Aftermarket alusil M60 pistons?

[paulmer]

Hey guys, I've got a spare M60 I want to hot-rod, and am mulling over my options.

I'd like to bump up the compression and get some nice lighter pistons..

I know VAC has a sleeving service and they sell CP pistons which you can order in whatever comp you want to go with..But I'd like to keep the alusil walls. I've already got a machine shop in line whom can recondition the alusil walls.

Does anyone know of a company who sells alusil pistons? Or should I just give up on that and get the block sleeved and go with conventional pistons?

Btw, would 11:1 comp be appropriate running 91 octane pump gas?

Also, has anyone had their conrods lightened by removing excess material, or gone with aftermarket rods?

[ESSSupreme]

Maxsil?

[m60b30530i]

read around about the m62 a few members on here have swapped them and have done extensive custom work to them.

[xatlas0]

Hey guys, I've got a spare M60 I want to hot-rod, and am mulling over my options.

I'd like to bump up the compression and get some nice lighter pistons..

I know VAC has a sleeving service and they sell CP pistons which you can order in whatever comp you want to go with..But I'd like to keep the alusil walls. I've already got a machine shop in line whom can recondition the alusil walls.

Does anyone know of a company who sells alusil pistons? Or should I just give up on that and get the block sleeved and go with conventional pistons?

Btw, would 11:1 comp be appropriate running 91 octane pump gas?

Also, has anyone had their conrods lightened by removing excess material, or gone with aftermarket rods?

Raising the CR is going to be a fool's errand, unless you plan on running the thing on 100 octane all the time. Any power gain (~3% for an increase of +0.5:1) will be minimal, and you'll be giving the knock sensors a real workout on a daily commute. I've seen CRs that high on the S54 and such, but that's more for those rare instances when you can actually get the full power out.

I've seen a few different piston manufacturers that could likely make the pistons in varying materials, like CP, Weisco, Arrow, and a few others. Rods are generally oversized, but the FI guys have managed to find aftermarket groups that make lighter rods with similar strength.

So, it really boils down to what kind of engine you want. Larger displacement will give more power, higher RPMs will give more power at the expense of driveability. Were I hot-rodding a M60, I'd go the large displacement route with custom pistons and rods to reduce rotating mass. Add in some custom cams, long-tube equal-length headers, P&P-ed head, bigger valves, and a custom tune to get a nice, faster but useable engine.

[paulmer]

A fools errand? Plenty of engines out there run 11:1 comp and can run on pump 91 octane gas (S62, etc)..So why can't I?

How on earth would you do equal-length headers in an M60? There is NO room even with the factory ones!

I'd rather not bump up the displacement, but lower rotating mass would be nice..Has anyone had a machineshop lighten the factory rods? Maybe I'd do that and get some new Wiesco factory CR pistons, have the cylinders rehoned, have the block thermally cleaned, painted, crank xrayed, crank+rods balanced...I was thinking bumping up the CR would be a nice addition, but finding aftermarket pistons doesn't seem worth it.

[xatlas0]

A fools errand? Plenty of engines out there run 11:1 comp and can run on pump 91 octane gas (S62, etc)..So why can't I?

How on earth would you do equal-length headers in an M60? There is NO room even with the factory ones!

I'd rather not bump up the displacement, but lower rotating mass would be nice..Has anyone had a machineshop lighten the factory rods? Maybe I'd do that and get some new Wiesco factory CR pistons, have the cylinders rehoned, have the block thermally cleaned, painted, crank xrayed, crank+rods balanced...I was thinking bumping up the CR would be a nice addition, but finding aftermarket pistons doesn't seem worth it.

I called it a fool's errand because in most non-ideal conditions (aka, daily driving) those engines pull the timing so the extra compression is immaterial. Also, like I mentioned, you are looking at a less than 8% power increase. The $/power ratio just isn't here.

As for the headers, SuperSprint makes a set.

