demetri

So ... got the car back. Transmission rebuilt on the cheap, using same converter to be safe.

I cannot test drive the car before the carb issues are resolved. The main issue right now is that when you get off idle in drive, the car dies. part of the problem is the accelerator pump, but it also appears that the car is lean. If I get the idle screws out, its a bit better. Better yet, if the choke gets stuck, I can drive it (I drove it like that back from the shop, and the high idle through traffic got the car to run hot, 220F, in 80F ambient).

I will first check for vacuum leaks. But then, I am trying to decide if I should try to rebuild this carb, or should I buy another AFB 750 cfm. This carburetor was running fine before I took it to have the head work, but the mechanic insists that somehow the carb deteriorated. ??

If I get another carb, wondering if I should get something bigger. My other Imperial has an 800 cfm Rochester, and these tend to be cheap. But I like the reliability of the Carters.

RacerHog

Why not rebuild the carb that is on it?

demetri

The engine builder insists that this carb is junk. I don't know why he so sure. He was saying something like the jets are too tight, or something of that sort. But I am not sure what to believe.

Let's see if we can have vacuum leaks. WD-40 is next in the shopping list.

But overall, the engine idled real nice, and it felt like it had good compression. No smoke from the pipes.

RacerHog

What carburetor is it again?
If its for any of the big blocks? I think I would try rebuilding it first.
Just my thought's

demetri

Update ...

The Rochester that I had may not have been the 800 cfm version, and it was too messed up. So, I had the AFB cleaned up (750 cfm "competition", may or may not be enough for this engine). I finally got the shift linkage to work. But I have not been able to see WOT yet, the throttle linkage is not yet set right. I think I will be able to fix that this weekend, and have some feel of how the engine performs (hope it will be much stronger than my other Imperial with near stock 440, which is doing pretty good). The engine, as is now, has a slightly lumpy idle, but it is very smooth under rpm, and even at idle, it does not physically shake much. Also, low end torque seems fine (I can test that, since my primaries open fully).

The guys that did the transmission did not tighten up the torsion bar cross member. It would suck if this had fallen off! Hope they will do that today.

So, let's hope the cam will not go flat. I changed the break-in oil with Castrol 20w50 plus ZDDP, and Purolator oil filter plus oil filter magnet. This oil will probably stay through the summer with may be 500-1000 miles on the car (but hard miles!). Car has no working AC, so it will be a "night warrior"!

RacerHog

Keep us post on how it runs...

demetri

Still no WOT test, but I was watching the exhaust in correct illumination from sunlight, and watching for smoke. As you recall, we did not do any work on the rings, and have no idea how many miles are on this engine. Anyway, there was a trace of oil on the fight exhaust pipe as I let off the gas. That looks like valve guide leak, right?

I talked to the mechanic however, and he insisted that there is no oil leak from the heads any more. He said that the compression was about 138, ranging from 120 to 150. That was probably cold, and one plug at a time (the FSM states 160, as I recall, but with all plugs removed and engine hot). The engine has no visible blowby from the oil filler, and in fact it feels like a reasonable vacuum in there.

The rings and cylinders are obviously not in new conditions. Do you guys that this wear state will have a noticable loss in power? From driving the car around, the low end torque (which would be the first casualty of blowby) feels good ...

demetri

Finally, got the carb to fully open. The shift linkage is still not all there though, so I could not test the 1st gear acceleration, and given that one of the tires was very low on pressure, not a good idea to rev it up fully on 2nd. I did get it to 60 though with 2nd, and in the 2000 rpm range did not feel very strong, but as soon as we got close to 3000, it felt like it was really waking up. Just about what I expected.

One question regarding the radiator though. This was a brief drive, but the temp reached 180F with pressure. The radiator did not feel as warm on the driver side as it did on the passenger side. Is this an indication that the radiator is clogged up? I have seen some aluminum 2 row radiators on line for under $200. Are these good deals?

demetri

More updates. I finally had the transmission guy come and adjust the shift linkage on the steering column, so that I can hold 1st gear. Now, I can feel the whole torque curve under 60-65 mph. I have not revved it over 4500 rpm yet, but small coolant leaks (wetting the distributor) and fuel starvations have prevented me from having a good full test. From what I have been sensing so far is that low end torque is certainly acceptable, which was my biggest fear. I hope I will be having lot more torque than the other car in the 4000-5000 range, but I have not been able to confirm that.

