only 2 cyls. have compression

[sleeprrr]

hey all, I'm new here, but a 24 year veteran wrench, 1 of my clients dropped off their car to me, a '91 Q45a, actvsusp light comes on intermittent, go to pull it in, but it wont start...and the way it's cranking I know for sure something happened with the valvetrain.(inconsistent) Then I find all this crap about the timing chain guides failing on 1st gen Q45's. ARRRGGGHHHH! proceeded with a compression test on engine,only 2 cyls. have compression, other 6 have 60 psi or less. car has 153K, engine replacement the way to go? Or would it be better to save this 1(if it's even saveable?). thanks all, and please, pray 4 me...

[Q451990]

I think you're probably better off with a new engine with low compression on that many cylinders. People more knowedgable than I am will weigh in though...

Heath

[ScottJackson]

yup, engine replacement is the best way to go. Is the active suspension good? If it also needs rehabbing and the rest of the car isn't in excellent shape, it may be time to part this one out.

[Q45tech]

Remember that ALL JDM junkyard engines will need new chain guides before swapping just as it is a high probablity the domestic junks will have the same problem.

Rehabilitation of either engine will take a day and $1000 in parts and hoses. An expert can do all this in 25 real work hours.............why we charge $3125 plus the price of the newish engine [$850-$1200 delivered to our shop] we usually throw in a few hundred for misc rounding to $4500.

[sleeprrr]

thanx guys, really appreciate your inputs and knowledge, uh, by the way, any suggestions on dodging the 'blame' bullet on this 1? it happened exactly as described.

[maxnix]

Well as an automotive technician, you realize most stress is put on the valve train at start. Timing chain guides are a known problem with 1993 and earlier VH45DE. Perhaps your account justifies what I tell all early VH45DE owners, don't start the engine until the guides are known good.

Chances are if you pull the front timing chain covers, you will probably find the guides in pieces, and that didn't happen entirely on the last start.
Modified by maxnix at 6:53 AM 2/14/2007

[sleeprrr]

duly noted...thanx

[Q451990]

I've been thinking of something here...

Any chance here that it's a flooding issue? Maybe it was moved and shut down quickly before a warm-up?

This is a common issue on the Q in cool/cold ambient temperatures. The excess fuel could have washed the rings... Might be worth your time to diagnose it a little more before ripping it apart... Maybe squirt some oil in the cylinders to try to re-establish compression?

In most guide failures (or at least many of them) the engine completely locks, so the fact that it's spinning and you have some compression seems interesting. The two cylinders having good compression seem interesting to me too... maybe Q45Tech could comment on the possibility of the engine just slipping time and this being a case of a "broken clock being right twice a day"?

Heath

[Q45tech]

When one has a low compression test the next step is to squirt oil in the cylinder to make sure the rings have not been washed clean by excess fuel.

Pull the valve covers to look at the valve motion while you turn engine over from crank with a wrench.