Why are you fixed on altering the rotating mass? The power losses due to accelerating the rotating mass are not particularly high in this engine. A lightweight flywheel will make it zippy, if that is what you are looking for. I used to drive a 99 540i/6 with a lightweight flywheel, and it behaved much like a later Mini Cooper S JCW, in terms of how zippy the engine was. Changing the flywheel drops ~20lbs out of the rotating assembly, far more than pistons and rods combined.

To get more power, you are going to need more displacement, or at least some cam work, which will compromise the low-end for high-end gains past a certain point. Just bumping the displacement by 10% shows, on average, a 15-20% gain in rwhp. I'd love to see some M62B46 dynos for comparison, but I haven't seen any to add to the data set.

[ross1]

A fools errand? Plenty of engines out there run 11:1 comp and can run on pump 91 octane gas (S62, etc)..So why can't I?

How on earth would you do equal-length headers in an M60? There is NO room even with the factory ones!

I'd rather not bump up the displacement, but lower rotating mass would be nice..Has anyone had a machineshop lighten the factory rods? Maybe I'd do that and get some new Wiesco factory CR pistons, have the cylinders rehoned, have the block thermally cleaned, painted, crank xrayed, crank+rods balanced...I was thinking bumping up the CR would be a nice addition, but finding aftermarket pistons doesn't seem worth it.

You've asked for advice, xatlas has offered sound advice and you argue?
Seems you already have a plan, let us know how it works.
Oh, I've had lots of high compression engines. Unless you have plenty of overlap in the cam grinds you'd better plan on using race fuel or mitigating detonation by other means.
If you want a driveable, more powerful V-8 swap a Chevrolet in there and don't tell your friends.

[zubbie]

look for posts by "BigM62". He has a full "hot rodded" engine and lots of advice on where to make power. Without question, though, you'd better have deep pockets.

[T444E]

Start with an M62. Seriously.

[MacR]

So, you're going to throw in some AM pistons and wish for 50hp? xatlas has some great advice, I'd recommend doing some extra research. You'll find that pumping out power from the m60 is not easy. There's a reason most of us that beef up the block start with an m62. There's a handful of m62 swaps documented on the board, check into it.

If you want to DD it, don't touch it. After the work on mine, it's not really a joy to drive around the city it. Out at the reservoir however, :devillook

[paulmer]

I called it a fool's errand because in most non-ideal conditions (aka, daily driving) those engines pull the timing so the extra compression is immaterial. Also, like I mentioned, you are looking at a less than 8% power increase. The $/power ratio just isn't here.

As for the headers, SuperSprint makes a set.

Why are you fixed on altering the rotating mass? The power losses due to accelerating the rotating mass are not particularly high in this engine. A lightweight flywheel will make it zippy, if that is what you are looking for. I used to drive a 99 540i/6 with a lightweight flywheel, and it behaved much like a later Mini Cooper S JCW, in terms of how zippy the engine was. Changing the flywheel drops ~20lbs out of the rotating assembly, far more than pistons and rods combined.

To get more power, you are going to need more displacement, or at least some cam work, which will compromise the low-end for high-end gains past a certain point. Just bumping the displacement by 10% shows, on average, a 15-20% gain in rwhp. I'd love to see some M62B46 dynos for comparison, but I haven't seen any to add to the data set.
Aftermarket pistons really aren't that much more money compared to Wiesco replacement pistons (on VAC, +300 dollars)...so it isn't that big of an expenditure to go with the higher CR pistons, if I wanted to.

Do they? I was looking on their site, it's very hard to find supersprint parts for "old" cars, none of their retailers carry them anymore..

I'd like to go with a lighter flywheel, but I don't want to cause too high NVH. Compared to the OE dual mass, how was the NVH with the lightweight one?

