Need some advice with a problem

[Russ Pottenger]

X2 on putting a notch in the bearing.
Slinging a little extra oil on the camshaft isn't going to hurt.

I don't know for sure, but manufactures eliminating the slot in the bearings could be for purely cost reasons.

A while back Clevite was acquired by Mahle and have noticed a slow decline in the quality of their bearings.
Rather than being the best now they are the same as everybody else's.
For example they've recently they've eliminated the CB960P bearing and now replaced it with an aluminum composition bearing identified as CB960A.
Soon to follow because of cost cutting reasons bearings won't be sold individually but in packs of 6 or in the case of eight cylinder engines, packs of 8

It's a shame, but the bean counters are making it harder on us that are more concerned with quality than cost.

[optmaxx]

And just an fyi, King makes the rod bearings with the notch. To make sure that I didn't have any air bubbles, I bought a thermostat with a burping hole on it and the Lisle no spill funnel to make things easier.

[jcsj]

clearance for forged pistons .0025 a little tight? diamond says .005 ic says .0035 to .005 depending on use.

[SilverXJ]

It is definitely on the low end of the tight side

[jcsj]

interesting, summit site list ic944 as t-6 2618 aluminum, that's where i came up with .0035 to .005.If they are 4032 alloy, your chart fits.A lot of piston makers will get down to .003 with the 4032 alloy.

[SilverXJ]

The first run of 944s were 2618. After that they were 4032.

[jcsj]

thank you.at .0025 to .003 should quiet for forged pistons.you can hear my diamond 's rattle with .005.

[jsawduste]

you can hear my diamond 's rattle with .005.

Diamonds rattle but they get stuck.

+.080 Diamonds swinging on Eagles with SBC FF pins. 10 years of abuse.

[SilverXJ]

thank you.at .0025 to .003 should quiet for forged pistons.you can hear my diamond 's rattle with .005.

It might be quiet, but it might also lead to problems like OP's (not saying that that is his problem). I have .0045" on my KB944s. They make a bit of noise for the first 2 minutes from a dead winter cold. After that they are quiet. In the summer you don't even hear them.

[amceaglesx4]

Welcome to my knocking world. Im having a shop look at mine tomorrow. Comp 68-232-4 cam with a weird knock. Ill let you know what he finds. Does your knock sound go away when you let go of the gas pedal ? Say youre at 3g rpm and let go of the gas. Thats my situation.

[Raggedyman]

thank you.at .0025 to .003 should quiet for forged pistons.you can hear my diamond 's rattle with .005.

It might be quiet, but it might also lead to problems like OP's (not saying that that is his problem). I have .0045" on my KB944s. They make a bit of noise for the first 2 minutes from a dead winter cold. After that they are quiet. In the summer you don't even hear them.

I thought about that as well but all cylinders are nearly exactly the same. And I'm talking less than .0005" generally.

Welcome to my knocking world. Im having a shop look at mine tomorrow. Comp 68-232-4 cam with a weird knock. Ill let you know what he finds. Does your knock sound go away when you let go of the gas pedal ? Say youre at 3g rpm and let go of the gas. Thats my situation.

No mine doesn't. Once mine starts to knock, it never stops. It's much less perceptible at higher rpms while driving, but as soon as I come to idle it's there every time. However, once it starts to knock I tend to get it home as soon as I can. My knock is definitely the piston though.....just need to figure out the root cause.

I just did a quick check on my injectors and none are leaking or sticking. Each one opens and closes nicely with no noticeable issues. I'm gonna have to start leaning towards overheating due to the possible air bubble issue.

[Raggedyman]

Thinking along the lines of the air bubble possibility, I checked my block and I'm right at 4 degrees high to the front. Does that seem higher than normal? The floor and frame are level and I don't have a trans drop kit. I'm using a Cherokee block with my old 4.2 mounts.

[Raggedyman]

Update:

Engine is all reassembled with just over 100 miles on it. I drove it in to work tonite and so far no issues with starting or knocking.

Some of the things I did: notched the rod bearing on #1, bled the air out of the block at the gauge temperature sensor at the rear of the block, switched back to the wrangler water pump so I can run a mechanical fan, ditched the electrical fan but left the wiring in place for future use just in case. I had to run a water pump pulley from a 2000 grand cherokee to get the belt where it needs to be, and I ran the cherokee mechanical fan because I didn't have a wrangler fan. The cherokee fan might be smaller but has more vanes and it definitely moves some air.

Temperature readings on the passenger side of the block show about 8-10 degrees cooler around #1, and there's a definite drop in temp at the header for #1. Altogether I'm happy so far but only time will tell.

[SilverXJ]

Temperature readings on the passenger side of the block show about 8-10 degrees cooler around #1, and there's a definite drop in temp at the header for #1. Altogether I'm happy so far but only time will tell.

Its also at the very front of the block, which will naturally get the most cooling on all accounts.

[Raggedyman]

Well it's got a bit over 500 miles now and it's running strong like a champ....

I really can't believe the difference in power compared to my '01 TJ with the 4.0.....my butt dyno is screaming awesome so I think I'm gonna try to find a dyno shop just to see what it's putting down.

Peace!