cribbj said:
Interesting point about the crank walk. We've had a few 2JZ-GTE blocks suffer crank walk, but it was attributed to the mondo clutches with high clamping pressures that the owners were running, and lack of lubrication at startup. Many have "fixed" their crank walk problem by disabling the clutch switch, however the engine was rebuilt in the process, so time will tell whether the problem is truly fixed or not.
Yeah, I disabled my clutch switch as well, since mine is one of the problem years engines. I think that is a major cause for it, but also as you said, a lot of people with heavy pressure plates got it too. However, the amount of completely unmodified engines which walked, some numerous times (the replacement engines walked too), was enough to rule out the pressure plate as the sole cause. I'm running a 2500-lb plate in my car, and I'm fine so far.
Magnus Motorsports tore apart an engine and tested the oil squirters to see what pressure they'd open at. None of them were the same. The range was pretty large, if I remember correctly they were anywhere from 11-40 psi. They also tested more than just four, so it's reasonable to assume that the quality of these squirters in particular is less than optimal.
In previous years, Mitsubishi used a different design which did not need the ball/spring check valve, and very few of those engines have walked. Considering the huge number of people running around with plates anywhere from 2100-3500 lbs, it's a pretty good indication that those valves are where the fault lies.
cribbj said:
Of course the squirters in these blocks "should" have been disassembled and cleaned during the rebuild, so if they were actually the root cause, then that's been fixed too....
Good to have another point of view.
John
While I do agree that they at least should be cleaned, at least in the 4g63's case I think it's best to remove them entirely. Magnus
did clean them before testing, and the results were still erratic. With a tolerance as huge as that, I don't think I'd trust them.
Of course, as I have been saying, most of this applies to only the 4g63. However, I would be extremely cautious about any engine using a ball/spring check valve and I would be VERY interested to see someone test them, and get some data on when they actually open.
EDIT: I was quite a bit off on my numbers. Though 40 psi was mentioned, it wasn't when they were opening (I haven't read this in at least 2 years).
Here is the complete write-up, complete with pictures of the squirters and the block they hacked up. Good stuff.
The pressures are down about 3/4 of the page.