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Old 11-25-2016, 11:52 PM   #1
Hayzee
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1988 325ix M20 Build Help

Hey R3v

First post here. I have a 325ix that is burning oil on cylinders 5&6. Head has less than 3k on it since rebuild. Compression is above 150 on all cylinders. Believe the oil has to be coming from the lower half though and believe it is time for a rebuild.

What I Want to Accomplish:
- A fun street car that won't see track use; limit mpg loss
- low maintenance post build
- keep car and electronics as stock as possible (limited tuning/wiring knowledge)
- DIY as much as possible
- NA motor with no plan to turbo in future

Budget:
4 grand

Current Plan:
Crank: ETA
Pistons: MM 10:1 86mm
Rods: S52
Cam: Schrick 272
AFM Delete
Big Bore Throttle Body

What I need help with is refining my build from the experts here at r3v to get the most out of my money and to limit my mistakes. This will be my first engine build so I want to spend time doing the proper research.

Thanks in advance

Connor
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Old 11-26-2016, 04:32 AM   #2
berlow94
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For a street motor I would just use stock pistons and have them fly cut to lighten them up. What's the need for high compression? I think you are better off spending that money on a 5-angle valve grind, heavy duty valve springs, and heavy duty rockers.

You realize you can't simply "delete" the AFM without getting a standalone ecu to run the motor using speed density or the VE equation for fueling.

With that being said, if you do want to protect your hardware investment and want better than factory street driveability on a heavily modified motor, a properly set up quality standalone computer will be your best bet. Vipec/Link, Motec, Haltech, Emtron, etc.
If you adapt the motor to use Coil Over Plug ignition and mount a cam sensor then you can use an OBD1 m50 harness and use the $1.1k Link plug and play ecu. You can then utilize hundreds of safety limits and triggers, fully sequential spark and fueling and VE fueling. Most other ECU's on the market that have the same functionality cost 3x this.

Remember, 90% of the time, the hardware in these engines don't fail because they weren't designed strong enough. These motors fail when you modify them as heavily as this and expect 30 year old electronics to run it reliably.


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Old 11-26-2016, 11:39 AM   #3
essi1553
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As someone with similar goals (but a bigger budget) let me first tell you, it always costs more than you expect, always. That being said.

Crank: Get a forged crank {anything from an E36 (M50/M52/S50/S52)} I went with an 84mm stroke from an M52 iirc.

Standalone: Megasquirt is the most cost effective ive come across (Though tuning is not my forte either)

I personally bored out to 85mm for my build (I prefer the thicker cylinder walls, although no problem if staying NA) The reason for the higher compression is more power.

Throttle body is kind of pointless (I'm sure it makes a difference but it's probably not worth it without a ported cylinder head)

You're gonna need:
1. Main bearings
2. Rod Bearings
3. Main bolts (or studs)
4. Head Bolts (or Studs)
5. Tensioner
6. Water pump
7. Head Gasket Set
8. Crankcase Gasket Set
9. Timing Belt
10. Random Dowels

Then there's the recommended:
1. If you're replacing the cam you should replace the rocker arms at the very least

2. Depending on the MM piston set the non interference ones should have any problems with cam clearances, but if you going with any other brand and raising the compression be sure to designate what cam you will be using with the manufacturer so they can cut the appropriate clearance between the piston and valve.

3. No offense to berlow94 but theres no way you can afford a vipec/haltech/motec with a 4k budget and the build (I wouldn't spend that on a m20 anyway). The easiest solution would probably be a war chip with a MAF sensor, though a far better option would be the addition of a MAP and megasquirt if you're on a budget. Even the megasquirt setup runs bare minimum of $800 for the plug and play solution.

4. Replace fuel system. Filter, clean/rebuild injectors.

5. Test your oil spray bar in your cylinder head before you button it all back up, you'd be surprised how bad some of those spray after 25 years of use.

6. Oil pressure cylinder looking thing in the oil pan (I'll look it up later) should be changed.

By this point you're asking yourself if you should change the clutch while you're in there, maybe a couple transmission upgrades (brass pin, new fork, slave cylinder,etc) Is it wise to change the starter now? Oh wait since everything is out not would it be the proper time to upgrade the subframe, and since it could use some attention maybe its time to do the front suspension (I think you see where i'm going with this...)

Who knows. You're damned if you, and you're damned if you don't. Be prepared to be delayed.
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Old 11-26-2016, 02:13 PM   #4
berlow94
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Quote:
Originally Posted by essi1553 View Post
As someone with similar goals (but a bigger budget) let me first tell you, it always costs more than you expect, always. That being said.

