964 cams on 993 engine?

[mmasse]

I am rebuilding my 993 (Varioram) engine. I am planning to convert the friction style 993 sprockets to the mechanical 964 ones. The problem is that my 993 cams do not have the woodruff key on them.
I could get a hold a pair of 964 cams, but my question i:s are those interchangable? Can I use 964 cam on the 993 engine? What's the difference?

Thanks for your inputs.

[pete911]

You can have a keyway machined into your 993 cams. I just did this.

Pete

[pete911]

I forgot to add that you can't use 964 cams in a 993. The 993 cams have a groove in the first bearing journal. I believe this has to do with getting oil to the hydraulic valve lifters. Also the shape of the camshaft lobes are different due to the hydraulic lifters.

Pete

[mmasse]

Thanks Pete. I will have a keyway machined on the 993 cams.
Hopefuly, I will find a shop which is willing to take such a small job...and capable to do it right!!!

[Sboxin]

You might want to contact Don at EBS Racing in Reno for machine shop info:

EBS Racing inc. | 4068 South McCarran Blvd. Unit B | Reno, Nevada 89502
Phone: 775-673-1300 | Toll Free: 1-800-462-3774 | Fax: 775-673-2088

[pete911]

Dave Coleman in Summit Pt. WV did mine. $100 plus shipping both ways.

Pete

[mmasse]

Pete911

I just got a call from the machine shop. He was about to machine the groove for the key, but he first fitted a 964 sprocket and trust washer, and according to him once you do this the sprocket will sit a bit far out. He mentioned that the edge of the 993 cam has bit of a shoulder at the end which makes the sprocket to not fit completly in once the trust washer and alignment shims are in.
Did you face any issue with this?
Thanks

[pete911]

Nope. Had the keyway machined and everything went together without any problem.

Pete

[mmasse]

do you recall if your cams look like the ones below. You can see the shoulder mentioned by the machine shop.

[pete911]

To be honest I don't remember.

Pete

[Bill Verburg]

Why not just buy a new set of RS or SS cams w/ the correct sprocket attachment?

[mmasse]

Bill,

Two reasons:

1) I am trying to keep budget under control and those cam are $1K.

but, more importantly, I will be running a TPC Supercharger on m y engine, and I was recommended by the guys at TPC not to go with more agressive cams.

I got a hold of a pair of 1996 993 cams which came with the keyway in. It seems from your table that they have the same profile as the ones on my engine "97 RoW Varioram

Hope this solves the problem.

Thanks for you input!!

[dgmatt]

Mario,
Can you tell me the part number of your cams? I'm trying to see if I'm going to have the issue your mechanic described.
thanks,
Don