Changed timing belt, now won't start

Post by **erikv11** » 03 Dec 2010, 17:11

Yes, jerrymcc's post is entirely consistent with what I saw in my engine. And I looked very carefully and over several days, it was my first time pulling a head off and I wanted to be absolutely sure to put it back together with the same timing.

So this is making sense now: the timing marks on the cam, either the front hash marks and/or the rear cam slots being parallel one over one under (like if you used some front-rear cam locking to the cam covers), are meant to correspond to the engineered markings on the crank and oil pump. That is, you want the cam marks to be paired up with #1 being slightly before TDC.

Worry about the marks, not TDC. If the crank mark is screwed up like on Timberwolf530's car, then going to absolute TDC and aligning the cams to that will get you close, but will not exactly hit the factory timing.

zanzabar · Post by **zanzabar** » 04 Dec 2010, 00:20

Timberwolf, I think you might want to take another stab at setting the timing correctly. I can imagine that this is not exactly what you want to hear, but better safe than sorry. Now, the question is, how do you go about finding the crank mark???

Retired MVS Contributor · Post by **Retired MVS Contributor** » 04 Dec 2010, 06:57

Knowing where TDC is is important, but for valve timing in this engine it is really a non-factor...If one were to paint his own timing marks onto the sprockets, no matter WHERE the engine stopped when it last ran, and if he did not move anything, then re-assembled using his own marks, timing will be correct...That should be obvious...I would not recommend doing it that way, but it would work...

Jerry

zanzabar · Post by **zanzabar** » 04 Dec 2010, 13:49

True, and that's been suggested before and is basically how I did mine. It doesn't help timberwolf though. What's the method when the crank mark is in the wrong place or not visible? I suppose you could find TDC #1, back it off ccw (?) 2 or 3 notches...put the belt on with cams on their marks?

I'm just curious because I never did really know if I had my crank timing mark correctly ID'd or not, and if there was a bullet proof way to check that all three shafts were aligned perfectly, I'd like to know.

Post by **precopster** » 04 Dec 2010, 15:23

Part number designations from Vadis:

Volvo 850 '94 vs Volvo 850 '95 (photo supplied)

Part # 3531531 Pulley (crank)
Part # 1275932 Oil Pump
Part # 1275801 Oscillation Damper (harmonic balancer)

This thread has caused much discussion so just to set the record straight there is no variance b/w 94 and 95 models' part numbers for the three items required to set cam timing.

Retired MVS Contributor · Post by **Retired MVS Contributor** » 05 Dec 2010, 06:29

zanzabar wrote:True, and that's been suggested before and is basically how I did mine. It doesn't help timberwolf though. What's the method when the crank mark is in the wrong place or not visible? I suppose you could find TDC #1, back it off ccw (?) 2 or 3 notches...put the belt on with cams on their marks?

I'm just curious because I never did really know if I had my crank timing mark correctly ID'd or not, and if there was a bullet proof way to check that all three shafts were aligned perfectly, I'd like to know.

Volvo has an alignment tool that requires removing the starter and a small cover...The tool is inserted into the crankcase and then the crankshaft is rotated until it strikes up against the tool...At that point the timing mark on the crankshaft sprocket should be lined up with the mark on the oil pump...

I had been a little dubious about missing or incorrectly located timing marks and have not read the posts about it, but it makes me wonder why a special tool is needed if the marks are present...It makes me think that maybe they DID put out some engines without the marks, or, with the marks in the wrong place...But if that did happen, how did they know in advance to provide a hole in the crankcase for a special tool?...The only other possibility that I can see is if someone removed the sprocket and then re-installed it incorrectly...It looks like it is splined onto the crankshaft and if so, it is easy to install it wrong unless the spline were "keyed" with a blank slot...

Jerry

Post by **precopster** » 05 Dec 2010, 07:27

The hole in the crankcase is there to help you undo the crank nut as well as time TDC. When the tool (which can be a small 3/8 drive extension) is inserted into the engine through the hole the engine can't turn anti clockwise because cylinder 5s crankweight hits it at exactly TDC; quite ingenious really.

However because it still allows clockwise rotation it isn't really helping you when you tighten the cam sprocket bolts, which naturally turn the motor clockwise. I used a large screwdriver inserted through the cam sprocket and this gives enough leverage against the tightening of these bolts.

Retired MVS Contributor · Post by **Retired MVS Contributor** » 06 Dec 2010, 15:57

precopster wrote:The hole in the crankcase is there to help you undo the crank nut as well as time TDC. When the tool (which can be a small 3/8 drive extension) is inserted into the engine through the hole the engine can't turn anti clockwise because cylinder 5s crankweight hits it at exactly TDC; quite ingenious really.

However because it still allows clockwise rotation it isn't really helping you when you tighten the cam sprocket bolts, which naturally turn the motor clockwise. I used a large screwdriver inserted through the cam sprocket and this gives enough leverage against the tightening of these bolts.

The tool is intended ONLY for timing...It is only a wire loop that would bend and shear off under the stress of undoing the crankshaft nut...Since the block is aluminum, there is the danger of cracking the block at worst, or damaging the hole at best...The prcedure is to rotate the shaft slightly CLOCKWISE, insert the tool, rotate the shaft COUNTERCLOSKWISE until it contacts the tool, then check for the timing mark on the sprocket...

There is a special holding tool for removing the nut that is attached to the pulley while the nut is removed or tightened...In my humbled opinion, which is not worth much, it is a very bad idea to use the timing tool hole to hold the crankshaft while the nut is removed...

Jerry

Post by **precopster** » 07 Dec 2010, 04:19

Come to think of it, I've seen something like this which mounts to a suspension point from the crank.

I used the info from a tutorial on the web which had great success with this method. My thread was untouched on both motors after using this method and very smooth to re-insert the plug. I'll take a look at the crank on my B5252S (on a stand) this weekend to see if I can find the wire loop you mention. I'll post some photos too. I wouldn't want anyone to damage their motors on my account.

Retired MVS Contributor · Post by **Retired MVS Contributor** » 07 Dec 2010, 06:39

precopster wrote:Come to think of it, I've seen something like this which mounts to a suspension point from the crank.

I used the info from a tutorial on the web which had great success with this method. My thread was untouched on both motors after using this method and very smooth to re-insert the plug. I'll take a look at the crank on my B5252S (on a stand) this weekend to see if I can find the wire loop you mention. I'll post some photos too. I wouldn't want anyone to damage their motors on my account.

Mike...

I guess I did not make myself clear, my bad...There is no wire loop in the engine, the TOOL is a wire loop attached to a round metal handle that you insert into the port in the block...Interestingly, the tool is not indicated for use in all engines...I find it in the XC70 and S60, but not the 850...

Jerry

Changed timing belt, now won't start

Re: Changed timing belt, now won't start