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Discussion Starter · #1 ·
I am real new to the forums. I have a 1mz-fe [vvti] with a wiped cam bearing on the #1 exhaust cam bearing. The #2 bearing cap is also slightly wiped, but not near as bad as #1. This is the left bank [front head]. The bearing journal has lost a solid .010 and the aluminum under the cam is melted. The symptom was an oil leak out the cam seal. 157K miles.

I went to the local U-Pick-It and purchased a new head. In the process of scouting a good head, I found a 97 Lexus with a cam broken in two at the #2 exhaust bearing cap [left bank], and a 2000 Avalon with a cam broken in two pieces at the #1 exhaust bearing cap [left bank]. On ebay, left bank heads are scarce, while right bank heads are plentiful.

I have seen hundreds of engines at the salvage yard, but never a cam broken in half except on these 1mz-fe engines. I have soured the internet looking for someone who might know why, but found nothing.

The local machine shop said it was the result of oil starvation to those bearings. I need to know why. Have I got a bad oil pump? Has anyone encountered this problem. I cannot go to time and expense of installing a new head just to wipe out the bearings again. I HAVE NOT checked oil pressure yet [the engine is still apart] and the machine shop, whose owner is a Vietnam vet and a friend, suggested I check the pickup tube screen to see if it was sludged up. There is not a low oil pressure light.

The head is clean and not sludged up. The oil has been changed every 3000-4000 miles.
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