Original Bore, Pistons And Compression Ratio Rb25det

[h2k]

I've searched the forums but found to many different answers. I'm doing a rebuild of my RB25DET wich was in a R33 s1. My piston in syl1 actually cracked between the piston rings and i got marks inside the sylinder wall so I have to have it bored up to oversize. So Im shopping for new forged pistons and conrods. I also need a new headgasket to suit the new bore.

Now I have been browsing trough nengun and greenline and found that Tomei supplies bore 87mm and 88mm headgaskets to my RB25DET in heights of 1.2mm, 1.5mm and 1.8mm.

What is the original bore on the RB25DET ? Cuz I need to order pistons that are slightly larger so I can get my bottom end bored out according to the them.

Do you know any other good suppliers to forged pistons and conrods?

Nengun charge 1203 USD for pistons and 1073 USD for rods from the brand Tomei.

Greenline is slightly more expensive for the same Tomei parts.

JE can custom make forged pistons to me after whatever compression rating I want and they charge 1283 USD for pistons and 1395 USD for rods.

Now I am on a tight budget so I want to get away cheap.

I allready have bought a stainless header, xspower super T70 turbo, external 38mm wastegate, 800cc inj, PowerFC with Q45 afm, FMIC, airfilter, 3" exaust and are planning to mildly port and polish my engine top and fit it with tomei poncam set.

Does conrods from a RB26DETT fit bolton to my RB25DET crank with std bearings?

Any good suggestions to what should get? I know I have to go oversize on the bore and get the bottom end and top machined.

If anyone is interested I have a rebuild thread in a norwegian forum, but with lots of pics:

RB25DET rebuild thread

[Abo Bob]

Standard bore is 86mm.

I would use a stock thickness headgasket (1mm) and get your desired compression ratio by machining the head to suit. You need to decide on what CR you want. Cometic make a good quality hrad gasket which is cheaper than most.

RB26/GTR rods do indeed fit and a good cheap upgrade.

We can usually get pistons for about $1300AUS or less. I like Wiseco but there are several other brands that are good.

[sinistaGTR]

if your on a budget mate, why dont you get a cometic head gasket, and dont buy tomei, i think a guy spandex on ns.com can do arias for bout 1100. dont forget thins like gasket set, timing belt, idler/tensioner (i have just learnt bout that as im rebuilding mine atm lol), and be very careful of your t70 i had one and my turbo and engine blew at the same time......

[al_r33]

I was aware that a Std r33 s1 rb25 head gasket was 1.2mm! Is this true or not?

[RS500]

h2k,

if you're after a cheaper option regarding pistons, this could interest u.

http://www.aclperformance.com.au/NissanRB2...rgedPistons.htm

i'm not too sure but apparently, their forged pistons are made by ROSS, although i find that strange given that ACL are owned by Mahle.

btw, they also make oversized pistons.

good luck

[sinistaGTR]

unique autosports sell these i rang them up and apparently there very good pistons

[h2k]

I was aware that a Std r33 s1 rb25 head gasket was 1.2mm! Is this true or not?

I think I've read it's 1,318mm.

I'm not after the cheapest pistons, but the best value for money. Since it's a major upgrade I want it to be good. The JE pistons for 1283 USD has:

-Total-Seal Gapless rings

-High Heat Ceramic Coated crowns and Moly coated

skirts

-Contact Reduction Grooves

Now I don't know what this means but it sounds great

And I can't find similar specs on the other brands of forgies, are they just crap-talk?

And I can't seem to find a ACL seller with price quotes :\

Edited September 28, 2006 by h2k

[`nigno]

Look at Horsepowerinabox.com, they have some decent priced pistons and rods and provide a few different brands (Eagle, Arias and CP from memory) Aussie company all prices in AUD and ship immediately.

[discopotato03]

Depending on what static CR you want possibly first oversize Nissan RB26 pistons rods and crank ?

A few more cubic inches never hurts and RB26 pistons almost certainly best from the factory . Probably best bang for buck .

Cheers A .

[sinistaGTR]

MR331307 can do acl at a very good price thats who im getting mine through or spandex can do arias for 1090 on ns.com his webpage is www.midnightmods.com.au, you can get cheaper and same quality mate.

[[200]]

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Edited October 2, 2006 by [200]

[Spoolup]

spool rb25/26 forged 4340 h beam rods with arp2000 rod bolts are $750

arias forged psitons with rings are $1190

[h2k]

As I am rebuilding my RB25DET engine after a piston crack I have searched for new forged pistons. I am going to bore up my engine to oversize since I have wearmarks inside one of my sylinders.

So I have checked the manufactors homepage about technical data on their pistons, but they do not all supply the same info. And they use different names on their coatings on parts. But here is the comparison I made, with some missing info on some brands:

So far the Wiseco pistons come out very well compared to bang for buck.

If you know of any data I should input or change please PM me.

[h2k]

I also made a conrod comparison, if you know more brands with technical data sheets let me know and I'll fill them in.

[sinistaGTR]

Interesting mate,

there doesnt seem to be much different between the pistons, it just seems you have more info on wiseco than any lol. With the ACls does any one know how bad the skirt coating affects them....and where can you get wisecos for that price please inform me just interested lol.

[h2k]

Interesting mate,

there doesnt seem to be much different between the pistons, it just seems you have more info on wiseco than any lol. With the ACls does any one know how bad the skirt coating affects them....and where can you get wisecos for that price please inform me just interested lol.

The wisecos can be bought on Wiseco Online but I actually found them even cheaper on a ebay shop: http://cgi.ebay.com/ebaymotors/Nissan-RB25...sspagenameZWD1V

The product nr matches the Wiseco catalogue and datasheet I have used for the comparison.

[ookami]

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Edited October 3, 2006 by ookami