Your comments on my upgrades / dyno results added

Ok, today's worklist:

The warm air system works. I have a tube downwards but it is not attached to header yet.

I checked the caps on the carb; I did not open them, just checked that the screws are tight. The gaskets seem old and they are paper, if I open 'em up they'll be unusable.

I started to play with timing. Total advance did not seem to raise more than about 10 degrees from the basic setting, so it seemed that the venturi vacuum port don't produce vacuum. This made me check the advance diaphragm; it works.
I switched the vacuum advance to spark port, and there seems to be good vacuum for the distributor. Also I tested various basic timing settings and now it is set at as much as 17 degrees. The advancers kick the total near 50 now but there is no pinging or knocking while the engine is warm. I revved it up to 5000 on the highway. Don't know yet if it'll knock cold.

Well, now it is not so lazy at all, there is noticeably more power available. It will take some 2-3 days next week to empty one gas tank, so mpg can be measured.

Vacuum is not measured at this time, I did not have access to a gauge. Next week I'll buy one. I adjusted the idle to 800 and the mixture "by the ear".
 
Sounds like you're back on the right track, at least. That 800 idle is better, but a little high for my tastes (but, I also have a stock cam).

If you take that 1946 apart (kits are available almost everywhere for them), you'll probably find the float level is too high - that's part of what causes the wetness you're seeing. This also makes idle mix adjustments difficult. If everything is close to normal, that air screw should be between 1-3/4 and 2-1/4 turns out from closed position, depending mostly on altitude. The 1946 is a very accurate carb, unlike the earlier 1100 families. The other thing I would do if I had it apart and had lower vacuum (like yours) is: I would cut 1 turn off of the power valve's spring. This will let it stay shut better at the lower vacuum numbers you are seeing, which will improve your idle adjustability and your MPG.

One word of caution, though: the vacuum passage that pulls the power valve closed in this carb is VERY NARROW, both in size and in wall thickness. This means that you MUST use a new gasket every time you disassemble it, or it will leak. When it leaks, the power valve opens too soon (or never closes at all) and makes everything rich and difficult to adjust. Of course, this ruins the MPG.
 
If possible, it will usually be best to use manifold source of vacuum and get the most advance possible at idle without pinging on part throttle acceleration. They started using ported sources in order to reduce emissions at idle. Your advance curve will depend on the distributor's map, be it diaphrams, springs and weights or digital data. Even if you do not have a vacuum can, your timing curve may have to be altered since you changed the cam and vacuum characteristics of the engine. The point being, that the stock distributor is not going to be tuned to your current setup for optimum power. But the ignition timing can have a huge effect on performance. I have a '66 Pontiac with a Heinz 57 of parts that was doggy. The culprit is the distributor which was off of a later HEI ignition system. The distributor curve did not match the needs of the engine. I am still working through it.
 
Well, that 17 deg setup gained mpg by 10-15%, now it is about 20-22. The engine runs colder also.

Now I have a vacuum gauge and a digital timing light of my own, don't need to borrow them all the time. Life became just adjusting and adjusting.

I still would like to see 10% gain in mpg. I just set the basic timing to 20 degrees, which helped the vacuum quality and the needle is much more stable now. There is some effect on the idle mixture screw also. Can't get more than 14 Hg at idle. I think I have a vacuum leak at brake booster and that of course has some effect while on the road. I adjust with the booster vacuum plugged.

The centrifugal advance; the setting at the moment is 10R and I heard that it gives double, i.e. 20 degrees more. I metered it today, the weights give 10 degrees more at 2000 rpm and the same at 3000, didn't test higher rpm. Maybe with this distr it is just that and not doubled, does anybody know?

This setup does not knock at least while the engine is hot. The engine starts very easily so the timing can't be way too much advanced.

The road test session ruined the mpg metering, have to fill the tank up again tomorrow. Somehow the pedal hit the metal..."more power is more good". That 20 degree setup feels like more torgue, even at lower rpms.
 
80,
I was goning to tell you to turn up the ignition timing more. Also the 8.8 rear ends that came in GT's are usally 2.73 for 5 speeds or 3.08 ratios for autos
optional was 3.08 for 5 speeds and 3.27 for autos.
 
The 8.8 rear end is 3.08, the same ratio as the original 7.5 unit was. It came from a 92GT that was equipped with a T5. Along with that rear axle I installed the stabilizer bar (13/16") that came with it, so I swapped in the GT's 1 5/16" front bar also and cut one round off the front springs. Now it behaves great on icy and snowy roads, it's fun to drive and there is no traction problems even though I swapped the 14" winter tyres with studs to 16" studless. The tracktion locking rear end is great in these weathers.