One question. In this car, I have the stock mechanical pump, which provides 3-4 psi under normal driving, but at WOT (especially when warm) it cannot keep up. I think this is related to the ethanol in the fuel. I was hoping that the new cam will bring in a new eccentric, but no, even with the new eccentric we still have problems. I have a gigantic electric pump in there, but I need a regulator that can handle the 20-30+ psi pressure without a tank return. Any ideas?

demetri

Hey all. We had a very hot day on Sunday, and I took the car for a test drive on the freeway (speeds two digits, I still have old tires on the back). The car ran a bit hot, as expected. It was 95 out, it got about 200-205 on the freeway, and hotter when I got off the freeway in traffic. The correct approach is to test the radiator, but I am looking for a temporary short cut. I have been told that I can replace the thermostat with a hollow washer of about 3/4 or 1 inch hole in it, in order to flow more water than an open thermostat. My local speed shop does not have these washers. Any ideas where to get them?

Thanks

Mr.4spd

Any hardware store worth it's salt will have something like this. I don't think it's going to help, other than to delay the inevitable.

RacerHog

Make sure the water Pump Fins are all in good shape
Back Flush the Block
180* thermostat
Viscous Mopar 6 blade fan
Fan Shroud
3 Row Radiator
Proper Drive pulleys For 440 with A/C
1 Bottle of water wetter good for a 20* drop in temp
2 Gal of Concentrate Engine Coolant the fill the rest with Distilled water.
Make sure all the hoses are in good order and not collapsing at speeds higher than idle..
If you still run the A/C condenser make sure there is at least a 1" Gap between it and the radiator.
Double check your timing and make sure it is not retarded... This make engines run hot....
Also If the engine is running very lean that will also cause the engine to run hot....

Just my 2 cents...



Problem solved..

RacerHog

Oh...The only problem with running the washer, there is nothing to slow down the water to allow it to cool once it is hot... So it just stays hot, and just runs around...

demetri

Yes, everything in the car is original. Original 3 core radiator, shroud, AC setup (not functioning, but there), 6 blade fan (which does not do much at 65-70 or more), etc. There has been a lot of rust inside this engine, which is very hard to get rid of. But since we did the cylinder heads, at least much of this rust is gone. I don't think its as bad as it used to. I do not have any radiator shops in my area that I can trust, otherwise I should try to have this one rodded out. I am considering buying a new aluminum two row radiator, which should outperform the original.


Yes, the washer may allow too much water. The idea is that if the car gets too hot, you replace the washer with a one with a smaller hole. This is apparently and old hot rodder trick. But my local speed shop does not have the set of washers for 440's (they do for chevies and fords). I was hoping somebody would know of a source for the 440.


Please clarify on a few points.


"1 Bottle of water wetter good for a 20* drop in temp" ?? Are you suggesting more water and less antifreeze?


""Make sure all the hoses are in good order and not collapsing at speeds higher than idle..""

You mean the lower radiator hose. I will ask a friend to rev the car and I will watch it.


It was probably running lean, as I was having very low fuel pressure. That was not helping, but was that the driving factor? I do not yet know about the timing. I need to adjust the dwell some more (it was 25) as the electronic tach is not showing a stable reading. Once I do that, I will advance until I can hear a bit of ping at WOT, and then retard a hair. The, we will know its as far advanced as it can take. Then, will try another test drive again.

RacerHog

1. http://www.redlineoil.com/Products.aspx?pcid=10

2. If the hoses are not stiff get some that are..

3. If you have pluged tubes... It going to over heat... Have a rad shop open it up and find out....

demetri

Turns out that my timing was way retarded since my last drive. After advancing it a bunch, the idle speed went from 500-600 to 700-900 without any other change on the idle screws or mixture. The low speed response substantially improved as well. I did a brief WOT up to 4K, and the mid range seems improved too, and still no spark knock, despite the 89 octane gas I had. That means, I can advance more. May be that will bring down the temps.

I am still thinking of using water wetter though. Does thing thing really work?

Thanks

demetri

Update. I have the timing set so that the car pings a bit with 89 octane under WOT. So, with 93 it will not ping, and the timing will be very close. I also realized that my tach was now showing higher rpm (up to 500 rpm), so I had to get a new one.

I have done nothing about the overheating yet, other than I bought some water wetter. Will see if that is effective after a longish freeway drive.

