Cam Sprocket Alignment Help

1972_911T · 12-02-2005, 01:33 PM

I am trying to align my cam sprockets, I made the mistake of strip down of not noting how many were on each side however I know one had 3 and the other had 4 as suggested for basic setting in Wayne's book.

Not knowing which one should have the 4 I started with 3 on each side. The left side is perfect, withing 0.07 of a mm. The right side is borderline its about 0.2mm out withing the 0.25 recommended therefore adding the shI'm to this side would make me 0.3mm the other side of this which would be out of the range. This leaves me with the problem that I'm one shI'm less than was used originally. I have now packed in for the night and I'm going to double chk my measurements tmrw. I'm just curious to know if anyone else as found this on rebuild that they have a shI'm extra. All the cams and cam towers are original and nothing has changed as far as they go.

If my measurements check out tmrw should I carry on with just 3 on each side or is it likely ive not done something right?

Thanks Steve

Eagledriver · 12-02-2005, 03:38 PM

I think I'd just double check my measurements and call it good. Make sure there is no axial "slop" in the intermediate shaft or camshafts. When I did my engine I actually measured the distance between the sprokets on the intermediate shaft and found the distance to be about .5mm different than the book number. If you have your case together (it sounds like you do) then you can't do that measure so just use the book number.

-Andy

ChrisBennet · ChrisBennet's Garage

I would trust that the motor has the correct number of shim (3 & 4). I found the measurement to be rather tricky before I got the special tool for it and prone to error on my part.
See my comments in this post: First time rebuilder gaining momentum!
-Chris

Jeff Alton · 12-02-2005, 06:46 PM

Get Stomski tool, pretty inexpensive and hard to do it right without it.

Cheers

stevepaa · 12-02-2005, 10:17 PM

I would suggest getting a long true flat edge from Starrett.

When I did mine it started with only two shims per side, I forget what I ended with.

1972_911T · 12-03-2005, 04:35 AM

Chris I read your post in that link and I think its interesting you say that every engine you have ever rebuilt has had 4 on the left and 3 on the right, because although as I said I never noted at the time of dismantle how many shims were on each side, I did bag up all parts and label them as I took them off and sure enough in the bag for the left side sprocket I had 4 shims and 3 in the right hand bag. However the reson I didnt copy this when I reinstalled them was because in the book it states a good place to start is 3 on the left and 4 on the right oppasite to what I thought I had so I started with 3 on each side because I wasnt sure if my engine was different to the book or if I had got the bags mixed up.

I will try adding the 4th shim to the left side and remeasure and see what I come up with.

Thanks Steve

Jeff Alton · 12-03-2005, 12:22 PM

The stomski tool comes with a Starrett straight edge....

Cheers

stevepaa · 12-03-2005, 10:58 PM

Not to be picky, but the flat bar that comes with the stomski tool is not a true straight edge. Starrett can not make them true in the thickness of that flat bar.

ChrisBennet · ChrisBennet's Garage

Stomski advertises that their tool comes with a Starrett straight edge but like Steve says, the Stomski tool comes with a piece of Starrett ground stock. Like this:

Technically it's not a machinist's "straight edge" but it's pretty straight..

-Chris

Jeff Alton · 12-04-2005, 06:21 AM

However, Starrett does offer "Prescision Straight Edges" up to 7mm thick in their online catalogue, not sure of the tolerance.......

Cheers

hcoles · 12-04-2005, 06:54 AM

When I rebuilt I got the Stomski tool. It doesn't come with a Starret straight edge..it comes with ground flat stock...which is good enough. I placed my edge from Stomski on a granite block and no daylight.
Anyway getting this measured correctly requires practice or you will get wrong numbers.

For me after all the measurements and horsing around I came back to the original 3 and 4 or what ever it was....but it really took some work and I made a spreadsheet system so I could put in measurements along with a diagram and not get confused...

I can send in more if you need.

-h

1972_911T · 12-04-2005, 07:53 AM

Ok guys thanks for your advice I have now added the fourth shim to the left hand cam and re measured it, its now in spec. I used a standard engineering straight edge but made the measuement several times on both edges of the bar to make they are accurate I got it 0.2 - 0.22 4 times I measured it.

Steve

stevepaa · 12-04-2005, 10:14 PM

Yup, that's what I did also. I have a Starret straight edge I bought years ago. I had help from my wife and daughter as far as holding it and doing my measurements. I repeated many times to be sure.

88911coupe · 09-25-2008, 07:38 PM

OK...sounds like I might be okay on my situation. I had 4 on the left and was worried something was wrong since Wayne's book says 3 on left. I have not replaced anything so it appears that engines can in fact have 4 on the left....