absolute maximum displacement M10 build

[jrcook320]

I have been daydreaming about building a maximum displacement m10 using an s14 crank and forged pistons for a future m10 turbo build. I’m wondering if you guys can help me out with some info. I need to know:

M10 rod length = 5.315" - 135mm
M10 rod journal dia. = 1.8898" - 48mm
M10 block deck height = ?? (not squish)

S14 rod length = 144mm
S14 journal diameter = 1.88877" - 1.88940" - 47.97-47.99mm

My current thoughts are a 92mm bore and 84mm stroke crank which would yield 2.23L, but I want to know if anyone has ever offset ground an m3 crank for longer stroke? If so, how far is possible? I want to keep a favorable rod length/stroke ratio. If I have to I’ll be searching for rods from another motor altogether that has the length and big end diameter that I need. Ken, tell me everything you know.

[TheNeek]

Did you just get your tax return or something?

[jrcook320]

haha, yes and no. Our tax return and Nikki's bonus check combined will be big enough to pay her e46 off, fund a vegas trip, and have some left over for hotrod cash.

but I'm not going to be doing this any time soon. I need a wide band setup, coil overs and a front suspension rebuild before I build a motor. I hope to run my current setup for a few more years before I blow it up. When it is time for a rebuild I'll also need to switch to efi and slap a much larger turbo on there. My goal would be 300+ hp. I just want to have a plan for when the time comes.

[e21Jason]

Hi

Metric mechanic do a 2.5 basicaly the s14 2.5 bottom end I have 2.3m10 (s14 crank, rods & pistons) in bits, but it took 5 blocks for the guy who done it to get it right.

Jason

[DrewDude320i]

in the words of the great Jeremy Clarkson:


"POWERRRRRRRRRRRRRR!!!"

[jrcook320]

How are they boring an m10 block to 93.4mm? Sleeves?

What is the stroke on the s14 2.5L crank? I assume 90mm? A 2.5 crank is likely out of the question for me.

[TheNeek]

An S14 bore is 93.2mm. Is that not possible on an M10?

[e21Jason]

Hi

you can take an 10 to 94mm just look over half a dozen blocks and pick the one with the most meat, later e30 blocks are 8kgs lighter plus have extra strengthing.

It could be easier to use an s14 block if you want a big displacement m10

[jrcook320]

heh, wikipedia listed it as 93.4mm. With that number punched into my spreadsheet all the numbers added up:

2302 cc's for the 2.3L and 2467 cc's for the 2.5L

I don't know how big you really can go. I've always read 92mm is the accepted safe limit.

[jrcook320]

wow, 94mm? Would you run that with 15 lbs of boost?

[jjgbmw323]

For an Ideas I would ask Metric Mechanic or VAC, who both can get you a s14 crank. And Josh, I think rather than doing this to the m10, I would just build an 2.5 S14 turbo.

[charbel]

or e23 3.5 turbo..

[blitzed310]

For an Ideas I would ask Metric Mechanic or VAC, who both can get you a s14 crank. And Josh, I think rather than doing this to the m10, I would just build an 2.5 S14 turbo.

or e23 3.5 turbo..

Not the point of this thread.

[jrcook320]

Thank you CJ.

I am aware of those options along with many others. I don't want an S14 or an m102, I want an m10. No matter what, on my next m10 build I will have machining costs and will have to buy forged pistons, efi, and a larger turbo. The only additional cost I plan on incurring over a normal 2.0L build is the s14 crank.

Either of the swaps you've suggested would require me to completely toss everything I currently have invested.

And Joe, why would I over-pay VAC or MM for an S14 crank when there are plenty of sources to get one cheaper?

[e21Jason]

Hi

if its for boost stick with the s14 crank, m10 rods, m30 pistons for a cheap 2.2, replace the rod/s pistons with forged after market ones if you have the $

Jason

[cheechthechi]

Josh, talk to kpiloto99? on the 2002 boards. He's running a 2.3 litre m10 with an s14 crank if I remember correctly.

[kdanielson]

I can't add much more than has already been said. I don't think I would go larger than 92mm especially if you plan to boost it much at all.

I have not found an aftermarket rod from another engine that is a direct swap in but some are pretty close and Eagle or Scat MAY be willing to do the final machine work to your specs on a set.

With the 92mm stroke a 5.7" (144.78mm) rod would be good and a 6" (152.4mm) rod would be even better but custom pistons will definitely be necessary.

I don't think you could offset grind a s14 crank to get more than a couple mm or so extra stroke without loosing too much strength where the rod journals meet the crank counter weights.

I think the best way to go would be a s14 crank, 92mm light weight pistons, the lightest forged rods you can find and then lighten and balance the crank to match. Be sure to include the front pulley, chain drive gear, flywheel (lightest you can find), clutch and pressure plate when balancing. With long rods it would be a quick reving 2.2L and make good power depending on the head, cam, intake, and exhaust used.

ken

[winstontj]

a 2.2L m10 has been done over and over... if you want to do a 219xcc m10 then use an m10 block & head, bore to 92mm (some say 93 is unsafe, I plan to bore to 93mm, jeff ireland & jim rowe says 93mm is fine) s14 144mm rods and and custom pistons with the CR of your choice.

