TO EVERYONE that is making or has made a stroker.

[Sean]

I recently learned of some new information that I didn't know before, or quite understand, anyway.

This piece of information is that the BUDGET SuperEta stroker will not lost very long, driven like a BMW is normally driven - hard. For some reason, I thought a rebuilt motor, doing a budget stroker type build, would last just as long as a normal M20 motor. (yea, call me stupid)

The reason for this is the shorter rods. The shorter rods cause a lot more strain on the engine, at the same time, the heavier weight causes a lot of banging around inside the cylinders. These shorter rods are not made to rev high, that's why the I's have longer rods, they are better for revving higher.

The question I have for all of you that build strokers - has longevity ever been a deciding factor for you? From what I read, on Metric mechanic and talking to Jim Rowe, a SuperEta budget stroker, driven hard, will only last to 100,000 miles max. That doesn't seem like a whole lot in relation to what a stock motor will go to.

Am I being anal thinking about this now that my engine is apart, or not?

How long have these engines lasted for other people? What combinations have been done to increase the power, without sacraficing life?

I know forcing more power out of a motor can decrease it's life - but when there's ways to get more power, and still have a long life - why not go that route?

I don't think I can afford the Metric mechanic pistons and rings, at $1300 for the whole deal. These pistons, paired with I rods will last as long as a normal m20, up to 200,000 miles driven hard.

I kind of want to get other people's opinions on my build. If I decide to get brand new pistons, I'll have to let my car sit a while, since I need some cash flow first. OR, I can just put it together with a honed block, possibly a decked block, and the old SuperEta pistons and just go for shit.

Essentially, it comes down to this. Should I wait, spend the money on the more expensive pistons, get more power and more life from my motor (and stick to N/A) or should I cheap out, use the pistons I ahve now, pray that it lasts at least 70,000 miles and possibly do a turbo later in its life which will only decrease it's life more?

And with that, i ask your opinions as well as what you've done. With that, how long have you had it, and how much longer do you plan to have it running?

Discuss. :)

[nando]

actually, I just had a thought - are you totally set on keeping the M20? $1300 could go a long way to a motor swap (M52, S50, etc). I don't really have much choice, and I like the M20 for what it is, so I don't mind "wasting" money on it. but you have options I don't.

btw that's about $1300 for the pistons and a set of used (m52) rods, the pistons come with rings and pins for $1050.

I think you should consider going with your original plan, and your options later on. or maybe a stock rebuild and forget the i cam an dual valve springs to get you through college. but if you are dead set on a stroker I don't think you will be disappointed if you do it the right way.

[DrMcDave]

actually, I just had a thought - are you totally set on keeping the M20? $1300 could go a long way to a motor swap (M52, S50, etc). I don't really have much choice, and I like the M20 for what it is, so I don't mind "wasting" money on it. but you have options I don't.

btw that's about $1300 for the pistons and a set of used (m52) rods, the pistons come with rings and pins for $1050.

I think you should consider going with your original plan, and your options later on. or maybe a stock rebuild and forget the i cam an dual valve springs to get you through college. but if you are dead set on a stroker I don't think you will be disappointed if you do it the right way.

are you sure the rings are included in that 1050 i don't think they are.

[Sean]

actually, I just had a thought - are you totally set on keeping the M20? $1300 could go a long way to a motor swap (M52, S50, etc). I don't really have much choice, and I like the M20 for what it is, so I don't mind "wasting" money on it. but you have options I don't.

btw that's about $1300 for the pistons and a set of used (m52) rods, the pistons come with rings and pins for $1050.

I think you should consider going with your original plan, and your options later on. or maybe a stock rebuild and forget the i cam an dual valve springs to get you through college. but if you are dead set on a stroker I don't think you will be disappointed if you do it the right way.

If I had known everything I do now, I'd be looking at an S50. You're definately right - the amount I've spent so far has turned this stroker into a not-so-budget stroker. All the more reason I go ahead and do this right the first time.

I've already dumped more money than I care to think of into the stroker idea. My top end is ready to be put to use, all I had left is the bottom. Wish I could just put everything back together and run it, without knowing what I know now, but I can't.

