Roller Cam Retainer Bolts

[pontiacgp]

I have a light knock coming from the front of the engine. I'm thinking it's the cam timing gear hitting the bolt heads for the retainer. The retainer was bought from GM and no bolts came with it so I just used a grade 8 1/4" bolts. I did notice that the head of the bolt was close to the gear but it did have clearance and I thought I had the cam fully seated when taking that measurement. I haven't found any cautions online about the need for a shallow head bolt for the retainer but I do know GM uses a torque screw for the retainer and I would think that if there was any clearance issues the bolts would have come with the retainer. The knock will be present as long as I let the car idle but will lessen and go away at times when reving the engine and after driving it the know is very light so I'm thinking the cam is moving out like it would when reving the engine. Just wondering if any of you guys have any input on this...

thanks

 

[tc1959]

I have a light knock coming from the front of the engine. I'm thinking it's the cam timing gear hitting the bolt heads for the retainer. The retainer was bought from GM and no bolts came with it so I just used a grade 8 1/4" bolts. I did notice that the head of the bolt was close to the gear but it did have clearance and I thought I had the cam fully seated when taking that measurement. I haven't found any cautions online about the need for a shallow head bolt for the retainer but I do know GM uses a torque screw for the retainer and I would think that if there was any clearance issues the bolts would have come with the retainer. The knock will be present as long as I let the car idle but will lessen and go away at times when revving the engine and after driving it the know is very light so I'm thinking the cam is moving out like it would when revving the engine. Just wondering if any of you guys have any input on this...

thanks

Check to see If the cam gear or chain is hitting the inside of the timing cover where the timing pointer is spot welded on. Gm Had A service Bulletin about It way back when.
Also I think Mine has a tapered seat torx screw that sits flush with the cam retainer plate. I do rember it takes a special bolt .

 

[pontiacgp]

I have the same heavy aluminium timing cover I used before and I have the same brand double roller timing chain I used before, with the roller cam gear of course. The pointer is riveted on and it never hit before. I did put a few fingers on the cover with the engine running and felt nothing. Looking at your bolts I'm going to be ordering them tomorrow and I think it must be those bolts I used are sitting too high...

thanks for the input and picture of the bolt, I had only seen the face of them in other photos...

 

[pontiacgp]

and while on the subject of bolts the kit I bought from GM performance comes with the lifters, lifter guide retainers and spider it comes with 4 bolts and washers. There are only 3 bolts used for the spider and I doubt they give you a spare bolt with a washer so I spent some time trying to figure out where the extra bolt goes and I still don't know... :|

 

[pontiacgp]

I ordered the bolts at the local speed shop but they were sent retainer bolts for an LS1...so I went to the GM dealer and they had to order them which would have been ok but they come in a package of 10 and I would have to buy them all at $2.65 each...so I got the GM parts guy to print me off the specs for the bolts and headed to Fastenall and got them there for $0.00. They had an open box and he was too lazy to do the paperwork for 2 little bolts... 😀

 

[tc1959]

I ordered the bolts at the local speed shop but they were sent retainer bolts for an LS1...so I went to the GM dealer and they had to order them which would have been ok but they come in a package of 10 and I would have to buy them all at $2.65 each...so I got the GM parts guy to print me off the specs for the bolts and headed to Fastenall and got them there for $0.00. They had an open box and he was too lazy to do the paperwork for 2 little bolts... 😀

SCORE

 

[pontiacgp]

And what a difference in the size of the head compared to what I used. I should have realised the clearance was too tight with a stock hex head bolt.

 

[pontiacgp]

soooo, I removed the hex bolts I used for the retainer and they were not marked so it was obvious I was wrong with thinking they created the knock with the cam timing gear hitting them. I changed them anyway with the proper fasteners. Put everything back together and the noise was gone at first but came back with a few knocks but with much less volume. It get worse the more I ran it. Since I had done nothing I knew of that would change the knock I figured it had to do with the harmonic and pulley since I didn't use a torque wrench and I didn't align the pulley mounting holes with the way it came off. The knock has changed so it had to do with my installation of the balancer and pulley. So I took a bit of torque off the pulley bolts and the knock is gone. I can't recall how many harmonic balancers and pulley I have installed but I have never had an issue like this.