Tried putting on my optispark today, it wont seat into the custom comp cam. Its like the hole in the comp cam is too small for the opti drive gear to fit into. Murphys law i guess. It fits into my stock cam fine. Here is a pic. I may have to drill the inside of the billet cam bigger?

 

Before you start drilling things get a micrometer and measure.

 

I believe you needed a 94 type cam for the spline drive opti. That cam has the pin drive for 95-96 type optis

does your opti look like this??

http://shbox.com/1/93-94_opti.jpg

 

^^^ this

 

No i have a 96 z28. It simply doesnt slide into the cam. Unbelievable. I will mic it tom.

 

yup. the first time I was installing a cam, I had to cut down the dowel pin because it was too long.

 

FWIW, Comp sent my cam out with the wrong pin and Karl had to have it fixed before he installed it. Sometimes you can use a brass hammer and tap it down to where it should be, other times it has to be cut or removed and the correct pin installed.

Also, though it may seem obvious, it can be tricky to get that pin into the correct slot on the dizzy. From the "been there, done that" camp...

 

If it" s not an LT1 spec cam you will have to drill the snout. .500" x 1.0625 '' deep for the "96 opti. The drive pin sticks out max of .685" .

 

Drive pin measures out good! My opti shaft measures .480. My STOCK cam hole measures .482-.484. Thats why it fits! My custom comp cam which is installed i am unable to measure with my caliper, i need a tool that will reach! WHAT DRILL BIT would be the correct size to make the hole slightly bigger? Is there a drill bit that measures .481-.485???? If its my cloyes timing set making those 3 bolts stick out too far im really screwed!! this is a pic of my timing set.

 

It might be an optical illusion with your pictures, but it almost looks like your cam gear bolt heads are hanging over the center hole in the cam gear. Maybe those are blocking the opti shaft?

Attaching a pic of what mine looked like for reference.

To measure cam center hole, you could pick up a cheap set of telescoping snap gauges and use your calipers. Would not be super accurate but would tell you the size within a few thousandths.

Sucks if you have to take it apart. My Lunati cam came with a short pin even though the paper work said long pin. Did not think of checking it. Noticed it when installing the opti after the engine was all together and sitting on the K member! Had to pull the cam to replace the pin. Easy fix, just time consuming.

 

The opti goes past the timing gear, but not into the cam? If true, then the only way to have it repaired correctly is for it to be done on a lathe. You don't want to go free hand drilling that out or you may end up replacing optis on a regular basis due to wearing out the opti shaft. If it's the hole on the cam snout you need to take it back out and send it to Comp. Don't shade tree it.

 

I think my shade tree drilling would be better than these aftermarket companies shitty tolerances. I already sent back one comp cam that was absolutely horrible. Im starting to think that keeping engines stock and just doing headers and tune was the way to go. Or just buy a machine shop so i can mic and fix all the junk i keep buying.

 

I know how you feel! I had visions of having to part out my original 57,000 mile 96 SS because more problems kept popping up while I was working on the motor. Mine ran great too when I just had headers and a tune.

The best thing to do when you are having problems is to take a break for a day or so. Then figure out exactly what the issue with the opti fitting is and then go from there. It sucks pulling the cam again if it comes down to it, but everything is much faster the second time around. Definitely do not drill the cam in the car.

 

Sure looks that way to me, too......

 

Yeah....i see that one bolt kinda looking like its in the hole circumference a tad. I will have to check that out!

 

Update....... the cam hole is fine. I can stick a 1/2bolt in it over an inch just like the stock cam. Thats not the problem. The cam pin appears to be the same length. The cam sprocket is the same thickness as stock. So whats going on?? Can anyone measure how far the cam sprocket bolts are behind the opti seal??? Mine appears to be 1/4inch behind the seal as you can see in my pics. The pin drive comes out as far as the opti seal, that is the pin is equal with the farthest back part of the optiseal. Something is seriously ffff'd up! Could my cam and cam sprocket be to far towards the front of the engine? Doesnt seem possible.

 

Edit: After thinking about it, I'd really give those cam sprocket bolts another look. Maybe tighten the one that's got a point hanging into the path that the opti stem uses (first pic, 1 o'clock). I don't think its hanging deep enough into it to stop the opti from seating, however, but it is hanging deep enough to make installing it a PITA. If you look at the hole in the cam, its chamfered at the opening and is a smaller diameter than the opening in the cam sprocket. This is to help guide the opti into the hole. With the bolt head hanging out like that, you've got to get it 100% dead-on in order for it to go in.

Also, if you put viton seals on the opti shaft, they can be really stiff and need more force than the OEM seals to go into the cam. A little engine oil on the shaft-seals helps here.

To see what's holding you up, get some (edit) marking compound and rub it on the bolt heads and the pin head. Then try to re-install. On the chance that the opti seats correct, the compound won't hurt anything. If it still hangs up, you'll see what is hitting and where.

Edit2:SS RRR's idea of compound is much better.

 

I would get some marking compound and apply it to the shaft of the optispark and try again.

 

New pics! After taking cam sprocket bolts out and putting chalk and erase marker on the cam pin, still a no go!!! And i cant see where any chalk came off the pin either. This is truly a mystery? It needs to go in another 1/4 -1/2 inch for the opti to seat against the timing cover and engage the cam pin. Next thread will be, " DOES ANYONE HAVE A STOCK LOW MILE LT1 MOTOR THEY WILL SHIP TO ME?"

 

Remove the o'rings carefully from the opti and see if it slides in.