Engine problems

[m38inmaine]

I have a restoration thread running but I thought this might get more attention here. I assembled an "A2" power pack from multiple engines, they were all originally A1 engines. This block was clean, but missing the head, PO said it was robbed to repair another engine with a leaking exhaust. So I bought an A2 heavy duty head, had the valves done at a machine shop that I have used before. Pistons were pulled and bores ball honed, rings replaced. I assembled the head using the exhaust leak kit, followed the instructions to the letter and all looked fine, 155-165 psi compression across the board, cold with no carb installed. Set valves according to the manual, #1 compression stroke, notch on timing pointer, oil drive gear "V" facing forward and parallel to the block, I marked the pulley 180 out from the v notch, adjusted 1342 firing order turning 180 each time, started with 17 thou and adjusted hot 15 thou.

Initial run, barely ran and violently surging like gasping for air, no smoke, 50+ psi oil pressure, cooling temp steady at 180. I attached a vacuum gauge on the top right of the intake manifold where there is a plug, little to no vacuum, surging like mad barely running. So I figure I have a massive intake leak, remove the intake and notice the bottom of the ports are wet with fuel and the gasket has left no residue like the upper sides have, clearly no seal. My theory/observation is that the leak kit gaskets have moved the exhaust manifold further away from the head so when clamping the intake to the head now the lower portion of the intake is pivoted away further creating a gap the gaskets cant fill. So my "fix" was to wrap some sand paper around a exhaust manifold and relieve some material from the intake saddle that clamps down on the center of the exhaust manifold to help close the gap. I used a 1/8 bead of ultra copper to the gaskets, and installed again per leak kit torque specs and sequence. Engine runs better but still like crap, about 8 inches of vacuum, engine not happy, tried adjusting the timing, I have the distributor clocked fully clock wise and I am still 1/4" away from the timing mark and does not seem to improve the running much at all. The vacuum gauge says late valve timing/intake leak in that range. I also notice that I have no vacuum reading when cranking with the ignition off, I read it is normal to have around 3 inches of vacuum when cranking. I am at a loss of what to try next, I have worked on several of these engines and have never had any problems, looking for advice on where to go next. It acts like a timing issue, cant get it on the pointer, engine is snappy-sputtering when giving it throttle, timing adjustment doesn't seem to affect the vacuum gauge like it normally would. I could pull the timing cover off to verify alignment but I thought the v notch position and timing marks aligning would make that pointless, perhaps I'm wrong. This is a real head scratcher, looking for advice on what to try next.
Thank you for looking.

[Hambone]

Just a guess, is your timing advance working properly? I had one gummed up, engine wouldn't run properly, have you tried carb cleaner around intake?

[rickf]

Have you done a vacuum leak test on it, especially around the bottom of the intake manifold? And the solution is NOT to sand the manifold!!!!!! Double gasket the intake if there is a gap at the bottom. What gaskets are you using for the exhaust? PM me your number so I can give you a call. Also check the PCV valve to make sure it is not stuck wide open and second the check on the timing advance. Although if the timing were stuck full advance and you set it that way it would run with no issues but have no power since it would not advance anymore. Vacuum would be close to normal. Are you positive the valve timing is set correctly?

[m3a1]

This is going to be a good thread. Since phone calls are involved, please make the time to keep the rest of us in the loop on this.

Cheers,
TJ

[m38inmaine]

I had time today before work and pulled the timing cover, yes the one I just replaced and verified the timing marks are correct, also verified the oil pump/distributor drive V notch is facing forward. So I believe this eliminates "valve timing" as a low vacuum issue. I also looked into the distributor and the weights and springs are fine. These engines are so simple yet it's proving to be a challenge, more to come.

[m3a1]

"...tried adjusting the timing, I have the distributor clocked fully clock wise and I am still 1/4" away from the timing mark and does not seem to improve the running much at all."

I'm calling attention to your statement. Go through that distributor with a fine-tooth comb. It is often the simplest things that elude us. Could be something as simple as a cracked rotor loose on the shaft (ask me how I know). That's a path I have trod and got a fine schooling for my troubles and I daresay it would have made for a very fine tattoo.

Sloppy Rotor Achievement Badge - AWARDED!

As to the matter of the intake, agreed this may be one problem among several problems.

I must say I am completely stumped on the matter of your compression numbers which seem pretty darned high. How did THAT happen and how long will that dainty little engine tolerate it? The world watches and waits....!

