1.3 Motronic Up-Grade & 2.7i How To

[mikegar]

slaping an i head on to an e block is a cheap and fast performance gain for the eta motor. the cost of one 885 head is much cheaper than the cost of the whole motor. and to say that it doesnt perform as good as an i motor without any real world experience with this motor is just asinine. here is a link for all the eta guys contemplating the 885 head swap

http://r3vlimited.com/board/showthread.php?t=97872&highlight=head+block

[lennon]

you guys just keep on swapping 885 heads onto your regular eta blocks... enjoy that awesome compression and pistons that dont match the combustion chamber... the options by price are: swap in m20b25, swap in m5x/s5x motor, build real m20 stroker. i head on eta bottom is not even in the list, see?

[jmc1590]

As far as I can remember, there is no difference between the e and "i" head gasket. However, since the swap will consume a majority of the remaining head gaskets, I found that purchasing an "i" gasket kit is by far the best option.

[mattygmoe]

headgasket?

hey guys when swapping the "i" head on to the "e" what headgasket do i use. Is there a deference between the headgasket for the two motors? And does anyone have an "i" crank pulley for sale? Thanks

[lennon]

yes just swap the whole motor and motor harness. definitely no point in throwing money at the great "budget stroker". the stock i motor probably out performs most peoples eta+i setups.

edit: to the person above^^^ why would he swap the i head onto his eta motor? its an 86 not a super eta. that combo would not yield good results when compared to the complete i motor he already has. thats insane

[jmc1590]

Do the "i" head swap. It is far easier. The only thing that will cause you some difficulty is adapting the '88 "i" harness to the '86 fusebox. (IIRC, the '86 still uses the rectangular C101. The '88 has the large round C101.)

When converting to M1.3, you can leave the block in place, only having to remove the head. (And everything attached!) If you chose to swap the entire engine, you'll still have to resolve the C101 connections, as well as remove even more from your engine bay.

As far as the differences betwen the manual and automatic, I don't belive there are any differences betwen the two engine harnesses. I know there are no differences in the Motronic 1.3 ECU. (Kickdown cable on the throttle body. I think that's all.)

Since you have both vehicles, you have all the needed parts. The question remains, is there something wrong with either vehicle that forces the swap , or are you looking to consolidate driveway space? :)

[TexasE30]

bump this back with this weird question

I have 1986 325es with 230k miles or around (manual). I also have this 1988 325is car also with only 133k miles (autotragic).

easier for me to swap whole motor from 88 to my 86? or its easier for me to do I-head conversion? I know I wouldn't use some of harness on the motor because of auto.

Thanks.

[884door]

I have learned something new the other day. Regardless of what the parts catalog says, if your super eta was made from 3/87-8/87, you may have the 4 bearing super eta cam and you will have to drill the bearings if you want to use the i cam. If your super eta is 9/87 on, it has a 7 bearing cam. I have spoken to someone that did the i cam swap on a late super eta, and he claimed the power increase was negligible, but IIRC, he did not do the full i swap. There you have it.

haha YES! Mine's 9/87 :)



Okay motronic 1.3 wizards I have a question for you. I found a mostly clean shell I want to put my engine in for a good price, but it's an 85 eta. How hard would it be to put the m1.3 system from an I in it with my super-eta motor? I'm completely confident in being able to do the swap other than that part, well even if I have to splice every wire in the harness I know I can still do it I just don't really want to. Will it be mostly plug and play since I'm using a m1.3 engine AND ecu? Or will I have to do a ton of cutting up of the harness?

I'd possibly like to even put the 85 eta motor in my 88 after and sell the car but that's technically not legal in CA.

[mooseheadm5]

You do not have to drill squat in a super eta head. It already has a 7 bearing cam since it is an i head, the only difference is the cam profile and the dual springs. However, you cannot (easily) replace the springs without pulling the head, which is fine since your head gasket is probably old and could stand to be replaced.

I have learned something new the other day. Regardless of what the parts catalog says, if your super eta was made from 3/87-8/87, you may have the 4 bearing super eta cam and you will have to drill the bearings if you want to use the i cam. If your super eta is 9/87 on, it has a 7 bearing cam. I have spoken to someone that did the i cam swap on a late super eta, and he claimed the power increase was negligible, but IIRC, he did not do the full i swap. There you have it.

[structured]

The 731 head is almost identical to the 200 casting, and should work keeping an 11:1 cr. Flows better (not quite as good as the 885 head), and can take advantage of the "i" intake. Only downside is the smaller valves.



While the combination should be sound, the 10.2:1 pistons are still dished, not so much as the standard eta pistons. When paired with the 885 "i" head, you should see something in the neighborhood of 9.5:1. The only drawback is that the pistons do not match the combustion chamber of the head, and may leave a few HP on the bench as a result.

Given a choice between the two, I'd choose the 10.2:1 pistons with the 731 head. That at least gives me some options when at the pump!

I assume you are talking about octane. What would be necessary for the 11:1 setup?
Also, would any special engine management be necessary? Or just some 2.7I software?

[jmc1590]

Now that I have converted to i electronics and '89 engine harness, I'm wondering if it is possible to do the stomp test. I don't have a "check engine" light (1986 325) but it seems like you could wire up a bulb to act in its place. Any thoughts?

1986 Model year, or build date? I was pleasantly surprised to find the check light portions of the harness present in my 12/86 528e. It just required a little digging behind the instrument cluster to un-earth.

And it works fine. Stomp test and all. Mind you, all it really does is inform you that the ECU has detected a fault with a sensor. (Which can be helpful after you complete the ECU swap. Did you know the engine will run (poorly) with the temperature sensor wiring swapped? :oops: )

[jmc1590]

M20B27 crank, block and rods
11:1 cr pistons (from early euro eta)
will the 731 head work with these pistons?

The 731 head is almost identical to the 200 casting, and should work keeping an 11:1 cr. Flows better (not quite as good as the 885 head), and can take advantage of the "i" intake. Only downside is the smaller valves.

M20B27 crank, block and rods
10.2:1 cr pistons (euro eta)
i head (I can use the i head because the 10.2:1 Mahle pistons have flat tops, right?)

While the combination should be sound, the 10.2:1 pistons are still dished, not so much as the standard eta pistons. When paired with the 885 "i" head, you should see something in the neighborhood of 9.5:1. The only drawback is that the pistons do not match the combustion chamber of the head, and may leave a few HP on the bench as a result.

Given a choice between the two, I'd choose the 10.2:1 pistons with the 731 head. That at least gives me some options when at the pump!

(Related to original post - Just finished an e to "i" swap on a 528e. Thanks to this thread (a few others like it), it went off with out a hitch! Well, maybe a few minor ones. But those get filed under lessons learned.)

[structured]

Can you guys let me know what you think about this recipe?

M20B27 crank, block and rods
11:1 cr pistons (from early euro eta)
will the 731 head work with these pistons?

OR

M20B27 crank, block and rods
10.2:1 cr pistons (euro eta)
i head (I can use the i head because the 10.2:1 Mahle pistons have flat tops, right?)

[mooseheadm5]

Find the wiring diagram and hook up a light bulb and you should be good to go. I think the signal comes from the small plug in the engine harness next to the ECU. It won't really tell you much, though.

[rcfanatic]

Now that I have converted to i electronics and '89 engine harness, I'm wondering if it is possible to do the stomp test. I don't have a "check engine" light (1986 325) but it seems like you could wire up a bulb to act in its place. Any thoughts?