I have thought about just putting it together, following my original plan - but that will only go so far. I'd love to some day put an S38 into my car, but that won't happen for a while. I was thinking - well, this will last a while, then I'll get tired of it, and change it out. But then I thought - maybe I won't? Maybe I'll like having a strong, long-lasting stroker that will leave me room for improvement in terms of airflow and headwork. I mean, I love the idea of throwing a cam in there, and actually being able to get some cool use out of it! :)

I thought of that Nando, the fact that you're stuck with the M20, and that's why you're doin it. However, the thing I really enjoy about the M20 is it's torque. I've been driving my dads M3 a lot recently, and I really enjoy the M20's power curve a lot more than the S50. It just seems more perky.

Finally, knowing that that piston will be knocking around in the cylinder the entire time I run the engine is knowledge learned, and knowledge used. Because of that, I'll always be listening, and being careful not to rev high for long. I'd hate to do that - I wanna be confident in my engine, mostly my bottom end. The way Jim put it - the bottom end is the basis for the engine - skimp out there, and you skimp out everywhere.


And, I don't think the rings are included - Jim said they were an extra $125 or so?


Nando - I really appreciate all your input. It's helping me to make an educated and thoughtful dicision on the matter!



Here's what I'm thinking right now:
I have a bunch of little things to do on my car - install the Z3 rack, fix my subframe, run wiring for my electric fan, thoroughly clean out my engine bay, get one of my trannies ready for use, and powdercoat misc pieces. my thought is, I can get all that done, with no rush, and do them well. Then when I've raised the money, I can purchase the pistons and hopefully some M52B28 rods and put the bottom end together the way it should be. Then I can put the engine in, making sure everything is right along the way, and run it as soon as it's in! The way I'm thinking - I wanna do this right the first time. I want this engine to look good, and run strong - knowing full well that those pistons are banging up inside there the entire time. It will only nag me in the long run.

But, the idea of finishing my original idea and just goin for it still lingers...hmmm.. I'm so indecisive. :-?

[DrMcDave]

Sounds like you have it worked out pretty well. I am also stuck w/ an m20 if i weren't i'd have an s50 already. more efficient more power, less maintenance. However i like the idea of the m20 because it keeps the car more original.

maybe think about selling the head

[nando]

are you sure the rings are included in that 1050 i don't think they are.

pretty sure, I asked Jim myself :p

bearings were extra though (I think $174 for a set).

guess I'll find out today though, going to order them so the machine shop can bore the block properly.

btw I enjoy the M20 for what it is - and actually I'm not so sure I'd do an engine swap if I could anyway. I've been there and done that in the past, it's usually a big PITA, and I always end up wishing I'd just built up the motor I started with. The bottom end is definitely the base of the motor - I'll still have the stock AFM, intake manifold, and computer for a while after I finish, but once the bottom end is done, I can add whatever I want up top - ITBs, MAF, piggy back, long-tube headers, etc. even the head is pretty easily worked on, once you pull one a couple times you get pretty good at it. ;)

I'm guessing you have another car you can drive, so yeah, no rush. that's the scary thing about my project, I'm doing a tranny swap, new motor, new steering rack, and a bunch of other stuff, and I don't have another car to drive if I screw something up (plus I don't want to miss any of this year's autox season!). fortunately I live within walking distance of work, so I could deal without my car for a while if I had to. that's why I'm not half-assing anything, I can't afford to melt a piston or have an engine that burns 1 quart of oil every 500 miles because I wasn't willing to spend an extra couple hundred $$ up front for the correct parts! also, pulling a motor on an ix is a lot of extra work, definitely not something I want to do twice!

[madjurgen]

youre piecing together a modified motor and 100K miles isnt reliable enough for you?

[DrMcDave]

i thought i had remember jim saying something different back when i talked to him but i am sure you are right. i was thinking about just rebuilding my head but you are so right about the bottom end being the foundation for an engine. I figure start there and make that how you want. pulling a head does get easy after a few attempts.

care to post your engine specs nando?

