350 not running right spark plugs hit....???Compression test results

[Reumster]

Ok I just pulled all my plugs and #s 5 4 6 have been hit and broke. I also did a compression test. 1/155 3/150 5/129 7/150 2/150 4/100 6/130 8/165 as you can see the spark plugs that where damaged have lower compression. What is my problem? and how do I fix it? I'm going out to squirt some oil in each of the cylinders to see if its valves or rings, but seeing as the plugs are damaged I'd lean toward valve adjustment right?

Any ideas? words of wisdom?

[Longhorn Man]

If your valves were hitting your plugs, they would have to be sitting on top of your pistons.
Are you sure that tehy wer hit with something, or could they have melted? Any pinging or knocking when you floor it?
Sounds like it is time for expoitive surgery to me.

[Reumster]

Maybe the pistons hit the plugs? I don't know, All I know is that them plugs had the tab bent into the electrod ,and some ceramic broke off.

[Longhorn Man]

Well, what ever is in there, needs to come out.
Onless someone has a better idea...it's time to yank the heads off.
Good luck on your findings

[Zkast]

have a digital cam? lets see some pics!

Look for marks on the electrode obviously it was hit by something, but it will help if there are any markings on it.

Is this a stock engine or have the heads been milled or the block decked?

Did this all happen at once? If the engine has alot of miles on it, its possible you had carbon break loose and lodge itself just right between the piston and plug. Strange it happened on 3 though.

last question I promise lol... Did you hear any noise just before it started running rough?

[Reumster]

The lower half of the motor has less than 10,000 miles, KB flat tops, balanced, the heads are trick flow 23 degree, less than 1500 miles, Comp Cam full roller. every so often I hear a bad noise like valve train but then it just goes away. New roller lifters where installed right before the new heads.

[bigjimzlll]

this maybe not what you want to hear but, ive heard some horror stories about comps roller lifters.....is pull the intake to check them..if they froze up, a valve could of struck a piston...I hope it aint that, but you had better check.

Jim

[Reumster]

Yes I allready had a set of Comp Cam hydra roller lifters colapse, but the ones in it now are new. I just pulled the valve covers, I have all the plugs out so I turned the engine over several times and everything sounds and looks normal. ???? The lifters seem to be pumping up fine.

I dred taking the heads off them damn blue head gaskets are expensive!

[fluffytx1]

I had one jump time on the chain and cause a similar problem but surely you checked that. Compression test looks reasonable. might just try rolling #1 to tdc and check timing ???

[Reumster]

If it jumped time would it still run normal? Because it runs ok, just no power.

Actually I haven't checked timing yet, I'll do that. Just turn #1 to TDC and pull cap and see if it's pointing to #1 on the cap right?

[Huck]

Some blocks had a plastic cover on the timing gears for quiet. When they breakdown, your belt loosens and can jump a tooth which is what happened to me. The only way you damage plugs in a cylinder head is for the timing to go out and a piston hits the top of the plug--that's assuming you are using correct plugs. I would carefully check the timing chain, cam & crank sprokets before I pull heads. Good luck--Huck

[Reumster]

I'll pull the timing cover to be sure. But when I got the engine built balanced etc they where suppost to install a new double roller timing set. But who knows. I hate taking the timing cover off without the pan, they never seem to seal up right. any tricks??

I here that you can't run gear drives with full roller engine??

[crazy longhorn]

On the chain cover, toss the rubber seal & trim the back lip that holds the seal in place(just enough so it slips in), & load the groove with High temp RTV. I have done many covers this way. good luck.....Al

[Reumster]

Thanks for the tip

[TERRYP]

Sounds stupid, but do you have the right reach plugs?

[Reumster]

Actually I'm going to move to short plugs this next time, and see if it happens again.

[CoryM]

What plugs do you have in there? part #s. Then we will be able to tell ya whether they are correct or not.
CoryM

[Johns70]

i've heard of this happing before, i would check your dist. gear for abnormal wear since your runnin roller motor that will play with your timing.and second i would change heat range of plug or brand of plugs. i don't think its inside your motor. good luck let us know john

[Reumster]

I was using Boshe platnuims #5 thats all thats on the plug is a 5.

My distributer is a completely new unit Accel. Less than 3000 miles on it.

[Super Chevy]

All ive had were bad experiences with Boshe platnuims ,they alwas fail on me,either fauling or just plain not firing,really disapointed with they're $4.99 plug, now all i run is autolite, runs ALOT better and lasts alot longer...

.02 S-C

[Reumster]

Yeah I'm going to go buy some Autolites right now.

I really want to try Platnuim 4s, I run them in my girlfreinds Neon they work good.

[crazy longhorn]

Im runnin Autolite double platinums in my 383,& no complaints.

[Reumster]

Allright I messed up I ment I was running AcDelco platnuims #5

I tried looking for a plug that wouldn't go into the head as far and all the parts store came up with was a #4 Acdelco

Any ideas on a shorter plug

[crazy longhorn]

what is the thread reach on your Trick flows?

[Reumster]

I put in the ACDelco #4 plugs and it runs alot better. But the noise came back like a loose rooker, then it just goes away, I'm thinking its a lifter thats sticking. That really sucks because they're the second set of retro fit hyrda roller lifters from Comp Cam I put in it.

But would a stuck lifter cause damage to spark plugs?