M20B27"i" Stroker | Important Piston Info!
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- Опубліковано 1 жов 2024
- If you have an m20 powerplant in your old beem, you've probably heard of the stroker conversion! What you'd be unlikely to have heard, is that there are two different kinds of pistons that come in the 2.5i block. Only one type will work, the other would be a sad day...
When we mention, if you're building this engine use early stuff, we mean in terms of cooling system, early car - two neck water pump, late - single neck.
The production dates discussed in this video are pertinent only to the U.S Market. Refer to Realoem.com for further info on your market
Piston Part Numbers
Long skirt Original 325i : 11251714807
Weight improved piston from 325i produced post 7/20/1990: 11251735755
325e Piston: 11251714801
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When we stroke m20s in South Africa we use m20 block m52 328 crank
320 m20 rods
N Opel superboss pistons
278 cam
Lite flywheel
Gas flow n port head
High revv kit
Any chance you have access to any of those parts? Would love to play around with some stuff the US doesn't have easy access to.
For those who don’t know the 320 m20 rods are the same as the e30 eta rods here in the US that are 130mm.
how do you get the M52 crank into an M20? It's not plug & play afaik.
dokterkarel the crank drops in no problem, but you’ll need to make sure the pistons you choose clear the counter weights on the crank and the rods. You’ll also need a custom made nose piece for the crank since it’s based on chain and the m20 has a belt.
@@michaelwinfrey2047 are they the same weight?
Good advice. If you have a good shop you can machine off the skirts from the pre '90 pistons to allow for the rod clearance as well but if you can use the post '90 once so much the better....
This vid is very relevant for stroker builds and im grateful you guys cleared this up. I wish i found this sooner so i was 100% certain my pistons would work. Thankfully i got lucky and got the right ones without knowing, i wouldve been very sad if it didnt work. I had no idea there are 2 different “I” pistons so for others keep your eye out! Thank you DBO!
Thank YOU for making me doubt what I was saying and double check lol ended up helping everyone out!
So for the rotating asembly you have to use the b27 crank and rods and the post 1990 325i pistons (11251735755)????
I am restoring a 1980 323i. It takes a few times to start, runs good but dies at a stop. Got a cold start valve from Germany, however it still won’t idle, just dies, been to two shops $$$. I’m thinking of a m30 swap. Suggestions on getting my m20 to idle?
Lew
Vancouver, Wa
What is the resulting compression ratio achieved when using the 11251735755 piston with the B27 bottom end and an 885 cylinder head?
Чи можна описати весь комплект для строкера м20б27
HELLO THE FRENCHY please one e30 e36 327 i stroker turbo ou the compresseur bmw for sale just one cars bmw e30 ho e36 2 porta please seur
Hello, good I'm in need of spare parts for pistons and pinion of time, how can you help me, I am located in Colombia, I have a bmw 528i e12 1973 engine m20 b28
Just chuck the pistons in a lathe and turn the skirts down. BANG, now you have "weight improved". Yes, I have done it multiple times. If you are shaving the block ~2mm and using the eta rods/crank, they put down about 180whp on a stock cam. I have a long m20 dyno thread on r3vlimited, username is "forcedfirebird".
I love this guy, I have 2 e30 one that I use daily with more the 500K Km and a pristine one, besides a few S54 and 1 S55, I love your devotion to the M20 engine, hope one day visit your garage and perhaps have u build me an spare M20
Hey I have a 2.7 and cant find stock pistons. Can I use 2.5 pistons in my 2.7 block?
Thank you for making the videos bro. For taking your time to do the videos.
No problem! Glad people are enjoying it!
I've read that running the entire b27 rotating assembly leaves you with a compression ratio of 8.4:1. with late b25 pistons, what does the compression ratio end up at?
I have a low-boost b25 that smokes and I suspect failing piston rings. Wondering if an entire b27 bottom end is the move, or just crank and rods if I don't want a lower compression ratio losing me low end torque.
you are correct it is 8.42:1. Using b25 pistons yields 8.8:1. If turbo I would definitely just use the entire b27 short block and just throw the 885 head on it.
Thanks for the info. I'm building my first stroker this weekend, this info and clarification came just in time! DBO coming in clutch!
Happy to help! If you have any questions “in the moment” hit up Mile_high_euros on Instagram!
Awesome video, I did not know there was a difference. I do now! Thanks. PS have you guys ever had any issues cracking heads between 5-6 cylinders on a striker build? I head on E bottom end. I’ve cracked 2 heads in a row now at 15 psi of boost. Tune has very mild timing. The crack is in the water galley and as soon as it pops coolant starts coming up into the valve train. You can see the crack when you take the valve cover off. Never happened on my I motors with the same boost and the same head. Anyway cool vid!