I guess I still haven't finished the manual swap, all of the parts are laying on the garage floor, trying to get the 540 sent to the crusher this week, RIP mevils car! I'm sure the biggest part of why it feels sluggish is the automatic, I bet with the manual it will be exponentially more zippy

Speaking of cams, the schrick cams that Korman sells alongside their DME tuning have no loss at any rev:
http://www.kormanfastbmw.com/v8cams1.gif

I know Dinan has cams that produce more high-end power, but probably at the loss of low-end. I noted how they didn't show any dyno graph, heh.

The gains from the Schrick cams are conservative...if I were to go with aftermarket cams, this would be what I want. Out of the factory, the high-end is already strong enough!

I'm not looking to build a 600 supercharged hp beast..I want to retain good drivability (being that this is going in to a 7 series....). It seems if you really want to go with high hp you really need to either bump the displacement much more, go with highly aggressive cams and ruin your low-end or supercharge it. None of these are options I'm willing to take, I just want to do conservative mods here.


Start with an M62. Seriously.That is a solid option. Get a M62 block, throw the M60 heads, intake, etc on and use M60 DME...This of course has been done many times and has good results.

[944CS]

Call Racer's Edge, they sell Wisecos that are alusil compatible.

[skylinergtr]

Forged JE pistons?

[moroza]

Conservative mods? There aren't any for this engine. Anything meaningful is going to cost at least $1k; anything with a major power increase and drivability will be much more than that (S62, basically).

Start with an M62. M60 heads won't fit without some work, but the extra 400cc's are a much better power/$ proposition than anything else we're discussing.

One advantage the M60 has is a dual-row timing chain with an idler gear, as well as more stock cam lift. It would be relatively easy to get M60 cams to fit in an M62 head, allowing you to use the stronger chain setup more appropriate for a higher-spinning motor.

I have a lightweight flywheel - the UUC V12 conversion kit with an OEM 850Ci clutch (sprung). These transmissions - even when brand new from BMW, apparently - have a tendency to rattle in high-load low-RPM applications with a light flywheel. It's not a dealbreaker but the noise is there. There's also chatter from the trans when idling with the clutch out (varies from car to car; mine's inaudible with the windows closed), even with a sprung clutch like I have. I take it easy with my trans, and the way this thing absolutely flies through the rev range makes me have to blip the throttle even on an upshift, but it feels and sounds awesome, and being able to downshift with a flick of my right toes puts a smile on my face every time. If I had an SSK and no regrets about killing synchros, my shifts would be about as fast as the average automatic.

Turner sells the Supersprint header kit. They were unable to tell me whether it would fit an E34 chassis. I'm not too familiar with the E39 subframe and body to say for sure, but my hunch is that with minor modification at most (like, a slight bend or two), the kit will fit.

Shrick's graph starts at 3k. My understanding is that it's right impossible to make more torque at all RPM ranges with cam changes, at least not compared to stock cams from a good engine manufacturer (BMW). It'll idle lumpier and probably have less guts off the line, but it's probably worth it.

I was drooling browsing though VAC's selection of M60/M62 parts the other day. They sell, among other things, a solid lifter conversion kit. The hassle notwithstanding, reducing the reciprocating mass (pistons and conrods) and strengthening the valvetrain (springs and lifters) could probably net a meaningful revlimit increase, with cams, intake, and to a lesser extent exhaust tuning to actually make power up there.

My feeling on spinning these motors high is that they're mechanically able to do considerably more than their factory redline, they just don't make power. Before dumping several thousand on lightweight pistons and conrods, I would find a cheapie 530i with a decently healthy engine, use some software to remove the revlimit altogether, and see how high you can get it to go before it explodes, or how long it lasts being spun to 7500 on a regular basis, or something in between. When that happens, you've blown up a $500 (at most) engine and have some good info for a high-spinning M6x build.

If you want to spin high, there's also the option of destroking - say, an M60B40 crank with an S62 bore. By all accounts it's not worth it, however.

MacR, you're awfully shy about what's actually in your build. I know you don't like build threads, but could you shed some light on what's in your engine?

[bmwhiteman]

I want the link for those cams!

[e34Croak]

:eatpop:Finally.