1995 M3 (S50) rebuild questions

[m3f_LuckyM301]

Hello im new to the forum and I'm not sure if I posted this right or not

I've looked through plenty of threads but it's all mainly short lived and parts pricing

I recently just bought a 95 M3 with 200,000 miles. It has a blown head gasket and since I'm already going to pull the head I want to rebuild it. I've heard that the bottom of the block is pretty sturdy but if I'm rebuilding the head should I rebuild the block too? I'd like to get a long life out of the engine so I feel I should get new rings and pistons along with a head rebuild. And when I rebuild it what could I do to add power besides forced induction? Hopefully I can get some insight and when I do a rebuild I can write up a DIY( yes it will be a long one but full of pictures and info for people like me). Thanks everyone

[m3f_McGyversM3]

If you have the time and money yes refresh everything new piston rings, main bearing, light hone the block (so long as there isn't any major scoring on the cylinder walls). Maybe a new oil pick up. Pistons and rods should be check for sizing you should be able to reuse the old ones unless you plan to go turbo or want the option in the future then new pistons and rods would be beneficial.


As far as power goes with the NA route schrick cams, headers, exhaust, intake, lightweight flywheel and clutch (it is 5 speed correct?) OR lightweight crank pulley. from what I've heard you shouldnt do both LWFW and LWCP.

Lightweight water pump pulley stewart water pump, lightweight power steering pump pulley. The pulleys wont add power but it will allow more power to reach the wheels. And definitely look for a tune to match all your upgrades.


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[m3f_Richardsperry]

Ok, I'll bite.


At 200K it already has had a long life. The question is how much do you want to put into a car that has that many miles and wont be worth more after you rebuild the engine?


A total rebuild with new parts will cost about $4000 or more. So unless you got the car for free, you end up with a car worth $4000...


If it were me, I'd pull the head, take it to a machine shop, have it checked, decked, do a valve job, guides and seals, check the spring pressure, make sure the retainers and collets are the newer version, then put it back with a new head gasket and head bolts. You can probably do that for less than $1000. I'd be really tempted to replace the lifters, but at about $24 each, x24... that's $600...


Speed is a question of money, how fast do you want to go?

[m3f_vmbray]

A total rebuild with new parts will cost about $4000 or more. So unless you got the car for free, you end up with a car worth $4000...

There is a lot of truth to the this, and depending on your ability to part and sell the car off might be better than the second sentence.



If you tear the bottom apart, the 4k is totally on the mark. For example, one of my oil squirters was totally shot and several were slack of spring, so that's 6x$25 = $150 for some tiny brass things with check valves in them. Hard to swallow in context of the overall build and when you think you've bought everything. I lucked on low mile lifters (and got two sets while I was at it, one with 5k and one with 25k) and the difference between a 150k mile lifter and a 25k one is not subtle. One is stuck, scored, and useless and one springs back like butter when you squeeze it. Even at the very top of the engine, you can do it later but do you want to re-time everthing? It'll take a less experienced person a full day to do the work just to swap lifters. Chains, guides, oil pump parts, pickup tube, might as well baffle the pan, etc. Rings $180 for aftermarket, $600 for bmw. Machine shop, crank, block, etc. On and on. Oh and you probably need attention to accessories too, a reman starter at least, rebuilt injectors (you weren't gonna slap those old dogs back on were you?). Rubber, all the cooling hoses, all the breather hoses, new oil separator, etc, etc. Electric fan, I wouldn't put it back any other way.



Is it worth it? If your car is clean and you're keeping it, and you won't get bored with it, then do it. If any of those isn't true then maybe not. If done right, it will run sweet and be worth it. A hone and new rings and a good break in and you will notice the engine stops spinning abruptly when you shut it off. The ring gap on a 200k engine will probably be near double the max spec, what that means in real terms to power I don't know but it's what you'll find in there.



