Cam Bearing Shells

[chuckbrush]

After replacing an intake cam, 2ZRFE 1.8L., I noticed that the lower shell was slightly out of place and drifted it flush with a nylon dowel, then I started wondering what keeps the cam shells from turning, ie. what locks them in place... Do they have little tabs like a rod bearing, a pin perhaps, or does the cam cap just squeeze down on them and lock them in place? If they are located with little tabs I will have to disassemble everything, loosen all the cam caps and retorque so I'm in earnest about finding someone who has seen what the backside of a cam shell looks like and what locates it.

Thanks,

Chuck

 

[Donabed Kopoian]

Usually they do have a tab, similar to main bearings on a crankshaft or rod bearings. One of the nice things about OHC engines. On OHV engines, changing camshaft bearings was a pain.

Out of curiosity, when you replaced the camshaft, did you plastigauge it with the caps torqued to ensure that everything was in tolerance? Did you apply oil or assembly lube to the camshaft?

 

[chuckbrush]

Thanks for the prompt responce. I'm in Warner Springs just inland from you. The engine isn't worn, only 42,000 miles on it. Yes assembly lube and oil. Specificly, I need to know what the lower shell on 2ZR-FE looks like and if it has any locating tabs on it. Have you had one of these appart lately?

Chuck

 

[Donabed Kopoian]

It has been a long while since I have torn down an engine.

I can't find a picture of the camshaft bearing for a 2ZR-FE to save my life; however, the 1ZZ-FE camshaft bearings don't have a tab (guess Toyota engineers put a lot of faith in tight-tolerance machining to keep them in place), so chances are, the 2ZR-FE lacks them as well.

 

[chuckbrush]

I'm crossing my fingers....... Ordered a bottom shell, seperate part numbers for top and bottom, just to see what the darn thing looks like. I couldn't find a Google image of one & nothing on EBay either. I'll know tomorrow as Toyota called and said it was in. We'll all know tomorrow how these things are held in place. My hats off to Toyota if they can consistantly make them .0005 oversized on the OD and then sell the part (actually 1/2 the part) for $7.00 ($4.00 online)

Chuck

 

[Donabed Kopoian]

Yeah, take a picture if you can, that would be awesome.

Just out of curiosity, why did the cam need to be replaced?

 

[chuckbrush]

I haven't figured out how to post a photo, however, should someone stumble accross ths post wondering........ The lower cam bearing shell has no tabs, pin holes, or any way of locating it. It is just a plain bearing shell, no holes, grooves, or anything, front or back.

I had some cam worms, not too many, but I didn't want to risk them spreading to the crank or oil pump. Nasty little bastards, they only eat the high carbon parts.

Concurrently, there was a problem with the intake cam sprocket that caused a rattle during a cold start. Common with these engines I'm told, and I wanted to fix that also.

Chuck

 

[Donabed Kopoian]

My girl has the noise during cold start (and only when it is 55° F or below outside). I guess that one is a starter noise, where-as there is a similar noise but it happens on every cold start-up irrelevant of the temperature, and I hear it gets bad to the point where it rattles constantly when it is the cam timing sprocket.

Seems like some did the cam sprocket and it went away, others changed the starter and it went away.

 

[chuckbrush]

Mine appears to have been the sprocket as the noise is gone, so far. I thought it best to address this problem sooner than later as waiting is also putting extra wear and tear on the tensioner, guides, and chain.

Mine was intermittent on cold start and always there after the car sat for 45 min. and the oil drained out of the advance-retard camgear gizmo. My theory is the problem is with the camgear locking mechanism which is supposed to engauge when the engine is stopped, but doesn't on the defective units.

The problem is evidently common enough for Dorman to make a replacement cam gear which is reasonably priced. I used a genuine Toyota part as I didn't want to expariment on the wife's car, but a friend used the Dorman part and it fixed the problem.