optispark problem
10-12-2014, 05:55 PM
#1
Registered User
Thread Starter
Join Date: Aug 2014
Posts: 26
optispark problem
So I just finished a cam swap and went to install the opti and it won't seat all the way against the engine. The dowel is lined up with the correct hole and the dowel pin is stock length. Idk why it won't seat. Please help. Tia
10-13-2014, 08:01 AM
#8
Administrator
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,646
Re: optispark problem
He doesn't have a signature, and he speaks about the dowel pin going into the hole in the back of the Opti. That would make his engine a 95-97. But the "93" in his screen name is confusing.
I've suggested several times that he add a "signature", but he has chosen not to add one, making it difficult to help him.
I've suggested several times that he add a "signature", but he has chosen not to add one, making it difficult to help him.
10-13-2014, 02:54 PM
#11
Administrator
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,646
Re: optispark problem
Use the full site.... my post immediately above was done from an android phone - no problem with the signature.
Are you measuring the length of the dowel pin from the surface of the cam nose, or from the outer surface on the cam sprocket?
Courtesy of Shoebox"
http://shbox.com/ci/ci289.jpg
Are you measuring the length of the dowel pin from the surface of the cam nose, or from the outer surface on the cam sprocket?
Courtesy of Shoebox"
http://shbox.com/ci/ci289.jpg
10-13-2014, 03:52 PM
#13
Administrator
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,646
Re: optispark problem
From Shoebox's site:
Before you install the cam, it is a good idea to check the dowel pin length. Compare the new length to the old and make any adjustments if needed. If the dowel pin is too long, it can ruin a vented optispark in a short time (non-vented optisparks aren't driven by the dowel pin). Some have said GM specs indicate that the dowel should be .620" long (protrusion from the front face of the cam) for the vented optispark. Others have said it is supposed to be .685". Mine was actually .650" and still was in no danger of bottoming out in the optispark drive (I'm thinking .685" might be the max it could be).
Here you can see the difference in the Comp Cams dowel (right) to the original. The CC pin was .840". That would put pressure on the back of the optispark and destroy it in a short time. If you have any doubts about the length, use some modeling clay (even PlayDoh :-) ) to test fit the opti and check the clearance. Comp Cams advises you to check all clearances.
If you don't want to change the pin, it can be dressed down by a grinder with relative ease.
Here you can see the difference in the Comp Cams dowel (right) to the original. The CC pin was .840". That would put pressure on the back of the optispark and destroy it in a short time. If you have any doubts about the length, use some modeling clay (even PlayDoh :-) ) to test fit the opti and check the clearance. Comp Cams advises you to check all clearances.
If you don't want to change the pin, it can be dressed down by a grinder with relative ease.