bad valve stem seals? 1986 thunderbird turbo coupe

Kevmustang83 · 10-13-2009

Would bad valve stem seals cause erratic idle? and im pretty sure they are bad since i get that puff of smoke on start up. also could it possibly blow the valve cover gasket off the front cam tower? on mine a 2 inch section got blown off.
Thanks,

Kevin

TOM RENZO · 10-13-2009

NO if you have bad seals all that would happen is a smoke condition and a oil consumption problem. If you are bloeing the valve cover gasket you are getting preasure in the crankcase. Bad PCV or ring blow BY. Do you havw a check valve in the PC system?? That would be my first thoughts. The PCV is different on turbo motors.

Kevmustang83 · 10-13-2009

yea when i tired to get a new one they didnt have it at the parts store they only had the "F" type. i cant find one thats like the plastic one. should i check compression to be sure its not a bad ring or valve stem seal? how would a pcv go bad? i shook it and it rattles fine. if its bad rings then thats going to suck.

TOM RENZO · 10-13-2009

The pcv is still available at the ford store last time i checked. If not a check valve can be used from a nisson or something like that. I make my own from parts i get from Home Depot. They are easy to make. Shaking a pcv valve is not a good test. The turbo valve has a special seal arrangement to keep boost out of the crankcase.

Kevmustang83 · 10-13-2009

Ahh that makes sense since the boost changes. If i do have bad rings how much of a pain would it be to pull the engine?

NavySVO · 10-14-2009

Use a Motorcraft PCV only. Others will disappoint you in the end.

get them at www.forced4.com

Kevmustang83 · 10-14-2009

i just did a compressio test and i got 155-160 in cylinders 1,2 and four and 130-145 in 3. what could that mean?

TOM RENZO · 10-14-2009

Cyl 3 is low but not crazy. A compression test is not always accurate. I would do a leak down test. Number 3 is getting low but not yet a problem to speak of. @ a difference of 20 lbs something is going but not a problem to speak of YET. The difference is a little high but sometimes the test will do that. Leak it down for an accurate answer.

Kevmustang83 · 10-14-2009

I forgot about the leakdown

. Thanks again Tom ill post the results tomorrow. got to work on my school work

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Kevmustang83 · 10-19-2009

So I finally had time to do a leakdown test. In cylinders 1,2 and 4 for a normal compression check i got 160 across the board. For cylinder 3 i got 120. I did the leakdown and it jumped to 180-200. Does this mean bad rings?

Kevmustang83 · 10-20-2009

Any clue on whats wrong?