Offroad-Express

I have read a lot of info on the web re Silver top vs Black top...this is my take so far.
I can not find any hard facts...eg: info Nissan themselves have released as opposed to "mechanics who have worked on Nissans for 20yrs" (hard to verify) that proves one is better than the other. Therefore I have pigeon holed the topic as "train spotter prattle". Am I wrong? ...or does anyone have something to add that helps.
Cheers VW

aaaarrrhhh this again! there are a few differences, black tops are weaker but my black top one is the fastest i have ever owned and its my ninth safari. the differences are lighter internals, hence why they are better reving.. i am sure someone better qualified than me will be along with all the tech data. still bloody good engines though, i love mine, alot better to drive on a daily basis than my sluggish silvertop. i believe they cant run high boost like the silvertops with aftermarket turbos.

sorry i'm going to wade into this with the specs.

GU turbo black top, has the turbo oil drain cast into the block. 28mm gudgeons, different bolt pattern on the back of the crank. Vacuum pump driving off timing gear below fuel pump.
Good for 900+ Nm if you build them properly,precombustion chamber ports are larger.

Compression ratio 22.5:1
Engine number starts with TD42nnnnnT

Silver top (which dont all have silver rocker covers) Build date to somewhere around August 1995. Vacuum pump on back of alternator. Good for 650-700 Nm at 30 psi in short bursts if you watch your gauges with standard internals. 30mm gudgeons. "small/standard" back end on crankshaft. small precombustion chamber ports. Compression ratio 22.7:1. I've just blown one of these up being an idiot and the block and liners have disintegrated between #3 and #4. I'd keep it to under 650Nm with these. Engine number starts with TD42nnnnn

Good for mild boost only:
non turbo GQ and GU "black tops" built post august 1995 approx. Vac pump driven off timing gear below fuel pump. No turbo drain cast into block, "small/standard" back end on crankshaft. 28mm gudgeons.
12 psi non intercooled, 15psi intercooled, Thou Shalt Not Pass this boost level. reasonably lively engine due to the lower mass pistons, especially if you use 4.375 diffs. small precomb chamber ports. compression ratio 22.7:1
the pick of the bunch for moderate applications because everyone wants the "strong" ones and the lower reciprocating mass helps performance.

that is the most useful post I've read in a while. I've even had arguments with people over whether or not some Safaris run two identical oil filters and some run two different filters. Book marking this one. Cheers Crash!

Edit: I take that back

Re: the different oil filters.

Anyone can correct me if Im wrong.

I believe that if you have 2 different filters that your engine has the Emmisions pipes that run around the back of the motor. (Exhaust to intake)

Same oil filters means you dont have the Emmision pipes.

Also cheers Crash I have always wanted to know the difference in motors aswell.

Cheers
Ray

You mean to say I have EGR? (two different filters)
I was under the impression some models came with a pre filter setup.

if your truck has the two different filters then yes it has the prefilter.
Afaik the "silver top" motors also have an oil gallery that squirts the piston skirt from underneath to aid with cooling. Think this is one of the main reasons people prefer them for turbo applications as the piston doesn't get as hot therefore expanding and pushing hard on the bores which causes them to disentergrate(the pistons)

Crashes post is certainly very good. I can put some of those specs to good use

All so i think that the reason the block with the larger gudgeon pins = is weak purely because of that fact, that they take meat away from the piston and top of the conrod and make them more susceptible to distortion and heat saturation which is where it all starts.

I'd recommend if any of you guys with these engines and are thinking about rebuilding that you source the conrods and pistons that are 28mm from the GU turbo black top.

In this case more meat on the body of the piston the better

How much info do you want?

6 pages here including crash bandicoots cut and paste

http://www.patrol4x4.com/forum/nissan-p ... top-68546/

aw noooo bandicoot.

Two diffs. some people can't use google. but i won't hold that against them

eh?....nah I didn't mean it like that mate

It's a good few pages of info and I found your exerpt when looking through it. I had it bookmarked for future reference so knew where to find the info .

But the post below that about the gudgeon pin diameter is to take note of.

Thanks for the replies...really useful info...Cheers!

Thanks guys...I really appreciate the clarification