death Valley. I think our sixes tolerate lean carbs to the point that some fantastic fuel economy can be achieved by an out (of factory spec) of tune carb.

Later versions of EEC-IV actually would lean out the fuel mixture during extended cruise. EEC-IV had all kinds of hidden things like that.
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

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Re: big six max rpm

Post #13 by motzingg » Fri Nov 08, 2013 2:15 pm

have you tried adding something like that with C code in MSII? I'm sure guys are doing it, I just never got that far into Megasquirt where I had a running, driving, daily driver to play with things like that and do long term testing. I cant go on the DIYautotune forums or I'd end up sucked in for months.

With the additional I/O's on MSII you could have a switch that put it in econ mode or just do it like closed loop on the KE Jetronic where there were 4 inputs (TP, ECT, O2 and Load) that all had to be within a narrow margin to put it into a special economy mode.

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Re: big six max rpm

Post #14 by MechRick » Fri Nov 08, 2013 3:39 pm

Haven't played with MSII much. MS1 with ms-extra code may do what I want. It has a staged injection mode to ramp in a second set of injectors for cars originally equipped with progressive throttle bodies (a-la RX7).

If not, and since I'm a babe in the woods when it comes to C programming, I would probably just run 2 boxes with the one controlling the tbi injectors running in a fixed rate maf mode (fixed resistance for ECT, ACT, TPS).
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

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Re: big six max rpm

Post #15 by MechRick » Fri Nov 08, 2013 3:58 pm

67chrrybucket wrote:And with the carb style efi should i still run intake heat?


To un-hijack the thread, yes. :oops:

The problem with TBI is when it is running in closed loop. When you step on the throttle the same thing happens as with carbs. The lean fuel wants to drop out of suspension with the air (because of the pressure change). Because of this, TBI systems need a big shot of fuel on throttle transitions, something like 3-4 times as much compared to port injection. Manifold heat helps this.
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

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Re: big six max rpm

Post #16 by THE FRENCHTOWN FLYER » Fri Nov 08, 2013 7:45 pm

67chrrybucket wrote:So frenchtown your saying that the efi injection systems are no good for the big six i was looking at a msd or fast efi and the proffesional products efi but if i could save myself some money and go with a carb mabe a street demon from demon carbs?


NOOOooo - I said Throttle Body Injectors have some inherent problems. Short answer: They work fine at idle. They work fine at WOT. But at just off WOT, say 80 - 90% of WOT, the fuel distribution goes to heck because the conical spray cone gets pulled together and the angled plate biases the fuel off the backside of the plate, upsetting the fuel distribution. The first time I ran fuel distribution on one of these setups I had a A/F spread of FIVE RATIOS! Oh it was Hawarible!!!

But I love EFI. It solves a lot of driveability issues.
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Re: big six max rpm

Post #17 by StrangeRanger » Fri Nov 08, 2013 8:57 pm

Is fuel distribution the reason that ford never put CFI on the 300?
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
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Re: big six max rpm

Post #18 by pmuller9 » Sat Nov 09, 2013 4:47 am

Most of the new aftermarket TBI systems like the FAST EZ EFI have the injectors below the throttle plate.
I will be at the PRI show this December and can check all the different TBI systems just to be sure.

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Re: big six max rpm

Post #19 by THE FRENCHTOWN FLYER » Sat Nov 09, 2013 7:44 am

StrangeRanger wrote:Is fuel distribution the reason that ford never put CFI on the 300?


I dunno. But it may have been. Certainly the cylinder layout on an inline would have amplified the problem. I would like to hear from somebody who tries an aftermarket system how it works.
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Re: big six max rpm

Post #20 by Firepower354 » Sat Nov 09, 2013 10:05 am

Back to the RPM question, is there any thing besides the stroke, rod length, and component strength, as limiters?

7500RPM @ 5000 FPM?
6000RPM @ 4000 FPM?
It gets 10MPG, but goes up to 14 if I lie.

