300 pistons for the 240 rod

pmuller9

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67chrrybucket":2ja3fqi7 said:
Not really well luckily i just found a set on eBay no oil hole about 225$ but worth it
Did you check with B & P rods out of Texas?
 

67chrrybucket

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Thats who i got them from :cool: and according to my engine builder here should give a 1.71 rod ratio a 240 rod 300 crankshaft. :beer:
 

67chrrybucket

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Wouldn't 6500 rpms be a bit high for the stock crank? And would you be able to port the head enough to take advantage of that rpm range. My car will mostly be street driven so i probably won't need that much. But im curious
 

pmuller9

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67chrrybucket":145pup8h said:
Wouldn't 6500 rpms be a bit high for the stock crank? And would you be able to port the head enough to take advantage of that rpm range. My car will mostly be street driven so i probably won't need that much. But im curious

FTF has the most experience with high rpm use.

I wasn't planning on anything passed 5500 rpm on the street.
It mostly depends on the piston and rod weight, obviously the lighter the easier it is on the crankshaft.
I suspect the biggest concern is the connecting rod strength.

What is your horsepower goal?
 

worken2much

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My good friend had a 240 turning 7,200 when it came apart. Per the tell tale tach. He was ahead of me a half dozen or so car lengths when it happened. It had the spit hole rods. That's what broke. The rod bolts were still in place of what remained of the rod big end.

Sure made lots of smoke.

Worken2much
 

67chrrybucket

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My horsepower goal is 325hp to 350hp i know i will sacrifice some low end torque but im running this in a lighter vehicle than most. Being that its mostly street driven im looking for a 4500-5500 as the horsepower peak rpm
 

pmuller9

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67chrrybucket":77mum74b said:
My horsepower goal is 325hp to 350hp i know i will sacrifice some low end torque but im running this in a lighter vehicle than most. Being that its mostly street driven im looking for a 4500-5500 as the horsepower peak rpm

That's about what I'm looking for in this engine build. I was waiting for the owner to get the rest of the parts needed but I may just have to do it myself and get this engine on the dyno.

What are you doing for head work and cam?
 

pmuller9

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Heads have been CNC ported to over 200 cfm intake and 160 exhaust
232/232 .050" on a 112 LSA, .524" lift with 1.6 rockers

I'm figuring a 95% VE
1 inch pressure drop across the carb
.50 BSFC with a 12.5 A/F ratio

I'm showing 324 hp @ 5600 rpm and 350 hp @ 6100 rpm

The cam grinder's sim program showed about the same.

However there's no substitute for field experience.
It'll be fun to see the actual results.
 

CNC-Dude

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I don't know if its ever been said, but what type of vehicle are you going to put this engine into.
 

pmuller9

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Its going in a 1977 F150 with manual transmission.
The kid that owns it wants to be faster than his friends 350 V8 Chevy pickup.
He said it wasn't that much slower to start with.
 

67chrrybucket

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Mine is going into a 67 comet a bit lighter than the truck yours is going in. Does that simulater also take into account the 120 degrees of crank rotation vs a bent 8? Most of the ones ive seen don't and they are off when it comes to torque
 

67chrrybucket

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I will be having the head ported to hopefully same cam flow as yours pmuller9 also 1.9/1.6 valves im waiting on having a custom cam made after i get head measure,d so i can also order custom pistons and i will be using 240 rods so if i have to ill spin it to 6500 rpm but id probably use a solid lifter then?
 

pmuller9

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67chrrybucket":1ojf34xy said:
Mine is going into a 67 comet a bit lighter than the truck yours is going in. Does that simulater also take into account the 120 degrees of crank rotation vs a bent 8? Most of the ones ive seen don't and they are off when it comes to torque

The software I'm using does not and I'm sure the simulator the cam supplier was using didn't either.

Which way is the error. Does it favor the L6 or do we lose torque?
 

pmuller9

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67chrrybucket":3kg1d1a9 said:
I will be having the head ported to hopefully same cam flow as yours pmuller9 also 1.9/1.6 valves im waiting on having a custom cam made after i get head measure,d so i can also order custom pistons and i will be using 240 rods so if i have to ill spin it to 6500 rpm but id probably use a solid lifter then?

Depends on how much lift and the rocker arm ratio you plan to use.

I stayed at .534" lift with a 1.6 BBC rocker. Spring pressure is right at 300 lbs open, 115 lbs closed
That's 300 x 1.6 or 480 lbs on the lifter.
If I were to use a 1.7 rocker, lift would be .567", 312 lbs open pressure, 530 lbs on the lifter.
50 lbs difference.

If you go to a solid, remember that the advertised duration is shorter because of the tappet clearance.
The duration should be measured at (Tappet Clearance/Rocker ratio)+ .006" lobe lift.
This is usually around .018" lobe lift instead of the .006" for hydraulics.
The shorter duration will increase your Dynamic compression ratio so you would need to decrease the Static compression ratio that you would have used for the same .050" duration hydraulic cam.

If you go to a solid, you could look at using the lifters with the EDM oiling hole in the lifter bottom.
 

67chrrybucket

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I'm not sure about solid lifter yet but since ftf mentioned id probably have to spin it to 6500 rpm i figured that was into solid lifter territory. Im more interested in doing a custom roller cam for various reasons one being a more aggressive cam and cam life
 

pmuller9

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67chrrybucket":1pwxty76 said:
I'm not sure about solid lifter yet but since ftf mentioned id probably have to spin it to 6500 rpm i figured that was into solid lifter territory. Im more interested in doing a custom roller cam for various reasons one being a more aggressive cam and cam life

You shouldn't have to spin it much past 5500 rpm.
If you need power above 6000 rpm, the cam gets fairly "large" with a lot of valve overlap and not very street friendly.

The roller cam is a very good move for the reasons you mentioned plus no cam break-in procedure.
 
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