M50 Intake "Hot Cam Swap" NO NO [face palm]

[E.Roy]

When Al Gore invented the internet, he couldn't have foreseen that misinformation could be spread so easily.

I really like the m50 Non Vanos (NV) motors, and wanted to boost the performance while my engine was apart. I turned to the internet for ideas. It is casually thrown around on the BMW forums that you can just use 2 NV intake cams in the NV motor, and you can, and many have done so, with varying results. It is now referred to as a "Hot Cam Swap"-it isn't. I decided to try it and bought an extra set of cams. Fortunately, I measured them before installing them. This swap is a terrible idea for two reasons.

The 1st and largest reason:

The intake cam sprocket mounting face is about .090" [2.25mm] farther out towards the timing cover than the exhaust cam sprocket mounting face. BMW designed it this way since the Primary timing chain sprocket goes onto the exhaust cam before the sprocket for the Secondary timing chain. Therefore, putting an intake cam on the exh side without machining the face of it, will result in both the primary and secondary timing chains being misaligned. Some people have commented that this resulted in a 'terrible timing chain rattle'. There are plenty of people causing premature wear to their normally reliable M50's after doing this swap. 0.090" is huge when it comes to engine internals and tolerances.

The 2nd reason:

By putting an intake cam on the exhaust side, you loose the proper way to time the cams and motor, as the rear timing square on the rear of the intake cam is at a different degree from the lobe center line than on the exhaust cam. Apparently, swapees have taken to simply eyeing up the cams, which could possibly result in a motor with no top end power, or only top end power, or bent valves. Unless you really know what you're doing, you have no way to properly time the motor. Please realize that the intake cam is driven and timed off the exhaust cam. Therefore, if you can't properly time the exhaust cam, both cams will be off, as in advanced or retarded.

The real Hot Cam Swap [unverified]:

The following info/idea is as yet unverified by myself. I would guess that the real "Hot Cam Swap" is to purchase an S50 exhaust cam, which according to the internet, has the same duration and lift as an M50 intake cam. Correct me if I'm wrong, but I believe the S50 exh cam is 240 degress and 9.7mm lift.

This would give you the mildly increased duration and lift, while keeping the proper timing chain alignment, and keeping the proper (and easy)timing method per BMW. This is much better IMO than getting the M50 intake cam, then paying for machining of the sprocket mounting face, and then being without a proper timing method.

I will try to get pictures to show the difference in the cam dimensions.

[Parallel]

Bump - I can't believe no one has even commented on this. I was thinking of actually doing this, but thought hey I wonder what I find if I google this subject and look what I find. Can anyone verify this info?

[locks325is]

S50 cams do not work in the nv m50, this is well known already. You will need to swap 1 cam (can't remember which) & buy a regrind for the other. This is the only plug & play option for the nv m50. Others have said that s50 cam work in the nv but I've yet to see it done.

[flyfishvt]

I can verify that many people have done the swap without machining and it works. His info is a bit confusing. He said the S50 cam has the same duration and lift as the M50 cam....then how does it change anything? How can it make any difference?

It is indeed a bit tricky to get the timing correct for exactly the reasons he stated but it is possible and it has been done. I don't think he did enough research. Just because HE couldn't get it to work doesnt mean it wont work.

[locks325is]

I can verify that many people have done the swap without machining and it works. His info is a bit confusing. He said the S50 cam has the same duration and lift as the M50 cam....then how does it change anything? How can it make any difference?

Learn something new everyday, you wouldn't happen to have a link? I would love to read a write up. His comment on the duration makes no sense to me either, whats the point of a swap if the duration is the same. And if they are the same then it give ppl another option to S cams.

[granlund]

I can verify that many people have done the swap without machining and it works. His info is a bit confusing. He said the S50 cam has the same duration and lift as the M50 cam....then how does it change anything? How can it make any difference?

It is indeed a bit tricky to get the timing correct for exactly the reasons he stated but it is possible and it has been done. I don't think he did enough research. Just because HE couldn't get it to work doesnt mean it wont work.

I can't attest to any offsets in mounting faces, but the S50 exhaust cam has the same duration (240) as the non-vanos intake cam, but supposedly 9mm of lift. I don't know if it has the same lobe center and whether it is symmetric though. All M50/M52 exhaust cams are 228 degree duration.

Considering that a few degrees of static cam phase actually makes a difference, I would not go about eyeball-installing an intake cam on the exhaust side without proper knowledge of the at what angle it's installed.

[Joshwa1234]

Sorry seen face palm in the title and couldn't help myself!

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[E.Roy]

I can verify that many people have done the swap without machining and it works. His info is a bit confusing. He said the S50 cam has the same duration and lift as the M50 cam....then how does it change anything? How can it make any difference?

It is indeed a bit tricky to get the timing correct for exactly the reasons he stated but it is possible and it has been done. I don't think he did enough research. Just because HE couldn't get it to work doesnt mean it wont work.