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Re: big six max rpm

Post #21 by pmuller9 » Sat Nov 09, 2013 11:28 am

Firepower354 wrote:Back to the RPM question, is there any thing besides the stroke, rod length, and component strength, as limiters?

7500RPM @ 5000 FPM?
6000RPM @ 4000 FPM?


Money!

With stock rod length and stroke
Force at TDC @ 6000 rpm = 2705 g
Force at TDC @ 7500 rpm = 4227 g

CNC-Dude mentioned the other obstacle, the cylinder head.

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Re: big six max rpm

Post #22 by CNC-Dude » Sat Nov 09, 2013 3:47 pm

All good points pmuller. Also, the camshaft dictates an effective RPM as well, but it doesn't make sense to install a cam capable of 7000 RPM use if the head and intake and other support components can't operate in that RPM range.
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Re: big six max rpm

Post #23 by Firepower354 » Sat Nov 09, 2013 5:57 pm

Sorry, I'd thought that as an obvious.
Similar bore/stroke/rod LS's twist 75HP+/hole at 6500-ish
What I was getting at is, are there any BB6-specific issues, limiting RPM potential?
It gets 10MPG, but goes up to 14 if I lie.

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Re: big six max rpm

Post #24 by 80broncoman » Sat Nov 09, 2013 7:15 pm

THE FRENCHTOWN FLYER wrote:
StrangeRanger wrote:Is fuel distribution the reason that ford never put CFI on the 300?


I dunno. But it may have been. Certainly the cylinder layout on an inline would have amplified the problem. I would like to hear from somebody who tries an aftermarket system how it works.


CFI is this the one that uses one injector and tubes to the ports near the head??

When I was at Crane Chevy came out their 4.3L EFI with one injector and nylon tubes running to the ports for the fuel distribution.
I remember telling our R&D guys that I thought people would love to retro fit EFI for inline engines........ of course I was 27 or so years old and ignored... lol
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Re: big six max rpm

Post #25 by StrangeRanger » Sat Nov 09, 2013 7:57 pm

CFI is Ford-speak for TBI (which is a GM term and we discourage the use of such profanity on this site.)
1996 F-150 (tow missile)
1993 Mustang 5.0 (hot rod and auto-x monster)
1982 Tiga Formula Ford (SCCA racecar)
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Re: big six max rpm

Post #26 by THE FRENCHTOWN FLYER » Sat Nov 09, 2013 8:06 pm

CFI= Central Fuel Injection (Injectors were mounted over the throttle body throttle plates).
EFI= Electronic Fuel Injection - an individual injector placed in each runner.
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Re: big six max rpm

Post #27 by 80broncoman » Sat Nov 09, 2013 8:16 pm

For the record I thought the nylon tubing "Brand C" used on their central injection would have made a aftermarket unit easy to make for different intakes.

I've seen aftermarkt CFI don in Several different ways

1 used what looked like a holley 4 bbl carb center and lower throttle plate and the injector injected fuel into the Tubes the Venturi were mounted on . Yes the Venturi were still there?!?

2 another one was MSD's I think where it had 4 injectors cept he outlet on the injectors were Right under the throttle blades.

Would either or both of these fix that 80-90% throttle blade opening problem?
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When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

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Re: big six max rpm

Post #28 by pmuller9 » Sun Nov 10, 2013 2:43 am

Firepower354 wrote:Sorry, I'd thought that as an obvious.
Similar bore/stroke/rod LS's twist 75HP+/hole at 6500-ish
What I was getting at is, are there any BB6-specific issues, limiting RPM potential?


Yes, by the comparison you made between the LS7 and the BB6 you can get some answers.

The LS7 makes over 3 times the power of the EFI Ford 4.9 six per cylinder.
The stock LS7 head flows around 360 to 370 cfm on the intake and between 220 to 240 cfm on the exhaust both @ .600" lift.

The stock Ford 6 (240) head intake levels off after .450" lift and is just over 100 cfm by .550" lift
The stock exhaust levels off after .500" lift @ 80 cfm

The stock head limits the engine rpm by limiting the airflow.
You can port the 240/300 head and add larger valves to gain over twice the stock airflow.