This ratio also helps with the economy, along with the gear box. The box is SROD, which has a 0.73 ratio 4th gear. These ratios result to pretty low cruising rpms, about 60mph@2100rpm. Obviously, that setup is not very aggressive, and the gear box is like a 5-speed unit without 3rd gear, there is huge cap between 2nd and 3rd. But this is a daily driver, some 85% of what it sees is highway miles. Maybe I'll amuse other people next summer and try it at the strip...just for fun.
 
One more tank of gas gone. Current setup run 23,3 mpg but there may be some 10% fault in the odo, that is not exactly calibrated or metered against known distance. And of course, one tank is just one tank, it is pretty easy to get half a gallon miss.

Meanwhile, I went into the carbs. Last weekend purchased a 1946 (complete except for choke cap and spring), and tore it apart. On Friday I'll get my hands on a 1946 that is coming in with a complete 200cid engine from another '80 Mustang. That replacement carb is said to be bought in late 90's, should have pretty low miles on it as the car has been a project for years now.
Can anybody just give an idea how much a rebuild kit costs in the States? Where to get? If it's reasonably priced I may rebuild one or two of those carbs. The current one in the car can't be too bad, but it's nice to know what a rebuilt one would do on this engine.

To help the intake side I thought of going for a 2V application, with the adapter. Another way of course would be milling the log of the incoming E0 head for a direct 2V setup. Third way to go would be to flat out the whole intake and fabricate something for a small 4V for example. I already have started this way by cutting one intake log away, but that head is a C6 so we know it is small in valves and passages...E0 would be a lot better for this. Obviously, the amount of work needed is related to these options, but how about gain in performance?

Still working on a daily driver, with a budget, and trying to minimize "down-time".
 
Back on-line with this one;

more done to the car after previous messages. Now I have a FSPP single out header installed and some less destrictive exhaust system behind it with absolutely no KATs in it. Just one free flowing muffler.

Timing became interesting, and may suprise some of you. Basic setting is now at 25,5 degrees. I experimented various settings and the engine starts knocking at about 27 degrees basic timing. With current 25,5 setting, sometimes it has a little hard time cranking, so I'll retard timing 1 or 2 degrees maybe tomorrow. MPG does not seem to change at all between 17-25, it still is somewhere in 22-23 range.

While planning to modify the extra head I have, I'd like to make the current setup better; I have 1946 carb just being rebuilt with a kit, and for that I have a question. I learned from this forum that to make it run leaner the power valve piston's spring should be cut shorter. Now anybody know how many rounds should I take off?
 
Mark P.,
I am not familiar with Holley's, but does the power valve function like the stepped metering rods on the Carter/Edlebrock AFB's, in that engine vacuum holds the metering rod in a jet orifice at high vacuum. At lower vacuum, the AFB's metering rods pull out of the orifice, richening up the mixture.

On AFB's, if you have a wilder cam with low vacuum, you may have to change the metering rod spring to a weaker spring that can be pulled down by the reduced idle vacuum. Does the Holley require similar tuning?
Having not worked on a Holley, I am just trying to understand the Holley tuning remarks.
Thank You,
Doug
 
Doug,
as far as I understand the function is similar; there is a manifold vacuum operated piston in the cap of the carb and when the vacuum drops the spring wins it and the piston moves downwards and opens the power valve at the bottom of the bowl. I understand that the spring should be cut shorter to make it weaker, thus delaying the power valve to open.
 
Ok, not too many dyno numbers here so I though I could publish mine.

So this is the setup; all the previous plus basic timing set at 24, with rebuilt 1946 (w/weaker power valve spring). I had the air cleaner off while dynoing.

The staff had some hard times to keep rolls turning while shifting from 2nd to 3rd during acceleration (that transmission really feels like a 5-spd. with out 3rd; huge jump from 2 to 3). The car was run to 4800 rpm as is clearly visible that it won't go further.

Wish I had a better flowing head.

The results:
www.ponikorjaamo.com/ti80/80_dynonumbers.jpg

www.ponikorjaamo.com/ti80/80_dynograph.jpg

(the links work now, I also added better pics)
 
It's near perfect! Any engine which has the torque peak more than 1000 rpm different is getting somewhere. You need only to check:-

a) the cam timing and

b) rejet the carb or power valve channel restrictions to get more torque.

In my opinion, the engine is down about 25 Nm at the rollers due to one or both of these factors.

Stock 3.3 Mustangs only had 83 hp, and about 135 lb-ft. (62 kW and 185 Nm) You've got a 33% more power but only 14% more torque. I'd expect almost 33% torque gain as well. With smaller cams like yours, you should expect a torque gain everywhere, with great drivablity.

Some important pices of info to consider.

