Dual valve springs into an eta head? Cam options?

[RedBaron86325]

I just ran a search on cam gears for a 1990 325i, 1988 325e, and 1986 325e and the part numbers are all the same so the cog difference must be on the cam, not the gear.

I have an 86 325e cam gear and an 89 325i cam gear. Not only are they designed different, the keyway for the cam (on the cog) is in a different location for each. The difference is not huge, but it is at least one tooth off, but looks more to be 2 teeth off. The eta cog appears to be stamped steel while the i cog is definitely a casting.

[Jand3rson]

[The i cam virtually eliminates the power below 3000rpm. Above 3000 it starts to come on strong all the way to my limiter of 5400. If you can find an old Veloz chip for the eta (6000rpm limiter) it would probably be worthwhile. Another problem you'll face is the amount of airflow of not only the eta intake manifold, but the eta head also. You won't get the punch of the i at the higher rpm. Out of all of the setups I've tried for more power in my eta, by far, the best have been the differential change, chip, and valve springs. Everything else such as an i TB, big AFM, cold air, remote crankcase ventilator, etc... have either moved the powerband or decreased power.

--edit
Don't forget that the e valves are substantially smaller than the i valves. This will also limit the quantity and efficiency of air entering the combustion chamber. It is concievable that this bottleneck may also affect the atomization of the fuel. By all means, play around with it and have fun; but, financially speaking, it would probably be less expensive and easier to find a good used i engine for a transplant.

I plan to have a 325i intake manifold and throttle body, so I'm not worried about the airflow in those areas. I also plan to get a 3.25 or 3.73 LSD.

I'm not too concerned with high-end power, so sticking with the e cam will probably be a good idea.

Also, I have complete i engine in my car that I'm parting out, and I'm going to wait until I get everything else sold off the car before I list the head for sale. If I can make enough to buy another E30 just by selling everything else, I may just end up keeping the i motor that I've got now. But I REALLY don't want to do another engine swap.

[rs4pro3]

There deffinatly different, compared side by side an eta cam gear and an I gear look completly different I didn't notice the difference in the mounting point but I've got both in the attic i can get some pics of and let you know.

[modifiede30]

Is the super eta cam gear the same as an "i" or an eta? Now I'm worried about my timing - maybe that's why the belt was so tight when I installed it. At least I have the "i" parts to switch them if I have to.

[rs4pro3]

Red.. Youre sure about that? I just layed an eta and I cam gear ontop of each other with the TDC markes lined up and the two locating pins lined up also.
I gear on the left and eta on the right

[RedBaron86325]

I'll check again when I got home. I know mine are different. I remember looking and looking and looking at it because I didn't see why they would be of different alignment. I think I even showed JasonH too. I'll definitely check them again.

[rs4pro3]

hum get the part number off it. The two I've got they line up perfect.

[Jand3rson]

This thread has been absolutely awesome, so much great information.

Keep it coming, I need as much info as I can get.

[rs4pro3]

No problem Josh, worried for a bit we were stealing your thread but it is info reguarding the swap.

[rwh11385]

This thread has been absolutely awesome, so much great information.

Keep it coming, I need as much info as I can get.

I've been thinking......

how you can make more grunt from the eta.....and I dunno. Seems you're screwed because it's built up as an economy motor, and not much is really going to change that. Sorry, but it's the frank truth.

I forget what post it was, but someone was calling the valves the bottleneck of the eta. So switching over to i intake or exhaust will only do little, the real problem is the eta head. You're probably just wasting time and effort.

Do a legit stroker man, or something else than tack on a few i parts to the eta and think it'll make you happy......

My input for today: TURBO THAT BITCH!
Someone recently has given fire to my old love of turbocharging technology.

I believe Dinan turboed the eta.

Here's my 2 cent, yo.

With a N/A motor, you are just trying to remove restrictions and get that air pump to draw in more air.

a) Valves suck ass on eta head
b) The motor isn't designed to be gas hungry (hence not air hungry)
c) You can SHOVE ass down its throat with a turbo!

9.0:1 CR would make it not as tolerant as boost, and the ECU I guess would not be as adaptive, but it would surely increase HP and TQ significantly.....and probably be easier than a motor swap. Go for dual valve springs, but instead of moving the power band up, just make it way fatter with forced induction!

peace

EDIT: Talked to Josh. Just interested in quick eta, not trying to find more HP than he could really easily get, in my eyes. That's fine, so what would be the most efficient build up for cheap? Eta cam, dual springs, I intake/exhaust, chip.....etc

[modifiede30]

My current project is a stroker based on a super eta. There was mention that the eta cam gear differs from the "i". I still haven't seen anyone mention whether the super eta cam gear differs from teh "i". Anyone know?

[Jand3rson]

The super eta head is just an i head with single valve springs, so I imagine the cam should just be a standard i cam, and cam gear.

[modifiede30]

I know the cam is an eta cam but the casting for the head is the same as an "i". I just rebuilt it using "i" components and am worried about the cam gear now.

[Jand3rson]

I know the cam is an eta cam but the casting for the head is the same as an "i". I just rebuilt it using "i" components and am worried about the cam gear now.

Is it causing you any problems? If not, I wouldn't worry about it TOO much, but get an answer.

[modifiede30]

Its going in this weekend so if they are different, I might as well swap in the one from my "is" engine while I'm in the process. I'll be replacing it with an adjustable cam gear soon anyway but I don't want to have timing problems since I've increased lift and duration, and shaved/decked. If the timing is too far off, I'll likely slap the valves.