Timing belt broke. 99 S80 2.9

uncletom · Post by **uncletom** » 24 Aug 2008, 10:39

Wife driving at 35 mph. Engine lost power and coast to a stop. Found timing belt broke when I removed the front cover. 144K and was replaced at 105K. Left the old tensioner in and installed the nylon grommet that comes with the belt kit. Looks like the tensioner had collapsed.
My question is on the 2.9 in 99 is it possible that the valves may not have been damaged? I was planning to replace the belt and tensioner re time the engine and see. There was no unusual noise when this happened and I heard no noise when I tried to start the engine.
I thought I might try to pressurize each cyl through each spark plug hole and see if they will hold pressure with the piston down and the cams turned to close the valves.
Is this engine guaranteed to have bent valves!!
Thanks for any help.

Post by **vegasjetskier** » 24 Aug 2008, 10:52

You're not thinking of turning the cams and crank independently when you do your pressure test are you? If there is interference you just might find it. I'd try to get everything back into alignment by turning the shafts the least amount possible while feeling for any resistance, then get the belt on there and get it tensioned. Then turn it through and do your pressure test.

I don't know if you're guaranteed to have bent valves or not, but you need to have the piston UP (near TDC) when you do the pressure test to make sure the valves are closed.

Post by **MadeInJapan** » 24 Aug 2008, 12:24

uncletom wrote:Wife driving at 35 mph. Engine lost power and coast to a stop. Found timing belt broke when I removed the front cover. 144K and was replaced at 105K. Left the old tensioner in and installed the nylon grommet that comes with the belt kit. Looks like the tensioner had collapsed.

It is essential that Volvo's with manual tensioners get replaced at EVERY timing belt change. I've heard your story more than a few times on other forums. Your wife may not have bent valve(s) but I would say that at least there are some extra nicks in the internals. Certainly a compression test as described by Vegas would be helpful for you to know what's going on without taking the head off.

I wish you the best luck.

uncletom · Post by **uncletom** » 24 Aug 2008, 13:20

My intention is to not install all new parts now and then find I will have to disassemble and remove head to repair. If engine is toast I may just junk or part out as much as I would hate to. We have never experienced as many problems with any car in the fifty or so years I have owned vehicles. Not new to mechanical repair and maintenance. Designed and built engines for racing in drags,unlimited hydros and owned and repaired all of my diesel machines and trucks for my excavation company.
The 99 was truly a work of art but had many potential problems that if I had known I would have waited a few more years before trying the S80.
I will try the compression testing by putting cyls to bottom dead center and turning cams all by hand seeing ther might be a chance the pistons and valves may have missed. (BDC for the reason the crank wont spin on compression)
If you can confirm this is an interference engine then even this will most likely be a waste of time. The 99 S80 is a butt full of problems

Post by **MadeInJapan** » 24 Aug 2008, 15:13

I believe it is an interference engine (apparently some S80 6 cylinders from '00 on were not). All over the internet, if you look for timing belts, it lists them for your car and mentions that yours has an interference engine...example: http://www.autopartswarehouse.com/mmp/v ... parts.html
Best to call the dealer however and double check on this.

Post by **billofdurham** » 24 Aug 2008, 15:36

All of my books say all S80 6 cylinder engines are interference. They also say that "damage is most likely to occur". So there is a glimmer of hope.

Bill.

uncletom · Post by **uncletom** » 24 Aug 2008, 22:55

Thanks guys for your help. I think I will air pressure test each cyl through spark plug hole before doing anything else. If I hear no air in ether exhust or intake I will continue with belt and tensioner. If air is leaking then I will decide which direction to go. I will post what I find
If pistons are not damaged is the head reconditioning a worth while project.
The car drives and looks nice inside and out still.

Post by **vegasjetskier** » 24 Aug 2008, 23:11

Uncletom, I was thinking a way you might be able to test it is to put one cylinder at BDC like you were saying, then lock the crankshaft in that position, maybe with a socket on the crankshaft nut and a breaker bar. If the Volvo straight sixes are like others, the crank journals are 120 degrees apart. So you would have two cylinders at BDC and the other four pistons would be partway down their bores. That should give the valves enough clearance so that you can rotate the cams without the valves hitting the pistons. Then you can add air like you were saying after setting each set of valves to the closed position. Is there a way to tell visually that you have a particular set of valves closed on a cylinder?

uncletom · Post by **uncletom** » 25 Aug 2008, 10:43

Good idea. I can find BDC with a dowel and check 2 cyls at a time. I should be able to turn cams and crank all by hand. If i charge a cyl and turn cams I should be able to tell when valves are closed.
Got grand kids for a couple days so project on the back burner for a day or so.

uncletom · Post by **uncletom** » 28 Sep 2008, 10:46

Well I am finally getting back to the S80 and the pressure testing confirmed the #3 & #5 had bent intake valves. No damage to the pistons but two tiny marks on each that I am sure will not be a problem. Hope to re-assemble in the next week.
Any one help with the torque specs on the new head bolts?. All I know the removal of the original ones required close two two hundred lbs to break loose and my 1/2 air impact wouldn't budge them.
I should be investing in technical help but plan to dump the P.I.T.A. ASAP
Thanks.