Broken Timing Belt Help

Ethan5150 · Post by **Ethan5150** » 05 Aug 2016, 15:23

Hi everyone, I'm new to the Volvo community and would love any help you could offer.

I purchased a 1994 850 Turbo last year with about 80K miles on it. Unbeknownst to me (and certainly my bad for not checking), the timing belt had never been changed.

Last week it snapped.

So I talked to my mechanic who said that despite this car having an interference engine, he's worked on 2 Volvos (similar years) that blew their timing belt and when he replaced the belt, low and behold, they fired right up. His suggestion was to spend the $23 for a belt and give it a try.

So I went through the entire process of installing the new timing belt. I made sure the marks lined up on both the intake and exhaust cams as well as the crank.

When I go to start the car though - it doesn't turn over. In fact, other than all the wheels that the belt runs over spinning, it does nothing. No firing, no noise - just the whir of the wheels spinning around.

So my question is this: I noticed that for every turn of the crank, the cams turn twice. Is it possible that one or the other, or both, of the cam wheels need to be turned exactly 360 degrees to fix the problem? My mechanic said that it's possible that the valves are open when cylinder 1 is at TDC and that's why it's not firing - because the cams are exactly 1 full turn off. Is this making sense? Is there any truth to this?

The walkthroughs I went through to do the belt assumed that I was pulling off an old belt and that those marks wouldn't be moving much during the change (certainly not a full turn) but in my case, who knows how many times each of those wheels spun around when the belt snapped.

Or am I overthinking this and if all 3 marks line up and the car doesn't start it's just plain dead? I would have thought that if the valves were messed up I'd at least hear something that sounded like the engine trying to do something but no - just those wheels spinning around - no activity at the top of the engine whatsoever.

Someone else suggested that maybe the timing is just off because the old belt had stretched out. I'm not a mechanic - I don't know how these things work...

The suggestion to figure out if valves may be open was to make sure cylinder 1 is at TDC by putting a screwdriver in socket 1 and spinning the crank until it's at full height - (I'm assuming it should be at TDC if the crank is on the timing mark - is this right?) - and then doing a leakdown test on that cylinder to see if air is blowing out either the intake or exhaust end - and whichever end is leaking, spin that wheel exactly 360 degrees back to the timing mark. In theory, if the valves aren't toast, then I shouldn't have air leaking through if everything is lined up correctly - yeah?

I'm hoping this car isn't completely toast but you'll know better than me.

Any thoughts? Suggestions?

I appreciate your consideration!

- Ethan

101 · Post by **101** » 05 Aug 2016, 16:47

Ethan - the condition of the valves after a timing belt break would largely depend on what the engine speed was when it broke. If the belt broke at start up or at low speed, there might be a chance of minimal valve damage. If it was at higher engine speed, I'd wager most of the valves are now bent.

You have the engine operation reversed. The crank turns twice for each one rotation of the cams.

If your marks are lined up on all three sprockets, you're good. The engine doesn't really care if the if the crank has been rotated an additional 360 degrees during the in the process as long as the marks are now lined up. The timing marks are just that - marks. They are actually not TDC marks.

If the engine is just spinning and not wanting to attempt to start, my guess is that your valves are bent on most if not all cylinders and there is no compression as a result. Your next step now that you have the timing belt on would be to have a quick compression test performed. That will confirm the condition of the valves. Zero compression in any cylinder = bent valves.

It does not sound like a good situation, but keep us posted.

Post by **theWIFES_S70** » 05 Aug 2016, 16:52

If a belt breaks off on a 240, then yeah, not a problem. But far as I know, on these interference engines, a broken belt usually means disaster.

When you lined up all the timing marks, what did the engine feel like when you manually cranked it over?

Ethan5150 · Post by **Ethan5150** » 05 Aug 2016, 20:34

Anyone have a ballpark idea of what I'm looking at for repairs? Should I just sell the car as a hunk-o-metal and start looking for a new vehicle? I'm in Hawaii so shipping a new engine here is out of the question. I'm somewhat mechanically inclined and I have a fair bit of tools but I'm also not into taking on a million-hour project or dropping thousands of dollars on this car. Damn shame - it's in great condition... other than the fact that it no longer runs...

Post by **rspi** » 05 Aug 2016, 21:15

Ethan5150 wrote: I'm hoping this car isn't completely toast but you'll know better than me.

Not the entire car, just the head.

I don't believe a word from the mechanic. I have never heard a story about a white block not bending valves when it tossed a timing belt. Even at idle it's turning at 840 rpm's. That is a lot of force for a valve to stop.

Sad to say, broken timing belts actually started all of my video post to YouTube.

If a car has a timing belt and timing marks on the cams/crank, please remove the phrase TDC out of your mechanical process, it will only cause you more confusion.

I posted the video to let you know that there are other things that can cause these cars to implode. Failure to deal with other maintenance items can land you back at a blown engine in no time.

Post by **tryingbe** » 05 Aug 2016, 21:19

Call them up and see if either has a turbo engine for you.

https://honolulu.craigslist.org/oah/pts/5648920121.html
https://honolulu.craigslist.org/oah/ptd/5712172560.html

Post by **abscate** » 06 Aug 2016, 00:32

Classic no-start due to bent valves. The top end job is mostly labour so it's economical to DIY. I don't like to be too judgement all from afar but this mechanic doesn't know Volvo too well. Chances s/he saved two white block Volvos from snapped timing belts without valve work are near nil.

Post by **tryingbe** » 06 Aug 2016, 03:40

Chances are the mechanic changed the timing belts on two redblock (RWD) engines.

Redblock - non interference.
Whiteblock - interference.

If no documentation on timing belt, change it along with waterpump/tensioner/idler/etc!!!!!!!!!!!!

Post by **cn90** » 06 Aug 2016, 10:37

I imagine the car does not have more than 100K miles, so if you can save it, it'd be great, one fewer car in the junkyard.

Since the car is 22 years old, even though it is around 100K miles, I'd do the following if this were my car:

- Remove the head and send it to a shop for a new valve job, this maybe around $500-$1000, depending where you go.
- New Aisin Water Pump ($60)
- Timing Belt Job (new TB, both pulleys, hydraulic tensioner by Aisin).
- New Serpentine belt and pulley.

All info is below:

1. DIY: 1998 Volvo S70 Timing Belt, WP, Cam Seals, SB Overhaul:
https://www.matthewsvolvosite.com/forums ... hp?t=53722

- Consider new cam seals by Corteco.

2. Info taken from "Tracy True Soap Volvo Head Gasket DIY:
How to replace the head gasket on a volvo 850

3. Videos by "rpsi".

Ethan5150 · Post by **Ethan5150** » 08 Aug 2016, 12:39

Hi everyone - thanks so much for all your feedback. I'm not sure what I'll do yet. I'll plan to do a compression test this week but I think we all know what the verdict is. I really appreciate everyone's input - you guys rock! I'll be sure to post what I end up doing with this situation.

Thanks again.

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