As far as the rpm limit before breaking, the bottom of the stock cast pistons skirts break off.
I have a piston sitting here where part of the skirt was sitting in the oil pan and the engine was still running fine.
Eventually the rest of the piston would have broken.
Replace the stock cast piston with a Hypereutectic aluminum piston or a forged piston.
Hyper pistons run a tight piston to cylinder wall clearance.

Recondition the rods with ARP rod bolts and have them resized.

Rod Option 1 would be to find the early rods that do not have the oiling hole in the big end which can be a point of failure.
The only problem is the early rods use the smaller .912" piston pins.

Rod Option 2 is to use the early 240 rod which is .500" longer and use a much shorter and lighter piston.

The LS7 has a forged steel crank, titanium rods and valves, lighter and stronger pistons, cross-bolted main caps ......
Last edited by pmuller9 on Sun Nov 10, 2013 3:53 am, edited 3 times in total.

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Accidental post

Post #29 by pmuller9 » Sun Nov 10, 2013 3:16 am

Oops

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Re: big six max rpm

Post #30 by MechRick » Sun Nov 10, 2013 3:11 pm

StrangeRanger wrote:CFI is Ford-speak for TBI (which is a GM term and we discourage the use of such profanity on this site.)


Oops. I guess I've been in the aftermarket too long. :lol:

80broncoman wrote:CFI is this the one that uses one injector and tubes to the ports near the head??


Ch*vy calls that one CMPI, or Central Multi Port Injection. The early versions had tubes with poppet valves in the end that were prone to sticking. Later versions (retrofittable) moved the injector with it's wires down to the end of the tube. Not sure the reason for them, although they did get reasonable fuel economy.
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

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Re: big six max rpm

Post #31 by Firepower354 » Mon Nov 11, 2013 9:37 am

pmuller9 wrote:
Firepower354 wrote:Sorry, I'd thought that as an obvious.
Similar bore/stroke/rod LS's twist 75HP+/hole at 6500-ish
What I was getting at is, are there any BB6-specific issues, limiting RPM potential?


Yes, by the comparison you made between the LS7 and the BB6 you can get some answers.

The LS7 makes over 3 times the power of the EFI Ford 4.9 six per cylinder.
The stock LS7 head flows around 360 to 370 cfm on the intake and between 220 to 240 cfm on the exhaust both @ .600" lift.

The stock Ford 6 (240) head intake levels off after .450" lift and is just over 100 cfm by .550" lift
The stock exhaust levels off after .500" lift @ 80 cfm

The stock head limits the engine rpm by limiting the airflow.
You can port the 240/300 head and add larger valves to gain over twice the stock airflow.

As far as the rpm limit before breaking, the bottom of the stock cast pistons skirts break off.
I have a piston sitting here where part of the skirt was sitting in the oil pan and the engine was still running fine.
Eventually the rest of the piston would have broken.
Replace the stock cast piston with a Hypereutectic aluminum piston or a forged piston.
Hyper pistons run a tight piston to cylinder wall clearance.

Recondition the rods with ARP rod bolts and have them resized.

Rod Option 1 would be to find the early rods that do not have the oiling hole in the big end which can be a point of failure.
The only problem is the early rods use the smaller .912" piston pins.

Rod Option 2 is to use the early 240 rod which is .500" longer and use a much shorter and lighter piston.

The LS7 has a forged steel crank, titanium rods and valves, lighter and stronger pistons, cross-bolted main caps ......



I had posted, a mundane 4" bore 6.0 block with a 4" crank, for same B/S, not the uber-snazzy LS7. Steel valves, garden-variety stuffs.
Again obvious, I'd thought, stock pistons would not be used in a max-rev build. Head sucks. I was moving past the obvious stuff, to see if there were limits of the block and crank.
NASCAR runs even smaller pins that live, so .912 351W aftermarket slugs are cheap/easy fix.
It gets 10MPG, but goes up to 14 if I lie.

