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3KGT Holy Grail

50K views 166 replies 30 participants last post by  MichaelMR2 
#1 · (Edited)
Found a 3.8l 6G75 Block (4.0l + potential) specifically to fit the 3000GT / Stealth chassis





Found in these.. V77W Pajero



and you'll need one these.. JDM 6G74 DOHC (use everything off this but the block)



P.S- For the ppl who dont know the 6g74/75 block have the same deck height so you'll need most of the gear of this engine to make up added deck height, the 72 dohc gear doesn't fit - check Wrench Monkeys page to get a better understanding of what i mean --- http://wrenchmonkey.com/Webpages/6G74swap.html

and to top it off one of these..

NBF 6g74 4.1L short block - Welcome to the New Racing Generation Forums .

and hey Presto !!!!!!!!
 
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#70 ·
well, I gotta say I'm VERY impressed this thing did not manage to spin a bearing, my 74 had a spun bearing and was in BETTER condition.

Took off one of the head covers and was greeted with this:

Opened up the Pan and the Sludge art continues



anyhoo, the front and back of the blocks are absolutely identical, the sides are a bit all over the place


 
#71 · (Edited)
74 block base (note the orange sump sealing paste)



75 block base


74 block left side


75 block left side


74 block right side


75 block right side


More pictures than you could possibly poke a stick at: Index of /car/74 vs 75/6g75/My V77W6g75

an accumulated collection of bdranks 6g75 from an Eclipse and the work he's done on it:
Index of /car/74 vs 75/bdranck

What I'm doing now is sourcing an oil pump + water pump, they should bolt straight up from a 6g72, then I need to source the brackets listed below and see what's missing on the block/needing adjusting.

Mounting Brackets
-72/74 AC Bracket
-74/74 Upper PS Bracket
-72 Lower PS Bracket/Tensioner
-72 Motor Mount Bracket
-74 Alt Bracket
-72 Rear Motor mount Bracket
-72 Right engine side bracket
-72 Left engine bracket
-72 left and right Gearbox Stays.
 
#72 ·
if I can remember I'll take more photo's of the Eclipse and Pajero Cranks I have, and weight the blocks and cranks to see what the differences are, might also compare the Eclipse block to this one since the eclipse appears to have more bracing.

the block I have seems to have been reconditioned, judging by the half arsed black painting and weird non mitsu gaskets (very very thin rubbish) so I might get the caliper out and see if the bore is still 95mm.

Any requests?
 
#73 ·
Have you tried what BDranck suggested? I know he used the 74 oil pump housing but had it machined so the billet 72 gears fit since they're a little more stout. I would definitely be interested in more info on welding the bosses when available. Are the block and crank weights between the 72 and 75 or are you going to weigh all three?
 
#74 ·
I don't have a 72 to weigh, so maybe someone else can do that one? I will weigh the 74 and 75 blocks and cranks tonight

thankfully I don't need to go through the stuffing around with converting the oil pump like bdrank did either, a 72 oil and water pump will bolt straight up, as will the oil filter hanger.
 
#78 ·
wow. thats going to be crazy! what is your ultimate goal at the end? (4.0L?)

questions:
what is the girdle like compared to the 3.5L girdle? can you have it milled to use the 2nd gen oil pan?
i see on the parts you need that you said a 72 ac compressor bracket... i have a 72 bracket, but would like to get a 74 to just have a direct swap. let me know when you start mocking stuff up how everything pans out. im very curious. i will take lots of pics when i start mocking stuff up on my build.

i assume (as im sure you have) that a 72 oil/water pump will bolt up. you using the montero sr timing belt? or... i guess you are going with mivec...?

helluva build. brings more questions than it does answers at this point hahaha
 
#79 ·
well, Ray said it should be good for 4.2L, not sure at what bore he's talking when it gets further along I'll get both blocks ultrasonically tested to see what they are made of, I'm getting the feeling that your best just boring out a 74..but we'll let the tests do the talking

Going to grab a 72 AC bracket just cause they are easy to get, will then see what needs moving around etc and go from there, let me know if you find a source for a 74 one and I'll get one too :)
will see what I can do about looking over the girdle and rest of things this weekend, I assume it's the same as the 74 but I don't remember my 74 having the crank scavenge thing the same though..
I did dump the 3sx pan on top and it looks like it will fit, again there is still the dip stick and girdle grinding most likely.

The cranks seem identical between my Pajero 75 crank and the Eclipse 75 crank
 
#82 ·
oh no, i dont need anything, youre awesome though for all the documentation!!

i will keep an eye on the thread and progressively keep your mind on its toes ;) i personally dont like the concept of getting bosses welded onto the block... not saying it wont work, just saying i wouldnt want to do it. its gonna be awesome if you get it all to work though. wiring up those mivec heads correctly will be interesting. they flow awesome though!
 
#83 ·
all the 75 blocks I've come across side by side...



Everything I'm finding is ending up here: Index of /car/74 vs 75/6g75

74 crank weighs more (to go with heavier pistons/rods)

75 block weigh's considerably less..BUT when the 380 guys (Australian version of the Diamante?Galant?) weighed their they found that it was heavier than my pajero one.
V77W 75 block is 43.1kg

74 block is 47.1kg

V77W 75 Girdle is 5.6kg
74 girdle is 5.8kg
 
#84 ·
Someone asked about the bearings...not sure who...

the 75 ones have 3 x openings for the oil to go through.

as you can see the block has a large valley cut in it push oil through to those extra openings

nothing to write home about on the girdle side of the bearing though (and I imagine they want this part to stay as large and flat as possible as it takes the big bang.
 
#85 ·
Comparing the oil filter housings..




the gearbox plate fits with no adjustments needed (so far)on the 74


on the 75


all the stock 72 front stuff fits, oil pump (one shown is a 91 so does not clear PS fitting) water pump, front mount, tensioner setup.



the front cover WOULD fit bar the cam's hitting it



I did have a whole heap of girdle comparo pics if anyone wants
 
#87 ·
The Magna guys weighed their block (think I'm going to call it the second generation 75, more or less from 2006+) and it came out at 46kg as opposed to this ones 43, I'm guessing it's due to a fair amount of reinforcing the block bdrank has.

just waiting for some clean front shots of the 75 gen 2 block to see if all the 72 stuff will mount up to it too.
 
#88 ·
well, I measured the bores and wall thicknesses and all that rubbish

here we go

6g75

water passages (widest part) 10mm
edge of bore to inside of block 21mm
edge of block to inside edge of block (thinnest)138mm
water passage to bore ~8mm
water passage to edge of inside of block ~8mm

6g74

water passages (widest part) 12mm
edge of bore to inside of block 23mm
edge of block to inside edge of block (thinnest) 138mm
water passage to bore ~8mm
water passage to edge of inside of block ~8mm

keep in mind none of this is sonic...that will have to be in a few weeks or something :) (probably a month) pics showing my measurements are in the usual spot :)
 
#89 ·
one odd thing...check these pictures, the 75 block has a stepping on the bore side which in theory makes the the bore even thinner just after the top 6 or so mm...wtf?

pix:
75:


74:



unfortunately the 74 is so damn disgusting that I can't see if it has the step too, from what I could see while looking at it there wasn't anything..but weird!

last thing, what are these marks?


 
#91 ·
I can do 74 and 75 but the 74 were pretty badly worn so i can only go off the very edge...

also one of the guys on another forum found the bearing thickness based off lettering stamped into the corner of the block, so i could just scribe this out and tell you off that and the manuals...your call?
 
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