Crank: Get a forged crank {anything from an E36 (M50/M52/S50/S52)} I went with an 84mm stroke from an M52 iirc.

Standalone: Megasquirt is the most cost effective ive come across (Though tuning is not my forte either)

I personally bored out to 85mm for my build (I prefer the thicker cylinder walls, although no problem if staying NA) The reason for the higher compression is more power.

Throttle body is kind of pointless (I'm sure it makes a difference but it's probably not worth it without a ported cylinder head)

You're gonna need:
1. Main bearings
2. Rod Bearings
3. Main bolts (or studs)
4. Head Bolts (or Studs)
5. Tensioner
6. Water pump
7. Head Gasket Set
8. Crankcase Gasket Set
9. Timing Belt
10. Random Dowels

Then there's the recommended:
1. If you're replacing the cam you should replace the rocker arms at the very least

2. Depending on the MM piston set the non interference ones should have any problems with cam clearances, but if you going with any other brand and raising the compression be sure to designate what cam you will be using with the manufacturer so they can cut the appropriate clearance between the piston and valve.

3. No offense to berlow94 but theres no way you can afford a vipec/haltech/motec with a 4k budget and the build (I wouldn't spend that on a m20 anyway). The easiest solution would probably be a war chip with a MAF sensor, though a far better option would be the addition of a MAP and megasquirt if you're on a budget. Even the megasquirt setup runs bare minimum of $800 for the plug and play solution.

4. Replace fuel system. Filter, clean/rebuild injectors.

5. Test your oil spray bar in your cylinder head before you button it all back up, you'd be surprised how bad some of those spray after 25 years of use.

6. Oil pressure cylinder looking thing in the oil pan (I'll look it up later) should be changed.

By this point you're asking yourself if you should change the clutch while you're in there, maybe a couple transmission upgrades (brass pin, new fork, slave cylinder,etc) Is it wise to change the starter now? Oh wait since everything is out not would it be the proper time to upgrade the subframe, and since it could use some attention maybe its time to do the front suspension (I think you see where i'm going with this...)

Who knows. You're damned if you, and you're damned if you don't. Be prepared to be delayed.


The extra time you will need setting up that $800 megasquirt (not to mention all of the extra sensors you will need to buy) will be far more $ and time intensive than the Link ecu for $1k. The link will plug in and start the car. The megasquirt will need hours of setup and calibration. And more importantly, the megasquirt will never offer the same driveability of the link.

Otherwise, I agree with everything else that he said.

People have this pre-conceived notion that Megasquirt is cheap and reliable and the only other aftermarket computers on the market are $4k+ and are very difficult to tune. This is not true.
The other opinion that everyone has is that an aftermarket ecu will not offer the same driveability as the factory ecu. This is also no longer true.

With that Link ecu that I mentioned, you WILL get BETTER driveability than factory. You will spend less than half the time calibrating it as you will megasquirt. And you will spend less than half the time installing it. And it only costs $1.1k!!!
http://www.aceperformancesystems.com...0-plug-in-ecu/


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Old 11-26-2016, 03:28 PM   #5
essi1553
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http://www.r3vlimited.com/board/showthread.php?t=204722 - Under an hour install, and with the purchase of tuner studio $60 it will give you a base tune. Please show me where you find a Motec or vipec ecu with the appropriate wiring harness for this application for $1.1k (No sarcasm intended I am truly interested) I don't see a M800 going less than 4k new, and that is very far from plug and play.

Your link is for an e36, and it looks like overkill for a mild built m20.
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Old 11-26-2016, 03:34 PM   #6
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m52 crank and Mahle MS 2.9L pistons over the MM pistons and eta crank
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Old 11-26-2016, 07:01 PM   #7
berlow94
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Quote:
Originally Posted by essi1553 View Post
http://www.r3vlimited.com/board/showthread.php?t=204722 - Under an hour install, and with the purchase of tuner studio $60 it will give you a base tune. Please show me where you find a Motec or vipec ecu with the appropriate wiring harness for this application for $1.1k (No sarcasm intended I am truly interested) I don't see a M800 going less than 4k new, and that is very far from plug and play.

Your link is for an e36, and it looks like overkill for a mild built m20.


All that would be needed is COP and a Cam sensor. Then you can use an M50 harness.
It can do everything the Motec unit can at 1/4 the price. It might be overkill for this specific motor. But that's part of the beauty of it. It can be used for many different setups. The amount of ridiculous setup steps involved with even the PnP Megasquirt units just seem silly. I can't remember the last time I used a timing light to setup a standalone computer...


