Thrust Plate to Pin and Spring Conversion

[chadillaca]

My 99 Wrangler had a thrust plate design. I purchased a Clegg stroker kit which only has the pin and spring option. My timing cover does have the nipple. My question is, what holds this thing from walking backward besides the cam chain tension and the pin/spring. Will the cam gear rub against the block? I can push the cam gear back until it hits the block with minimal force. What stops it from moving rearward? I don't have my rear cam freeze plug in yet, but also couldn't it rub on that too? Or am I overthinking it and since there is no real reward force, the timing chain will pretty much keep it in place all by itself (well with the pin and spring for the forward motion)?

[eugenebuilt]

The cam is physically able push back through the freeze plug during early assembly before the valve train and timing is assembled.

When fully assembled geometry holds the cam in a tight mechanical loop. The spring and pin help it avoid walking forward while also pushing the cam back gently into the distributor gear angle, also gently pressing the helical cam lobe angle into the slight angle at the bottom of the lifter keeping the cam from walking backwards.

If you haven’t already, look into a different timing set than the stock set for your year. 99+ timing gear sprocket is very different than the earlier sprocket design.

I had this stuff out already so a quick photo below was easy, earlier pin & spring design cam and timing sprocket left (98 and earlier), later thrust plate design cam and timing gear right (99 and later).

IMG_7322.jpeg

A lot of cam bearing failures reported here and other forums. Take a close look at a new grind on earlier style blank on left vs later style stock cam on right.

IMG_7323.jpeg

The earlier style custom grind on left is missing the bevel or chamfer seen on the later style stock cam on bottom. Except for those reusing their original camshaft, most of us likely have an aftermarket cam without this bevel.

I suspect that the sharp edge at the rear of a custom grind may be causing bearing failures due to improper cam installation. Even the slightest drop in angle while that sharp edge is passing through a bearing could cause damage enough to result in catastrophic failure down the road. It’s critical that cam journal surfaces pass perfectly parallel to bearing surfaces during installation.