Home » Public Forums » GMCnet » [GMCnet] Fwd: Roller Cam issue - please read if you have one.
| [GMCnet] Fwd: Roller Cam issue - please read if you have one. [message #150689] |
Sat, 26 November 2011 11:32  |
emerystora
Messages: 4442
Registered: January 2004
Karma:
|
Senior Member |
|
|
Begin forwarded message:
> From: gmccoop@yahoo.com <gmccoop@yahoo.com>
> Date: November 26, 2011 6:18:30 AM MST
> To: Emery Stora <emerystora@mac.com>
> Subject: Re: [GMCnet] Roller Cam issue - please read if you have one.
>
> Emery and others,
>
> Let me help out a moment, including a roller cam set up requires more that looking up the part to bolt it up!
>
> The letters get a unique treatment because of the wear issues they create. Push rods must be special, there are stronger springs so the rockets are all new with steel bridges. Valve stem height and machine work in that area must be treated differently than with a Chevy motor. The dust. Turns backwards so swimming the dust. Is different and of course now all of you know about the dust. Gear thing.
>
> Not only does a roller cam set up add @ $1000 to the cost of a build but it also does add some complexity to the build--- and some unique issues. I felt though that the benefit outweighed the exposure if what we wanted was superior performance for a low rpm torque motor--- and it seems to be true. After set up and break in (there were initial failures we had to deal with), but after in and working, we have 85 motors out there with only 1 death to date. So far those a good odds, they will eventually be more, things don't last forever but so far I feel we have proven our combination and there is way more considerations than I mentioned here. Why do you think Joe Mondello made a life of investigating the possibilities.
>
> So if looking for that perfect motor without breaking the bank is the goal, a proper set up using a roller cam works-- that is if you use the right set up. Production builders just don't get it, that's why we're now doing it all ourselves. This is all a part of the Chase------
>
> Jim Bounds
>
> Sent from my HTC on the Now Network from Sprint!
>
> ----- Reply message -----
> From: "Emery Stora" <emerystora@mac.com>
> Date: Thu, Nov 24, 2011 10:25 pm
> Subject: [GMCnet] Roller Cam issue - please read if you have one.
> To: <gmclist@temp.gmcnet.org>
>
> Jim Bounds just told me that he can supply a nitrate hardened gear which he says will solve the problem.
> I don't know anything about that gear so please contact him for details.
>
> Emery Stora
>
> On Nov 24, 2011, at 11:18 AM, Emery Stora wrote:
>
> > The particular cam that is being written about is a Comp Cam made of billet steel. Comp Cam indicates that the distributor gear must be a bronze gear or a synthetic plastic gear. It will chew up steel gears in no time and even cast iron gears with the graphite Mehinite process. Steel or cast iron gears on the distributor will also chew up the billet steel of the cam and then leave hardened steel particles in the engine.
> >
> > Comp Cams have advised the GMCer that has that cam that the bronze gear is a sacrificial part and that the expected life is 5000 miles. Obviously that particular cam is meant for a dragster or race car which would be worked on after each race and not a GMC. It appears that the owner will have to ether change out the bronze gear every 5000 miles at a cost of $85.22 plus shipping from Comp Cams or else replace the cam with one with a pressed on cast gear if he wants to use a steel gear on the distributor.
> >
> > On Nov 24, 2011, at 10:56 AM, James Hupy wrote:
> >
> >> Matt, the phophorous bronze distributor gear should only be used with a non
> >> hardened cast camshaft. When you use a heat treated cam like the comp cams
> >> roller, the proper distributor drive gear should be the mehinite one. It
> >> has the appearance of steel, but is in fact cast iron that has been alloyed
> >> and recast and is friction compatible with the hardened roller camshafts.
> >> What your acquaintance with the bronze gear found out is that the two
> >> materials are not compatible, and the distributor gear will wear
> >> prematurely. Probably another case for reluctor wheels and digital timed
> >> ignitions with crank position sensors instead of distributors. Still need
> >> the distributor shaft to drive the oil pump, though, but the oil pump is
> >> not timed and if a bunch of slack shows up in the gear train, it is not as
> >> bad of a problem, unless it strips out completely. If that happens and the
> >> engine continued to run, bad stuff happens. Do not ask me how I gained this
> >> knowledge, it is too painful to the wallet. It seems that when a person
> >> modifies an engine, sometimes it sets up cascading failures that they did
> >> not consider. BTDT myself. Everyone, Eat lots of turkey, take frequent
> >> beverage breaks, and spend the day kicking back with your loved ones.
> >> Jim Hupy
> >> Salem, OR
> >> 78 GMC Royale 403
> >>
> >> On Thu, Nov 24, 2011 at 9:01 AM, Matt Colie <matt7323tze@gmail.com> wrote:
> >>
> >>>
> >>>
> >>> To all GMC people with roller follower cams, please be aware of this issue.
> >>> An owner has had a recent issue with an engine built and installed last
> >>> year.
> >>>
> >>> The engine was built with a Competition Cams 42-413-9 Roller cam kit.
> >>>
> >>> It wore out the distributor drive gear in about six thousand miles. In a
> >>> query to Competition Cams, he found out that they only expect five thousand
> >>> miles of life from the bronze distributor drive gear.
> >>>
> >>> If you have a Comp Cams Roller, carry a distributor drive gear and the
> >>> tools to replace or a back-up distributor and plan to replace this gear on
> >>> a regular basis.
> >>>
> >>> Unfortunately, this owner only works the GMC-EFI group.
> >>>
> >>> More information will be available as more is learned.
> >>>
> >>> Matt
> >>>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
Current Time: Sun Nov 17 12:29:35 CST 2024
Total time taken to generate the page: 0.01714 seconds
|
GMCforum
Search
Help
Register
Login
Home
