2.8L M20 build - Now with 2.7L!

[acolella76]

Thank you! But that is not my garage :( I'm building it at a friend's house because my garage isn't very roomy.

I have already bought the febi's and installed them. I didn't completely polish them though. I would have liked the IE HD's but at the time I was rebuilding the head the HD's were out of stock and it wasn't something I was really willing to wait for. The head i'm using is already built and installed on the engine that's in my car, don't really feel like building it again lol

[MR 325]

Wow, that oil drain tube is terrible!

Looking forward to the outcome of this one. :)

[20gmr]

They are lighter and less has to be machined off of the crank to clear the shorter skirts. Although I have heard some people that they did not need to machine anything.



Cool, thanks for the info! So something like Simple Green would be fine?

You will have too machine the counter weights for sure. I was planning on doing a 2.8 m20 for a while and here is some info that may help you.

A signifigant amount of counterweight must be removed from the crankshaft, this obviously makes this a difficult combo to balance.

E blocks and I blocks are not identical....there is .5mm deck height difference

The machine shop I was dealing with said expect about 800 in balancing work, they said because of the counterweight size they would need to drill and press "heavy metal" (used for balancing when there is not enough room to get the proper weight using steel) into each counterweight.

I decided after 1k machining bill, and another atleast 500 in parts it wasnt at all worth the hassle and picked up an s52. Best of luck too you man...ps I also still have all the parts I rounded up to do build this engine.

[MR 325]

I keep telling him he will have to machine the crank down, he doesn't believe me.

As far as you saying that cutting down the crank makes it "difficult to balance", that is 110% NOT true. Sounds to me like your machine shop was taking you for a ride with the pricing.

Here's a friend's M52 crank that was already bobbed and during balancing:

[acolella76]

You will have too machine the counter weights for sure. I was planning on doing a 2.8 m20 for a while and here is some info that may help you.

A signifigant amount of counterweight must be removed from the crankshaft, this obviously makes this a difficult combo to balance.

E blocks and I blocks are not identical....there is .5mm deck height difference

The machine shop I was dealing with said expect about 800 in balancing work, they said because of the counterweight size they would need to drill and press "heavy metal" (used for balancing when there is not enough room to get the proper weight using steel) into each counterweight.

I decided after 1k machining bill, and another atleast 500 in parts it wasnt at all worth the hassle and picked up an s52. Best of luck too you man...ps I also still have all the parts I rounded up to do build this engine.

After doing a test fit of everything, I do realize that it will have to be bobbed down but not 'a significant amount'. It is really not that far off...

You definitely got taken for a ride by your machine shop. I was quoted not even half of that...

I keep telling him he will have to machine the crank down, he doesn't believe me.

As far as you saying that cutting down the crank makes it "difficult to balance", that is 110% NOT true. Sounds to me like your machine shop was taking you for a ride with the pricing.

Here's a friend's M52 crank that was already bobbed and during balancing:

The reason I didn't believe you is because it looked like my crank had already been machined down a little. Nothing personal :)

[LJ851]

A signifigant amount of counterweight must be removed from the crankshaft, this obviously makes this a difficult combo to balance.


The machine shop I was dealing with said expect about 800 in balancing work, they said because of the counterweight size they would need to drill and press "heavy metal" (used for balancing when there is not enough room to get the proper weight using steel) into each counterweight.

Sounds like they didn't want to do the work, that is a crazy price. Also an inline 6 crank is balanced to it self only so it doesn't even need to have counterweights. You can remove many pounds off the crank it you want to.

A crank that requires a balance factor (like an american v-eight) could run into the need for mallory (heavy metal) to be added if the counterweights are lightened.

[red_e30]

acolella76 here is some info on mm stroker motors and combinations they do, could be some hlep to you http://metricmechanic.com/pdfs/metri...ne-booklet.pdf

[Cinnabar325is]

I appreciate the info, you don't have a part number handy do you?

Just looked through my records for it and I don't have it and I don't know why, sorry.

Here's the rundown of the machine shop labor on my bottom end (I did complete assembly):

Degrease and prep surfaces: $80
Sonoflux block: $74
Hone cylinders: $120
Machine counterweights: $160
Balance complete 6 cylinder: $180
Clean crankshaft: $16
Sonoflux crankshaft: $38
Polish crankshaft: $68
Install freeze plugs: $40
Install oil seal spacer (had to be machined extra to fit): $40
R&R pistons and clean: $120
Bore and install IM shaft bearings: $160

Add in the tax and the machine shop bill cost me $1200.

