m62B44 engine rebuilding

[seabass07]

Kenny, excellent digging for info. Now we have specs for S 62 cams that I asked about. Also bears out my choice of piston, with Teflon skirts. The desire to bore and hone was to reuse scored blocks and with no over size factory piston available, that forced the rod change etc. The issue of boost and your difficulties are good to know as I have temporarily gotten off the engine build and have been full steam on mounting the S/C. You must have had some detonation that you were unaware of. Coated Forged pistons are the next thing I'll search for, but first I need to see if we can get ring seal on a N/A motor. On a side note, the old rules from the days of cast iron engines were that you got one point of compression "forgiveness" by having aluminium heads. All aluminium block was good for a little more help against detonation. That's how I thought all the F/I people were getting away with running 10.1 compression. Group question; how much compression and how much boost before problems. And like the article pointed out, is there that much difference between the kinds of boost and problems?

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Also, could an uncontrolled vanos be building extra cylinder pressure at the wrong time?

Out of curiosity, were you monitoring afr and knock fairly regularly?

[wagons ho]

Tptrsn. I'm only going to chime in to say you got this and my confidence.. It also means I'd like to gap the rings on one of my lesser cores and boost it, prior to rebuilding it. I'll be ready to test shortly.

[Kenny1958]

Yes I had an afr gauge fitted and all was good, it was only when I went for a dyno run that I found it had been going below 10 on boost.

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[philly98540]

Watching this thread intently. Hope I'm good on my car.

[seabass07]

Is there any decent software to log knock etc?

[philly98540]

With Testo you can log timing. Once you know what your timing normally is at WOT, you can see when timing gets pulled. I think my DME pulls it in 3 degree increments when it detects knock of varying amounts. I can see timing pull when it's hot out on my car. This is pretty normal from what I hear. The DME is good at keeping things safe is what I'm told.

I think Brian (Redshift ) logged knock on Testo but it's hard to decipher the data as the sensor output goes up with load and it's noisy. The DME must analyze that data using a formula to detect knock and then pull timing.

There are other ways too, but this is free.

[seabass07]

It's probably got an across the board timing adjustment table based on coolant temp, iat, and who knows what else.

I'll look into testo. Thanks.

[philly98540]

It's a knock detection timing pull I'm referring to. There are other influences too, but the sudden pull can been seen in the graphs due to the knock.

[tptrsn]

Remember that the knock detection systems on these engines were designed to work within N/A operating environments. They might not be extremely accurate with bewst. Best to keep close watch on your plugs, and if possible get some det cans going to help determine if your detonation might be occurring at low RPM non-boost conditions like mine was once. Once I fixed my timing in that area, no more det showing on plugs, even with big boost.

Ok, I sound like a broken record now, so no more talk of plug reading from me!

[BMW540san]

Very interesting thread.
In the end, it comes down to how much you're willing to spend and what's the end result.
We've all seen few threads where 401k cash outs or whatever ended up in endless build with no end result and spent money equivalent to cost of low mileage E39 M5 S3.
Just advising to proceed with caution.
There are a lot of good shops having the best intentions but not backing up screw ups and the owner is left with a huge bill and no result.

[Kenny1958]

I'll PM you later!

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But wait, did you have the funky four-strap plugs in there, or what exactly?

Yep these

[tptrsn]

Would you happen to have them marked as to which one came from which cylinder?

I got busy yesterday and last night, I'll shoot you that PM now.

[Kenny1958]

I'm sorry I didn't keep track of the cylinders from which they came.

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[wagons ho]

540san, my position on getting results with low or justifiable costs have been repeated several times. I have too many cars to get 4-5000 dollars tied up in on engine, plus supercharger costs. But faced with continuing, dwindling supply of good engines and need for improved performance I'm plowing ahead. On a continuing note, the neighboring business can tin coat forged pistons which would add a half mil to the surface. He just had his 505 mopar dyno'd at 800 crank and has a 300hp nitrous for a little more.(a lot more,1100hp)

[Kenny1958]

Very interesting thread.
In the end, it comes down to how much you're willing to spend and what's the end result.
We've all seen few threads where 401k cash outs or whatever ended up in endless build with no end result and spent money equivalent to cost of low mileage E39 M5 S3.
Just advising to proceed with caution.
There are a lot of good shops having the best intentions but not backing up screw ups and the owner is left with a huge bill and no result.

I understand what you are saying but i have enough sunk into this car to make rebuilding necessary, i will be doing most of the work myself at home, i might get some help building the motor though from some friends who are mechanics.
The biggest No's i'm now looking at are, 8 forged low comp pistons and 8 bores relined, plus head and crank work probably about 2.5 - 3 grand.

[jon316i]

Seeing those pictures of the other Pistons scares me a lot Keith!

mine is booked in for tuning with Chris on Thursday and I'm worried the same thing happening with mine.

I pulled the plugs on mine the other day as I had missifire codes I think this is because it's running so rich had another map sent across which has helped a little. Here's a picture of the plug I pulled. What plugs are you running there the lower temp ones Steve suggested? I brought some and there single electrodes



i still can't understand how you were running 12 psi, we should have the same size pulley and I only get 9 psi

[philly98540]

I'm a bit confused so maybe someone can set me straight? Been a busy couple of weeks, and I have not fully followed whats going on in this thread. I apologize.

