maybe I'm working too hard and too long...

[Deleted]

Fresh pistons
Fresh rings, set/clocked correctly and verified.
Fresh rod bearings, torqued by the book
Fresh pan gasket.
Cleaned and reinstalled the oil pick up.
All mating surfaces were checked with a straight edge and visually checked under extremely bright light and high magnification for cracks and imperfections.
Fresh head gasket. Properly prepped, installed and head torqued down 75lbft, Warmed up, cooled down and re-torqued.
Fresh spark plugs, properly gapped. Properly torqued.
Basic timing was set with the head off. #1 at TDC, compression stroke. Visual verification of rotor position. The motor was not turned in any direction after that.
Battery is older, but maintains a top charge of 12.6 volts and at 700 RPM the generator is putting 13.2V to the battery.
Clean fuel filter
Fresh oil and filter
Clean air filter, properly filled with clean oil.
Fresh thermostat, and cup. Installed in proper orientation with 1/8" hole drilled in it.
Fresh coolant.
Fuel pump was putting out 3 psi. Changed pump with new gasket. Now 4.5 psi
I did have to replace two head studs.
I did have to repair the #2 spark plug hole
I did have to replace one manifold stud.
Dry compression test after some hours of operation is 110psi nominal across the board.
Temperature rises steadily to 185 and drops back to 180.
Vacuum readings are 20-21 during warmup but diminish to minimum with choke opening.
Best idle I can get is 15-16 Hg and 800 RPM.
I've been through 10 combinations of manifolds and five manifold gaskets.
The latest entry has been relegated to the "Vent It, Shit parts section."
I've installed two 636SA and two 539S WO's.
All freshly rebuilt with new shafts and bushings, internals set to factory standards.
NONE WILL IDLE WITHOUT CHOKE.
NONE HAS A VACUUM LEAK.
Here's my question. Is it possible that the manifold gaskets being supplied to us these days are just a scosch too thin?

[zooke581]

I don't know it the gasket is the problem. The carb I rebuilt that was on my 46 and now my supersonic acts the same as with the thin gasket on the 46 and the thicker with the V atomizer like piece. No difference in either motor that it was on. Got me stumped as to what it might be. Obstruction in the exhaust pipe for a manifold piece?

[Deleted]

I should have been more specific. The gasket in question is not for the carb. It's between the manifolds and the block.

[Deleted]

Ok, step back. If you have to add choke, you have one of two problems, not enough fuel at a idle, or too much air. One of the things that frustrates me is when you let your Jeep sit and it won't pull fuel from the tank until you prime it. It has a leak in the fuel line right? It won't leak gas so finding it is a royal pain. Maybe you should try the elimination game. Like a seperate gas supply tank, plugging off the PCV valve, spraying carb clean in the intake to check for fuel starvation, Air cleaner, or no air cleaner, etc. Back to the basics again, one check at a time, and see if something got missed. I have a incorrect idle also. I'm waiting on a fricken head gasket since I had to pull my engine's head to fix a valve spring. All this---------to get a idle setting. I discovered that metering rods and main jets are quite different. The Omix ada jet held the metering rod up so high that it was almost out of the adjustment slot. I changed to another set of original jets from the suspect set. I can't test it for some reason----------No head on the engine! You have tried 4 different carbs and had the same result, that eliminates carburators doesn't it? You say you have no vacuum leaks, and excellent compression. How tight a valve clearance did you set? Plug off vacuum wiper port? Leak on PCV circuit? Leak on side pan cover with a PCV system? crappy omix ada jets that are too small? timing spot on?, fuel pressure?, piece of brass in slow speed circuit jet?, not drinking enough? and last but least, did you hold your mouth just right? It's right there somewhere, and you have to add or subtract something to find it. Hang in there. Oh, my other recommendation: buy 3 or 4 more Jeeps so at least one will run when you need it. Oil

[Deleted]

May 4, 2015 7:49:14 GMT -5 @oilleaker1 said:

