EA82 piston to valve interference theories

Gannon · Post by **Gannon** » Sun Jun 26, 2011 7:28 pm

The guy who bought my L series EA82T wagon rang me last week, apparently he noticed that the engine was running on 3 cylinders and that there was a knocking noise coming from cyl no. 3.

He got his mechanic to have a look and noticed that the drivers side timing belt had skipped 3 teeth. He asked me if the valve can strike the piston, I told him that the engine is a non interference design and piston and valve contact is impossible.

He rang me tonight to tell me the mechanic took the head off to find that intake valve no.3 is bent and there is a mark on the piston where it struck.

His mechanic also said that when sourcing new valves, turbo ones, although being physically the same size as non turbo valves, they are made of a different metal to cope with the higher heat

What are your thoughts?

P.S.
The guy who bought my car isnt blaming me or asking me for any compensation (he has put 35,000kms on it since he bought it)
He just asked me cos i know more about them than he does.

nncoolg · Post by **nncoolg** » Sun Jun 26, 2011 9:23 pm

Dunno Gannon, I had one jump a few teeth years ago and it was fine, just missfired like all hell, thought the gasket was gone, thankfully took the beltcovers off before the heads! I wonder if something foreign got between the piston AND the valve?
Did it break the rockers and lifters? The wife's Barina did when it jumped!

Yeah, the valves are different, they even look different if you hold them side-by-side.

I'd have some second hand ones if you wanted to give them to him, but that's your choice...

YouTube · Post by **El_Freddo** » Sun Jun 26, 2011 11:05 pm

nncoolg wrote: I wonder if something foreign got between the piston AND the valve?

Or bent the valve, was let go then hit the piston or vise versa.

I'm very sure that the EA82s are all non interference engines.

Same for the EJ's - the dual cams units don't interfere with the piston tops, just the valves of the other cams as each cam slows down at a different rate. The piston is struck if a valve is A bent enough or B a valve is broken and that piece floats around in the chamber/cylinder.

Got any pics?

Cheers

Bennie

steptoe · Post by **steptoe** » Sun Jun 26, 2011 11:14 pm

non interference in stock form but dunno how close valve gets after a surface grind.
Great, someone who knows they are different after a now quiet member nearly shouted me down there was no difference. FSM spec two valves, with like 0.1mm difference in length, shape not specified.

After market replacement lists quoted by above - only one valve for both NA and turbo

Gannon · Post by **Gannon** » Tue Jul 05, 2011 6:51 pm

I dropped into the mechanic that has been working on this car and he said that there was a piece of carbon that fell into the combustion chamber and got stuck between the piston and the intake valve.

He replaced the valve, had the head pressure tested and re-installed.

Engine is still running on 2 cylinders, compression in cyl 1 is 25psi, cyl 3 is 70psi and the other side is fine.

He thinks the lifters are not compressing enough and are holding the intake valves open

Thoughts?

nncoolg · Post by **nncoolg** » Tue Jul 05, 2011 7:30 pm

I wonder has that cam been timed off the DTC mark or the belt timing marks on the flywheel? Made that mistake myself, no compression!

Failing that, the Lifter or even the rocker could be damaged from the valve hit, but surely that would have been noticed. Even then it should'nt have affected the other neighbouring cylinder.

Gannon · Post by **Gannon** » Tue Jul 05, 2011 8:03 pm

Nah timing of the belts is taken off the middle of the 3 lines, and the crankshaft was turned one revolution between both sides.

He used a leakdown tester with the piston at TDC and we could hear air coming back up through the throttle. Points to intake valves stuck open.

The mechanic quoted the guy 7hrs labour, he us up to 25hrs and still has issues

YouTube · Post by **El_Freddo** » Thu Jul 07, 2011 1:41 am

Gannon wrote:The mechanic quoted the guy 7hrs labour, he us up to 25hrs and still has issues

Bugger! I'm guessing a slightly bent valve causing the air leak would have been found during the strip down?

Cheers

Bennie

Gannon · Post by **Gannon** » Thu Jul 07, 2011 6:21 am

Sorry, i forgot to mention, intake valve was found to be bent so it was replaced. The head was given a pressure test before it was put on. Thats why we think the only thing that could be doing it is damaged lifters, or a rooted piston