Is this the story?... The motor that is currently on this thread with the blown piston was running 12 psi, but the tune was not good, the car ran lean, and that is the why the motor failed? Did I get this right? Just trying to assess where I am to compare to. If someone could clarify, I would be grateful.

[Kenny1958]

Hi Jon I understand your worries after having a Ringland fall apart, as I was removing a ring, leaves me thinking that our pistons can't take the power of boost . I'm saving for forging it now with new internals and even thinking of an aftermarket ecu that controls boost better.

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I'm a bit confused so maybe someone can set me straight? Been a busy couple of weeks, and I have not fully followed whats going on in this thread. I apologize.

Is this the story?... The motor that is currently on this thread with the blown piston was running 12 psi, but the tune was not good, the car ran lean, and that is the why the motor failed? Did I get this right? Just trying to assess where I am to compare to. If someone could clarify, I would be grateful.

Hi Philly its my engine we are talking about. It was using a jag blower and it had been running fine with a bit of a rich map. Having been to the tuners for a power run we found out it could do with a better fueling map and that was what had been happening prior to blowing. The tuner had just finished getting the fueling right and was about to start to tune for power when the motor blew at lowish revs.

[jon316i]

Hi Jon I understand your worries after having a Ringland fall apart, as I was removing a ring, leaves me thinking that our pistons can't take the power of boost . I'm saving for forging it now with new internals and even thinking of an aftermarket ecu that controls boost better.

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Hi Philly its my engine we are talking about. It was using a jag blower and it had been running fine with a bit of a rich map. Having been to the tuners for a power run we found out it could do with a better fueling map and that was what had been happening prior to blowing. The tuner had just finished getting the fueling right and was about to start to tune for power when the motor blew at lowish revs.

Makes me wonder about doing any more with mine if it's only going to end the same way bit lost on which way to go as from you pictures looks like det has been the killer but with it running rich seems strange to off happened
ive seen people mentioning centrifugal blowers in here just to add Kenny is running a roots blower.

[tptrsn]

Man, how does a fantastic thread like this go so long without a bump? Lol

Anyway, after inspecting Kenny1958's plugs from his recently failed engine, I conclude that there wasn't very darn much detonation occurring in there... There were some traces of it, tiny flecks of what appeared to be aluminum stuck to the porcelain up in the plug, and some characteristic black speckling. But then I took a look at the last set of the similar type of plug out of my N/A engine, and wow, I had a lot more evidence of detonation on my plugs! I also looked at some old plugs from a factory 4-banger I boosted the crap out of, and they showed more detonation too.

So at that point I'm thinking, if a tiny bit of detonation like I see in these plugs is all it took to break two pistons, then we have a problem. Either the engine is very fragile, and the only way to run reasonable boost through them around peak torque RPMs (unlike normal bolt-on centrifugal setups that ramp in the boost kind of slow/late), must be to only run e85 like the Swedes seem to be.

But still I thought, the pistons don't "appear" to be especially fragile in the hand, to they contrary, they seem like quality pistons. Is there something about the alloy of them being made for running in an alusil bore that renders them weak for F/I? Seems like not really, again... Swedes...

So that brings me back to ring end gap butting, and pulling the pistons apart. I bothered Kenny1958 about this since he had a recently expired engine torn down, and wha'd'ya'know, he gets basically about 11 thousandths for his top ring gap, and 19 for the second rings. I confess that I don't know how much tighter you want ring gaps to be with a purely aluminum alloy block than for a cast iron block, so I called my local sprint car engine shop that I love, and ran the idea past them. Suffice to say they didn't know exactly how much bigger the gaps should be either, but they thought that sounded REALLY tight for a F/I setup making any reasonable amount of boost.

What they did suggest is that if anyone would know how this sort of a setup should be, it would be their buddy at CP/Carillo. Of course I called him right up and learned that for a reasonable boost setup in an alusil block he would ordinarily suggest .019-.022" for the top ring end gap, and about 5 more for the 2nd ring.

One bit of information I haven't seen yet (and don't think it is causing our problem) is piston to wall clearance on the factory engines with some miles on them. Normally I think someone would have reported significant galling on the piston skirts if there was a problem with this, and nobody has complained of that as far as I know. Anyway, this guy at CP said that he would usually shoot to setup forged pistons for an alusil block with about .0025-.003" of piston to wall clearance.

HOWEVER! What he said first was that they cannot make the pistons for that application because the EPA will not allow the tin/something alloy coating used by Mahle for the factory pistons... He did say that Polymer Dynamics in Houston, TX makes a coating that is used on forged pistons in alusil bores for race applications, but he doesn't know how it would fare for street use...

[Plattus1000]

Wagons Ho, This is all awesome but when will you be ready to dial in a 4.6is motor and then do all the work for me!?

I'm gonna be pissed if one day you overtake me going up the pass.

[AK_5eries]

Wikipedia mentions that the M62 had split forged rods? Is this true?


If true, it explains why so many SCed M62 are able to take the PSI they are taking.

[JimLev]

^___The big end is cracked. Powdered metal.

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[tptrsn]

Yeah, the rods are decent enough. I'm really thinking it's end gaps that are the main problem at this point.

Excellent pics Jim!

[philly98540]

Is meth enough to keep stock ring gaps from binding up? I guess a higher mileage motor has larger ring gaps.