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big problem need help !!! update 9-10-07 finally see last page

it could be that the carb is getting too hot...check for vacuum leaks and such. spray stuff with wd40, carb cleaner, those style things. Check the basics.

EDIT: you said taht this just started? if so the the carb getting too hot wouldnt make sense...it would have been doing this.
 
Go ahead and check the bellhousing bolts too. I had mine make some wierd noise once and it turned out to be that. I figured it out by just laying under it with it running and started pusshing up on everything. I saw a crack of daylight come between the block and tranny and was like WTF? :yikes: Torqed em down and used a dab of locktite and all was good. I know, this still doesn't address your miss fire.
 
well today i was able to spend a little time on the engine.
so i decided to pull plugs. i started with no8 cylinder and i found the insulator to be eaten away plus the prong up top was bent over to the side of the electrode :eek1: . then i pulled the no6 plug and it just was eaten up around the electrode also. all other plugs look good.
so i assume the problem lies in the passenger side back two cylinders
i put another plug in the no8 cylinder and started it to see what happens and it still runs messed up once warmed up and the tinging/clanking is still there.
also, i pulled the distributor and everything looks good.
so what is my next move ?
remove the intake and the cylinder head ?
what could have happened to make that plug get bent over ?

MVC-005S4.JPG

MVC-006S4.JPG

MVC-007S2.JPG
 
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I can't think of any causes of what happened to your spark plug other than the plug touching the piston, screwed it up when you installed it, or a foreign object in the cylinder.

Plug with too long of a reach could cause that, but obviously if it's the same plug as the othes, that's not the problem.
 
Look like you are narrowing down the culprit. That may be caused by what they call detonation. Not really sure what causes that though. Does it look like the tip is burned off or possibly broken off? If the tip of the plug did break off I suppose maybe the noise you hear is the tip getting tossed around in the piston. That could make an intermittent noise as it sticks someplace then gets knocked free. Your next step I would think is to pull that head.:doah:


I had a 307 years ago and kept having problems with the no 8 cylinder- plug fouling and missing. It turned out that the PO didn't take the old, under sized gasket off when he put the headers on. The smaller opening gasket was restricting the exhaust of that one cylinder to such a degree it would foul the plug and then start missing. Something to check anyhow. :dunno:

New thought-I wonder if your head is cracked. No compression test on this engine yet? I'd be curious to see the numbers- especially on those two cylinders.

Hey can you hit a couple returns between the pics above so this thread isn't a mile wide?
 
If I understand you, the porcelion insulater is gone from the 8 plug. And its chipped on number 6 too. Thats bad because that porcilein is hard and very abrasive. It can mess up lots of stuff.

You need to run a compression test and a leakage test. If those show no problems then you need to look for a vacuum leak around the intake ports to cylinder head joint. But I'm guessing you need to take the head off and find all the loose parts in that cylinder. Hope this helps.

If you could beg or borrow a borescope to look inside that cylinder you might see how much damage you have.

George
 
The tips of the plugs were crushed by somthing loose in the cylinder bore. This motor does not "Run bad when warmed up" - it is simply running when on high idle on 6 and then runs like crap at idle. Keep running it and it will probably end up damaged beyond rebuildable. Borescope it or pull the heads! I'd hate to see it trashed beyond repair:(
 
thanks for all the ideas and help everyone.
as you can see from the pics, the no.8 plug is messed up. the electrode is bent over and the porcelain is kinda eaten away. we did do a leakdown test on the no.#8 cylinder and it would only hold up to 30psi. so we didnt go any farther. i am going to pull the head off later this week. i guess its engine pulling time. i will post pics once i pull the head. let you all see what happened.
 
Checked out your pics again. I see whats going on now. The electrode is bent over- not broke or burned off. Dis-regard the detonation comment I made earlier. Keep us posted. Good luck.
 
scrappyk5 said:
thanks for all the ideas and help everyone.
as you can see from the pics, the no.8 plug is messed up. the electrode is bent over and the porcelain is kinda eaten away. we did do a leakdown test on the no.#8 cylinder and it would only hold up to 30psi. so we didnt go any farther. i am going to pull the head off later this week. i guess its engine pulling time. i will post pics once i pull the head. let you all see what happened.

Sorry to hear, but hopefully it's still a builder! Let us know what you find out.
 
scrappyk5 said:
thanks for all the ideas and help everyone.
as you can see from the pics, the no.8 plug is messed up. the electrode is bent over and the porcelain is kinda eaten away. we did do a leakdown test on the no.#8 cylinder and it would only hold up to 30psi. so we didnt go any farther. i am going to pull the head off later this week. i guess its engine pulling time. i will post pics once i pull the head. let you all see what happened.

yeah, but where was it failing from? thats the purpose of a leakdown over a compression test.. it tells you rings, intake or exhaust valve... nice to know that before pulling it apart...
 
we will see either tomorrow or saturday when i pull it apart.
I do not know if its an easy fix, but the motor has lots of age on it and has been re-built once before so i have no intensions of fixing it. i do have another motor i will be dropping in. once finished at the shop.
i will post pics of the damage come sunday or monday.
 
today 9-10-07.



finally got the head off and this is what i found;
MVC-046S.JPG

the larger piece is about a 1/4" long by 1/8" wide. they are metal . the cylinder wall is pretty scratched up, i assume that is why i am only getting 30psi and it runs like crap when warm. The piston top is pretty banged up as well.
soo, WHAT THE HACK ARE THESE THINGS AND WHERE DID THEY COME FROM?????
 
Probably so beat up they don't resemble what they came from anymore. The edges look pretty rounded.

Metal, but ferrous or non-ferrous? Doesn't really matter, but if it's AL, then it might be a part of a carb or intake, iron could be just about anything.
 
the pieces are pretty heavy, most likely iron. i looked in the carb barrels, nothing missing. not sure what they are , but i guess it doesnt matter since i am not keeping this motor.
 

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