Measuring isn't good enough for you? I did say that the S50 exh has the same duration and lift as M50 intake, which has been used also on the exhaust side, understand now? I know people have done it, but some have reported awful noises, and how long will it last?
I believe that:
The s50 exhaust cam is 240deg and 9.7mm lift (not 9mm lift)
The M50 intake cam is 240deg and 9.7 lift
The M50 exhaust cam is 228deg and 9.0 lift
(Also, numerous people have mixed up the cam specs in posts, again wrong info out there)


Edit: Here is the problem, people comment on complex things they have not tried, only read about on the internet of other people talking about things they too have not tried. I TRIED IT, I MEASURED IT, VERIFIED THAT IT'S NOT ADDING UP. Don't be one of those people


I'm not the first to notice this, see post #38 in this thread http://www.e30tech.com/forum/showthr...t=86954&page=4

"Quote:
Originally Posted by etexis
i did this INTAKE INTAKE cam swap on my NVM50 no its sound like shit tons of timing chain noise !! Anyone have this issue ??

320guy: The intake cam is slightly longer than the exhaust cam and throws off the cam chain alignment. This is likely to be your issue.
I had the front of my cam machined down to the correct length."

[chuulo]

If the title wouldn't have [face palm] in it, I've wouldn't have posted this but here it is:
It's fairly easy to make the B50B25 intake cam work. It's all about skill but if you want to spend the extra $ then be my guest.

1. It's not hard nor expensive to machine a few mm off to get the alignment right. (It's actually 1,7mm off) Cost me a bottle of "Mõrnaja" vodka (about 10$ in my country).
2. You just need a degree wheel set to time the cams. https://www.youtube.com/watch?v=la6-EgnCOl4
Here's the timing
Intake opens: 19 BTDC
Intake closes: 41 ABDC
Exhaust (NV intake cam) opens: 41 BBDC
Exhaust (NV intake cam) closes: 19 ATDC

[E.Roy]

Thanks for posting info. As you can see by the posts in this thread, people don't know what we know

[92E36PNW]

I found this info over on another forum but I think this is where everyone is getting their idea of the swap. If you Google Pete McHenry there's lots of info about him. Here's the piece I pulled.


"We spoke with Pete McHenry of Precision Performance in Winston-Salem, North Carolina. McHenry is a well-known expert on BMW engine swaps and parts interchangeability. He advises: The M50 2.5-liter VANOS cams are 228-degree duration, while S53 3.2-liter M3 cams are 252 intake and 240 exhaust. They fit fine and give a nice boost to the top end on a 2.5-liter M50. You can use the S52 cams with the M50 lifters and springs. The S52 uses smaller lifters (33mm vs. 35mm diameter) and conical valve springs with teeny retainer washers. Net saving with this stuff is 20 grams per valve. Get the S52 cam trays, lifters and springs if you can but the swap is OK with cams only as mentioned earlier. If you have a 1992 M50, you can switch the intake cam to the exhaust side. Timing is 240 on both, but the intake has 9.7 lift vs. 9.0. Buy a 252 Schrick intake cam and you have the same cams as an M3 and only have to buy one camshaft"

[bimmerlin]

Damn, it got quiet after this last post^ cheers er'one!

[Luth]

I wonder if it's worth it on a 2.0 M50... Nah probably not :P

[bimmerlin]

^I'm sure it is... from what I've been reading. Specs and config's gotta be spot-on...

[motomanb3]

I know the intake on exhaust cam swap works on the vanos motor (done by many people) I haven't read about non-v. That may be where most confusion comes from

[Matt325e]

I know the intake on exhaust cam swap works on the vanos motor (done by many people) I haven't read about non-v. That may be where most confusion comes from

Can anyone verify this?

[bimmerlin]

I've recently, in the past two days switched the exhaust cams (m50 to s50) with no issue. The intake cam from the s50 is only for heads with vanos. I didn't realize it til I started to take things apart. I had a broken exhaust cam not too long ago (Dec.2013) and removed both cams and trays due to shavings from doing heli coils in the head. So, I didn't remember the hub on mine (non vanos) had a 4 bolt hub. As where the vanos (or s50) had a 3 bolt hub. I am now in the middle of swapping the m50 intake to the exhaust side and the s50 exhaust cam to the intake... so far the intake is intact, except the shield/arm thing for the camshaft positioning sensor, has to be modified a bit to fit on that cam. Had to come back on here and there to do more research. I'll keep you (those curiious) posted... (next day, Sunday, March 16, 7:38pm...
So I'm done for the day... I swapped the s50 exhaust cam to the intake side, and the m50 to the exhaust. It cranked, but I had to abort because it felt like it were struggling. So I removed the valve cover and decided to put it back to m50 intake and s50 ex. To my surprise, (I know I shouldn't be) there was shavings around the sprocket end of the intake. The torx screws/bolts threaded ends had carved a nice 'half-moon' around the e1 cap and tray. I knew going into this that, the hub(s) were slightly off in height or thickness. So, I buttoned it up, and now I hear loud ticking. Dont' know if it's cause I'm low on oil or my header gaskets are toast. The thing that sucked the most is that my flywheel does not have the timing marks tdc, O|T. But there is a white smear as if someone found the mark behind the flywheel and marked it on the front. I had replaced my 2 piece m50 exhaust cam, 2mos ago. and remembered that mark.made my own next to it. maybe do schrick it seems...

