Volvo 850 snapped cambelt.

stanley_changuion · Post by **stanley_changuion** » 08 Dec 2008, 01:10

Hi there guys! My mate also has an 850 and he snapped his cambelt(Good thinf I did mine two weeks ago!) Just want to know if these are zero interferance motors? IE does the engine suffer any damage if the belt snaps or do the valve clear the pistons? Thanks guys

Stan
Palmerston North, New Zealand

1994 Volvo 850 Turbo
1966 Volvo 122S B18B

Post by **Matty Moo** » 08 Dec 2008, 02:56

Bad news.

It's an interference engine.

Post by **JRL** » 08 Dec 2008, 06:10

If you mean the timing belt, his motor's history.
If he broke the big serpentine belt, just replace it

SnookWhaler · Post by **SnookWhaler** » 08 Dec 2008, 19:01

Usually just a valve job. Not that big of a deal.

Be sure a "Volvo mechanic" or a person familiar with Volvo's works on it. The valve train removal and install is a little strange for those not used to it.

Or just find a salvage engine. The valve job option is not that bad. Assuming the RPM's were low and the valve guides are intact (no major cracks).

It's not the end of the world... It is not that bad.

OVLOVaussie · Post by **OVLOVaussie** » 12 Dec 2008, 10:05

Hi guys, New to the forum but i may be able to help.

Volvo made both interference and non interference motors in the 850 range. Both the turbo and non turbo were made as SOHC and DOHC, so the only real way to check is to look at the engine number, but a quick guide is if you open the hood you will see DOHC written on the engine cover for the interference engine. the best and most comprehensive way is by looking at the engine code. it will start with a letter, (usually B) then look at the fourth number in sequence, if it is a 4, it is an interference engine. if it is a 2, it is not. The previous three numbers and letter do not matter. An example:

B5254s: interference DOHC, sorry but your in for a full rebuild.

However; the good news, if you see this:

B5452s: it's a SOHC not an interference engine, just change the timing belt and there should be no other side effects (you may want to change the idler pulleys and water pump at the same time, new belts often destroy the bearings on all of these parts).

I hope this quick guide helps! regards; Liam

Post by **MadeInJapan** » 12 Dec 2008, 16:54

This is new to me...are you talking about the 10Valve 850's, Liam? Some talk about them on here in the past but usually from England and never in the U.S.

GrumpyOldMan · Post by **GrumpyOldMan** » 13 Dec 2008, 20:18

Ok, so your saying that even though my valley cover says DOHC, it's a NON-interference because it's a 5252s ?

That would mean the cam lift and/or duration is different for the quad valve motors.

OVLOVaussie · Post by **OVLOVaussie** » 14 Dec 2008, 01:56

It looks like i have confused a few people! I will be having a good look at this over the coming few days, I know there are very few, if any DOHC motors before 2005 in any car that aren't interference engines. The 5252s motor here in Australia dictates that it would be a 10 valve SOHC motor, the DOHC engine was an option on all models except the late turbo versions where it was standard. All v70's were sold with the DOHC engine and the SOHC was discontinued in 1996. The cam/ duration should always be different for four valve motors, it seems to me that having four valves to operate would mean that the cam would have to be different, and that the duration would in effect be Longer, this is how the engine produces more power efficiently without using any more (in fact likely less) fuel.

however i just visited a volvo website in the U.S and it states that ALL volvo 850's had SOHC motors, and we all know that isn't true. I would suggest that if you are unsure, call volvo and get this cleared up; i would stick to the change intervals suggested by volvo and assume that if you have DOHC on the engine cover, it is in fact an interference engine.
The point of my post was that i was responding to a member from New Zealend, and their series are exactly the same as ours. We get the English editions (right hand drive) and therefore any differences between ours and the U.S i cannot comment on. I am sorry if i confused anyone, just thought i might be able to help. Kind regards, Liam

Post by **MadeInJapan** » 14 Dec 2008, 06:00

Conclusion:
So for all practical purposes, assume that you have an DOHC/Interference engine if you own an 850 or later x70 series Volvo.

bobsnow100 · Post by **bobsnow100** » 15 Dec 2008, 14:07

This happened to a 1984 850 I had. The water pump bearing went and the belt snapped. It is an interference engine. The engine only needs to spin around one revolution to do damage to all the valves.
I had ten valves I had to replace. Even if the valve looks good and appears to sit flat in the valve seat,you need to check them all. I was able to do the job myself . It can be difficult, especially removing the valves from the head and installing the valve cover. There is a special tool I had to fabricate.Lining up the cams is important also. I used the Haynes book as a guide.