SBC cam gear clearance issue?
 

I just slid my Thumpr cam into my block preparing for final assembly. After bolting the camshaft retaining plate (or thrust plate) in place, I bolted up the camshaft timing gear so I could check for endplay (camshaft run out) But the Cam gear is contacting the two button head style bolts that secure the thrust plate to the block. Has anyone ever run into this problem?

The block is OE roller casting # 10243880

The cam kit I purchased is http://www.summitracing.com/parts/CCA-GK08-600-8/

The cam kit included this gear drive set up http://www.summitracing.com/parts/CCA-4136/

No advice? No one can help me with this one? Comp cams tech line said they would go to their garage, test this kit in one of their blocks and call me back and I have yet to hear back from them. I cant seem to find anything on the net with anyone experiencing this issue. Even my machine shop has not ever had this problem. I am sitting on $6,000 worth of opened parts that are not fitting. Pulling my hair out and banging my head against the wall.

It seems as though the kit comes with a button. It goes in the nose of the cam and keeps it from walking forward by limiting itself against the timing cover. If it didn't come with one, get one at any local parts store, and simply remove the cam retainer plate. The plate does the same thing as the button and you won't have any interference issues. Just check for proper end play front and rear after everything is installed.

So you are saying, although my block is provisioned for a thrust plate and typically uses one, I should just can it and use the cam button with the retro style kit? I understand people doing this for a retro set up where the block isn't provision for a HR cam and thrust plate. But I didn't realize this was necessary for a OE roller block with a HR cam.

best would be to call summit tech line, if its not right , they wont fix it.

The only reason I am suggesting you use the button instead of the plate is because the plate fasteners are interfering with the cam gear. If you are set on the plate then you can drill the holes in the plate for counter sunk screws, then buy two new screws, and you'll probably have enough clearance for the cam gear.

http://t3.gstatic.com/images?q=tbn:A...BqaQs8lvRFVUtC

dead end cruiser.............. :( You share something in common with somebody that wanted me to build a Dart block 415 ci. (Stupid Thumper Cam and Gear drive)

First I ask why would he want that crap? I knew the answer. Cause your car will sound the coolest at the Hooters evening car get togethers!:cool: Then I just said, "I will not build it." I only build powerful functional motors.

I've worked on and built gear driven cam motors. The answer is you have to machine the front of the block for gear drive clearances. then the cast cover has clearance problems with a vette short water pump. then you have pulley alignment problems. then your power steering pulley doesn't clear the frame. But your car will sound:cool:

The reason why Comp Cams tech line didn't answer your question is because they are usually a bunch of high school drop outs that drive crappy fart pipe rice cars. Their only knowledge is from reading car mags at work. I know because I worked at Summit Tech line and I saw what the typical employee was and drove

I have the thrust button kit just in case, but I am not sure if this will offset anything being that the cam has a stepped nose provisioned for the plate. I am going to go look for a recessed style screw to see if I can get that to clear the gear, If not I may just bring the gear to my machine shop and have them mill the gear just to clear the two bolts.

Yeah, more or less, I know I could use a more mild cam and get more power, but 1 I don't want to twist the car into pieces and 2 I have other vehicles for power and going fast. Like you said, I want it to sound cool for those Sunday night cruises with a little bit of gitty up. Looks like there will be a little custom fitting going on to get it right as long as I don't throw off my accessories on the front of the block.

ditch the gear drive ... you SURE don't NEED it with that cam ... some experienced folks dislike their noise & "connotation." They're also hard-stressful on front main cap.

that cam kit uses retrofit roller lifters

but your 880 block is for OE roller lifters. And it probably has an iron Front main cap w/ 2 bolts.

ditch the hi$ lifters and install OE roll lifters & spider & dogbones as in ZZ4.

install timing chain set as in ZZ4.

that GK08-600-8 thumpr cam ain't so much ... so OE tc set & roll lifters AOK ... and WAY less $.


----or keep all that stuff & countersink the retainer plate.

I'm all for the noise! I need to own at least one obnoxious vehicle :D I was also informed that I should use gears with a cam that big. As for the kit, it actually came with the OE rollers and I bought the HR installation kit which came with the dog bones and spider. I know in the picture it shows otherwise. It is an OE roller set. I have some countersink screws already, and am going to have the plate countersunk tomorrow and see how that works.