Water Pump and Timing Belt

NightTrain · Post by **NightTrain** » 24 Aug 2009, 19:02

OK, here goes my first post. I've got 96 850 N-Turbo, and recently I blew my water pump and stripped the timing belt. I understand all of the above ramifications with the interference-engine, and all......but what I'm wondering, is: Is there a chance that I DIDN'T bend/break any valves? Anyone ever heard of a guardian angel looking over this engine and waving it's magic-wand and everything being OK? I've talked to a few indies and they've said that occasionally it won't destroy the head. The trip in question was very short and it broke down at the end of it.....we're talking about maybe 5 miles.

I've been told by some friends that I should put a new water pump and belt back on and do a compression-check. If so.....what are the logical steps that I should follow next. I'm a decent shade-tree mechanic, and I turn a wrench for a living.....but this type of engine is pretty new to me.

Post by **Ozark Lee** » 24 Aug 2009, 20:12

Sadly, I would put your chances at about 0.01%. If the teeth were well and truly stripped off of the belt the chances are lower. They can live with jumping 1 tooth, maybe 2, but after things are bending.

You can try replacing the pump and the belt and go through the motions but it sounds to me like a lot of duplicated work since you need to take the belt back off to remove the head.

Several of our members have had good luck with this company for replacement heads.

http://www.cylinder-heads.com/

You can buy new valves and lap them in but often just replacing the head is just as cost effective.

...Lee

Craigd2599 · Post by **Craigd2599** » 25 Aug 2009, 04:39

Having just lived the nightmare...my belt brok on an on-ramp in the middle of central Virginia. Because I wasn't up to speed yet, and because I instantly recognized the sound of the pulleys jamming up as the belt came apart, I "escaped" with only the exhaust valves bent mildly on 3 out of five cylinders. The head could have been re-used but the shop had an old 850 sitting out back with a good motor and blown trans and they swapped heads. Regardless...you don't know what kind of damage has been done and you'd be running the risk, (quite high risk in my opinion) of a piece of valve being broken off in there and getting someplace it doesn't need to be. Bite the bullet, pull the head and see what you have.

FCPEURO · Post by **FCPEURO** » 25 Aug 2009, 09:28

+100, you are going to have to replace the head. Out of curiosity, how many miles were on the car when the water pump went?

NightTrain · Post by **NightTrain** » 25 Aug 2009, 20:16

Well.....of course the odometer gear is broken, but the scan said 115k, which given the cosmetic shape of the car, I'm a little skeptical about.

I'm going to pull the head, this weekend, and see what happens. Given the short length of the trip, would there be a real possibility of any head-warpage? I've got nothing funky going on in the oil, so I'm confident there wasn't a blown head-gasket, or anything like that.

Also, what are the possibilities that any other parts of the head are damaged? Springs, seats, seals, valve-guides, etc.

Post by **Ozark Lee** » 25 Aug 2009, 20:38

Most of the warping problems are due to an overheating condition in the first place. If it was otherwise OK before the incident there is a good chance that it is still OK. Most of the damage is limited to the valves themselves in such an incident. It may ding the pistons a bit but that is not terminal. It is a matter of yanking the head and then assessing the damage. The valves are different between the turbos and the N/A models so be sure to get the correct valves if you go that route.

I have always thought of pulling a head as like unwrapping a Christmas present - you never know what you will find.

Throw up some pictures once you get the head off - it will help educate others.

...Lee

NightTrain · Post by **NightTrain** » 25 Aug 2009, 21:02

Thanks for the info.....if time permits, I may turn this into a tutorial for everyone.

Last question: I'm getting into the preliminaries tomorrow, pulling the cam-cover and inspecting the top-end, without pulling the head, yet. Will it be obvious from above.....which valves are damaged? The only reason that I ask, is so that I can get them online, and on the way.....instead of having to resort to going to the "stealer"

Post by **Ozark Lee** » 25 Aug 2009, 22:17

What you see from the top will not be conclusive. It may give clues but it won't tell the whole story.

One of the full time indy Volvo mechanics that does a drive-by on the site every now and then (Binlax09) swears he can get 2 uses out of the head bolts. They are not an insignificant part of the cost of this job. I don't know if I would be so bold as to try it but he claims you can get one reuse out of them.

...Lee

FCPEURO · Post by **FCPEURO** » 26 Aug 2009, 10:27

I have reused them on my 240 back in the day, but I do not recommend it. For the low cost of the bolts, I would just get new ones. It is like cheap insurance.

NightTrain · Post by **NightTrain** » 26 Aug 2009, 18:30

Update: A buddy of mine had a leak-down tester and we used it to evaluate each cylinder. 4 out of 5 were bad, so I guess it's worse than I thought. I think I'm just going to go with the remanufactured head and be done with it. Still will remain a major learning experience, even if it is the school of hard-knocks.

I will not be using the head-bolts, again.....so, you guys can rest easy.