Which 84mm BMW pistons and what's needed to make them work?

Digit Riaan · Post by **Digit Riaan** » Wed Feb 15, 2012 9:58 am

Apart for the valve cuts...For a tall-block n/a 16v?

Post by **panic-mechanic** » Wed Feb 15, 2012 12:17 pm

Apparently 328 e36.

Digit Riaan · Post by **Digit Riaan** » Wed Feb 15, 2012 12:38 pm

panic-mechanic wrote:Apparently 328 e36.

Thanks Stephan.

From what I can see on the KS Electronic Catalogue it has a compression height of 32.7mm vs ABF at 29.8mm and a 22mm pin vs 21mm for ABF...so I assume that's what needs machining.

Donavan · Post by **Donavan** » Thu Feb 16, 2012 11:19 am

PM marunu (excuse the spelling) he will be able to tell you.

Digit Riaan · Post by **Digit Riaan** » Thu Feb 16, 2012 11:28 am

Donavan wrote:PM marunu (excuse the spelling) he will be able to tell you.

Thanks, did.

I'm leaning towards the Nissan CA18 pitons at the moment...my block is 83mm and I do not really want to go 84mm.

Solo786 · Post by **Solo786** » Thu Feb 16, 2012 12:34 pm

Are you trying to build a 2.1?

Digit Riaan · Post by **Digit Riaan** » Thu Feb 16, 2012 1:51 pm

Solo786 wrote:Are you trying to build a 2.1?

No, 2L...

CRASH_IT · Post by **CRASH_IT** » Thu Feb 16, 2012 3:06 pm

whats the benefits of doin this? i mean you increasing capacity not even 100cc.

Abnormal · Post by **Abnormal** » Thu Feb 16, 2012 4:07 pm

every little bit adds up

Digit Riaan · Post by **Digit Riaan** » Thu Feb 16, 2012 4:21 pm

CRASH_IT wrote:whats the benefits of doin this? i mean you increasing capacity not even 100cc.

I'm not doing it to gain, I'm going from turbo bottom-end to n/a. KS 16v n/a are more than R4k if you can get, the BMW and Nissan pistons are less than R1.5k...83mm is standard on the Nissans and 84mm on the BMW ones.

Wit Ark · Post by **Wit Ark** » Thu Feb 16, 2012 9:06 pm

I had a discussion with sarel the other day regarding this, if memory serves i recall compression ratio's as high as 14-1 with the nissan pistons fitted

Post by **panic-mechanic** » Fri Feb 17, 2012 7:38 am

It depends on which nissan piston you are talking about wit ark. There is a very nice piston from the CA 18 that will not bump your CR that high. ALL of the 'other' pistons though will need some sort of machining and rebushing of the conrod ifyou are using the longblock.

boost'd · Post by **boost'd** » Fri Feb 17, 2012 8:35 am

i know completly off VW but i can add some info here.
I built a honda B20 vtec (2.0L)
with CA18 pistons (40 thou) which were 84mm, they were the CA18DE pistons, the normally aspirated with a domed crown, comp would have been crazy high, but i got them machined down and valve pockets machined in, it dropped the compression down to around 11:1 with enough Piston to Valve clearance for STG3 cams.
The only other mod i had to do was get the rods bushed with 1mm copper bushes for the gudgeon pin of the pistons.
All in all it cost me R1300 including pistons and all machining!

Car made 142kw ATW in dbn with stg2 cams

Digit Riaan · Post by **Digit Riaan** » Fri Feb 17, 2012 9:08 am

Yes, there are domes ones and flat-top ones. I'm after the flat-top ones, which I think is CA18DET.

Domed:

Flat top:

Post by **panic-mechanic** » Fri Feb 17, 2012 9:27 am

Those are the ones i was talking about. The flat top 83 mm. Semi forged piston.

boost'd · Post by **boost'd** » Fri Feb 17, 2012 9:28 am

here the pistons machined

CRASH_IT · Post by **CRASH_IT** » Fri Feb 17, 2012 10:59 am

very interesting.
Im sure with higher compression comes a small gain in power also.

shuaib · Post by **shuaib** » Fri Feb 17, 2012 8:01 pm

these bmw e36 328i pistons are they 84mm or 84.5mm? what sorta compression ratio would that give on a abf motor?

16V Dub · Post by **16V Dub** » Sat Feb 18, 2012 7:38 am

Hwzt guys...

I've been playing around with the BMW pistons and the CA18 domed Nissan piston for my current build.
The BMW piston is 84mm, with alot of machine work needed.
The Nissan piston is 83mm wit little work needed to work on a 2.0lt 16V high compression build.

I settled with the 40" nissan piston (84mm). I'm looking at about a 12+ compression ratio...

Post by **Killerwatt** » Sat Feb 18, 2012 8:44 am

Sorry for the hijack but do you have the compression height and dome cc on those dome nissan pistons?
They seem perfect for a fsi head swap.

zaahir · Post by **zaahir** » Tue Feb 21, 2012 2:25 pm

im running those (semi forged) nissan 83mm pistons, they work but cant take revs, they show scuff marks on skirts. wont work in 20v, you would need higher compression than flat top.

() they are anodised, will need to machine for valve clearances

Digit Riaan · Post by **Digit Riaan** » Tue Feb 21, 2012 2:33 pm

zaahir wrote:im running those (semi forged) nissan 83mm pistons, they work but cant take revs, they show scuff marks on skirts. wont work in 20v, you would need higher compression than flat top.

() they are anodised, will need to machine for valve clearances

In your 16v? How much do you rev to and how frequent?

Why would you say a dome piston is needed if ADR use flat top pistons?

zaahir · Post by **zaahir** » Tue Feb 21, 2012 2:45 pm

16v revs to 7800, every race meeting.

How much power does adr make?

Digit Riaan · Post by **Digit Riaan** » Tue Feb 21, 2012 2:49 pm

zaahir wrote:16v revs to 7800, every race meeting.

How much power does adr make?

92kW stock IIRC...so not much at all.

So you have any suggestions for an alternative? Are you running pump fuel and what's your CR?

Digit Riaan · Post by **Digit Riaan** » Tue Feb 21, 2012 2:55 pm

How's 10.5 cr?

Which 84mm BMW pistons and what's needed to make them work?

Which 84mm BMW pistons and what's needed to make them work?

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Re: Which 84mm BMW pistons and what's needed to make them wo

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Re: Which 84mm BMW pistons and what's needed to make them wo

Re: Which 84mm BMW pistons and what's needed to make them wo

Re: Which 84mm BMW pistons and what's needed to make them wo

Re: Which 84mm BMW pistons and what's needed to make them wo

Re: Which 84mm BMW pistons and what's needed to make them wo

Re: Which 84mm BMW pistons and what's needed to make them wo

Re: Which 84mm BMW pistons and what's needed to make them wo

Re: Which 84mm BMW pistons and what's needed to make them wo

Re: Which 84mm BMW pistons and what's needed to make them wo

Re: Which 84mm BMW pistons and what's needed to make them wo

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