93 grand am 4th head gaskett,timing,oil leak

[bjobotts]

Bent 3 valves this time trying to start it. Backfires through intake and bam...bent another valve. After replacing head from overheat from water pump and replacing coil pack housing, car ran fine for 2days but had massive oil leak when car running behind timing housing. Replaced gaskett behind timing chain housing bottom which showed leaking but no effect...didn't even slow leak down. Drove perfect for 2 days. On 3rd day wouldn't start. Kept cranking cause it ran as long as I was cranking engine but stopped when let off key. Kept trying to start and then back fire. Again with another backfire through intake. Got compression test and none in 1-3, compression 210 in fourth.Head back off and bent 3 valves. Mechanic said must be jumping time. Have new chain and tensioner already and timing was perfect when pulled head off. I believe gasses built up from cranking which caused backfire which caused bent valve. Crank sensor checks good, coil packs equal at 5.4kilohms. This time I am replacing cam seals as did not last time and new oil appears on top of head behind timing cover when cranking. Timing chain cover gaskets have no leaks. only car I know can bend valves while trying to start. Getting ready to put back together but still haven't found oil leak cause or why ran perfect, then no start. please help...Fuel delivery perfect...don't want to put back together just to break again. Thanks for any thoughts 'cause been working on this all summer. Also...upper timing chain housing cam gasket has 4bolt holes but has open slot at top and cam cover has matching slot..can oil come through this..is it supposed to be plugged up or something..cam seal on other end of cam is good. Please help???

[Rolm]

Which engine do you have ?

[skibum1111]

I'm going to assume you have a sohc quad motor. As for the bent valves, if the pistons show no signs of impact, then the timing was set correctly and something else caused the valves to bend. As for the oil leak, setting the timing cover gasket on can be tricky, and if it slips even a little you are going to have a big leak. The slot on the cam housing is supposed to be there to relieve pressure from built up gasses and to allow oil to flow back into the bottom of the motor. Replacing the cam seals is a good idea, also make sure the gasket surfaces on the back of the timing chain housing and on the side of the block and cylinder head are clean and that there is nothing getting pinched between them. Good luck.

[bjobotts]

Yeah, sorry. It's a 2.3l SOHC. Thanks for the info on the slot at the cam housing. The pistons have marks from the last time the valves hit but not this time. What else could cause valves to bend. I believe they bent while cranking for so long and gasses built up causing backfire thru intake which bent valves this time. Going slow putting back together. There were no signs of leak around timing cover gaskets but the gasket behind the timing housing at bottom has leak signs but replaced it and still have leak. Someone did this before cause there were no bolts through chain housing to hold outer bottom gasket in place except for the 2 tensioner bolts. Tensioner works off oil pressure so making really sure nothing keeping tensioner valve from perfect fit thru housing into block. Planning to crank engine without spark and timing housing front cover removed to see if it leaks again. Know that someone forgot bolts before me and hoping to fill all holes just in case. Thanks for your input. Really really appreciated. History...New head, water pump, chain, tensioneer, battery, fuel filter, coil housing, plugs...gaskets and valve job times 3. Last attempt to fix.

[xeroinfinity]

I would fill those holes with bolts !!
Other wise it's going to leak.

I would also say the timings off,
and thats what caused the backfire and bent vavles.


........Just my

[bjobotts]

Everytime I check the timing even after the bent valves its right on...perfect. So I don't get why I shut it off working perfect and next time go to start it it just cranks like it was going to start but doesn't and then backfires loudly through intake...each time bending a valve I guess. Shouldn't have kept trying to start. Machine shop says oil leak and bent valves connected...that leaves new tensioner which seems to work perfect. Putting together today so wil keep you posted. Thanks for the help. PS: Anyone have a pic., schematic., etc of the timing chain housing lower portion for 93 grand am 2.3L SOHC. There's a gasket that only a Mitchell manual pictured that goes behind the chain housing and 5 bolts go through the housing plus 2 tensioner bolts and oil valve through this gasket and I'm not sure if one is supposed to have a bolt through it. It's 1/4 in above tensioner post but bolt head may interferre with tensioner arm. Stuck the end of a small screwdriver in it and it extends 6in. back so guess it goes into oil pan. I put a bolt in there in case oil may come out there but don't know if I should have?????

[bjobotts]

10/15...2pm cst...Well guys just though I'd let you know I found the source of the problem. Had friend crank engine while I watched timing chain and oil started just shooting out of the relief valve on the tensioner (that little hole in tensioner). So why is this happening. It's a new tensioner and I checked for correct parts match so why is oil shooting out of there????

[catback23]

The valves aren't sticking are they, you say you keep bending valves yet the timing is dead on, I don't see gas bending metal in any way since every time one of the valves opens the gas is vented and a valve can only be bent when it's open so it's pretty hard for escaping gas to bend a metal part. But that's just my take, also my theories are incorrect valve timing, jumping time, sticking valve (sticking open).

[packen]

What would cause a valve to stick open?