1.The bearing of rod ratio on the US 200 and all 221 and 250 I6's

The stock Australian 2-bbl 3.3 found in 1983 XE Falcons, with alloy head, large valves, cross-flow porting, Bosch Duraspark ignition, Weber ADM 2-choke 34/34 carb, and long 6.27" rods, does:-

about 90 kW at 4200 rpm,
240 Nm at 2400 rpm on a 9.35:1 compression ratio.
Max revs was 5500 rpm.

It did that much since the rod length to stroke ratio (L/R) was 2.0:1, as good as you'll get to improve rev range. The US 3.3 is very poor in L/R ratio. It's the same as the Aussie and US 250, at 1.51:1. You loose 700 rpm at the top end just from the rod ratio alone.

The fact is it takes quite a lotof work to exceed the 4800 rpm range due to the rod ratio and breathing of the carb and cam. Even with custom rods and pistons, you can't go any longer than 5.37 to 5.45" in the rods, using a thick copper or steel compression plate, and very shallow pistons with a 29,5 mm compression height. Thats a 1.74:1 L/R ratio. The block is too short to do any better. Even fitting a set of 221 Argie or Oz I6 rods, or 302 V8 conrods is hard, so forget about any cheap improvement in this area. It's not cost effective.


2. Expectations on what kilowatts and Newton Meters for various cams

I'd expect that the milder cams can be advanced to gain more low end torque on any 200, 221 or 250 six.

In meterics, engines with a near stock cam and short rods should produce

about 2.75 to 3 Nm for every 1kW produced.

As the engine gets are a more aggressive cam, you loose torque for each kW produced. 200 and 250 sixes with cams more aggressive than 265 degrees total duration and more than 0,440" lift and more than 205 degrees duration lift at 0,050" lift will produce

about2 to 2.25 Nm for each kW.

In Australian 3.3 HQ Holden racers, single 1-bbl engines with 9 port head, a header and 260 degree cam give about 123 kW and up to 255 Nm at the flywheel.

(It's depeandant on a thing called the L/R ratio, and its the 4.71" rod divided by 3.126" stroke for the US 3.3, but 6.27" verses 3.126" for the Australian 3.3) . Do a literature search against L/R verses Nm/KW, and you'll see the relationship.

I'd look at the cam timing. Actual timing may not be to spec, especially since even a 5, 000 km journey will cause an I6 camchain to streach more than 0.5 cm as measured according to the specification. Awefull for perforamnce. The stock cam sprocket timing dot could additinally be off a mile.

Since the engine is still very mildly cammed, and has a quite reasonable head, I'd expect advancing the cam would make a big improvement in low-end power. That's a five hour job to change, but a 2-3 degree advance should add bulk low-end torque.

Headers and there bearing on stock power.

Jetted to an optimum, very good headers on 250 sixes add about 18% to the peak power, and about 12% to peak torque. If carb jetting is lean because of the improved scavenging of the headers, it looses low end torque, and its a jetting issue to correct it. The part throttle economy improvement is equal to the basic % of torque increase, since it reduces the need to open the throttle. I'd expect a 12% boost in fuel economy over the stock cast iron header.


Hope this helped. It's a bit technical, but I'm sure this has the key information to help you.
 
Great response, thanks!

I've got std timing chain hardware that came along with the rebuild kit, don't remember if it is possible to advance with that but possibly not. Obviously can't do a thing for the poor L/R ratio.

What I've been thinking attacking intake restrictions. Something should be done to the ports, log and carb. I have a redline 2V adaptor, planning to install it on another head. Some pocket porting, runner touch-up with the help of the Falcon Bible and some touch on the log restrictions like the bosses in the log at both sides of the carb (they are there to provide metal for threads to fasten EGR equip and do restrict the log). If I mount the 2V, these bosses will go anyway.
Another idea has been to somehow modify the head for long steel tube runners and a selfmade intake to have a 4V carb mounted. Third idea has been to drill the log to accept injectors for an EFI setup, but that has to be a long term approach.
The latest route came up with a sudden availability of a cheap T03 w/pressurized carb. I know my current setup won't handle boost (110 lobe cam, too much CR) but I've got possible buyer for that engine already. I'm thinking of rebuilding the original '80 block with all new parts, ARP bolts, with stock or Crane's 112-lobe cam, all balanced. The main question is the pistons, will the cast pistons do with the T03 doing fairly low PSI? Also, I'd like to build a suitable block for such a case that the T03 won't go in, so some CR should be there. So, should the tempo flattops be ok in terms of strength and CR (if I don't mill the other head more than it needs to get it straight it would be near 8.5 CR with flattops).