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Old 11-26-2016, 07:48 PM   #8
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Although I love tuning with my haltech I still think megasquirt is the best bang for you buck because of all the support you can get right here from all the other megasquirt guys,

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Old 11-26-2016, 07:56 PM   #9
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Quote:
Originally Posted by digger View Post
m52 crank and Mahle MS 2.9L pistons over the MM pistons and eta crank
This x10.


OP, the moment you decide to change stroke/compression/cam you will break your third provision.


If DON'T want to break your third provision, then consider a quality stock rebuild (.50mm over oem Mahle pistons) with a light 272 cam, a chip (perhaps the miller MAF combo to rid yourself of the AFM), and lighten your flywheel. Boom, no custom tuning, no headache, no learning curve.
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Old 11-26-2016, 10:15 PM   #10
digger
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I would look into a sssquid chip to get you started and run in. Then if you want something better ecu wise that allows AFM delete Perhaps something that is pnp with low setup time, the whodwho setup has a good rep, though keep simple And You don't need fancy coil on plug or sequential fuel
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Old 11-27-2016, 05:37 AM   #11
Hayzee
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Thanks for all the advice everyone, this being my first build you all are helping me a ton!
Just to clarify a few things. I have either replaced or own all the front suspension parts.
On the AFM delete I was thinking Miller mass air with the war chip.
Doesn't the m52 crank require modification and additional parts to work on the block? If so what is that part list? Also don't the pistons have to be modified as well due to clearance issues?
What is the need to uprated valve springs when doing the stroker motors?
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Old 11-27-2016, 05:47 AM   #12
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You are better off using a stock ecu than the Miller setup. They suck big time.
You will need a crank spacer to fit the m52 crank into the m20 block.
Uprated valve springs are needed with a higher lift cam. Has nothing to with the motor being stroked or not.


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Old 11-27-2016, 12:14 PM   #13
digger
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Quote:
Originally Posted by Hayzee View Post
Thanks for all the advice everyone, this being my first build you all are helping me a ton!
Just to clarify a few things. I have either replaced or own all the front suspension parts.
On the AFM delete I was thinking Miller mass air with the war chip.
Doesn't the m52 crank require modification and additional parts to work on the block? If so what is that part list? Also don't the pistons have to be modified as well due to clearance issues?
What is the need to uprated valve springs when doing the stroker motors?
you need a sleeve for the oil seal to ride onto, a longer crank bolt from e36 iirc and modified washer. its not hard to do.
there might be some minor/minimal clearancing work in the block so the counterweights clear but again its easy to do with a die grinder.

the IE 2.9L MahleMS pistons are designed to work with that crank, normally people use the 130 mm rods with the m52 crank and big skirt OEM slugs giving issues with clearance between crank and bottom of piston but if you get the IE pistons with shorter piston compression height and different slipper skirt shape then you can use longer 135 mm rods which gives the clearance. the Mahle MS pistons are probably the best aftermarket piston you can get for a street engine. they are much nicer and cheaper than the wisecos from MM

schrick 272 you can use stock springs id get new ones though
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Last edited by digger; 11-27-2016 at 12:57 PM.
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Old 12-05-2016, 05:29 PM   #14
Hayzee
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2 Options

So after a few weeks of research and a lot of help from Andrew (Ski Free) I am weighing the following 2 options:

OEM Upgrade:
.5mm Over Bore Pistons
272 Cam
S52 Rods
Miller AFM + Chip
17lb/hr Injectors
Gaskets, Seals, Guides etc
Oil Pump + Level Sensor
New OEM Rockers

Full Stroker:
85mm Mahle Ultimate Street Pistons
M52 Crank
S52 Rods
272 Cam
24lb/hr injectors
Megasquirt
Gaskets, Seals, Guides etc
Oil Pump + Level Sensor
IE Heavy Duty Rockers

After getting pricing from Pelican, Bav, Turner, IE, My Local Dealership and OMG Motorwerks (Owner is member dude8383) I'm coming up with a parts cost of $2987 for the OEM upgrade and $4661 for the Full Stroker. Does this seem reasonable on the cost for the parts? Everything is new aftermarket/new OEM, no used parts in the prices.

Thanks Everyone
Connor
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Old 12-05-2016, 05:59 PM   #15
digger
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what crank on "OEM upgrade"? still b25?
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Last edited by digger; 12-05-2016 at 06:04 PM.
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