I just got an e-mail from another cam company that I had 'queried' a long while back and they have a roller cam blank that has a racer brown profile on it, but they say it has narrow lobes for use with the racer brown straddle type lifter....

This doesn't sound like a roller cam so much to me...and I've seen several types of lifters in cam articles, but never heard of a straddle type lifter...

Anybody in the 'know' have a good explanation of WTH this is?

thanks,

-D.Idiot]

The lifter has extentions that ride the side of the cam lobes to keep the lifter from rotating, they don't use the blade type anti rotater between two lifters

Thanks.

I can see why that design isn't covered anymore since any minute cam walk would cause a problem...

interesting...

-D.Idiot

Not to mention that small base circle + loose lash = disaster.

Straddle type lifters are not a good option for a Slant.
In concept, they do solve the issue we have with vary little room for the lifter's anti-rotation bars. (tie bars)

The bad news, this design makes for a narrow roller wheel and lobe that is subject to early failure. Also, (as noted) you need a big base circle on a small shaft diameter so there are walls for the lifter to follow. The SL6 does not allow for larger cam lobes (cam bearings are kinda small) and we need big shafts diameters to keep that long cam ridged.
DD

In the early 80s, I bought a 340 W2 motor that had the Racer Brown straddle roller lifters. It had about 100 passes when I bought it. I put another 200 on before I sold it. The buyer moved from the area about a year later so I never knew how long the lifters could go before rebuild (if they were rebuildable).
The base circle wasn't any smaller but the shaft was, to clear the lifter 'legs'.
To get rid of the tie-bar, racers now use a lifter that has a keyed slot in it. A bushing with a key(like a woodruff key) is installed in the block, the key intersects the slot in the lifter keeping it from rotating. It's an expensive set up.
Anyway, the straddle roller lifters were made by the original Racer Brown in CA. The current RB has been in MD for the last 20+ years and no longer carry these type roller cam and lifters.

Cecil

Here's the mail I got and I think I'll pass on it...

I got more details on the 225 roller cam. It was originally made to use Racer Brown straddle type lifters so it has narrow lobes. They are .375 wide. You can use standard lifters. The cam is roughed in to a 258 duration @.050 with .350 lift. Body diameter is .900.


I see the stock /6 cam in my garage has a lobe that's almost .619" wide, with a 1.4" base circle (or somewhere there abouts with 100K on it)...

I'm very leary about using a solid roller lifter on this cam if the 'path' is only 3/8" wide.... Not really sure how much flex and minute amounts of walk would affect it...


At least the guy got back to me, much better than the other cam companies that probably sat back and laughed at the e-mail in their box....

I was preferring to envision something more along the lines of the base circle we have on the regular flat tappet cam, I already have a lift in mind along with some specs that aren't really radical...

Well, if the magic slant six fairy suddenly comes up with a better solution and plants it in my e-mail box, I'll let you guys know...

-D.Idiot