To the resale value, I would hope a documented build with receipts would increase the value like other maintenance does (why not?) If not, a rebuilt engine with documentation should be worth at least 4k by itself if not more, and a roller probably 1500 depending on condition.

[m3f_LuckyM301]

If you have the time and money yes refresh everything new piston rings, main bearing, light hone the block (so long as there isn't any major scoring on the cylinder walls). Maybe a new oil pick up. Pistons and rods should be check for sizing you should be able to reuse the old ones unless you plan to go turbo or want the option in the future then new pistons and rods would be beneficial.


As far as power goes with the NA route schrick cams, headers, exhaust, intake, lightweight flywheel and clutch (it is 5 speed correct?) OR lightweight crank pulley. from what I've heard you shouldnt do both LWFW and LWCP.

Lightweight water pump pulley stewart water pump, lightweight power steering pump pulley. The pulleys wont add power but it will allow more power to reach the wheels. And definitely look for a tune to match all your upgrades.


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[m3f_LuckyM301]

There is a lot of truth to the this, and depending on your ability to part and sell the car off might be better than the second sentence.


If you tear the bottom apart, the 4k is totally on the mark. For example, one of my oil squirters was totally shot and several were slack of spring, so that's 6x$25 = $150 for some tiny brass things with check valves in them. Hard to swallow in context of the overall build and when you think you've bought everything. I lucked on low mile lifters (and got two sets while I was at it, one with 5k and one with 25k) and the difference between a 150k mile lifter and a 25k one is not subtle. One is stuck, scored, and useless and one springs back like butter when you squeeze it. Even at the very top of the engine, you can do it later but do you want to re-time everthing? It'll take a less experienced person a full day to do the work just to swap lifters. Chains, guides, oil pump parts, pickup tube, might as well baffle the pan, etc. Rings $180 for aftermarket, $600 for bmw. Machine shop, crank, block, etc. On and on. Oh and you probably need attention to accessories too, a reman starter at least, rebuilt injectors (you weren't gonna slap those old dogs back on were you?). Rubber, all the cooling hoses, all the breather hoses, new oil separator, etc, etc. Electric fan, I wouldn't put it back any other way.


Is it worth it? If your car is clean and you're keeping it, and you won't get bored with it, then do it. If any of those isn't true then maybe not. If done right, it will run sweet and be worth it. A hone and new rings and a good break in and you will notice the engine stops spinning abruptly when you shut it off. The ring gap on a 200k engine will probably be near double the max spec, what that means in real terms to power I don't know but it's what you'll find in there.


To the resale value, I would hope a documented build with receipts would increase the value like other maintenance does (why not?) If not, a rebuilt engine with documentation should be worth at least 4k by itself if not more, and a roller probably 1500 depending on condition.

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[m3f_LuckyM301]

I will be keeping the car that's the only reason I am rebuilding it plus I got it for 1500 with these mods

Meyle HD full front end overhaul

Mishimoto radiator

Mishimoto thermostat

Mishimoto radiator hoses

Stewart water pump

X brace

Solid Front and rear strut bars

Koni yellows

H&R race springs (trying to replace with sport)

Supersprint exhaust

AFE intake

New brakes, rotors, sumitomo tires

And a turner chip


I was going to buy it for 3 but talked him down because the headgasket, so I have 1500 I'm trying to find parts with until next paycheck

So what else should be upgraded besides retainers and collets? And anybody have a website for good aftermarket parts?


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[m3f_pat533i]

I used ecs tuning and pelican parts for all my non performance items. I had a 3000 order from ecs of "while your in there" items. 4000 is a laughable estimate to me. I spent more than double that rebuilding my s50. If your thinking about cams you'll need to factor in stiffer valve springs and definitely new lifters. Plus then you'll need larger injectors, maf, and tuning. Things add up really fast.


Most cost effective option (to add more power) would be buying a lower mileage s52 to make a Obd1 setup.

[m3f_dcfester]

Simple 3ltr stroker out of the m50 cost u 800 pound


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