Hi all,

Some of you may have seen my BHG thread where I replaced the head gaskets on both banks, as well as doing some modifications to the block to aid cooling.
I had since left the oil unchanged after putting the engine back in for too long and I guess all the leftover bits that weren't washed out wore out the connecting rod bearings and one eventually spun (or so I think that's the case).

I'm aware the top end of the engine may be a little worn too but I'll have the valve covers off soon to make sure the engine is still worth working on. I pulled it out, dropped the sumps and got all the bearings out (see photo). All were worn badly - no surprise - and no3 had spun.

Like I said, I don't want to pour money into perfecting this engine, I just need to change out the bearings to keep me going a little more, even if it's ~ 10k miles. I checked Rock Auto and they sell some generic bearings for around $10. OEM on Z1 Motorsports is around $17. Not too bad prices but they all have various sizes or "grades". I'm not sure about checking for clearances and such. The journals on the crank shaft all look great apart from the one with bearing deposits.

I've repaired a spun bearing before (Volvo XC90 2.9L TT) by removing spun bearing, sanding down journal to remove bearing deposits and I actually just threw in a used bearing from another engine because I wasn't sure my method would work. But it did and that car ran great for 1000's of miles until I sold it. Now, with my G35, I am replacing all six pairs and I just want some help as to which sort of bearings I should get. Size of the bearing and if it really matters where they come from - OEM or not. Really to tide me over whilst I keep my eye out for a good second hand engine to rebuild and have ready.


I know loads of the engines have suffered low oil due to the general oil burning, various 'OEM' oil leaks, lack of oil pressure gauge and the general high miles they're reaching now. So, any ideas?

In the next few days, probably the weekend, I'll do what I did with the Volvo engine (also was rod no3 of 6) and clean up the Journal. Once it checks out I'll have the bearings on order from the best suggestions of you all.

 

Bump during the day for some answers

 

OMG! I don't even know where to start. I'd start by tearing the entire motor apart and cleaning it. If debris caused that to happen to your rod bearings than there's no telling how much garbage you have stuck in every oil passage and every other bearing in the motor i don't even want to know what the heads look like! Then I'd get a service manual. Those different sized bearings are meant to be matched to the appropriately sized journal. If you don't mic those or at the very least use a plasti gauge on it then your only going to have issues again. People get flamed on here all the time and you wonder why.

 

I'll have the heads checked out this weekend. I probably drove the car about 500 miles since the head gasket repair until this happened. The car already had around 160k miles. The easiest thing would be to polish back the con rod journal fit back new bearings correctly spec'd. Do you think the main bearings would be in as bad condition too? How much slower do they wear? (as they take less load than the con rod bearings).

I'm wondering how far would I get if I polished the journal and threw in new con rod bearings (buy some time to find a used block). Or if I should take out all the timing gear to get the crankshaft out and swap our mains. I should be able to check one side (bottom half) of the main bearings without removing the crankshaft though.........right?