Thread: Those of you with double roller timing chains....

Originally Posted by turbocharged406sbc

D

btw fer those of ya who run dbl's if i had a relatively cheap (and completly reversible) way to block the rear balance shaft bearing oil holes, how many of you would ditch the weight of the balance shaft? or would you still just pull the gear and leave it in with the 3 thou clearance blocking em?

cheaper than this?

I just had my Rollmaster doubler roller crank gear machined today. Copied the same chamfer as the stock crank gear, all in all the machining only ran me $10.00

The picture here:

with the rollmaster single on the right...the chamfer should look like that on the inside, back side of the double rollers, but does not for some reason. I corrected the problem, hope it works.

~F~

Originally Posted by archemedes

I hope it does, and if something so stupid as that radius (that was $10 to fix) is the problem, where's the supplier to take the effort to fix it

They're not going to fix it. According to JP their timing sets were not made for the US L67.

Well, that's 2 pieces to take to the machine shop now. The cover and the crank gear. Did you just hand them stock and double and say "Make it match"?

My crank gears. Left - Stock, Right - RM Double:


I actually have instructions for the cover :

Yup, showed him a stock gear and said make this double look like that.

He measured, got the right angle, and asked, sure want to wait on it. Set up his lathe, and did it while I waited. Cool to watch this guy work, cause hes been doing it for so long, he tells me he can hold as tight of a tolerance as a CNC machine. Once done, he was .00001 with in the stock gears specks, and that was achieved with a hand fed lathe. I'm a believer.


As for the oil pump cover, I do the exact same thing, I write on it with a sharpie too telling them ".20" off this side only please".

I believe that once you machine the chamfer on the crank gear, you get back your space you need, so after all we may not have to run two gaskets...or machine the oil pump cover, but personally, I am not taking a chance, and will continue to run, and suggest running atleast a machined pump cover regardless with a double roller chain set up.

~F~

Not to hijack the thread, but can anyone tell me the torque specs for that oil pump cover?

[QUOTE=GR8racingfool;35718]
As for the oil pump cover, I do the exact same thing, I write on it with a sharpie too telling them ".20" off this side only please".
QUOTE]

I thought it was .020"

I have the JP double roller and had the oil pump cover milled .020" on the surface that faces the pump as not to cut the countersinks down for the bolts. I did not check the chamfer, so I'm not sure if it fits exactly. However, I did check with a feeler gauge for clearance as the chain was spinning and I had plenty of clearance. I just hope the chain is spinning true and not at an angle.

Originally Posted by SyntheticShield

Not to hijack the thread, but can anyone tell me the torque specs for that oil pump cover?

Sure, while were on the subject...

11 N-m / 98 lb. inch

As with any bolts on a cover like this, torque them in a star pattern as you make/complete the circle.

And sorry, yes, you do remove .020" off the back inside side of the cover, not .20" as I said in that post. I forget to put in another 0 there, sorry, my bad.

~F~

I wonder if I should still double gasket. Can't hurt right?

Cant hurt, after all this is ZZP's recommendation for the fix for "those rare few who are having rubbing". After all, ZZP knows everything way ahead of their customers with the thorough R&D they do.


~F~

Originally Posted by GR8racingfool

Cant hurt, after all this is ZZP's recommendation for the fix for "those rare few who are having rubbing". After all, ZZP knows everything way ahead of their customers with the thorough R&D they do.


~F~

I can hear the scarasm in that statement!

ZZP didn't put up the double gasket recommendation until I sent them a pic of my chain hitting the cover. I made them send me a new chain cause there was no disclaimer about it hitting anywhere on there site and on the package itself. They were selling a product that they stated would work on our car without modification...and here we are today!

I just got a reply on the other forum that there was a coolant leak because of doubling up...... This chain should gome with a "Love me long time" coupon for all this trouble!

Originally Posted by VinnieGTP

"Love me long time" coupon

LOL, I like that, made me laugh, thanks!

As for the coolant leaks, I am sure they either didn't get the mating surfaces perfectly clean, or forgot to put sealer on the threads of the bolts for the front cover. Its really easy to get a leak if you don't know what to do to prevent it. Don't know what it could be...I ain't there ya know.

But, some things to check.

I'm putting my car back together with a single gasket, and keeping my machined oil pump cover on there. More than sure with how much was needed and was removed form the crank gear, that will allow the crank gear to full seat and line up with the cam gear just fine. I'm getting back the tolerances we lost, and had to make up for with machining the oil pump cover if that make since.

~F~