FIXX

iTrader: (2)

Chuck it up in a lathe and what needs to come on is takin off the nosof the step in the cam..the face of the widest point if that makes any sence to you,,or the part of the cam thats rubbing on the thrust plate..remember only take off what needs to be takin off because theirs no to fup the clearance..

Budman II

iTrader: (1)

Well, I guess turning the step down on a lathe to be a little deeper would be the ideal situation, but I'm probably talking about $75 to $100 when you factor in the machinist's setup time, and if something happened and a mistake was made, it could turn the cam into scrap. Rather not take that risk.

I bought a new retainer yesterday, and it mic'ed out to be 0.1195 in thickness versus 0.121, so at least that is a step in the right direction. I still think shimming the cam gear is the most logical solution, but I will need to investigate the chances that a shim could disintegrate in this application. When you look at it, the can has a locating dowel and the gear is bolted snugly to the cam. I for one cannot ever recall removing a timing gear and seeing any evidence of galling or pounding on the front of a cam or the back of a gear where it contacts a cam. If something like that were occurring, I would think you would see a lot more instances of people having cam bolts work loose and cam buttons being destroyed.

FWIW, BLP Racing Products makes shims that are designed exactly for this purpose, but they are .010 in thickness and probably only have the Mk IV bolt pattern available.

tpabayflyer

Thanks to Budman for steering me on to this thread! I have a similar situation with my Cam Motion cam and rollmaster double roller timing set with the Torrington bearing......... I am building a 502 now and have the short block done and I temporarily put a head on to mock up my valve train to measure my pushrod lengths so I can get them ordered....... of course I need to operate some valves to do this and had to put the timing chain on and.......... eff...... mis-alignment...... bad........ upper cam gear is quite a bit closer to the block than the crank gear by at least .050.........timing chain is binding and would not last 5 minutes like this............ I have studied this thread and I cant figure out exactly how the problem was solved????? I don't know if we had the same problem but shaving the retainer plate wont help me out? shimming the cam gear forward will help. Machining the lower cam gear to move it closer to the engine would help but I don't know how much meat is available on the crank gear to do this. I will check later. Machining the step on the front of the cam would allow the whole cam to move forward and move the cam gear away from the block? That would help as well but would that also affect lifter?cam lobe alignment? I can check this as well.

Is there another brand of timing chain that I could use? the stock big single chain will not fit as the Cam core has a smaller mounting hole pattern than a stock gen 6 cam. If I could use a stock chain I would have no issue with that as my valve springs are not super strong as I am only running .611 lift...... what is the cause for this issue? I am sure that the engineers at rollmaster know what they are doing..... Cam Motion as well??? am I not doing something right?? Thanks..... TBF

tpabayflyer

I should also mention that with just the cam gear only bolted on the Cam it feels very solid and has just a tiny bit of play..... hardly enough to barely feel without having a dial indicator so I think that the clearance is good with that and the cam turns freely......... just bad chain alignment..... TBF

supermx96

For sure i will not machining the step on the camshaft. If that problem was mine i will go for machining the lower gear if you have enought clearence between chain and block. Your problem is not the same in this tread.
BTW the end play clearence should be at .003'' when new mine after 80h is at .010''
I dont know for what reason they have some mismatch between some parts like this they make always some headache

tpabayflyer

Thanks Super..... great minds think alike! it seems like taking a bit off the crank gear would be the easiest solution. It looks like the cam gear sits on the cam perfectly with the correct clearance. The chain does get pretty close to the block but I think it would be OK. I have used all top quality parts in the lower end with a GM crank, Forged Probe pistons on Scat H-beam rods, H series bearings and file fit rings, cam motion cam and morel roller lifters and a top quality rollmaster timing set...... I really don't understand how using good quality stuff ends up getting me in a cluster like this. I think I will run this by my machinist and get his input. Joe up at fast forward race engines in New Port Richey has a nice shop and set up my heads for me. He also has access to a dyno that can run wet exhaust so I will have him tune the engine. I have never heard of this problem before and maybe I got a mis matched part or improperly machined crank gear?

Budman II

iTrader: (1)

TBF, I ended up making a shim out of .004 shim stock and put it between the cam gear and the front of the cam. I know several people advised to take material off the cam retainer instead, but I cleared the shim idea with two reputable engine builders whose opinions I trust. It was the simplest solution and got the cam gear out where it should be. With the chain off, no shim, and the gear installed, I had preload on the Torrington thrust bearing, and it was stiff to turn the cam. After the shim, I had right at about .003 end play.

I am running a cam that I bought off a member here, but it was brand new, and also came in a Cam Motion box. I am wondering if they had a run of blanks that for whatever reason did not get the step machined quite deep enough. Kind of strange. Good luck with your build.

tpabayflyer

Thanks.... I think our problems were different but the common thread here is the cam motion cam??? I think I will be calling those guys on tuesday....... The only other thing that I could think of is that mahbe my crank snout was machined wrong or maybe the cam retainer area was machined down? I kinda doubt that but who knows.....

tpabayflyer

Updated my other thread but all is good now! Simply found that my crank gear was not pressed on all the way so always doub le check everything! It certainly looked as ifit was seated all the way on but I was able to crank it down and move it it a bit more. alignment looks good and everything spins nice and smooth!!! TBF