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Re: big six max rpm

Post #32 by pmuller9 » Mon Nov 11, 2013 9:58 am

Firepower354 wrote:
I had posted, a mundane 4" bore 6.0 block with a 4" crank, for same B/S, not the uber-snazzy LS7. Steel valves, garden-variety stuffs.
Again obvious, I'd thought, stock pistons would not be used in a max-rev build. Head sucks. I was moving past the obvious stuff, to see if there were limits of the block and crank.
NASCAR runs even smaller pins that live, so .912 351W aftermarket slugs are cheap/easy fix.


When you said 75HP/hole that looked more like the LS7.

FTF would know more more about the block and crank limits for a max rpm build and where the failure would be.
For street/strip use the iron crank with main studs seem to be good for 6000 rpm.
Stating the obvious, the lighter the piston and rod, the higher the rpm the block and crank will tolerate.

What are you looking at doing?
Last edited by pmuller9 on Mon Nov 11, 2013 10:03 am, edited 1 time in total.

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Re: big six max rpm

Post #33 by THE FRENCHTOWN FLYER » Mon Nov 11, 2013 10:02 am

Firepower354 wrote:... I was moving past the obvious stuff, to see if there were limits of the block and crank...


Not so oibvious stuff:

The cranks will crack at the #6 rod throw unless steps are taken to remedy. Larger fillet radii are needed.
Some wrist pin failures have been reported on max. engines running in the 8500 - 9000 range. Pressurized pin oiling was employed.
Cylinder walls move around.
Occasional main bearing cap failures.

These things happen when an "all out effort" build is attempted. Probably none of these things will occurr for the build the original poster had in mind.

Any component can be broken if the stresses placed upon it are high enough and / or long enough. Google 'S-N diagrams'.

My race engines are exceeding the 75 hp per hole but I use reworked or aftermarket rotating components. I just pulled the head off my racer after two full years of use. The head gasket was leaking a little and was probably a few runs away from blowing out. I am giddy with delight that I got this much use out of it. I will re-hab the head and check the bottom end for (hopefully) another year of service.
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Re: big six max rpm

Post #34 by motzingg » Mon Nov 11, 2013 11:29 am

"The stock Ford 6 (240) head intake levels off after .450" lift and is just over 100 cfm by .550" lift
The stock exhaust levels off after .500" lift @ 80 cfm
"

:shock:

I think i just threw up in my mouth a little... that is less than my '89 VW GTI 1.8L DOHC....

i guess the good news is there is plenty of room for improvement!

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Re: big six max rpm

Post #35 by Firepower354 » Mon Nov 11, 2013 1:34 pm

I'd forgot that the thread had started as a humbler inquiry than a max-effort, with all the detours it took :rolflmao:

But, thanks, FTF, for the ultimate max-rev answer.
Reducing rod journal size, or welding in material for the radius, or having Greg at Ro-dy spin up a billet one, all should work?
A few inches of concrete in the base of the bores, with modest overbore?
Billet caps, maybe with strapping?


75hp/hole is an easy number for a street-built LS, in the 6500RPM range, so I was using that as a baseline.
And, why I was inquiring in the similarly-meandering "LS head on a 300" thread. I have a bare 300 and 6.0L heads. Seems easy enough.
It gets 10MPG, but goes up to 14 if I lie.

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Re: big six max rpm

Post #36 by THE FRENCHTOWN FLYER » Mon Nov 11, 2013 2:35 pm

Firepower354 wrote:And, why I was inquiring in the similarly-meandering "LS head on a 300" thread. I have a bare 300 and 6.0L heads. Seems easy enough.


I really would like to see someone build a beast like that and iron out any kinks involved with the build-up. Like my granny said just before she fell off her Harley, "Sonny, don't confuse simple with easy."
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Re: big six max rpm

Post #37 by pmuller9 » Mon Nov 11, 2013 9:55 pm

Just weighed a stock 1983 300 piston and pin.
Piston is 669 grams and the pin is 148 grams for a total of 817 grams.

For a max rpm build you can use the new web and rib "Caged" style piston.

