ultraviolet70

I'm doing some test fitting and partial assembly. I've run into a clearance issue and am wondering if others have. I have a '91 L98 obviously running an OEM style roller cam. I have a Cloyes 9-1145 timing chain set that I know have seen others run and never mentioned the clearance issue I'm having (Yes I did search). Problem is the chain is hitting the center oil channel circled in the first pic, in the second pic (which isn't the greatest) circled is with the cam gear installed I only have about .006 clearance and in the third pic you can see with the chain on the gear I need alot more clearance than that. Has anyone else run into this? Do I just grind down the necessary material? If so how do I keep from getting metal shavings everywhere with a completely open/exposed engine?
Thanks in advance for your help.

Demonic85

I see you're using a double roller. Those usually dont fit without some clearancing, how bad is it hitting the block?

floridamale

Do the double rollers also have clearance issues with the stock timing cover as well? Seems I read that some where also.

rodj

I have fitted a double roller to both my '89 block and Vortec block I used for my 383 build with no problem.
Out of left field.
Is the cam retainer/ thrust plate worn enough to let the cam float back?

mseven

I didn't have that issue, what I did see was that after checking crank and cam endplay the crank gear need .012 removed from the back side to get proper alignment.

I wouldn't be afraid of grinding the block (masking everything off first). BUT, before I would do that I would be looking at everything. Rod brings up a good point, w/cam plate. I would also check cam endplay (.006 if I remember right) w/a mag base dial ind.. The rear cam "stop" may need to be "tapped" in (if too much endplay and front plate is not worn or bad). Another option would be to have the back of the top gear being machined.

ultraviolet70

The gear does not hit the block when unloaded it's once you put the chain on the added thickness of the chain is what contacts the block. The cam plate has a little wear, but nothing substantial (I have a new one any way, but again the few thousandths it will bring it out is not going to make a difference). As far as the rear cam stop, they are not actually a cam stop on the factory roller cams the cam is purely postioned by the retaining plate and the gear.
So it looks like I'll be clearancing the block, and this is ok?!
Also is it ok to tap the plug in slightly deeper in the oil passage, I don't want to grind into it have it loose tension and fall out, I just want to make sure the passage doesn't widen as I tap it in and it becomes loose?
Thanks for your responses guys.

engle1147

The back cam stop he was refering to looks like a big freeze plug in the backside of the block...she might need a tap or too if there is too much end play on the cam. I wouldn't hesitate to grind the block back on an angle where the chain is hitting you shouldn't even come close to the plug your refering to to gain the necessary clearance. I agree mask it off or drap towels (damp...you know for the sparks/fire) in and around the area.

steven mack

I would not mess with the oil plug in the front of the block .I have seen a motor where the plug came out and wedge itself in the crank gear and broke it you could also lose your oil pressure .I would get another rear cam plug and drive it in deeper or shim the cam gear where it bolts to the cam.

mseven

I was unclear of what was exactly making contact (my appologies).
However, you really need to put the gear on (not really tight) and get an indicator on it and see what is going on (you may have stated that, if so I missed it). I have used the same gear/chain set on my 90 block before, and while close it made no contact. This leads to me suspect possible endplay issue. (it also seems strange having to trim that deep into the plug area) Like I mentioned I wouldn't have a problem doing some trimiming, but only after knowing first the endplay.

ultraviolet70

Endplay with the gear installed was fine. I did some research and found some pics online of bare blocks and noticed most had the oil passages machined down some (unlike mine) so I tarped the car and engine ground down some and cleaned up. I did not move the plug, but did restake it once done. Test fit the chain and reinstalled the cover with the old compressed gasket to verify clearance and clears the block fine and does fit fine under the stock timing cover.

Qiken

engle1147

pletzvet

Interesting thread...a TC upgrade is on my to do list for this spring. Is there any chance that the clearance issues are being caused by the timing gear going on backwards? I don't know if it is even possible to put the gear on the wrong way, or if it matters but thought I'd throw the question out - just in case?

ultraviolet70

It is physically possible to put on backwards, but it is obvious which way it goes. It was simply a matter of some blocks have the oil galley bosses recessed more than others. If hadn't already bought the timing set I'd probably have gone with the GM heavy duty single roller kit from what I've researched it gets good reviews and fits all with no mods.

http://store.summitracing.com/partde...t=NAL-12371043