[JRowe]

Anytime you go with a stroker, you have shorter rods and a longer stroke. It does change the angle of the rods to the pistions. I don't buy the banging around in the cylinders line. If the pistons are properly fitted to the cylinder, it shouldn't be a problem. The rod angle is increased, but it shouldn't substantially shorten the life of rebuilt engine. Driven hard, 100k is about right for any rebuild. Driven normally on the street look for more.

MM has optimized the M20 stroker by using stronger rods and lighter pistons. They have an interest in people buying their kit. It doesn't mean that the 2.7 budget stroker is a bad engine, just not as good as theirs. The MM website says as much. It admits the 2.7 stroker is the best way to go on a budget. It comes down to a question of cost vs benefit and what you are willing to live with. Personally, for a street driven 15-20 year old car, I think the 2.7 supereta stroker is a good way to go. Not the best, but still good.

BTW - don't get confused by my user name - jrowe. I'm not Jim Rowe, rather Jeff Rowe - not relation that I know of. For simplicity, I just use the same user name as assigned to my computer.

[nando]

i thought i had remember jim saying something different back when i talked to him but i am sure you are right. i was thinking about just rebuilding my head but you are so right about the bottom end being the foundation for an engine. I figure start there and make that how you want. pulling a head does get easy after a few attempts.

care to post your engine specs nando?

81mm eta crank, S50 rods, 86mm bore. the head has some mild port work and a shrick 284/272 cam. will have rebuilt 19lb injectors, and an AFPR. the rest will be stock for now. ;)

as far as R/S ratios, yes any stroker will decrease the ratio, but the ETA rods are especially unfavorable because they are even shorter. that is one of the main reasons I decided against the 84mm crank.

[AdironRider]

Ask yourself this question, are you honestly going to keep this engine/car for 100k longer. Frankly since your still in school there is always a chance that once you get a real job/income, you might move on to bigger and better things. 100k is alot of miles. Just something to keep in mind.

1300 sounds like alot for pistons, and a stroker is only going to make so much power. If you have to rebuild the motor again at 100k, then so be it I say. Thats at least 5+ years down the road, and thats if you put 20k a year on the car.

[JRowe]

The 2.7 supereta/i stroker uses the 81mm stroke crank and 84mm pistons. No promblems with the ratios. Also, check some of the turbo threads. Guys push 300+ hp through these bottom ends with no problem. The weak spot on these engines for something breaking is the rockers at high rpm.

[madjurgen]

81mm eta crank, S50 rods, 86mm bore. the head has some mild port work and a shrick 284/272 cam. will have rebuilt 19lb injectors, and an AFPR. the rest will be stock for now. ;)

as far as R/S ratios, yes any stroker will decrease the ratio, but the ETA rods are especially unfavorable because they are even shorter. that is one of the main reasons I decided against the 84mm crank.

So you decided to go with 86mm bore after talking to MM? You using their pistons too? I hope i dont regret going with the 86mm crank. If it ends up being not very revvable i might invest in some ltw 139mm rods. Have decided how much of the work youre going to do yourself? I hope you plan on doing a write-up about all this.

[nando]

dave you were right, the rings are another $150. in any case, they will be here sometime next week, I will hopefully get my block torn down this weekend and go pick up my crank, then it's off to the machine shop :)

I think I'm going to end up putting it all together.. it's really not that complicated, as long as my bearing clearances are right there's not a whole lot to a bottom end. all the machine work will be taken care of by a shop of course (deck, bore, hone.. that's about it). I'd like to have it all put together by the end of june but I'm not sure if I will have all my parts together by then, otherwise I'll have to wait until after july 10th to put it in.

and yeah, personally I will never sell this car, although it's not likely it will be my daily driver 10 years from now. maybe I will move on to better things (like a lexus? har har), but there's no way I could sell it, as it is I can't go more than a day without driving it. a whole week of tearing things apart and putting it back together will be hell!

[DrMcDave]

yeah explain why you went a/ the 86mm bore? how many liters does that work out to, 2.9?

i want to keep the bore at 84 or 85 because i'd like to factor boost into mine when the time is right. seems it never is though.