how do i make my 325e a stroker and cheap

[Pdxseth]

I am looking at doing bathe same swap I have an m20b25 full swap but the bottom end needs rebuilt so I'm just gonna put the head on my eta would it be worth it to do a cam, port and polis, and itb's any idea what Kind of power gain I would have from this


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[Mr. Tasty]

325e bottom with 325i head is not a stroker. Christ

[tinkwithanr]

If you deck the head the maximum amount you can can gain a couple of tenths of CR. You'd have to remove a lot from the block to gain the other six tenths of CR (going from ~.8.0 to 8.8). And then you'd run into the problem of the valve clearance cuts in the piston faces and the requirement for a change in the cam sprocket timing (as stated).

The only realistic solution is SperETA or equivalent pistons.

You need to deck the block 2.0 mm to get back up to the proper CR. If you use 'i' pistons on the 'e' crank and rods, this will give you the stock quench area in the combustion chamber as well as 8.8:1 compression. The piston to valve interference your referring to is only an issue if you stick with the 'e' pistons, since they are flat top.

The 'super eta' pistons are very sought after because they are essentially 'i' pistons, but with a pin height 2mm further from the crown. This lets you avoid decking the block and head to raise compression.

[ForcedFirebird]

seta = 8.50:1
327i = 8.43:1
b25 = 8.80:1
i pistons/e crank/rods 2mm off block = 9.5:1
(all with stock full head height)

The seta pistons have a larger dish in them than the i pistons guys. Yes, even though they appear to be domed the i pistons are -1.2cc's, haven't measured the seta pistons, but will eventually as I have a set.

[frankenbeemer]

325e bottom with 325i head is not a stroker. Christ

In my opinion, it's not a stroker unless you physically modify the dimensions of the original crankshaft. Dropping in a crank from a different motor doesn't count.

See how superior I am?

Not to mention hipocritical, since I continue to call that a stroker. Most people know what it means, and I'm sure as hell not typing in "325e bottom with 325i head" every time. Maybe you have a better term for it?

[SkiFree]

Maybe you have a better term for it?

Howabout "hackjob"? Has a nice ring to it.


EDIT: sarcasm/low jokes don't translate well into internet speak.

[JA1991]

You can use the complete bottom end of the E with the top end of the I. You actually don't' have to deck anything, the valve interference isn't true.

[ForcedFirebird]

You can use the complete bottom end of the E with the top end of the I. You actually don't' have to deck anything, the valve interference isn't true.

What? If you shave the head too much, you WILL have interference, even on a stock "i" motor. The valves are close to the pistons to begin with, that's why all the valves bend when a timing belt breaks.

[Mr. Tasty]

In my opinion, it's not a stroker unless you physically modify the dimensions of the original crankshaft. Dropping in a crank from a different motor doesn't count.

See how superior I am?

Not to mention hipocritical, since I continue to call that a stroker. Most people know what it means, and I'm sure as hell not typing in "325e bottom with 325i head" every time. Maybe you have a better term for it?

it is called a 2.7i build. With your amount of posts, I would have imagined you would have figured that out.

[Mr. Tasty]

You can use the complete bottom end of the E with the top end of the I. You actually don't' have to deck anything, the valve interference isn't true.

I hope you know that the m20 is an interference engine.

[frankenbeemer]

it is called a 2.7i build. With your amount of posts, I would have imagined you would have figured that out.

I will write "2.7i build" 200 times. "Hackjob" is cool too. I also misspelled hypocritical, I'm putting myself in time out.

[e30trooper]

i like my hackjob :D

[Smash9002]

If someone will instruct me on how to take some measurements, I would love to put the super eta vs. i block argument to rest. I have one of each sitting in my shop right now, heads off. I have heard different opinions on the compression ratio of the stock US 325i motor vs. the super eta motor. Its driving me nuts because I have the option of using either one when I put my car back together!

Forced firebird, you seem like u may know your way around an engine, can you tell me what it is I need to measure to determine compression ratio?

[ForcedFirebird]

If someone will instruct me on how to take some measurements, I would love to put the super eta vs. i block argument to rest. I have one of each sitting in my shop right now, heads off. I have heard different opinions on the compression ratio of the stock US 325i motor vs. the super eta motor. Its driving me nuts because I have the option of using either one when I put my car back together!

Forced firebird, you seem like u may know your way around an engine, can you tell me what it is I need to measure to determine compression ratio?

You can see it by eye when the pistons are next to each other. The "i" pistons have an "|" stamped on them and the valve reliefs are larger/deeper since the "dome" is higher ;)

[Smash9002]

You can see it by eye when the pistons are next to each other. The "i" pistons have an "|" stamped on them and the valve reliefs are larger/deeper since the "dome" is higher ;)

Doesn't the extra stroke of the eta crank add more compression to balance out the difference in piston shape?