[60man]

I have the Simms cam retainer in my present motor and had it in my previous motor as well.....the same unit. All was good. Horsepower gains were done by back to back pulls...10-12 HP....that's a lot of friction !!I just think it relieves a lot of wear & tear from the roller lifter/lifter bores. Cam "walking" has to put side load on lifters..JMO..

simmsb53@gmail.com
Maybe you can blow up the thumbnails..

[rohrt]

Originally Posted by 2manyponchos

16 pages of info...

http://forums.maxperformanceinc.com/...highlight=sims

Thanks for the link. I'm finally up to speed on what everyone else know. I can't believe I did find that in my search. After reading up to 11 pages I jumped to the end. I found the link to his bike trip too. The only down side I see to the Sims unit was the price keeps going up.

[screamingchief]

Originally Posted by rohrt

I understand billet to be a cam machine out of one chunk of metal. The metal either being steel or aluminum. I thought the cam gear on rollers was too soft and would need a hardened gear if use with the iron distributor gear. I thought Isky made some hardened cam cores, if not wanting to use a bronze or composite gear?

Billet is indeed a reference to any piece that is finish machined from a rough shaped "blank" of raw material.

Billet roller cams = steel.

Flat tappet cams = cast iron.

NO such thing as a forged cam core AFAIK,all the flat tappet cores are made as castings,specific material may indeed vary some core to core,as will the hardening methods used,but from my understanding they all start out as castings,though the chosen material can help determine just how hard the finished product can become after hardening,so yes some specific flat tappet cores are more suited to a given application than other flat tappet cores would be.

Forging a cam core would be an extremely difficult & expensive proposition,all for what amounts to a negligible gain in any areas of strength or such.

And note that there are some cast iron core hydraulic roller cams out there as well,but they have a reputation of being a bit "hit or miss" in terms of overall durabillity in high-performance use when coupled with additional spring pressure,as a matter of fact there was a fella here that had a thread running not too long ago where his cast core HR cam had pretty much bitten the dust,you could clearly see "tracks" in the lobes where the roller lifters were riding.

Billet steel cores are the only way to go with rollers.

And again there are various materials used for billet cam cores too.

Mostly 8620 & 8650 IIRC.

The reason for using a bronze or composite distributor gear is simple,if something goes wrong,or the distributor gear(s) wears rapidly for some ???? reason,which would you rather replace,a $40.00 distributor gear,or a $300.00+ roller camshaft.

Also you gotta understand that "harder" does'nt necessarily always = "stronger",harder material often will fracture quite a bit easier than softer material will,so if there is a problem with the distributor gear,and you were using steel gears for both,there is a very good chance that the billet gear on the cam will break off teeth before the steel distributor gear would.

It's all about the lesser of evils.

It's kinda the same basic deal with hypoid ring & pinion gearsets.

Street gears are made of nice hard 8620 steel for longer wear and good overall strength,yet "Pro" gears are made from softer 9310 steel for better heavy shock load resistance,as that allows the teeth to "bend" before "breaking".

FWIW

Bret P.

[Schurkey]

The obvious solution is a steel cam core that's been machined to accept a pressed-on iron gear. (Some Buicks use a bolt-on gear.)

They're available from any number of cam companies. Lunati sold me such a cam for my boat. As they had the steel/iron gear cam "in stock" they sold it to me at no additional cost. I guess if they have to custom-grind the steel/iron gear camshaft, they may charge extra. I don't understand their pricing policies...just stating what they told/sold me.

[rohrt]

Originally Posted by Schurkey

The obvious solution is a steel cam core that's been machined to accept a pressed-on iron gear. (Some Buicks use a bolt-on gear.)

They're available from any number of cam companies. Lunati sold me such a cam for my boat. As they had the steel/iron gear cam "in stock" they sold it to me at no additional cost. I guess if they have to custom-grind the steel/iron gear camshaft, they may charge extra. I don't understand their pricing policies...just stating what they told/sold me.

I wish that was SOP for all cam companies I would rather have a stock gear then either the bronze or composit.

[Schurkey]

Originally Posted by rohrt

I wish that was SOP for all cam companies I would rather have a stock gear then either the bronze or composit.

All it takes is money...and asking for the product you want.

[critter]

Yes, that was me in that other thread someone linked. I didn't post over here because I'm pretty sure you folks are tired of hearing about all my broken crap.

The wear I saw was probably from inadequate oil delivery due to the pickup being off the oil pump. I don't want to blame that on the thrust plate because, after looking at the bearings, I wonder if that pickup hadn't been off the pump for a while and the fact that I tend to run a little overfilled on oil had prevented a major melt down in the engine. Lots of little things, like that wear on the thrust plate, uneven wear on the bearings, etc. make me think this.

The reason it failed when it did was because that was the first outing of the year and involved running an extended period on the highway. It finally sucked up that bit of metal and the distributor gear shearing off probably saved more expensive parts from failing.

Speaking of that bit of metal, it very well could be the spot weld I put on the pickup. I think the weld didn't penetrate and it eventually flaked off, allowing the pickup to fall out and then got sucked into the oil pump at a later date. Once again, no one to blame but myself because I was the one who tacked it. It's another example of why a person should never get in a hurry when screwing one of these things together.