Toyota 1GR-FE Block & Crankshaft

These engines are showing up a “weakness” in their main bearing and block design.

Problem: We attended a dealership last month to assist with diagnosing unusual engine noises in a late model Hi-Lux V6 petrol engine.
On arrival, a grubby 2009 model sat there with body damage on all four corners, a good dent in the door, and clearly mistreated.
At start-up, the engine was running uneven. I expected to find valve issues when stripped down as it was on LPG.
As the engine temperature came up, so did the low end heavy noise. Too dull for a con rod or piston so I considered main bearings but not prepared to bet on it. It had to come out.
I took the step to buy in a used 3/4 engine as this was a very urgent job and I knew crankshafts were very hard to find.

Cause: When we stripped the used engine down we found spun mains and sigs of poor maintenance. The crank would regrind but the block had a bit of damage.
Then the customer’s engine came in and we found even worse damage from spun mains. The rear cap had collapsed and it would need welding, milling, and then a line bore. The crank will be saved by grinding to -010.
The common element with the two engines was heavy sludge. Clearly, oil change frequency was the start of the problem.
The other part of the problem is that the bearing shells are not notched. The block has been factory machined for notched mains BUT the shells fitted on both engines did not have notched shells. The after-market mains also do not have notches.
Any oil starvation issues leave this design vulnerable to spun mains.

Cure:  We reworked the used engine block and saved it. Ground the crank to -0.010″ to installed clearances. Expect this to be normal for crankshafts out of these blocks. Note also that the main bearing cap bolts stretch. I expect that this is part of the problem as well.