S90 1997 timing marks

JBrown · Post by **JBrown** » 06 Nov 2009, 14:15

1997 s90 with DOHC.. nonturbo

I am doing valve repairs after a broke timing belt. while I have the head off I can see that the timing mark on the crank dose not have the number one piston at TDC. it's really about half way down in the cylinder. is this the way it sould be for cam timing?

any help would be great.
Thanks
James

Post by **billofdurham** » 06 Nov 2009, 15:51

Welcome to Matthew's Volvo Site.

The piston may not be on the compression stroke so you need to get it to that point.

Remove all the spark plugs.

Stick your thumb OVER the #1 cylinder spark plug hole. Rotate the engine until you feel pressure on your thumb. That's the compression stroke and TDC is at the top of this stroke. The timing marks should now be aligned.

Bill.

JBrown · Post by **JBrown** » 06 Nov 2009, 16:15

I have the head off. I can see where the piston is but when I line up the timing mark on the crankshaft the piston is about half way down in the cylinder.

drsugg · Post by **drsugg** » 06 Nov 2009, 18:02

What are you using for a "crank" timing mark? You should be using the mark on the crank gear where the t-belt is located. Should line up with a tab above the crank seal.

JBrown · Post by **JBrown** » 06 Nov 2009, 18:08

drsugg wrote:What are you using for a "crank" timing mark? You should be using the mark on the crank gear where the t-belt is located. Should line up with a tab above the crank seal.

that's what I am using.

drsugg · Post by **drsugg** » 06 Nov 2009, 20:50

Then use it, and it should work. I've only had the head of an S90 off a couple of times, the last about 6 years ago. I sort of remember something a little odd about it, but not really. I do know that if you line up the marks when you put the belt on, it works. Whether or not it's tdc #1, I don't know.

DanR · Post by **DanR** » 07 Nov 2009, 08:31

When the crank is on it's mark, the piston is not at TDC, since it is an interference engine, the mark lowers all pistons so the valve cams can be rotated without hitting any pistons.

DanR '94 964 345,000 miles (109,000 on the new engine)

JBrown · Post by **JBrown** » 07 Nov 2009, 17:32

Thanks for all the help guys.

now I just have to wait for parts to come in so I can put it back together

lindy8_man · Post by **lindy8_man** » 29 Nov 2009, 19:37

You can't quite see it, but there is a very faint indentation that lines up with a post coming off the case. I marked the top of the pulley where the little indentation lines up. Unless you have taken the pulley off, you need to rely on the marks. The cam marks are simple enough to understand!

JBrown · Post by **JBrown** » 30 Nov 2009, 12:43

it's back together now and runs great. I do have another problem now but will start a new thread.