[E.Roy]

I've recently, in the past two days switched the exhaust cams (m50 to s50) with no issue....I am now in the middle of swapping the m50 intake to the exhaust side and the s50 exhaust cam to the intake......

The S50 exhaust cam and the M50 NonVanos intake cam both have 240 duration and 9.7mm lift, so this is a pointless endeavor and will only screw up the easy timing method from BMW. Please carefully read my posts in this thread, and go buy digital calipers from Harbor Freight so you can measure for yourself. Leave the M50 intake cam on the intake side, and test the s50 exh cam in place of the m50 exh cam.

[E.Roy]

I found some info regarding the use of S52(or M52) cams being used in an M50 engine and why s50/s52/m52 trays would be required:


http://www.r3vlimited.com/board/showthread.php?t=103815
member Ed94r
The only difference is the cams are built from different cam cores, although they are both hollow cores. The S50 (M50 family) cams are built from "round" cores between the lobes and the S52 (M52 family) cams have areas where there is additional material on the cam between the lobes and this material is squared off instead of round. I would assume that if the cores are the same material and core thickness, the S50's would be lighter in weight because they have less material in the areas between the lobes.

The reason M/S52 cams won't fit the cam trays for the M50 (only) is the extra material between the lobes of the cams interfere with the tray. The M/S52 cams will fit an S50 tray, not an M50. The S50/M52/S52 exhaust trays are the same P/N 11121436224.

Be careful out there when buying cams. Don't assume what cam you have by the casting number on it. You have to measure the lift to know for sure.

Just as an example, a 1718888 cam casting correlates to a S50 exhaust cam and an M50 exhaust cam. It is precisely the same p/n stamped on the Group N 2.5 cam. These cams have the same casting#, but different lifts and durations. (E.Roy verified a 1992 m50 exh cam has 1718 888 in the casting)

s52 cam showing extra material between cam lobes


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I know the intake on exhaust cam swap works on the vanos motor (done by many people) I haven't read about non-v. That may be where most confusion comes from

No, an NV intake cam does not work on the vanos motor exhaust side either
http://forums.bimmerforums.com/forum...ntake-cam-swap

"I Have an m50b25TU (VANOS). I left the stock intake cam, and swapped in an intake cam from an M50b25 (NON VANOS) in place of my exhaust cam. Timing was a bit tricky, but I got it.
THE PROBLEM is, It sounds like a diesel truck engine. I am getting all kinds of timing chain rattle. Looking at the head, when the cams are tight, it seems as if the M50NV intake cam is longer than my stock exhaust cam, and it's pushing the chain forward......... making everything rattle......badly."

[chuulo]

So here's the tool I made for M50B25 for using two NV intake cams. Works perfect for NV. The exhaust cam is 62 degrees different from original tool.
Untitled.jpg

[Shelin323]

Are you willing to make one and sell it to me?

[M3blitkrieg]

So, im surprised no ones really considered easy fixes for this..
Why not just install the 2mm washer at the oil pump sprocket and weld it on the sprocket to fix the alignment? Again, another Vanos plate or washer on the intake Cam probably would solve that as well, maybe weld 2 Vanos washers together so there's no extra moving parts. Last time I looked at an m50, there was easily more than 2mm of chain guide space to either side. Sure dropping the oil pan might make this a bit more difficult, but no rattle or shavings. Why overcomplicate things?

[Shelin323]

Never mind i made one myself
If anyone needs a tool to make this work just pm me and i will give you my mail adress.
Also removed 4 mm of the gearing on the m54b30 and 2mm off the flange frome the non vanos intake cam no chain rattle20170724_112457.jpg

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[dangerwillrbnsn]

Never mind i made one myself
If anyone needs a tool to make this work just pm me and i will give you my mail adress.
Also removed 4 mm of the gearing on the m54b30 and 2mm off the flange frome the non vanos intake cam no chain rattle20170724_112457.jpg

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I can't pm you due to your low post count. Please, I would like to purchase or rent your modified timing blocks. I've already modified my e46 intake cam, and nvm50 intake cam. Just need too get the timing right now. Thank you!!

[GGug12345]

[QUOTE=Shelin323;29779363]Never mind i made one myself
If anyone needs a tool to make this work just pm me and i will give you my mail adress.
Also removed 4 mm of the gearing on the m54b30 and 2mm off the flange frome the non vanos intake cam no chain rattle20170724_112457.jpg

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20170724_112504.jpg

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20170724_112506.jpg[/QUOT

Same here. Would like to buy or rent tool. Even a stencil so i can make one but can not message you. Guglielmo123@hotmail