A flat top 4.030" SBC piston with a compression height around 1.200" comes in around 350 grams.

Combine that with a light weight 6.8" long rod and that should relieve a lot of stress on the block and crank
FTF I remember you saying that you use Oliver rods.

The flat top piston with a 60 cc combustion chamber LS head will have over 12.5:1 compression ratio.

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Re: big six max rpm

Post #38 by 67chrrybucket » Tue Nov 12, 2013 3:32 am

So did i read that right does somebody make custom rods for the big six? Or Are there aftermarket rods? Just looking for all the stronger parts i can get
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Re: big six max rpm

Post #39 by Firepower354 » Tue Nov 12, 2013 9:19 am

THE FRENCHTOWN FLYER wrote:
Firepower354 wrote:And, why I was inquiring in the similarly-meandering "LS head on a 300" thread. I have a bare 300 and 6.0L heads. Seems easy enough.


I really would like to see someone build a beast like that and iron out any kinks involved with the build-up. Like my granny said just before she fell off her Harley, "Sonny, don't confuse simple with easy."



Haaaa. True. But, I worked for CJ Batten, and do a little tinkering with single-cylinder engines that go WAY outside their original design envelope, so "easy" isn't in the work, but the planning. LOTS of welding, machining, are the "easy" parts. A manual Bridgeport with decent tooling is about all it would take. Backwards-order cam should be the biggest expense.
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Re: big six max rpm

Post #40 by Firepower354 » Tue Nov 12, 2013 9:36 am

67chrrybucket wrote:So did i read that right does somebody make custom rods for the big six? Or Are there aftermarket rods? Just looking for all the stronger parts i can get


Crower, Oliver, Pauter, lots of places will make custom rods for you.
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Re: big six max rpm

Post #41 by 67chrrybucket » Tue Nov 12, 2013 11:38 pm

Hey ftf do you think one of those tbi injection systems would benefit from say 7-10 psi boost to move the air and fuel through ive been toying with the idea of a power adder but i am afraid it will be too much for the street ;-)
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Re: big six max rpm

Post #42 by THE FRENCHTOWN FLYER » Wed Nov 13, 2013 9:46 am

67chrrybucket wrote:Hey ftf do you think one of those tbi injection systems would benefit from say 7-10 psi boost to move the air and fuel through ive been toying with the idea of a power adder but i am afraid it will be too much for the street ;-)

I cannot say - I have no experience with boosted TBI systems. A boosted 300 running in the 7 - 10 psi range is feasible. Ford built a test fleet of them at one time. I am trying to track down the (retired) engineer who worked on them to gather information for an historical perspective I may write some day.
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Re: big six max rpm

Post #43 by motzingg » Wed Nov 13, 2013 1:11 pm

that would be awesome!! a stock turbo six, i want all the knowledge! what turbo, intercooled? how was EFI set up?

the great thing about forced induction is that you don't need the high flow numbers, wild cams, or high rpm's to make power. you can do it down low with more use-able torque.

the 'just another turbo 300' thread http://www.fordsix.com/forum/viewtopic.php?f=22&t=64008 makes it look easy and will leave you drooling. he just posted a video in the last day or two and i'm gonna watch it right after this... maybe get a kleenex first.

IMO the stock EFI motor (maybe with the non-efi head and some porting/larger valves) running megasqurit is the ultimate application for this engine. High torque, decent power, and you can still de-tune it for good fuel economy and streetability. Pump gas at 5psi would be a ton of fun and probably maintain clsoe to stock economy, and having the ability to switch to E-85 to play on the weekends would silence a lot of critics.

I'm not sure how streetable those 'plug and play' TBI systems are, especially turbocharged. Plus packaging exhaust-turbo-plumbing-carb hat-EFI-offy just seems like so much work compared to the simplicity of the OEM system.

As i said on the 'ls head' thread on hardcore forum, why try to build an NA screamer out of a tractor motor... why not just build the ultimate tractor motor with lots of useable torque?