And the counter weights STILL interfered with the piston skirts, which we discovered when putting the block together. I was not happy. I am using late model short skirt 'i' pistons. Somewhere I know I've seen the number for how much to trim the crank weights, but I don't remember where. I just told the guy at the shop to shave them till they cleared and I'm guessing he didn't check his work the last time around.

Also, many people have said you'll need to cut the IM shaft down to clear the crank, that is definitely not true, not even close. I can say, however, that the longer stroke brings the rods VERY close to the block walls at the bottom of the cylinder bores!

I should go back and do a write-up of my build, I took tons of pics and it would probably be helpful to folks on here.

[red_e30]

I should go back and do a write-up of my build, I took tons of pics and it would probably be helpful to folks on here.

yea that would help me out when i do this build
and probably other people to :)

[acolella76]

acolella76 here is some info on mm stroker motors and combinations they do, could be some hlep to you http://metricmechanic.com/pdfs/metri...ne-booklet.pdf

Thank you, but I know all about Metric Mechanic. I have spent hours at a time on the phone with Jim talking about M20s :)

Just looked through my records for it and I don't have it and I don't know why, sorry.

Here's the rundown of the machine shop labor on my bottom end (I did complete assembly):

Degrease and prep surfaces: $80
Sonoflux block: $74
Hone cylinders: $120
Machine counterweights: $160
Balance complete 6 cylinder: $180
Clean crankshaft: $16
Sonoflux crankshaft: $38
Polish crankshaft: $68
Install freeze plugs: $40
Install oil seal spacer (had to be machined extra to fit): $40
R&R pistons and clean: $120
Bore and install IM shaft bearings: $160

Add in the tax and the machine shop bill cost me $1200.

And the counter weights STILL interfered with the piston skirts, which we discovered when putting the block together. I was not happy. I am using late model short skirt 'i' pistons. Somewhere I know I've seen the number for how much to trim the crank weights, but I don't remember where. I just told the guy at the shop to shave them till they cleared and I'm guessing he didn't check his work the last time around.

Also, many people have said you'll need to cut the IM shaft down to clear the crank, that is definitely not true, not even close. I can say, however, that the longer stroke brings the rods VERY close to the block walls at the bottom of the cylinder bores!

I should go back and do a write-up of my build, I took tons of pics and it would probably be helpful to folks on here.

See... a lot of this I probably won't need. The crankshaft I bought came from a rebuilt M52, and it's literally in perfect condition. I want to frame it and put in on my wall it's so pretty. All that I need to do is shorten the counter weights and piston skirts and I'll be in the clear. Also going to have the block resurfaced and depending on how much they charge I will let them hone it, but I do have one of those 3-stone honing tools just lying around. Maybe I am just naive and pessimistic, we will see. I'm in no rush to have this done, so if I have to wait till I have 1k to spend on machining, so be it.

I noticed the IM shaft was nowhere near close as well... It looks like it COULD be a problem with an S50 or S52 crank though. My counterweights aren't really all that close to hitting the block, what block were you using? I have heard some people say that the block walls are different between B25's and B27's, the B27s having more room.

[Cinnabar325is]

No, not that the counterweights were close to the block, it's the rods that get very close to the block, like 1-2mm close. I'm using an '87 B25 block.

And yes, I believe the IM shaft could become a clearance issue with the S50 or S52 crank. And I guarantee the block would have to be clearanced for the rods.

[Myster-E]

After doing a test fit of everything, I do realize that it will have to be bobbed down but not 'a significant amount'. It is really not that far off...

You definitely got taken for a ride by your machine shop. I was quoted not even half of that...



The reason I didn't believe you is because it looked like my crank had already been machined down a little. Nothing personal :)

You will still have to have a minimum gap of .080-.01" between the piston and the crank due to the expanding and stretching of the rod and pistons.

[acolella76]

This is probably going to be the only 'full race mod' I do before the MegaSquirt... SPAL fan clone.



Anyone ever use one of those 3 stone honing attachments for a drill? I have one lying around and just need to deglaze the cylinder walls. Free > paying.

[LJ851]

Anyone ever use one of those 3 stone honing attachments for a drill? I have one lying around and just need to deglaze the cylinder walls. Free > paying.

Yes, many times.
It is not nearly as good as a machine hone job. Have you measured you bores? do you have material to spare?

[acolella76]

I have not measured... Don't have a bore gauge. I was planning on leaving that up to the machine shop. I can't really find a shop in GA who will do what I need though... A lot of them are saying that I don't need to resurface the block, in fact one shop told me it would just be a waste. Hopefully Jordan from Technica will point me in the right direction.