Ok, step back. If you have to add choke, you have one of two problems, not enough fuel at a idle, or too much air. One of the things that frustrates me is when you let your Jeep sit and it won't pull fuel from the tank until you prime it. With a fresh rebuild I was able to prime using the military AC572. In lieu of that I have a small squirt bottle for direct priming. Fires right off. It has a leak in the fuel line right?No fuel line leaks. Fresh short flex line, clamped over barbed fittings. Bail on glass bowl is tight on fresh gasket. It won't leak gas so finding it is a royal pain. Maybe you should try the elimination game. Like a seperate gas supply tank, plugging off the PCV valve, spraying carb clean in the intake to check for fuel starvation, Air cleaner, or no air cleaner, etc. Back to the basics again, one check at a time, and see if something got missed. I have a incorrect idle also. I'm waiting on a fricken head gasket since I had to pull my engine's head to fix a valve spring. All this---------to get a idle setting. I discovered that metering rods and main jets are quite different. The Omix ada jet held the metering rod up so high that it was almost out of the adjustment slot. I changed to another set of original jets from the suspect set. I can't test it for some reason----------No head on the engine! You have tried 4 different carbs and had the same result, that eliminates carburators doesn't it? You say you have no vacuum leaks, and excellent compression. How tight a valve clearance did you set? Plug off vacuum wiper port?No leak there. Leak on PCV circuit? No leaks there. Brand new PCV Valve.Leak on side pan cover with a PCV system? No leak there either.crappy omix ada jets that are too small?OmixAda is absolutely my last choice. PACCO makes correct size valves and jets. timing spot on?,Set correctly with the head off. fuel pressure?,4.5 - 5psi piece of brass in slow speed circuit jet?, Clean and correct size in all four carbs. not drinking enough? Maybe. and last but least, did you hold your mouth just right? It's right there somewhere, and you have to add or subtract something to find it. Hang in there. Oh, my other recommendation: buy 3 or 4 more Jeeps so at least one will run when you need it. Oil

I have ordered three (3) NOS intake/exhaust manifold gaskets out of Chickamauga. I think the new manufacture may be too thin. Mouth has assumed many positions and spouted many epithets and obscenities. I have been offered the use of an MB by a friend. But I don't think Moosey will let me count that mileage in the race!

[Deleted]

On my way into town to work on my Jeep junk, I thought of a slogan posted under a member's post. "99% of carburation problems is ignition". Condensor is # 1, coil # 2, and then the points and cap and wires. Worth a try when all other things are exhausted. I fell into this trap on my M38. My brand new inner distributor cap had a intermittent bad internal connection between the inner post of the cap and the outer wire connection. No shit!!!!!!!!! I used a inductive pickup timing light to find it. It sounded just like I had fuel starvation at a low idle. I rebuilt another carb and replaced the original to no avail. Boy was I pissed like you! My loss here is your gain. I figured it was a plug, so I swapped. ----No! Then the wire, so I swapped-----No! All that was left was the cap-------Yes! Oilly

[Deleted]

.0005", multiplied by the circumference of an intake manifold port, multiplied by 2. What do you get? A pair of vacuum leaks that are huge! My suspicion was correct. After measuring the thickness of a fresh-off-the-shelf manifold gasket, I found it to be .0070". It being of modern manufacture, I suspected the maker was cutting corners with material to save a buck. I immediately...oops, wait a minute, UPS is here to pick up the messed up manifold for return to Carl...OK I'm back. As I was saying, I immediately began a search for NOS Gaskets. Our old Friend in Chickamauga just happened to have some for sale. I purchased three. Upon arrival two days later, I measured them. All three were thicker to the tune of.0005", giving me .0075" to place between the manifolds and the block. Put it all aback together again. Now I'm singing a happy tune again. I just today cleared two WO's (One belongs to our very own Splitpersonality) from my backlog after clearing a YF (for Splitpersonality) and a YS for guy on the 2A Page, yesterday. Two more will be finished tomorrow.

[Deleted]

If you sprayed carb clean, before the new gaskets, they didn't show a leak?? Curious Oil

[Deleted]

I knew it was leaking there. I didn't know at the time that it was because the gasket was too thin. Besides that, I was crying in my beer because I had cracked the ears on two (2) different intake manifolds on two new gaskets, and was busy thinking about how I was going to learn how to braze cast iron in order to fix them. It was only later I realized that I had cracked the intakes precisely because of the thin gasket. I went through three new gaskets before the light went on and I measured the last one before it went on.

[Deleted]

A 1/2 a thousandth is that critical!, Are the mounting surfaces 100% true. I know the thicker gasket solved your problem, that's good. But .0005 being a deal breaker I find hard to believe.

Lee

[Deleted]

What I know is this. With new manufacture gaskets and proper torque values, it leaked. NOS gasket, with proper torque values, it stopped leaking. With a .002" gap, in one location, it will leak. The cumulative effect of .0005", in two broad areas can be equivalent, or greater than that. It stopped leaking. I'm running again, although I'll never catch up to the Captain and Zookmonster, with their cumulative miles, in the race.

[Deleted]

Scout, those bozos are taking pictures of two different speedos. You are being shilled out of the mileage prize! Some sort of sealed speedo with a sealed cable on both ends, with proof of tampering is needed. I suppose they could pull the transmission and spin it with a drill or lathe to run up miles though. They will get you in the end. What a bunch of monkeys! Oil

[Haines Garage]

Just to throw my 10 cents in here....I have just a little bit of experience with gaskets. And that last sentence is being serious. I personally believe that thickness is more important than length....No No No....Get your mind out of the gutter.. I think the thickness measurement might attribute to a better quality gasket material! It would be interesting to know the composition of NOS gasket material and that of the modern junk! I have seen huge difference in multiple gaskets for these Jeeps in the build process. Just something to think about.

[Deleted]

Maybe it's asbestos, just a guess!