1996 and newer cam

[dwg86]

Has anyone looked into having a stock 1996 and newer cam reground into more of a performance cam? I know the base circle would get smaller, which would require longer pushrods, but decking the block to get a better quench would offset the smaller base circle. You could also use a 1.7 rocker ratio to get a larger lift, if needed. The only downside...they dont make a double roller for the newer style camshaft.

[Plechtan]

I don't know about the grinding, but it looks like you could bore out a Ford 351C gear to work on the newer cam. If you look in the Cloyes performance catalog, you will see that they use the same chain for the 351C and the 4.0. The 351C has a smaller hole than the Jeep sprocket, so it could be bored out. You would have to figure out the key, I think you could broach a keyway in the sprocket, then make a key that would fit into the cam.

It would be expensive, you would have to purchase the Jeep and the ford timing set and throw half of each away, then machine the gear. Maybe Cloyes will sell you the gears without them being a set.

You could also go the other way, grind down the stub shaft on the front of the cam and put a drive pin in it to match up with the 35C sprocket. Since they would be grinding the cam anyway, they would only have to grind one more surface.

[TurboTom]

I am looking into this now. I want to run the late cam due to the retainer.
May have some more info tomorrow.

[Plechtan]

Here is what i know, If you would like to use a 351C gear on a late model cam, you will either have to grind the stub shaft down on the front of the cam to .8750 diameter and drill a 5/16 pin hole in the front of the cam. It should not be hardened in that area, so it should not be too difficult. The other option is to open up the cam gear to 1.0625 ( 1 1/16) and broach a keyway into it. you will have to make a special key, but it should not take long with a dremel or die grinder. The gear needs to have .1 removed from the surface on the back that touches the cam face. Then a 1.415 diameter boss .157 deep needs to be machined on the back of the gear. so the boss will have a .10625 id and 1.415 od and stick up from the thrust surface 0.157 Now the face of the gear need to be .650 from the rear face that touches the front of the cam. The whole face does not need to be machined, only the part where the bolt and washer go.

If you have a newer cam, i like the 2nd method because you do not modify the cam at all, just the gear.

If you have an older cam, thing will get a little more tricky. If you have newer block, then you will already have a thrust plate, if you have an older block, you can drill it and put a thrust plate on it. The older cam will be 1/4" tool long. The only thing i can think to do is to take it to a machine shop and have them grind or machine down this extra 1/4" to a 1.650 diameter. Redrill the 1/4" pin hole to 5/16. Now the thrust plate is .156 thick, and you need .001 or more clearance. So the 351C gear has to have .257" removed from the face that touches the cam. ( .1 from above plus the plate clearance.157). now we will have .093 of the cam sticking out of the thrust plate, so a recess has to be machined into the gear 1.650 in diameter and .093 deep. This will locate the gear radially. The front of the gear will probably need to be counterbored .1 to .125 for the bolt and washer. You will have to open up the hole in the jeep thrust plate to at least 1.655 to clear the 5/16 drive pin.

Locating the gear on a .093 step is not the best, but the factory gears are aluminum or even pot metal. Hopefully the gears you are putting on are billet steel, so i think they should hold up just fine.

If you wanted to keep the stock old style cam, the 351C gear is about .050 short on material. You could machine 2" diameter recess .2" deep into the rear face of the gear and use a .050 bronze washer or a needle thrust bearing. this would give you the .250 spacing necessary. You would then install the spring and pin in the bolt as normal. the only other issue is that the 351C gear has a hole for a 5/16 pin and the jeep uses a 1/4" pin. you could make a step pin or use excentric bushings to adjust your timing.