Cheers,
TJ

[Mark]

I'd say the distributor is off a notch or so.But maybe you already checked that.I'd physically check everything.I found when I couldn't time it, the distributor was off a notch or so.I may be repeating something already mentioned.

[rickf]

Check your pm's.

[Hambone]

If you do a leak check and don't feel like spraying carb cleaner or WD40 all over that new engine, use a small stream of propane with caution.

[rupert's]

On one occasion, after changing the distributor, my engine would not start and I went crazy for a few days. The problem was this piece, which can have two positions. if you insert it in the wrong position, the distributor fits and you can bolt it to the engine but the engine won't start.
You may want to take a look at this part because when assembling an engine with parts from different engines you may have this problem.
Regards and good luck

https://www.g838.org/download/file.php? ... &mode=view

[rickf]

That is a very good point. I sent him a PM about the very issue. If in wrong the distributor will be 180 degrees out.

[svramselaar]

hi

if the rocker arms at cylinder 4 tumble`s cylinder 1 has ignition at ignition timing mark
rotor arm to front engine side cylinder 1 ignition
180 grade turn rotor arm at front fender side cylinder 3 ignition rocker arms tumble cylinder 2
180 grade turn rotor arm at rear fender side cylinder 4 ignition rocker arms tumble cylinder 1
180 grade turn rotor arm at rear engine side cylinder 2 ignition rocker arms tumble cylinder 3

i have one`s at a M38A1 the 2 and 3 ignition cables reversed the engine runs bud bad and backfired
M151 and M38A1 has different turn direction at the distributor m151 right and a M38A1 left

george

[m38inmaine]

George, thank you for your reply.

Today I brought in the engine that I originally had running for the m151( using this distributor and carburetor on the current engine) this ran great but I was getting water in the oil I suspect a crack in the block. I am going to use it as a test platform to compare the orientation of the distributor drive etc, I am going to modify a timing cover so it can be taken on off so as to be able to reference the timing marks.

I also remembered that I changed out the plug wires from what I had used to run the original engine(ran good) with some that "looked" better, of course I only marked one of the original wires, the rest went into the pile. I am going to check them all with a meter, perhaps I have some bad wires, I do know which wires I used on the new engine so that is a plus. Just trying to eliminate all the variables and think out loud as I go along, I'll post my findings/values of all the wires. I know my replies are a bit slow but my schedule at work makes it necessary for a couple of weeks.

Wire results, all readings in ohms:
Longest wire, 8 total, 6.0, 1.9(test lead), 1.3 (2), 1.0, 0.8(3)
Mid wire, 3 total 0.7, 0.8, 2.8
Short wire, 9 total, 1 with no reading/bad, 3.0, 2.2, 0.6, 0.7, 1.0, 1.7, 0.8(2)
Wires used on current engine Long/test 1.9, long normal 1.3, medium wire 0.7, short wires 0.6, 0.8

Test lead, I cut away some of the outer braid for timing light, bad short wire I never used. As to what wires I should use I suspect those with the lowest resistance.

[m38inmaine]

Today I made a cutaway timing cover so I could see the timing marks and be able to easily install/remove the crank pulley. I made two extra marks on the pulley showing TDC and where the distributor drive appeared to be exactly in line with the block. I made sure the new engine was on the compression stroke #1 cylinder, both engines show the distributor drive in the same location on all three pulley marks, so this confirms the timing alignment is correct on the new engine. I also installed the distributor in each engine verifying the rotor pointing at #1 and they both also had the same range of adjustment. Now I am thinking(hopefully)that I had the distributor in 180 out, that would explain the poor running and the inability to time correctly with the timing light and poor vacuum. I will put it all back together tomorrow and report back.

[m3a1]

That little bit down in there is simply an independent extension of the distributor shaft. First thing you do is mark it with a Sharpie so you can be sure you've reversed its orientation when you reinstall. Then, get yourself a magnetic pickup tool (just a little magnet on the end of a shaft) and that will allow you to pick that piece right up out of there.

From your posts, you sound like a guy who is very thoughtful in his work so you will probably give that little piece a good wipe-down and ensure that it's not beat up and re-lubricate it prior to installation. Note the slot on the top is off-set to one side. It may surprise you to hear this but guys have forced their distributors down into that slot even though the off-set is designed to keep that from happening.

Once the extender has been turned 180 degrees, it should go back in with the same ease it came out with and Violà! You've just inverted your timing. Easy peasy.

Cheers,
TJ