Engine Didn't Grenade/Something Happened/And Final Report

[Intech]

I will be doing the leakage test with the throttle bodies off. No question that it was gas. Oil would have been cloudy if it had coolant in it.

 

[AuroraTom]

I haven't done the leak down test yet as I still have another exhaust to adjust into tolerance. It wasn't just the exhaust that opened up either. All of the intakes went from the lower end of tolerance to the high end with 1-2 out of tolerance at .270.

Assuming that your excessive clearance is caused by carbon, wouldn't it be wiser NOT to reshim the valves back into "spec"?

If you find a way to "decarbon" the valves after you get it running again, your valve clearances will become too tight.

The only down side I can see (to leaving them a little loose) is a slightly noisy engine.

 

[Intech]

I thought of that too. Probably going to inspect the valves one way or another.

 

[Intech]

Did the leak down test this morning. 1,3,4 were all at or below 25% which is acceptable. #2, however, was 0! No leakage at all. WTF? That is not normal is it? I think the head may have to come off.

 

[Fred W]

I cant imagine a problem that would cause the leak down to be less.

 

[Intech]

Just ran the test again and got some leakage from #2, but <5%. Guess I will just get the shims I need to get everything at the middle of the range and put it back together and run it.

 

[Fred W]

As someone suggested already, you should be able to run the engine with the excessive exhaust clearances as is. Then assuming it runs halfway decent go ahead and blast the crap out with ring free

If you can get them decarboned that may tighten up the clearances again. Having excessive clearances is completely safe. Having clearances that are too small is what can damage the engine.

 

[FJRay]

I agree with Fred. get it running if you can and do the ring free . Valves a bit loose won't hurt anything and getting it up to temp a few times will help it a lot. After all that if it survives then adj the valves as needed.

 

[TownsendsFJR1300]

Did the leak down test this morning. 1,3,4 were all at or below 25% which is acceptable. #2, however, was 0! No leakage at all. WTF? That is not normal is it? I think the head may have to come off.

15% is the general limit, then time to tear down. 25% IS not acceptable.

Where is your leakage going? Thru the exhaust (exhaust valves), crankcase, etc. THAT, will eliminate most of the guessing...

5% on #2 is what I'd expect / normal...

It's possible the excess fuel (at the time of failure) blew out excess carbon..

I'm assuming each cylinder was tested at TDC, on the compression stroke?? If not on the compression stroke, major leakage would be expected as the valves would likely have some overlap and leak..

 

[Fred W]

Disagree while 25% leakdown isnt good. It is not terminal it is not the reason that the engine did not run

The key here is to separate the important facts from the trivial.

 

[Intech]

I ran the test again and got very similar results. #2 was just below 5% the second time. All the leakage was coming from the valves (more exhaust than intake) indicating carbon build up. The highest one was just above 20%. And yes, I tested each at TDC. Going to put I back together and get it running.

 

[chivvalry]

The suspense on this is murder...

 

[Intech]

Sorry, but I have a lot of other stuff going on to include a full time job. I need to get moving, though, as my brother wants to ride this to EOM.

 

[Jpotterauto]

Control Module failure / harness short could cause the open injector to flood the cylinder. Check the injector connector for grounding with Key On Engine Off prior to start attempt to avoid flooding the cylinder again. A Boroscope inspection would confirm the carbon theory.

 

[road runner]

What he said about ECU and harness. The ground is toggled to work injector. Make sure you have no ground at inj connectors with key on eng off. If you do its either a shorted wire in harness or a fried injector driver in the ECU.

 

[Intech]

Thanks for the info. I will check that out. I have already verified that the injector works fine.

 

[Intech]

Have it all back together. Checked all the injector connectors for grounds. All read the same with 82 K ohms on one wire and 8 meg on the other. Going to put the tank on and give it a shot.

 

[Intech]

Did I have the battery on the tender all this time? NO! Waiting for it to charge. No surprise that I had fast starter syndrome when I first tried it.

 

[Intech]

After charging the battery about 2-3 seconds of WO throttle with the fast starter syndrom it fired right up. Going to warm it up and treat for carbon and then redo the clearance checks.

 

[RossKean]

Glad that you have it running now. Still doesn't make any sense to me...