Sweet vid broskie love the info .keep shredding n slurping
So what would be the compression ratio with the short-skirt 325i pistons and the 2.7 crank? Are there not the clearancing issues that the long skirts have with the head?
I've just put together a m20 bottom end stroked to 2.8L with
M52b28 crank
M20b25 short skirt pistons
M20b27 130mm conrods
how do you get the M52 crank into an M20? It's not plug & play afaik.
Also: typo in your comment. 230mm rods? You mean 130mm
@@dokterkarel the m52 drops straight into the m20 block it fit perfectly, only thing it needs it a steel spacer for the front crank seal and timing belt gear. Yes sorry i mean 130mm conrods
@@adamm9903 Thanks for your reply. By accident you don't have any pictures of the install of the crank (as in where the spacer goes, as I have trouble visualising it. Yet I'm planning to stroke an M20 soon. Just finished my M54B30 rebuild & swap and looking for a new project)
@@dokterkarel I do actually I've been taking photos throughout the build of it, if you go to my instagram page ae_workz I have a few photos up already and can send you more
Keep up with the aweousome videos guys!
Put them in the lathe and make the clearance you need?
From Colombia
Hi from Finland! I just bought my first e30 cabriolet a few months ago and the engine was badly broken, one of the valves was in the piston. 😅 I haven't ever built any engine but I watched your videos for that head assembly example, and it was very helpful. I have driven it now maybe a month and it works great. The only thing what is bothering me is that the oil light is not working, i have oil pressure gauge there because of that. This Stroker build is very interesting because i have a few blocks, one head, eta crank and better camshaft allready. Hopefully u understood something from my bad english. 😅 Keep up!
Glad you enjoyed watching! Super glad to hear it’s been running without problems!
I'd love to see a video about pulling more power out of the S52B32. I know the M50 manifold conversion is a free bump in numbers, but what about Cams, Headwork, Pistons/Rods, etc. Not really interested in forced induction on this motor personally. Thanks guys love the 2.7 stroker content lately.
We’ll see what we can do! Our videos are generally opportunistic so if the chance arises, you’ll be sure to see it happen! Also you’re not alone in the drive for N/A power 😉
Thanks putting all of this out there for us weekend warriors Will.
Could you possibly measure the skirt height on the light weight 1990 piston? I’m thinking that with far more of the original variant i piston out there that this issue could simply be overcome with a lathe or mill. We just need to know the skirt height dimension to machine them down to.
Cheers...looking forward to many more DBO vids.
Already jn the works my friend! Going to machine a set of long skirt pistons to the same specs as the short one and list the dimensions.
Ghetto minds think alike! Awesome!
@@DENVERBEERANDOIL any update on the piston dimensions?
So if I do all the steps to swapping an 885 325i head with all needed accessories Besides the the pistons from the 325i and keep the 325es Diesel looking low compression factory piston
I will have a great turbo setup, right?
Which after boost will make more power than a stroker motor with the 325i pistons anyway.
If I’m correct I’m going boost.
Hi
If you do m20b27 stoker, what house power can be expected?
Thank you
Also most flat bottom late pistons have 8.8:1 compression
Early pistons are 9.4 and 9.7
They have numbers on them so you can check it online to see what compression they have
And 1 more thing the date is wrong
I open 2 m20b25 engines from e34 525i
1 from 1988 and the other from 1989 and both had the late flat bottom pistons with 8:8.1 compression
If building one of these motors for boost you said using the 2.7 pistons is best. How much boost do you think the stock pistons can handle before needing to upgrade?
It’s mostly hearsay, and we wouldn’t be comfortable putting a number on it. Though there’s a good deal of information on forums!
there is another m20b25 piston, its the euro non cat version with 9.7:1 compression. Rare here but runs motronic 1.0, zach had the red 1986 325ix which had those pistons in it
awesome video man, im using a b27 bottom end pistons and all with the b25 head and boosting it keep up the good content!!!!
Hey I’m going with the same setup What tune will you be getting?
I've got an 87' 325e superEta. Can i use my superEta piston rods with late 325i pistons?
I built my stroker with an m52 crank, 135mm rods and custom pistons. Unless you have the super eta pistons making a stroker work without massive machine work is not possible. I have all the piston, crank and rod options in my garage and I decided on custom pistons because the cost was less than machine work.