So, anyway, on a brief 1st gear test up to 4,000 rpm (about 47-48 mph based on the gearing of the car) the car seems to enter its torque curve above 2500-3000 (while there is enough torque at low speed to move the car well) but I cannot say I am impressed with the improvement over the other car. I think the AFB goes to WOT now based on the strong sucking sound. But its possible that the carb is a bit too small for the job (750 cfm). I am still dealing with the fuel pressure issues, so once I get a fuel pressure regulator installed and adjusted, I will be able to move the gage to manifold vacuum and see if the carb is generating a large restriction.

demetri

I finally got around to tearing up the oil filter that was used to break in the cam. After driving the car back from the transmission rebuilder, I had done a few driving tests around the block, two trips to the gas station, and lots of idling. May be total 20 miles and half hour of idling. Well, when I cut it up, I could see a few shiny specs here and there, but you had to look closely in the light to see them. So ... I think the cam survived the largest danger. I think that if I had to have a catastrophic cam wear, these would be full of metal pieces. I spoke with one of my hot rodding advisors, he tends to agree that the worse is behind us.


Now, I have to diagnose that miss that I seem to have at WOT. I finally took it on a 2nd gear WOT, which needs a lot of room, but with my new tires this is feasible. I did not take it more than 4500 because of the vibration (true ~ 90 mph), but although the car did well, it felt like one cylinder was missing occasionally, and for a split second, there was a total power loss. The fuel pressure was good. I will check dwell again, but I am wondering if anybody has any other suggestions. The engine is smooth under part load acceleration, no miss there.

demetri

I pulled a plug the other day, it is not white. But then again, I did not pull it right after WOT.


Is it possible for the mixture to be good at cruising, but with secondaries on to be leaning out?


Thanks

demetri

OK, update. Got a vacuum gage in the car.


On the first drive last week, I had a low 10-12" vacuum on a cold and unstable idle, going up the steep hills around the neighborhood with 10", and spinning the tires on wet roads at 5". Whatever I need to do for the idle, the vacuum gage readings looked OK.

I did a longer test this morning. On the freeway, at 2500-2600 rpm 75-78 mph (speedo approaching 90) the vacuum gage was showing 15". Healthy, what I expected. Hot idle, around 15", about on the low side, still. Then, tried to do a good WOT on 1st gear and 2nd gear. Despite 8:30 AM sunday, too much traffic. I had to keep an eye on the traffic, the radar detector, the fuel pressure, tachometer, and vacuum gage, but it seems that the vacuum drops to about 1" at WOT through the range I tried, 3000-4500 rpm (up to 90-93 second gear, speedo over 100). The vibration on 2nd gear persists, even though the acceleration is strong.

Conclusions: The carburetor is marginally sufficient, but a larger carburetor will not make a huge change. I will stick with this carb for now, and try to tune it.

Next step: Increase the length of the kick down linkage and add a bit of transmission fluid in case it is a bit low. Since I do not feel the vibration on 1st gear, may be the problem is transmission related. I have heard from the tranny rebuilder and others that torquflites will just expel excess fluid. Also, next test I should be watching the vacuum gage for smooth or vibrating variation (looked smooth to me, but I could not exactly stare at it).


If this makes no difference, rejet the AFB? (I heard from many that Ederblock AFB's are too lean). I am thinking of rejetting the secondary side only, as the car runs good at normal driving.

On the funny side, as I was done with hauling ***, I tried to slow down, and the car did not feel like doing so. I had a constant 10" without touching the gas. I tried to slow the car with the brakes and take my exit (270 degree sharp curve), but the brakes got hot, and the booster was not helping much (not surprising). I took the next exit, and I had to turn off the ignition. After 10 minutes of looking around, I found a lock washer being trapped between the idle adjustment screw and the linkage! Only .100" was enough to prevent me from stopping the car!

demetri

Brief update and a question.


I have not done much testing on the car yet, but on a part throttle acceleration on the freeway, the car was running out of gas (fuel pressure dropping, engine running lean), and I was feeling a similar vibration as the one I described above on 2nd gear. So, that reinforces my suspicion that the 2nd gear vibration at WOT was due to lean operation (have not measured A/F ratio though). So, I am thinking of re-jetting the secondaries only, since the engine normally runs smooth at part load. What do you think.


Also, cruising over 80-85 (just under 3000 rpm) seems to yield engine vacuum as high as 17". Engine is idling down the freeway.


Also, the coolant temperature did not exceed 195-200, but that was in relatively cool conditions (under 90F). I do not think the cooling system is yet fully up to the task of a super hot day.

demetri

Hey guys. We were thinking of replacing the jets and metering rods on this AFB 750 competition series without removing the carb from the engine. My carb rebuilder may not have the correct jet/needle size, so I was suggesting purchasing a kit. Any thoughts on a source of such a kit and the cost?


Thanks

RacerHog

Try Jegs????

demetri

Quick update: Not much new Other than the cam breaking in seems to be going fine, and I have 300 miles into the engine without any signs of trouble (I am trying to avoid traffic, and drive the car on freeways as fast as practical, and keep the rpm over 2500 rpm when possible).















