E30 Zone

Hi all,

I'm currently building a 2.7 stroker engine using a 2.7 eta block with 325i Piston heads and 130mm con rods, I'm also using the 325i head.... That's a little info on my build :)

Now What I'm wanting to know, will a 288 schrick cam work with this engine, if so will I need up rated valve springs?

Any ones help is highly appreciated

It should work fine. I have something similar but with the 135mm rods.

What CR? Early or late pistons?
I think it’s too much cam but you haven’t mentioned everything to say for sure.
Piston to valve clearance will probably be an issue

[quote="reggid"]What CR? Early or late pistons?
I think it’s too much cam but you haven’t mentioned everything to say for sure.
Piston to valve clearance will probably be an issue[/quote]

Well I have some early Pistons lying around but it's not a problem for me to get hold of some later Pistons as I believe these are better for the build......correct me if I'm wrong!

I'm all ears, what would you recommend?

early pistons will give better compression. the pistons are a bit heavier and skirts are larger but not end of the world.

are you going to deck the block? the pistons sit approx 2mm down the bore otherwise (very bad) due to 3mm extra throw but 5mm shorter rod. decking block you'll need vernier cam gear

early pistons that sit in the same position with respect to block (i.e. about 0.4-0.5mm above block) as OEM are the go if you want any sort of performance as you will maintain squish and have about 10:1

you dont want a low compression with a 288 it will be a dog. Id still use something smaller than a 288, the enem z45 with 280 duration looks like a nice option on paper but never seen anyone use it

using a 288 with OEM intake is overkill, the OEM intake will never allow you to get the potential from the cam.

what kid of engine are you building? race or street?

[quote="reggid"]what kid of engine are you building? race or street?[/quote]

So the early Pistons it is then. Am I right in thinking that the Pistons will need machining to shorten the skirts and how much needs taking of them?

So even with 130mm con rods and early Pistons the block still wants to be decked for better compression? If that's what it takes then yeah I will deck the block, performance is the key!

I've been offered the cam at a really good price and they're really hard to come by in the UK. So what are we talking about doing to get the full potential of the 288 can?

Thanks for your input so far... You're a huge help!

Well it's not my daily so I'm not to bothered about a lumpy cam, I am looking for power at the end of the day. It will mainly be for the street but like I said it's not my daily driver

they may need machining, iirc depend if KS or Mahle brand, i dont remember off hand. compare them to eta pistons for a quick and dirty way to see

the 81mm stroke crank has 6mm more stroke which is 3mm more throw. the 130mm rod is 5mm shorter so the delta is -2mm. so the piston will be down the bore. you're best measuring the block you have as there seems to be around approx 0.5mm variation in height of the bare block which would depend on the history of the block to. the exact amount to take off would give a squish clearance (piston to head at the chamfered part of piston dome) of 1mm.

most people run less the following but if you want to get the most from a 288 you'd want to think about getting some of the following, a ported head, 6 branch, RHD ITBs, custom tune, depending on budget and how far you want to go

Ok this all seems fairly possible to do.

The final question is how would I go about valve and piston clearance? Is it for certain that the valves and Pistons will clash and how do I get over this? Is it a case of getting the Pistons slightly scoloped out?

you would mock it up and measure with clay or plasticine, you could deepen them if needed

[quote="reggid"]you would mock it up and measure with clay or plasticine, you could deepen them if needed[/quote]

Okay then let's talk about the possibilities of supercharging the engine. I know we've been talking about getting high compression and that's great but over the last few days I can't stop thinking about supercharging the engin So obviously we need to bring the compresion down, what would be the best way of doing this?

use late pistons....will give about 9:1 CR which is fine

[quote="reggid"]use late pistons....will give about 9:1 CR which is fine[/quote]

And that's all? So build it up as I was going to, as well as decking the block? Also what super charger would you recommend?

An Eaton M90 supercharger springs to mind for an M20.

M90 is big enough.

The E36 boys mount the m60 down in the Air con pump spot but the m60 is only enough to feed about 300hp.
The M90 is too big for that location.

Suggestion would be to put a small Denso/toyota alternator in the air con spot and the M90 up where the alternator used to be.

E30coupwes wrote:

reggid wrote:use late pistons....will give about 9:1 CR which is fine

And that's all? So build it up as I was going to, as well as decking the block? Also what super charger would you recommend?

yeah on the bottom end thats fine, topend you probably wouldn't use a 288, itb etc

[quote="reggid"][quote="E30coupwes"][quote="reggid"]use late pistons....will give about 9:1 CR which is fine[/quote]

And that's all? So build it up as I was going to, as well as decking the block? Also what super charger would you recommend?[/quote]

yeah on the bottom end thats fine, topend you probably wouldn't use a 288, itb etc[/quote]

What's the reason for not using the 288 cam? Would it not be better if it's forced inducted to get the maximum potential out of the cam?

with an eaton it will probably be ok as it will make boost at low to mid rpm compared to a centrifugal type which wouldnt have any boost until topend and be a dog off boost. if i was going to the effort of a s/c id look at something a little more custom probably mix and match catcam lobes to give a bigger exhaust duration as it used to cost nothing extra to do this.