Inliners International Forums General Discussion Engines Cylinder #2 is missing on new rebuild??

Hey everyone,

For those who want the short story:
Cylinder #2 on my rebuilt 250 seems to be missing. There is a pop from the carb and out the exhaust when this cylinder fires. Any suggestions??

For those who want the whole story:
I put a newly rebuilt 250L6 from a 1969 chevy c-10 in my Jeep CJ5. I had a 1975 250 in it before the swap. About the miss, I know its #2 because the pop goes away if a pull the plug wire from the #2 plug. I have swapped the plugs and wires and the "miss" stays with #2 cylinder regardless. I put a new set of pacesetter headers on it and wonder if maybe this could be causing it, because we had to hammer in about a 3inch section to get it to fit around the clutch slave cylinder. Could it be restricting air flow?

It had the old points type distributor on it, but I couldnt get it to fire at all. So, I put the HEI distributor and coil that was on the 1975 model 250 that I had in it prior. It fired right up, and ran great, execpt for the miss .

I dont think I have let anything out. Any ideas and suggestions are greatly appreciated.

Thanks,
Nic Slay

Thanks for your reply.

I agree, a stuck valve is very possible. Whats the best way to check for this?

I haven't had a timing light on it yet, but I will check it. What gets me is that the **** thing runs SMOOTH on 5 cylinders.

-Nic

Greetings . . .

Have you got a compression gauge? I had a v-thingie with a bent exhaust valve. Engine shook like the dickens at idle and would smooth out with throttle. Thought I had gauled a cylinder (on the initial startup after rebuild) creating blow by. Did a compression test on every cylinder - they all read around 220 psi - except the one which was dead zero!

regards,
stock49

I do have access to one and will check that as soon as I get home from work.
Thanks.

Stock49, What did you do to solve your problem?

Hi JeepDude . . .

I had to pull the head and replace the valve. I didn't notice it was bent when I did my rebuild. Always time to do things over when you don't take your time and check the first time through!

stock49

With a cheap vaccum gauge you can pin down the problem in a minute

Here is how to detect engine problems with a vacuum gauge:

Vacuum tricks 1

Vacuum gauge tuning

hope that helps, Frank

I hope to have time to check this out this afternoon. I'll post the finding in the morning. Thanks.

Took the cover off and adjusted the valves a bit. One valve on the #2 was either stuck or too tight, got it movin good and the engine straightened right out. Prrred like a kitten. We had it timed by ear. Problem is, when we put a timing light on it, the mark showed it to be advanced to far. We could get it close to where it should be, but it did not run near as smooth. I was wondering if the fact that all the exhaust is right now is a set of long headers could be affecting it that much?? Thanks.

Dear JD;

The valves should be adjusted properly before you do anything else (tune-up wise). Losen each till it clicks then tighten till the clicking stops. Then tighten 1 more turn. This puts the lifter in the middle of It's 'travel'. If the engine stumples when doing this tighten 1/4 turn at a time.

Now the timing. Your dampner may have slipped or the Dist. is in a tooth off.

To set the timing simply retard (vacuum advance off) till the engine stumbles, then advance till smooth. That is TDC. Set & then hook up vacuum line.

Good luck, John M., #3370....

Just got time to adjust the valves, they seemed to be pretty close the first time it was done, but I adjusted them as you said to be on the safe side.

Hope to get the timing done this evening, please read my post about the plug gap on HEI.

Thanks for your help guys/gals.

-Nic

Oh, and I found the #2 cylinder. The miss is now gone. Thanks.

Okay, one of those valves was probably to tight.

When you get 5,000 miles on it adj. valves again as they will have tightened up some.

JM....

will do.

Walt,
Believe it or not, the darn thing was right between cylinders 1 and 3! Who'd a thunk??
Thanks for your help guys.