I have been waiting for the fellow that rebuilt the carb to help me with replacing the jets of the secondaries. However, I recently found out of an other easier approach. Just replace the metering rods, which seems to be a 5 minute operation. But, I found out affect only the primaries. Apparently, I can replace the metering rods with an identical diameter at the top end and thinner on the bottom (or vice versa), so that I can maintain the same mixture as I have now during cruising, but get richer at full power. The bad news is that with this approach the secondaries are unchanged. But this is much easier as I do not have to remove the carb, and the local speed shop may be able to give me exactly the metering rods that I need.


For those of you that have tuned 750 cfm AFB's before, does this make sense? Do you think that I will have to replace the secondaries jets eventually to reverse my suspected lean operation at WOT?

demetri

Quick update: Not much new Other than the cam breaking in seems to be going fine, and I have 300 miles into the engine without any signs of trouble (I am trying to avoid traffic, and drive the car on freeways as fast as practical, and keep the rpm over 2500 rpm when possible).



I have been waiting for the fellow that rebuilt the carb to help me with replacing the jets of the secondaries. However, I recently found out of an other easier approach. Just replace the metering rods, which seems to be a 5 minute operation. But, I found out affect only the primaries. Apparently, I can replace the metering rods with an identical diameter at the top end and thinner on the bottom (or vice versa), so that I can maintain the same mixture as I have now during cruising, but get richer at full power. The bad news is that with this approach the secondaries are unchanged. But this is much easier as I do not have to remove the carb, and the local speed shop may be able to give me exactly the metering rods that I need.


For those of you that have tuned 750 cfm AFB's before, does this make sense? Do you think that I will have to replace the secondaries jets eventually to reverse my suspected lean operation at WOT?

moe7404

Title: AFB and edelbrock carb / the short verson.

setting an AFB carb takes time. make only small changes. and give it time, dont make changes in an hour or two. drive it in different ways over a day or two. on AFBs or AVSs change only the jet OR rod at one time. and start with the jets. a .003" change can be felt if you try. dont forget .003" on a .060" jet is less change than .003" on a.100" jet. Then start changing the rod. A little is a LOT. i do have a computer program to cal any combo of changes. but it is lost in some main frame of my sons. Sometimes you can set the float level to 5/16”. the stock setting is 7/32. if at 5/16” at idle the fuel runs out of the main discharge nozzle reset to the stock setting. NOTE: do NOT change jets AND rods at the same time. Do not put the jets in tight, just snug is fine /////here is the computer program to cal any jet / rod change. *http://clarkehackworth.com/files/JetsAndRods.html

demetri

I started changing rods, since this is so much easier. The carb had 47/71 as the speed shop guy had predicted. That is 0.047 small diameter, 0.071 large diameter. Apparently, Ederblock sets them lean, because most people install too big a carb on their little engine. We went to 41/70. I think the car runs much better, and the intake sound is stronger. So, we are at the right path. I only did 1st and 2nd gear test though, a 3rd gear will be more revealing. But the engine revs from 2000 to 5000 with what appears to be a very flat torque curve.

demetri

Finally got a 3rd gear test. I took it up a shallow incline to 4000-4100 rpm (won't say how fast that is in mph). The uphill helps assess the improvement compared to previous runs in the same area. Even though the car is fast, I am not that impressed, and I think there is more performance to get out of more enrichment. This was a very humid morning, and the richer mixture could have allowed for a bit more advance, but I think the car should do better.


My carb rebuilder seems too busy to replace the secondary jets, so I am really tempted to just go one more step on the metering rods.

RacerHog

take a look at the spark plug to see how it's doing

demetri

Thanks Racer, but aren't you supposed to pull the plug right after the WOT test? Otherwise, the plug reading will be "contaminated" by the part load mixture. I was told to do a full throttle acceleration on 2nd, then turn off the car, coast it to a stop, and then pull a plug. This is not an option within the freeways of a city.


I looked up the humidity tables, this cannot account for much at 50-55F.


I was told to do a night drive and watch my rear view mirror for smoke, illuminated by headlights. That is something worth trying.


Here is another thing that some of you may be able to help. The speed shop guy told me that going from 48/71 to 41/70 will increase fuel flow by 9%. That would be a lot ... but I now think that he meant 9% from the primaries. Total fuel flow, assuming about 50/50 since this is a squarebore, would only by 4.5% if I am correct. Any thoughts if he meant from the whole carb or just the primaries? Does anybody know what is the jet size for the primaries for this carb? (looking for order of magnitude, ie, is it say about 0.080, or about 0.120? That way, I can try to estimate the flow area change.