I'll shut up now, because i still haven't built said 'ultimate tractor motor' and i'm just bench racing...

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Re: big six max rpm

Post #44 by CNC-Dude » Wed Nov 13, 2013 1:29 pm

While building a turbo engine has its own special "quarks" and parameters that need to be met, it is a growing trend with the inline crowd because of the "most bang" for your buck results.
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Re: big six max rpm

Post #45 by 1986F150six » Wed Nov 13, 2013 2:25 pm

THE FRENCHTOWN FLYER wrote:
67chrrybucket wrote:Hey ftf do you think one of those tbi injection systems would benefit from say 7-10 psi boost to move the air and fuel through ive been toying with the idea of a power adder but i am afraid it will be too much for the street ;-)

I cannot say - I have no experience with boosted TBI systems. A boosted 300 running in the 7 - 10 psi range is feasible. Ford built a test fleet of them at one time. I am trying to track down the (retired) engineer who worked on them to gather information for an historical perspective I may write some day.


Frenchtown Flyer,

I do hope you will do this someday. Not only have you had close contact with "those in the know" [engine developmental engineers @ FORD], but you have a true love and appreciation of this wonderful old engine.

Please enlighten us by telling us of the research done regarding what is now called "variable displacement". I think this was in the mid 80's?

May you stay healthy and obtain the information and honor us with the history of this engine. I would encourage you to finish the book with a chapter of what you believe the engine could have become if it had not been killed at the end of 1996.

Thank you!

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Re: big six max rpm

Post #46 by 67chrrybucket » Thu Nov 14, 2013 1:42 am

With so many people chiming in mabe i can ask one more question with recondition crank and rods arp at the bottom lots of porting and a good street cam and high compression what kinda of hp tq numbers realistically can the 300 achieve? Im shooting for a 300-350 hp 350-375 tq or more..... :nod:
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Re: big six max rpm

Post #47 by CNC-Dude » Thu Nov 14, 2013 2:40 am

Well, to give you a comparison for a comparable 6 cylinder Chevy a group of us did some extensive dyno testing with on Inliners a few years back. The 292 engine with 9.2:1 compression(a true pump gas engine) and an assortment of different heads, cams and intakes made a best of 300 HP and 330 Ft lbs of torque. The 292 has much more stroke than a Ford 300 has, and a cylinder head capable of much better performance output than the Ford head, so I really doubt you'll get over 300 Ft lbs of torque mainly because of the limitation the Ford head places on the engine without just getting too radical for a street engine.
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Re: big six max rpm

Post #48 by THE FRENCHTOWN FLYER » Thu Nov 14, 2013 8:22 am

With 12:1 compression and a .650 roller cam and 3 x 2 intake I was getting about 375 at the rear wheels with my best stock prepared head. That's a 'bracket racing' specific engine with full water circulation but that will give you an "upper limit" of sorts on an engine that can be started up, driven around, and not have to be taken down for maintenance periodically. Not streetable, but not a pain to own either.

With less compression and less cam I would think 300 crankshaft hp isn't out of the realm of possibilities.
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Re: big six max rpm

Post #49 by Harte3 » Thu Nov 14, 2013 11:09 am

http://www.bgsoflex.com/auto.html

There might be a calculator at that site that will give you a projection of HP and TQ.
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Re: big six max rpm

Post #50 by motzingg » Thu Nov 14, 2013 11:16 am

by 'best prepared' do you mean one of the ones that you welded/cut up, or a 'stock' head with porting and larger valves?

how critical is the roller cam to that setup? Do you think that a flat tapped cam could break the 300 hp mark? seems to me like the roller conversion is a huge expense for the n'th degree of performance, not having to go roller would certainly make the build a lot more straightforward and save, maybe a couple grand, on the build by the time you factor in a whole new valvetrain.

also, for the sake of consistency are we discussing 300 RWHP or 300 flywheel? You said 375 to the rear wheels, which could be as much as 420+ at the flywheel depending on your drivetrain

what kind of peak tq and hp rpm's are we looking at with a highly tuned motor like that?

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