OR DO THE MATH and realize that 2.3L is not possible from an m10. you can not bore to more than 93.5mm ~94mm max and that's for a one race only motor... if that.

Second choice:

S14 BLOCK with m10 head - 2002faq.com and look up user Grover or Norm. The s14 block is 95mm bore, choice of EVO (87mm) or standard 84mm s14 cranks, to acheive a true 2.3L-2.5L out of a quazi m10 motor (8v at least). If you go the EVO 87mm route you'll need custom rods and pistons... If you go 84mm stock s14 crank you need s14 rods and custom pistons only. a FI motor with an S14 block on a m10 head can make SERIOUS power. a guy on e30tech.com (good&tight) was making 359whp out of a 1.8L m10... if you are serious about building a true ~2.5L 4-cyl 8v motor and FI'ing it... WOW...

winstont AT direxionfunds DOT com if you are interested in more... I have all the parts but when its all said and done my 2002 is going to get a real M10 with S14 crank and early e21 NA intake with megasquirt...

let me know if you need more info...

[jrcook320]

doing the math, a 93mm bore and 84 mm stroke yields 2282cc's which is pretty darn close to 2.3L.

so, what is the accurate s14 bore and stroke? Every source I've seen has said something different now. My chilton's manual says 93.2mm bore. I've read 93.4mm and now 95mm. I assume the 2.3L s14 has a 93.4mm bore and 84mm stroke for a displacement of 2302cc's and the 2.5L s14 has a 95mm bore and a 87mm stroke for a displacement of 2467cc's.

The basic answer to my question is that the s14 crank cannot be offset ground a significant amount, and 93mm is the max accepted m10 bore. I don't plan on swapping blocks, this is still an M10 build, not an s14 with m10 head, I don't think that is worth it.

So that means my reasonably priced max displacement will be 2282cc's unless I find a 87mm crank which is not likely.

[jrcook320]

thanks for all the info guys. I'm sure this stuff has been beat to death for years but many searches and this post still haven't answered all my questions. I know I've read this somewhere before, but can't find it. What is the deck height of the m10 block? without that exact number I can't figure on anything.

I measured a spare 1.8 piston to have a compression hgt of ~47mm last night which would put the m10 deck height at 217.5mm (8.563")

With the numbers ken has posted, an s14 crank and m10 rods would require a 1.584" compression height. This would suggest a deck height of 217.233mm (8.553"). What is the actual deck height of the m10?

Ken, you say that with an s14 crank you'd want to use an aftermarket rod between 5.6 to 5.7" length. Why not just use the 144.25mm (5.669") S14 rods since you'll be in the market for custom pistons anyway?

[kdanielson]

By my calculations 8.553" is the correct crank centerline to deck distance. The s14 rod is pretty close and would work much better than the shorter m10 rod. My thoughts on the 5.7" or 6" rods go back to small block chevys with similar strokes to the s14 crank and what has been proven to make power and longivity and those sizes are common on the aftermarket though lacking the exact specs to be used on the m10/s14 cranks.

ken

[TheNeek]

Hartge made a stroker kit for the M44 (no I'm not suggesting it as a replacement). It's crazy riddiculuous, but they made a spacer for the rod journals. It essentially moved the whole crank assembly further down in the block. Not sure where they got a 4 cylinder crank witha 99mm throw, but I believe it was custom because it cost 15K. But talk about thinking outside the box.




This one was for sale on ebay a year ago. Went for 5K. The whole timing cover, oil pan, the whole shibang looks nothing like an M44 or M42.

[jrcook320]

wow, interesting. I wonder why go through all that trouble to build a 2.3 m44 when you could just buy a stock S14? I guess it's less trouble to not have to swap engines.

OR DO THE MATH and realize that 2.3L is not possible from an m10. you can not bore to more than 93.5mm ~94mm max and that's for a one race only motor... if that.

It is possible. If I bore to 93mm and offset grind the crank .5mm I'd have an 85mm stroke yeilding 2310cc's. I'd also be able to use standard .5mm oversized rod bearings. This will give me a compression hgt of 31mm and a rod ratio of 1.69.

[Stealthauto]

95mm is possible.

Dr. Gustave had his S14 block sonically tested and posted the results on his site.

Aparently the DTM cars ran 95mm bores in some of their versions.....

See the complete article and test data and results here

http://e30m3performance.com/tech_art...nic/sonic1.htm

[winstontj]

Send me a PM if you want. I have an 87mm S14 crank but it has a bad #3 rod journal that is beyond repair. If you are serious about offset grinding you can use audi 5000 rods or even GM rods with smaller big ends.

I would STRONGLY caution you against running a 93mm m10 bore. BMW and others ran NA motors to 93mm but searched for "thick cast" blocks with ~70k miles on them as the used blocks were found to hold up better under stress. The sidewalls will get too thin for a boosted motor at 93mm.

Also if you want to run 87mm crank you'll need to clearance the side of the block as the rod bolts will interfere with the base of the cylinders on the upstroke, the block on the downstroke and depending on what pistons the counterweights may hit the skirts. 87mm is a big crank to put into an m10.

Look here: http://www.ffwdconnection.com/butchercrank.shtml

I sent them my m20 eta crank a few months ago... For ~$400 they will turn your crank into that, re-harden it and ship it back to you. I expect my m20 crank back in early April. I'll put up pics then.