These are just some ways to go, feel free to recommend something. As previoisly stated, the car is a daily driver so I need to avoid downtime and also let's try to avoid gold-plated parts and keep costs reasonable. By the way this low-cost idea paid off yesterday, as we dynoed the old 64½ V8 car also; it made just a little less than another car with at least double the money invested in engine. Hmmmm...and my setup was not optimal.
 
I never dynoed the old 250 that I had, but from the times I was running at the strip, I think I was developing almost 185 hp. The combination had the same cam, roughly the same compression, big YF carb. The biggest difference was that I had ported the heck out of that head and added bigger exhaust valves. I think that is where you will find significant gains.

The intake and exhaust vavle poskets need a lot of work. The valve guide boss is very large and on several ports they are so restricted that you cannot get a finger past the guide. The exhaust port makes a slight curve at the end of the port that could be straightened. I removed all the bumps and matched the exhaust port to the header. Do not match the port to the stock gasket. It has a wide opening and the port really needs to be taller.

The intake is hard to work, but you can improve the area under the seats and the valve guide boss quite a lot.

Also, if you look a the combustion chamber wall you will see that even at high lift the valves are shrouded quite a lot. Relieving the chamber by laying back the wall away from the valve seems to help a lot.

The head is now your big constriction, so if you can make some improvements there, it should show up as a good performance gain.
 
:hmmm: Firstly, what Jack said. The Aussie Falcons had smaller valve guides and they look reasonable in the chamber. With the bigger valves from the later head, I'd guess shrouding is very bad. Look at head work if its part of the plan. Any increase in flow figures by smaller guides, less shrouding, or short side radius blending will yield additinal torque from idle to max revs. Free power, and better part throttle economy if the port sizes stay similar.



80Stang":33gta4a2 said:
..... The main question is the pistons, will the cast pistons do with the T03 doing fairly low PSI? Also, I'd like to build a suitable block for such a case that the T03 won't go in, so some CR should be there. So, should the tempo flattops be ok in terms of strength and CR (if I don't mill the other head more than it needs to get it straight it would be near 8.5 CR with flattops).....
Click to expand...

1.Turbo engines work best on very poor intake engines with poor head design. Air-flow benefits are hard going for a start. The right cam has to be used, and even then, your still down on power on a normally aspirated engine.

2. Any four cylinder piston is vastly better than a V8 or I6 piston. Four cylinder engines of the same family are pushed to the 6000 rpm level, are under more detonation and vibration, and have to cope with very lean mixtures. The difference between a Tempo/Topaz/Taurus 2.5 piston strength, and that of a aftermarket 200/250 or 255 piston is likely to be the quality of the casting, its thickness and its oil relief groving. I've seen stock cut down 1900 cc Holden L4 rods and pistons used in little six cylinder 2850 cc Holdens, and they were better than the stock bits. An I6x always carries less revs than an I4, so you gain an added factor of safety. A 2.3 HSC Tempo reving to 6000 rpm with a 3.30" stroke is like your 3.3 six reving to 6300 rpm!

Consider your 3.3 six with a 2.3 HSC piston at 4800 rpm. The piston speed is 31% less than the design maximum piston speed in the Tempo. With an extra 31% percent boost (around 6 pounds ), the engine will be under the same stress as it would be in the Tempo. The 2.5 piston is a little taller, but has a bigger dish. It is likely to be even stronger.

Consider a 500 Holley, a turbo set-up AKA Import Killer or Does10s, a reworked head as per Jacks old 250, and a nitrous set-up as per MarindaRacing. Collectivley, with only 6 pounds boost and simple exhast, you may get 180 hp (135 kw) with ease. Add some nitrous, you could get 250 hp (185 kW).

Checkout Cardomain. With a junked out, preloved 1966 with far worse breathing than yours, one guy with a 500 Holley and headers, all else stock, no cam change, was getting 13.6 second standing quarters in a 1963 Ford Falcon. Imagine just a 50 to 75 hp nitrous kit? Getting the picture? A stock six with a host of small and cheap mods giving 250 hp plus. In your Mustang, that would be a great performer. Like sub 13 second quarters at the drags, with good street performance and effortless drivability.

426826_5_full.jpg


See it at http://www.cardomain.com/memberpage/426826

Gus is a forum member from Australia
 
So that would make el-cheapo sense to go for tempo pistons, sacrifice some of the gained CR back by shrouding the valves. The only problem is that the Crane's mild turbo cam is expensive but would benefit un-turboed setup better than cheap std cam, that would still do pretty good with turbo.

I have to make fast decisions what pistons and cam to take, the bits have to be here at the other side of the world well before the 12th of July 'cause the machine shop will close then for holidays.

At the moment I'm thinking to go for L4 pistons and stock cam, if it has 112 degrees lobe. If the turbo will not be there I'll benefit more from doing the head than from a wilder cam.
 
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