My 95 90 was normally shut down from a smoothe idle.

My wife tried to start the car later and all she got was
a free spinning crank and no cam actiity.

To make a long story short, the tensioner pulley bearings
failed (fell apart) allowing the pulley to move (droop), eventually releasing the required tension on the timing belt. The crank was the only pulley that slipped
free, and the cam gears are still in proper relation to each other.

I surmise the belt became "not too loose" to keep the engine
running, but "too loose" to respin the motionless camshafts when the
crank began to spin up when starting.

My wife did not notice any "striking" noises when the crank
started to spin up. The crank spins freely, and quietly.

My questions:
1) Are there cam positions that will allow the crank to spin
freely without contacting any valves?
If this is the case I will try to determine what the correct
crank position should be for this cam relation and install a new belt/tensioner.

2) Am I peeing up a rope?

If your engine has not suffered any damage besides the belt and tensioner, I would say you are very lucky indeed, maybe you should by a lotto ticket. I suppose it is possible for the valves to be in such a postion where they are not fully open therefore evading the pistons.

The message from the kick inside suggests using a powerful torch to inspect the pistons for damage, he/she is referring to a flashlight not a propane or acetylene torch, just incase you were thinking of using a torch.

If you are doing the work, when the new belt is on, turn that engine over by hand at least four revolutions.

Good luck

DanR 94 964 211k miles
--
DanR

Dan,

You wouldn't work for Revolvstore in AZ by chance would you?

Lotto remark is same as I got from them.......

Regards,

Jeff (Shortcut)

No I don't. I live in the suburbs of Chicago, and I am just a shade tree mechanic to my vehicles. I had to replace my head gasket about 3 years ago so I can appreciate the shear luck to have the belt go and not destroy the engine.
Good luck.

DanR 94 964 211k miles
--
DanR

DanR-
What is the best way to turn the engine over by hand (for the home mechanic)?
-Steve

You don't have to remove the crank pulley to change out the timing belt. A socket wrench on the crank bolt or if the plugs are out turn the crank pulley by hand, it's fairly easy.

DanR 94 964 211k miles
--
DanR

Install the crank pulley bolt with spacers (washers.... or the pulley itself).
The reason that you need spacers is to prevent the bolt from bottoming
out in the threaded hole.

Then turn the bolt (Clockwise) with the BFW(Big Wrench) of your choice.

im by no means an expert ..but just a thought..

the reason that big time damage occurs when a belt goes whilst the car is running is that the valves and pistons meet at considerable velocity, repeatedly and the valves are damn hot so bend very easy...

there is a good chance that when spinning a car over if they did meet and the car was cold there might not be majour damage...but id certainlywant to check the clearences!

you might have got away with it! if not you have bent valves so wont get compression on the offending cylinder..now being all logical what we want to do is test the cylinders but without spending oodles of money...so how about...

remove rocker covers and roatate cam shafts till you can see the valves should be closed on the cylinder..then leak down test the cylinder...bent valves will show in the test...big style! you could go this very cheaply (if a little bit 'bodgerly' by modifying a spark plug to be an adaptor, clamping a hose to it and presurizing the cylinder with a compressor to say 20 psi and just seeing if it holds presure (oh make sure the crank is locked first..) repeat for all cylinders...

then get a small powerfull tourch and if you can see thru the park plug hole you may be able to check out the piston surface...

seems to me these test will cost you vey little if anything and may tell you a lot..

indeed just seeing how the valve stems react when the cams are turned is interesting...if one of the stems is miles out of adjustment its almost certainly bent....

if you want to know how i learned this...it was 3 days of trying to start a motor bike (kick start) that someone else had done an engine job on...(i.e. replaced timing chain, gears etc etc after snappngthe chain..) to find out they hadnt replaced the bent exhaust valve...

Thank you for your insight.

I'll update you all on how things pan out.

Kind regards,

Jeff Endrulat
N. Redington Beach, FL

At how many miles did this occur and were there any symptoms?

140K miles, no symptoms other than when the bearing totally
let go on startup; Crank spun, cams did not.

Still have not gotten to the job. Rahabing my 760 so that I
have one car that I can drive to work. New Engine seals,
rebuilt turbo, timing belt. etcetera, etcetera, etcetera.....
I expect to be at a point with the 760 this week that will allow
me to dig into the 960 and determine the level of casualty.

I am a semicoductor salesman covering Pensacola FL to St. Petersburg
(500 miles point to point)so you can imagine my dependence on
a reliable vehicle. And semi sales are sucking wind these days that
is why I am doing all of this myself!

BTW, Revolvestore (The Volvo Place, 1-800-28-volvo) in Tucson AZ has provided several
unsolicited, valuable pieces of info that have really saved my skin
along the way. Proper flex plate orientation for one..... nothing being
mentioned of it in Chiltons. Anyway, I use these guys every chance I get over
the local dealership which I have grown to despise.

Hi Steve!

This happened at 140K miles.
The belt was replaced at 50K and 100K.
The tensioner pulley should have been. Shame on me!
The belt did not fail. A lesson learned. Although Volvo performed
the R&R I really doubt that there is any recourse here.

The engine simply spun freely when my wife cranked it over.

A "coasting" valve train needs considerably less turning moment to
keep it moving than one that is stopped. Hence, the belt slipped only
on the startup condition. When I took the cover off the pulley fell out
with ball bearing scattered about.

Also another word to the wise. If you hear a squeeling noise and cannot fix
it by replacing the accessory drive belt tensioner or by replacing the accessory belt idler pulley.......... it is time to start looking a little
deeper into the system.

This is why wisdom comes with age.......

> 1) Are there cam positions that will allow the crank to spin
>freely without contacting any valves?

Miracles have happened before.

>If this is the case I will try to determine what the correct
>crank position should be for this cam relation and install a new belt/tensioner.

You could do that anyway. Lets face it, to get this thing running again you'll need to install a new belt&tensioner at the very least. Install them, see if it runs, maybe do a compression test to see if any valves are leaking (= usually bent). If it runs fine then great. If it doesn't all you'll have wasted is the time you spent fitting the belt. Seems like a worthwhile gamble to me.

Bram

That is the plan.

Thank you Bram.

I am just waiting on my service manual to
get started now.