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OK What would people classify as acceptable compresion in a nissan 4.2 diesel?
I have just had a vehicle I am looking at checked and it worries me a little.
varies from 360 to 400 psi between all engine has about 240k on it
there is no way I am going to spend big $ on getting a diesel rebuilt so am thinking I might have to revert to my original plan!!
Any advice will be greatly appreciated as I have to make a decision on this soon
I have factory manuals at home, PM me tonight remind me if you want me to check, I'll give ya my mobile #, or could scan in the page maybe and email to you
thanks a lot for that.
This is fucked!!!!
1 diesel guy I spoke to said the motor is way tired at that pressure.
Another one says it is ok but not new. (obviously!!!)
And Gregories says that standard is 2942 kpa which if my calculations are correct (kpa X .145 = PSI) means that the motor is good. The worst is 360 psi which is above the minimum.
There is a fair variation between cylinders which is a problem I guess.
Maybe I just fucken get it and save money on intercooling and shit and when the thing goes bang then I can put in v8 pety. HOPEFULLY A WHILE DOWN THE TRACK!
I fugen hate not being able to afford a nice new gu!!!!!!!!!!!!! lol
I've read in this forum and others that the 4.2 diesels are doing 300,000 without a drama and quite few report 350,000 before any minor niggles appear, so i guess at the worst you'll get another 60,000 out of it before worring about every rattle you hear.
The compressions are ok but I dont like the varyations you listed, seems a tad bit big of a differance for my likeing.
How much white smoke is it blowing on a cold start?
Is it using much oil?
personally I'd use the old saying here.....
When in doubt ............................. back out !!!
[color=blue][size=150][b]And your cry-baby, whinyassed opinion would be.....? [/b][/size][/color]
V8Patrol wrote:I've read in this forum and others that the 4.2 diesels are doing 300,000 without a drama and quite few report 350,000 before any minor niggles appear, so i guess at the worst you'll get another 60,000 out of it before worring about every rattle you hear.
Woop that just joined has ~530,000 on his TD42...
Mine has 300k on it going strong, mates has 580,000 on it still going strong.. Numerous others with 500,000 on them going well, Depends on the history of its servicing.. Shit I think I'd rebuild mine, get another 400,000 out of it would out last me!
I have a 1988 LWB GQ TD42 patrol with 280k on the clock.
At 260k I had ARB Southern install a Dynamic turbo to it.
Heaps of grunt, would spin the 34" simex on a gravel road in 3rd at 70km/h.
Unfortunately I only got 20k out of it before it gave way on the way home from Cape York in August.
It all started with a small rattling sound for 10 seconds before total loss of power and a white smoke trail that would make James Bond jealous.
The poor old car is still sitting in the driveway as my new born baby has savagely altered my budget.
Turbo on GQ diesel -: lots of fun, but like many things in life; "For a short time only"
PS, Does anyone have a CHEAP (but good/OK) 4.2 diesel in Melbourne area? (I would love to get her fired up again!)
When I drove it the other day it was strong. Only small amount of smoke on start up. The motor idles so smooth I was blown away. Heaps smoother than the old NA toyota diesel I had! Is this cause of the turbo???
And that nissan gearbox where have you been all my life!!! so smooth no crunching and scratching!
The car belonged to a mechanic most of its life so I think it has been looked after quite well. Has a pyro gauge on exhaust and all that too. The guys who did the check seemed surprized that it was so dry underneath.(ie absolutely no oil leaks anywhere!)
I am pretty sure it is a shwitzer(spelling?) turbo.
Anyone know what oil pressure is recommended at idle and at 3000?????
I had mine comp tested 6 months ago when it was about 230k and from memory they were all somewhere between 500 to 550. They thought that was good apparently.
Don't know shit about compression so i will refrain from commenting on the one you are looking at ....
At 240,000 its still a baby if its been looked after properly. It MAY have glazed bores possibly due to missed/late oil changes or the wrong type of oil being run. Mine now has 541,000km's on the clock and has only now just started to consume a bit of oil between changes. 1/2 a litre between changes.
I am thinking the same thing. The dude who has owned it for the last 5 months is a younger fella and seems to have no real idea about 4bys. Just bought it cause it looked good prolly. He knows the mechanic who used to own it.
I am going to change and a few things and get it tested again.
I really don't the motor is in bad shape cause it was idling so smooth and sounded good. No leaks whatsoever and seemed to have good power with not much smoke.
I may still sell the motor and turbo though and get a efi v8 cause I have the $ now but if I drive the current motor into the ground then I wont be able to sell it and by then I will have spent the money somewhere else!! I figure I would get reasonable money for a turbo (shwitzer) 4.2 diesel when you normally have to pay at least 3000 for a turbo set up!!!
fatass75 wrote:OK What would people classify as acceptable compresion in a nissan 4.2 diesel? I have just had a vehicle I am looking at checked and it worries me a little.
varies from 360 to 400 psi between all engine has about 240k on it there is no way I am going to spend big $ on getting a diesel rebuilt so am thinking I might have to revert to my original plan!!
Any advice will be greatly appreciated as I have to make a decision on this soon
Variations between cylinders might be a sign of sticky piston rings. It happens, if oil is'nt changed as needed. Another possibility are valves. Not closeing as needed and there you have it. Good mechanic should have the tools and experience, to tell you where the pressure is going:
1. Down to the block through the rings
2: Through the valves
I would suspect piston rings, since I have seen a lot of engines with stuck piston rings, thanks to crappy oil and overheating. What helps is pouring some acetone in to the cylinder (100-150ml or so per cylinder). Let it stay in for the night. Crank your engine with glow plugs still removed, to puff it out at the morning. Oil change is also advised, so do it before the oil change. Sometimes stucked rings get loose and you're happy. Oh and drive it around really hard after that, so the rings may burn loose as well.
If valves are faulty, then just get them done and thats it!
Of course there's the possibility that something is seriously wrong with cylinder walls and pistons. So you never know before you take it open. But these simple steps are worthy to try.
the car belonged to a mechanic most of its life so I think it has been looked after quite well. Has a pyro gauge on exhaust and all that too. The guys who did the check seemed surprized that it was so dry underneath.(ie absolutely no oil leaks anywhere!)
