Camshaft timing

richkel · Post by **richkel** » 10 Mar 2011, 10:17

Hi Folks, I'm puttin the head back on the 98 v70 wagon I'm working on. 5cylinder turbo. Manual on order but I'd like some help with the cam timing. I read a ton of posts here. They all seem to show the plastic cam gear cover with a piece in the front extended down with little cut outs to line up the marks on the cam gears. This car does not have this plastic extension or anything obvious to align to on the plastic cover. No problem, I'll get the slots at the back of the cams lined up horizontal.

My questions; How do I know the horizontal slot needs to be rotated 180 deg or not?

Others worked on this car, how do I know the cam gear is indexed on the cam correctly. (It can be put on in 3
positions)

If the cam gears are indexed correctly and the slots horizontal, are the cams in the TDC position, or in position to
assemble with the crank marks aligned.

thanks all

Rich

mrjacobrussell · Post by **mrjacobrussell** » 10 Mar 2011, 11:04

take a look at my post here last picture its a cam holding tool.
it can be purchased on ebay i would seugest buying the complete set its worth having i snaged mine for about $240 new

https://www.matthewsvolvosite.com/forums ... 1&start=28

you need the cams locked in place, and crank tdc ( crank needs to be tdc before cams and cam cover installed

if the cams are held in place correctly youll see the marks will point up.

richkel · Post by **richkel** » 10 Mar 2011, 13:23

Thanks for the reply mrj. I've read so many messages, links, etc. I'm about dizzy. Here's what I think I've learned; With the slots in the "back" of the cams parallel to the head surface, (the exhaust slot offset low, the intake slot offset high) and the crank up against the tool inserted near the starter OR the crankshaft marks aligned properly, the timing belt tight, and the cam gear bolts tightened, everything should be in alignment. Right? (BTW mine doesn't have VVT)

Now, one more thing to confirm; the alignment I described above is NOT TDC. Right?

Rich

VolvoTurbo850 · Post by **VolvoTurbo850** » 10 Mar 2011, 16:22

basically if you look at the cam sprocket by the firewall is should be about 2 o'clock, the one closest to the bumper should be about 10 o'clock. The cam sprockets can only go on a specific way so you wont have the issue with reversing the alignment of the cams. Hope that helps.

Post by **jimmy57** » 10 Mar 2011, 17:01

The cams must be locked in their correct positions using the slots on back of cam. The crank must be in the correct position either by locking pin in block with crank turned CCW against it or by CAREFUL alignment of crank marks with the pointing mark on oil pump behind crank gear.
The marks on gears are NO MORE than a convenience for removing and refitting belt when gears are not disturbed from mounting on cams. The gears are marked AFTER engine is assembled during manufacture. New replacement gears have no mark.
The gears on non CVVT engines will fit either cam and will go on in any of the three ranges.
I have known persons who successfully used eyesight referencing on cam slots on non-cvvt engines and had no problems. CVVT engines are more particular as cam travel must go to commanded positions or codes will set.

gilhuly · Post by **gilhuly** » 10 Mar 2011, 19:42

The above advice is all good. You've probably seen that the slots are off center. I believe its intake up and exhaust down. Also, when placing the camshafts into the upper head the lobes on cylinder 1 face in toward each other at 45 degrees or thereabout. The crank gear has different marks for different years, but if a pencil tells you #1 is TDC AND you find the mark, using all the above info anybody can do this visually with a good light and without a cam locking tool. One trick: Set the crank then back the crank gear counterclock a half a tooth. It will buy you the slack you need to get the belt on without disturbing the cam gears. The slack will get picked up after releasing the tensioner. Use the multiple data points to provide confidence.

Post by **erikv11** » 10 Mar 2011, 20:10

richkel wrote:Thanks for the reply mrj.
Now, one more thing to confirm; the alignment I described above is NOT TDC. Right?

Absolutely correct. With the crank mark lined up, number one is either just before or just after TDC, I don't remember which. This is so you can rotate the cams if/as necessary, and the valves will not hit a piston like they would if it was at TDC.

volvojosh · Post by **volvojosh** » 25 Aug 2013, 17:45

What does TDC mean?

Post by **Ozark Lee** » 25 Aug 2013, 21:29

Top dead center. It means that the #1 cylinder is at the top of its travel on the compression stroke.

Please refrain from bumping every old timing belt post on the board.

...Lee