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I could never get a straight answer about whether the Comp Cam 31-442-8, a retrofit hydraulic roller with small base circle for old SBF blocks, is made of steel and therefore require a steel distributor gear, or does it need to be used with a plain cast iron gear. So I've run it with a cast iron gear for a few months, and see a wear pattern on it. I tried installing a steel gear from an EFI distributor used with stock Ford steel cam, but the fit was too loose, and the engine would stumble above 3000 rpm. I also compared the pattern on the gear of an EFI distributor that's been run on a stock Ford steel cam.
Does the pattern on the cast iron gear look too worn? If so I will have to switch to a steel gear. Cast gear on Comp Cams 31-442-8 shaft EFI steel gear on Comp Cams 32-442-8 EFI distributor from stock Ford steel cam.
I'm no expert but from what I understand is that Ford roller cams require a steel gear. I have a 87 5.0 with a roller Comp Cam & using a 85 stock distributor (DSII) with a steel gear.
Thanks Moejr, I know stock type roller cams and their replacements are steel, so need a steel distributor gear. But the cam I'm using is Comp's retrofit roller cam for older engines, and they never gave me a straight answer as to whether it was steel or cast, or whether I needed a steel or cast distributor gear to work with it. That's why I'm resorting to looking at the wear patterns.
What year motor for the roller upgrade? Did the swap give you any problems? I had a old 70 302 and was thinking of a roller cam swap but scraped it and used the 5.0 for my project.
1968 block. I did the conversion with one of Comp's small base circle cams, a set of Ford stock roller lifters, dog bones, and spider from the salvage yard. I had to get new pushrods, which Comp spec'd at 6.4". I tried a couple other sizes, and it turned out 6.4" provided the best (though not perfect) pattern on the valve stem. I had to shim the rocker pedestals a little in order to get the proper lifter preload.
dont know if you got your answer, but here is excerpt from article below... it starts about half way down ..One of the most confusing aspects of converting to a roller cam in an early non-roller application is that of the distributor gear material, and what material is compatible with what cam. More confusion ensues when you consider that even within one manufacturer (like Comp Cams), there can be several different cam gear requirements depending upon the roller cam line being discussed. Roller Camshaft Conversions Engine Upgrade - Rockin’ And Rollin’
Hey Torq, thanks so much for that reference! It is the first time I see a definitive description of what I have, a -8 Comp Cam shaft, with Selective Austempered Ductile Iron. So this means I'm OK using the cast iron gear as I am now, and should not have tried the steel gear.
glad it helped, I wanted to know also, heard/seen a few too many horror stories about the composite gear they recommend, could be like everything else luck of the draw, and with Murphy taken up residence, I'm not banking on him leaving anytime soon.
So this means I'm OK using the cast iron gear as I am now, and should not have tried the steel gear.
I'm not sure how you came to that conclusion. If we boil it down to the very basics, if you are seeing actual wear on the drive gear after only a short period of use then you have a problem, these parts should last indefinitely with minimal wear. IMO you should be using a steel distributor gear but there may be something else you have overlooked, you can't assume that the hole in the distributor where drift pin goes is in the correct spot for your new gear. Just like when setting up a differential you need to experiment with gear mesh on these two parts to get a good pattern, that involves moving the distributor gear up or down slightly and once you get a good pattern drill a new hole for the drift pin.
I drew my conclusion from what the article stated:
"...Comp Cams, use a ductile-iron cam core that is austempered on the lobes to harden just the lobes for the roller tappets, leaving the cam gear area as the standard ductile iron and compatible with iron gears."
in reference to the -8 cam I have.
I understand about the need for proper gear setup, but how would I do that with a cam and distributor gear set? I might imagine using the same white grease I used to mark a ring and pinion set, but to stabilize the dist gear on the shaft so I could turn it under load to get a pattern, I'd have to fasten it to the shaft somehow, like with a pin. Would this be the SOP anytime someone needs to replace a cam or distributor?
In this case, both are new, so I hope they wear into each other, without one chewing the other up. The first oil change shortly after initial start up did not show any metal filings on the magnetic drain plug. The second oil change is coming up soon, so I'll check again.
Well that is new and makes we wonder how durable it is compared to a steel cam, but if that is the case then yeah cast iron should be fine. But that still leaves the gear mesh pattern to verify, the gear should be relatively snug on the shaft so you should be able to put in on without a pin and rotate the motor through a cycle or two by hand to produce a contact pattern.
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