No Compression

FR8TRN · Post by **FR8TRN** » 27 Oct 2005, 18:01

My son has a 97 850 GLT and it seems to have lost compression in 4 of the 5 cylinders. I've checked the timing belt and it appears to be intact, best I can tell it hasn't skipped either, though I'm still looking into this, having a hard time telling on the crank portion, TDC seems to be alot earlier than it should be according to the cam markings. I'm thinking it might have completely blown out a headgasket since he did overheat it. Also had a problem with the engine oil line going into the radiator, blew out a seal and was leaking pretty bad.

Any thoughts on this?? I've looked at what it's gonna take to get the head off this thing, doesn't look like alot of fun. Any help you all can offer would be appreciated.

White850Turbo · Post by **White850Turbo** » 28 Oct 2005, 02:08

Whiteblocks are very sensitive to high temperatures and will toast head gaskets rather easily if they overheat. I personally haven't pulled the head off on one of these engines, but I do know people that have. They're not the hardest thing out there, but they're not easy either. As for the oil cooler line, you'll need a new sealing ring, o-ring, and a retainer clip. Let me know which line blew off (upper or lower) and I'll post the part numbers for the parts you'll need. I can also provide any documentation needed for pulling the head off, etc..

FR8TRN · Post by **FR8TRN** » 28 Oct 2005, 06:55

Thanks Sean, I've already got the oil line fixed up, dealer had the seals and clip, only a few bucks. Guess I'll be rippin the head off this thing, got a Chiltons manual from the Library, may see if I can locate a Haynes though, tend to like thier books better. Biggest problem I've had so far is gettin the damper off, gonna drop some rope in a cylinder today to stop things up, can't get that big nut broke loose. Just wanna make sure the belt hasn't jumped before I tear into it. I can see what looks like a timing mark on the inside of the damper, and it is lined up with the mark on the block, but I'm not sure, perhaps the timing belt gear will have a mark on it, doesn't show in the book.

Are these zero tolerance motors (will the valves contact the pistons if timing jumped)?? Also how are these heads for warping when overheated?? If prone to are thicker head gaskets available to make up for the machining??

Great site ya'll got here, been looking around, alot of good information. I'm involved in a number of motorcycle forums and understand just how valuable these places are. Thanks for your help.

turbotim2 · Post by **turbotim2** » 28 Oct 2005, 07:28

Yes these are interference engines but a one tooth jump may not cause destruction. There are timing marks on both of the cam gears as well as the crank gear. These heads will warp but I don't believe it is a common problem.

White850Turbo · Post by **White850Turbo** » 28 Oct 2005, 09:20

Yeah, you'd really have to heat things up to warp the head. These engines are not zero tolerance. You can go about 10 degrees either way on both of the cams before you start running into trouble. Honestly though, I think you'll have more trouble idling w/ the stock "low profile" cams before you get far enough to start really breaking stuff. As far as a thicker headgasket goes, I'd imagine that there is someone out there that makes one, but I'm not real sure who.

FR8TRN · Post by **FR8TRN** » 28 Oct 2005, 09:54

Thanks TurboTim, I finally got the damper off and everything lines up, so I'm halfway into the head now, with the cams off it still has no compression so it's down to head gasket or the rings I guess. This is a PITA, broke the cam position sensor getting it off, that don't look cheap, cams came up with the valve cover, oil everywhere, I'm thinkin a gas rag and a match might take care of this easier. Hope it's not warped, but I don't see how it can't be with 4 cylinders showing no compression, 5th is up over 95#'s.

FR8TRN · Post by **FR8TRN** » 28 Oct 2005, 10:03

He probably overheated it good Sean, he's 18 so getting information is worse than pulling teeth (your own teeth). Best I can figure the low coolant light never came on because the wiring wasn't hooked up on the tank, he's probably been low on coolant for some time or lost a hose (that would be the steam he seems to remember now but failed to mention before) and drove a ways thinking he could get where he was going, just before turning into the parking lot the motor sputtered and died. There is no coolant in the oil (yahoo), probably because there is no coolant in the system......I guess thats a positive, in some distorted way.