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Autobahn Burner
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1,223 Posts
Discussion Starter · #1 ·
Especially T.F.S. or andy42uk as I've read your posts and you guys know your way around these motors better than anyone.

I am currently in the process of rebuilding my RB25DET, I have a set of 87mm Mahle powerpack pistons set to go in as well as a set of eagle H beam rods.
1) What should my piston clearances be, they didn't send that in the box! A website I went to said .005inch or .127mm. Is that the total clearance? total Bore size 87.127(.0025 Per side) or the clearance to one side(total Bore size 87.254)

2)nd question I am about to buy rod and main bearings, is standard size ok?


3)I wonder how much it would be to post my motor and all parts to you, My mechanic here is pretty good but the closest thing he has done to an RB is rebuiling a nissan patrol rd 28, the blocks look Identical! so I wonder if with differnet pistons, it might work as a stroker kit?

Thanks in advance guys.

Glenn
 

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Punch me.
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9,398 Posts
Hi Mate

Mahle pistons are the best IMHO

5 thou (0.005) sounds a "bit" big for mahle pistons but could be right (JE's are also 5 thou)

this is the total overbore clearance measured .0025 Per side

bearings are graded, you cant just buy a "standard size" set, you must check them first (grade on block and crank)
 

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Here we go again buddy. One rule for one an all that.
 

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Premium Member
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Edited at original poster request ;)
 

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Autobahn Burner
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1,223 Posts
Discussion Starter · #9 ·
Thanks TFS I appreciate the info and the offer!
They are charging me 300 euro to bore and hone the block
and 900 euro to rebuild. The shipping is the only thing then that wouldn't make it finacially viable.

I know you can't advertise so I appreciate the offer,
Mods I asked him if he could do it for me so it technically wasn't advertising, it was my fault:spank: sorry, I'll pm next time.:cheers:
 
G

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Jesus....I was having a laugh, guess as a Mod tho I'm not allowed to try and have a sense of humour.....

DaveGTST - care to explain what your comment meant and who it was directed at?
 

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Autobahn Burner
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1,223 Posts
Discussion Starter · #12 · (Edited)
grigor said:
What's engraved on the top of each piston?
Apart from front, it should have where to measure the piston's diameter (top, mid or bott), the bore clearance, piston type, date or code etc.

here are the numbers engraved on the pistion
RA9603_1.00_2284_03

That is exactly how it appears on the piston including underscores.
I think the 1.00 is for 1mm oversize but am lost on the rest

Thanks for the help guys. You'll be on the christmas list:cheers:
 

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Punch me.
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i dont know where that quote came from but the overbore amount would have to be on top of the largest part of the piston and the piston will normally go up in stages 87, 87.5, 88, 88.5 etc so its 5 thou larger than the largest part of the piston, this is because the piston swells up, the reason we need an overbore at all

so measure the piston with a mic and bore out 5 (4-6?) thou over that
 

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I would contact Mahle and ask exactly what the clearance should be. Different alloys have different expansion co eff's
 
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