Thanks for the info Will! I never thought about pulling up realoem or looking for a build date to see if there were different part numbers/ updates. I bet there is a TSB # that you could probably look up to verify the newer style pistons as well. I should've known this information and I can't believe that I didn't. I built probably half a dozen of these over the years but it's been quite some time and I always did it the way you have because I never knew. You do a valuable service by helping people decipher what works and what doesn't. Hell I've had these motors apart so many times, but even someone like me could benefit from a 'refresher.' DBO is my favorite channel by far, and definitely the most underrated and entertaining stuff on the interwebz. You planning on making a video with Hamish's m60 swapped e30? Looks cool, and those things are fun with the m60 installed. Even a m60b30 is an upgrade over an NA m20. Can't go wrong with the v8 torque and sound. I had two 540/6 e34's and they were just great daily drivers. I miss them honestly. One of mine had the e32 3.15lsd, ltw flywheel, full mandrel exhaust with a Magnaflow/ cat delete, e60 545i 'short version' shift lever, poly motor/ trans/ suspension bushings, etc. Those mods in my opinion, are the best for the m60 powered cars. Diff, flywheel, shifter, exhaust, mounts, maybe the bigger plenum (b44 or ITB's) are the most noticeable stuff that really improves the enjoyment of that platform. Everything else for the m60 is big money really....
I'd definitely like to see some video and details on that car. Great work as always!
Hey Pete! Hamish here, I already have two episodes filmed! Just need the balls to put em out haha, right now it’s an m60b44 with the getrag 420g 6, it’ll be mated to a 2.93 LSD, the shifter is an e46 m3 assembly, fits mint! I’ll try and get that video out this week!
@@DENVERBEERANDOIL Hey Hamish!
Yeah bro, definitely post those please. Love these type of builds. The m60b44 is the best one to go with, and I believe it already has the best flowing intake manifold IIRC. Pretty sure that's the one I threw on mine. You should definitely investigate what other diffs you can use on the e30. I know when I used the e32 3.15 on my e34 it was probably the best upgrade you could do with the 6 speed to get you a nice increase in acceleration. Since it was a 6 speed, the final gear is fairly tall and you won't be at high rpms with the shorter final drive. Only thing you need to do on the e34 to make it work is change the input flange. Otherwise FWIR it bolts right up. Obviously your case is a different size in the e30 but I'm sure someone has figured a different OEM alternative that it will benefit from. All my 2.93 diffs were open which sucked because both my 540/6 had ASC. That setup is a huge buzzkill, and even when its disabled, the intake boot and ASC throttle body is restrictive. BMW has a non-ASC intake boot which is an improvement, or you can make your own out of silicone couplers and a couple small chunks of 3.5" or 4" piping. I'd recommend chipping the DME if you haven't already as well. Hard to go wrong for the $ to pull the speed limiter, raise the rev limit, and add a better fuel and ignition map. There is a guy out there who does custom tunes for the 404 DME. I'm sure he does others if your running a later one, but afaik the 404 is the best one to go with. Check DUDMD on bimmerforums. Hes the guy that burns custom eproms. The lightweight flywheel is an enormous upgrade as the stock dual mass is heavy as hell!!! Pretty sure they're just south of 30 lbs! I had a JB Racing one on mine and what a difference. Also has the JB on my e36 track car and it never let me down in over 15 years of abuse. Some things to ponder for the future if you end up having a couple extra bucks to spend. Get those videos up broseph!!! Excited to see what you've got going on there!!!
Great vid man, Is there any m30b35 stroker mods?
There are a couple different combos of cranks/rods/pistons from the b35, s38 and m88/m90 that you can use for displacements between 3.7 and 4.0L but parts are much more difficult and expensive to source.
Great info.
Can I use the late b25 pistons with a stock b27 head as well? I’m trying to rebuild my b27 to stock but can not find good quality used b27 pistons.
It will raise compression, but yeah I think it would work.
what happened to kswap e30
On the backburner, currently. We’ll be revisiting it when possible, but for now, we can’t promise anything
Great info!
In the last video, you mentioned issues with the i piston contacting the head when running the e crank. Can you go into more detail about that?
That's only if you use the longer "i" rod in conjunction with the e crank and i piston
@@DENVERBEERANDOIL so to confirm, if I have the later i piston, e crank, and e rods, that setup will work? I have a Nov. 1990 build date 325i and hope to eventually make a stroker from it. Is there a performance camshaft you recommend?
@@DENVERBEERANDOIL I was curious if it was to do with the compression height difference of the i piston. You mentioned removing material from the i pistons for them to work.
@@ChrisJackson36 that is why I made this quick little video about the pistons. You would need to modify the long skirt early 325i piston but the late ones work
Yep! You have all the parts to make yourself a stroker. If you want a "performance" crank from stock parts, the m21 diesel crank is forged. Tough to find though.
Couldn't you just "modify" the early i piston skirt?
Absolutely. But you'd need a mill and preferably a very true mill and the ability to weight balance. I actually am having a machine shop do this in the near future so I can give the specs to everyone.
@@DENVERBEERANDOIL sounds like $$$. How about some backyard machining?