2000 tj have thrust plate?

[fsjeep13]

My builder used a comp cam without a thrust plate and I'm not sure if that's why my cam bearings are shot. Am I supposed to have a thrust plate? I don't want this mistake repeated. It's too expensive.

[SilverXJ]

If you are using a comp cam you can't use the thrust plate. You instead use the earlier timing set, the earlier bolt, pin and spring setup. I would recommend replacing the pin and spring with a solid pin and set end play manually.

[CobraMarty]

You have already ruined one set of cam bearings with that non-thrust plate setup. I would go back to the Thrust Plate. You can use the stock cam or get one from JonesCams.com that is reground from a wide lobe, thrust plate core that he can get. Talyn got one from him with specs of 204*I/208*E 0.472"I/0.478"E with 1.6 rockers. IDK the cost or lead time.

[fsjeep13]

What exactly is the earlier timing set? I wonder what I have on there. My timing chain had a lot of slack and I had metal flakes coming off the gears.

[SilverXJ]

This is what the later timing cog looks like, notice the bolt and washer.


This is an earlier double roller setup: with the stock pin and spring setup.


Post a pick of what you have on there now.

[SilverXJ]

You can use the stock cam or get one from JonesCams.com that is reground from a wide lobe,

Just to clarify, the Jones Cam isn't a regrind, that insinuates that it was from an already ground camshaft, not a blank core.

Talyn got one

Wrong forum.

[fsjeep13]

I can get a picture tomorrow. Engine is being pulled because it seems metal flakes from the timing gears ruined the cam bearings so we have to check the whole thing. Could that be caused by the newer style timing set?

[SilverXJ]

You don't have a newer style timing set. That or the Comp cam was never installed. If you have a Comp Cam you have the earlier timing set. The single row chain timing sets have been known to fail. What springs are you running? Doubtful that the shavings ate the bearings. What probably happened is the cam was walking in and out of the block, and that destroyed the bearings. The chain could have been damaged from the walking, or it just failed on its own.

[Knoxes]

You have already ruined one set of cam bearings with that non-thrust plate setup. I would go back to the Thrust Plate. You can use the stock cam or get one from JonesCams.com that is reground from a wide lobe, thrust plate core that he can get. Talyn got one from him with specs of 204*I/208*E 0.472"I/0.478"E with 1.6 rockers. IDK the cost or lead time.

Working on getting a Jones cam right now. I should have costs and lead time info shortly.

[fsjeep13]

So how did the cam walk in the first place? I don't understand what holds the cam in then. Springs were an sbc part number I think.

[CobraMarty]

Cam walk due to the pin and spring setup.
What was the valve spring installed height opening pressure and max pressure at your cam lift? Maybe too high.
I am interested in what Jones has to say.

[Cheromaniac]

The single row chain timing sets have been known to fail.

I can't understand why when the 4.0L engine has always had a single row timing set and that, together with the earlier-style recessed bolt/spring/pin set-up and stock cam, has been known to perform reliably for 200+k miles.
Something else is amiss either with the parts combination or the installation.

[SilverXJ]

1) On a stock engine its a weak stock valve train and camshaft. Upgrade it and it puts more stress on the parts.
2) The pin and spring was not originally in the new engines. It wasn't until a knocking sound was noticed that they added it. That knocking sound is cam walk. AERA even has a document on this.

[fsjeep13]

I looked today and didn't find exactly how it was mounted because its all taken apart. You can see how loose the chain was from the marks on the gears. Cylinder shots were looking at possibly antifreeze leaking into those two cylinders. What a cluster F*ck.

[fsjeep13]

Gear and bearing pics