Outer Limits 4x4 Board

So wheres the photos Nick?

For those that dont know, Woop is rebuildin his TD42.

He removed the head the other day, and with 550,000klms on the clock, you can still see the cross hatching from new in the bores!

Shows what a good maintanance routine does for you..
oil and filters every 5000klms using Shell Rimula X.

Sorry Bruce,

It got too cold outside tonight to take pics, so will take some tomorrow and post asap. Shop rang today to advise that CYL head needs a couple of new Precombustion chambers but other than that was fault free. No cracks could be found anywhere, which i was pretty happy with considering the KM's. I'm getting them though to put new valve guides and seals in though whilst its there.

Liners still have crosshatch clearly visible and suprisingly again with KM's, there seems to be no ridge at the top of the liners that i can feel. But i'll be getting out the bore guage out to find out just how much wear there actually is. Pics soon.

Nick

OK Nick..
Wheres the GQ 4.2 Diesel rebuid up to know??

Bazzle

Nothing much else yet. Brought some 120mm aluminium rod with the plan being to get it turned down to being an interference fit in the bore so i can press the liners out with my press at home. Checked all the bores with the bore guage today after calibrating it. The bores measured to being juuust under the maximum allowable limit. So will install new liners/pistons anyway as next size up piston would be too tight.

So thats it for the moment. will post pics soon.

Nick

Measuring the Cylinder bores using a Bore Guage. Dial guage was first calibrated to be zero @ 96mm using a micrometer. Bores were then measured 20mm from top.

Measuring the bores. Very fiddly and time-consuming

Nick

Oversize measurement. This was the deviation from the zero'd setting

Close-up of bore--walls sprayed with RP7 to keep rust at bay

oh yeah, there's a view I've come to know & love!

Looks good Nick
Just put new rings and bearings in and away you go.

Bazzle

Red Rover wrote:oh yeah, there's a view I've come to know & love!

Thats how worn it is after 550,000klms! I would gues 1,000,000 would be easily achieved...

WOOHOO!!!

After seein the new GU photos, the GQ will have to last another 40 yrs!

In regards to the rebuild -

conrod bolts - do u replace them? or do u use the existing bolts??

Just read on another thread - a bolt let go on a v8 causin the engine to basically fall apart - anyone shed some light on that...

Oh yer im doin my own rebuild soon..will take a piccy

Looks horn!!!

When tightening the cylinder head bolts, they need to be done up gradually in 3 stages stages. If this is done, they can be re-used. The Nissan factory manual makes no mention of requring to re-new the bolts.

Nick

yeah, just put new rings & bearings in mine, took the ridge off with the ridge remover, not that it was that bad except for no. 4, but it came up pretty good. Runs like a bought one now. Uses no oil which is good. Rings slowly starting to bed in. Yep if the clearances aren't too dramatic that's what i would do, just re ring it with new bearings to freshen it up. good luck with it.

cheers

GQ wrote:Just read on another thread - a bolt let go on a v8 causin the engine to basically fall apart - anyone shed some light on that..

It happens when the rebuilders make basic mistakes ..... usually lack of experiance is the only true cause.

In the example you are queering the motor had sized on a previous occasion, as to whether the rebuilder was told of this I'm unsure but he made several other mistakes as listed in the "OWNED" thread started by myself in the general chitchat section.

A sized motor usually results in weakened conrods, weakened conrodbolts, and other damage that is usually obvious to the naked eye.
In this example the engine was rebuilt without the rods being checked, the rod bolts being replaced and the original nuts being used.
.... a kewl recipie for total disaster which is what happened unfortunately.

Usually the nuts fail or become loose and then its just a question of when it lets go..... The conrod bolts wernt replaced either and remembering that the motor had sized previously this meant that the bolts had nodoubt been stretched.... they had been stretched when the motor sized and then stressed again when retentioned during the rebuild..... not a good combonation.

when rebuilding a motor ALWAYS replace the conrod nuts/bolts.... this rule isnt just for V8 engines either although they tend to break them easier in a rebuilt situation compared to other engines.

From what I have seen of this motor I asume it was simply refreshed with new bits and I think I am safe to say it wasnt done with any true knowlege of rebuilding motors .......especially V8's.

Anyone can pull a motor apart and replace the various bits that require changing without any true understanding of what they are doing.... a few years of experiance later and most ppl know what really works and what is really involved.........

Backyard mechanic = backyard warranty.

Kingy

Thanks kingy - pretty much summed it all up for me