Rediculous e36 rotary valve engine project

**pizzaman09** · 08-13-2016, 11:04 PM

Over about the last year or so, my twin brother and I have been designing and building a rotary valve engine head for a 1999 e36 328is that we purchased just for this project. Just yesterday it drove for the first time so I figured I would post up a few videos for those interested in e36s and crazy engines. If anyone here has read up on rotary valve engines before, we implemented a Cross style design which is best known for being successfully run by Ralph Watson in a 1930s vintage BSA roadster, and by the Mercedes-Ilmor formula 1 racing team.

First video is one of the first drives. All of the smoke is from some extra oil that has pooled inside of the intake plenum over the last few months of testing so it is burning out. The head has a constant loss oil system.
The second video shows the head during idle which nicely shows the general operation of the head.

**hotdish** · 08-13-2016, 11:21 PM

Over-the-top doesn't even begin to describe this

This will really confuse people at shows

Please post more details

**xxxxxxx** · 08-13-2016, 11:36 PM

what the.

**boarder2k7** · 08-13-2016, 11:48 PM

:

Now there's something you don't see every day...

I love the thought and work that's gone into this. Makes the Mech-E in me happy. I hope you share more of the process and details!

Subbed.

**MisterM52** · 08-14-2016, 03:55 AM

wow, a M52 with rotary valves!! now there's something entirely different and actually I dont care about it being different, its really nice sounding, my kinda nice

I know it will likely need much more work, and its not 100%, likely never will be for many of us to try out as kits per say, partially it will need attention from the engineers at every problem or so I assume, but something really nice non the less. really nice! man, you ought to do some dyno runs just for the lols.

**ultimatetester** · 08-14-2016, 05:45 AM

This amount of smoke is perfectly normal for a rotary engine

**MParallel** · 08-14-2016, 07:45 AM

Wow. My hat off to you.

**MisterM52** · 08-14-2016, 08:28 AM

Originally Posted by ultimatetester

This amount of smoke is perfectly normal for a rotary engine

thats no rotery engine,

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**pizzaman09** · 08-14-2016, 09:37 AM

Indeed dyno runs are in the future, as soon as we get it state inspected again. It won't have to pass emissions inspection since we didn't drive it over 5k miles last year. Currently the engine is running on a completely unmodified ECU so after an initial dyno run we also plan to have it professionally dyno tuned. The only system not being used is the vanos, that is causing us a lot of troubles throwing cam position codes.

We did baseline dyno the car before taking it apart. We were impressed with the numbers given it is a completely stock 328is with 163k abused miles on it.

I will try to upload some more photos of the build once my old Verizon DSL service decides to catch up with this decade.

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Originally Posted by MisterM52

wow, a M52 with rotary valves!! now there's something entirely different and actually I dont care about it being different, its really nice sounding, my kinda nice

I know it will likely need much more work, and its not 100%, likely never will be for many of us to try out as kits per say, partially it will need attention from the engineers at every problem or so I assume, but something really nice non the less. really nice! man, you ought to do some dyno runs just for the lols.

Currently we are running open headers, we are going to try to attached the rest of the exhaust soon. It is possible that we destroyed the cats with oil so that may need to be addressed. Our current expectation is that it will sound like a cross between an M52 and an old American V8 with how aggressive our valve timing is. With how it has been running thus far, it has some serious get up and go over 3000 rpm and below that it is a bit of a dog. Surf our youtube channel for videos of it revving.

**slocar** · 08-14-2016, 11:23 AM

This is so wild!

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**ultimatetester** · 08-14-2016, 02:57 PM

Originally Posted by MisterM52

thats no rotery engine,

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Ah my bad I didn't look very well and thought he retrofitted a rotary engine in the car..

**someguy2800** · 08-14-2016, 06:54 PM

Cool project, nice work. Any pictures of the head?

**pizzaman09** · 08-14-2016, 07:44 PM

This is the seal that is beneath the rotary valve, it is also the top of the combustion chamber, it contains the spark plug, and a coolant passage for keeping the seals cool. There are two rows of o-rings and teflon back up rings keeping the combustion gases, coolant, and ambient air separated.

Cutting velocity stack holes into carbon fiber air plenum. Yes I am using a hand brace and bit to cut the holes.

Machining of the bronze seals on my mini cnc mill. Sealing surfaces were lapped to size.

One of the rotary valves. One end of the valve is the intake and the other end is the exhaust. These valves rotate at 1/2 engine speed.

**slocar** · 08-14-2016, 10:25 PM

You're a crazy man! Good kind of crazy!!

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**jno** · 08-15-2016, 05:11 AM

This is mental!
I love these "let's do it because we can"-mods.

Oh, and dat sound!

**pbonsalb** · 08-15-2016, 06:47 AM

Very impressive work!

**dburt86** · 08-15-2016, 01:10 PM

My head hurts

**Moron95M3** · 08-15-2016, 01:31 PM

Wow!

**Gmfwd** · 08-15-2016, 04:10 PM

Mind blown. I am excited to see what comes of this

**pizzaman09** · 08-15-2016, 07:59 PM

Originally Posted by jno

This is mental!
I love these "let's do it because we can"-mods.

Oh, and dat sound!

More or less it was a, "let's do it because we can."
My brother had just been laid off, we are both Mechanical Engineers. We had always wanted to do the rotary valve to a real car, we were already quite successful on an old Briggs and Stratton. So, we found a cheap e36 on Craigslist, had a heck of an adventure purchasing it and started to work. We were going to do a 318ti due to the 4 cylinder engine likely being simpler and cheaper to build the head for, but then we talked ourselves into a 6 cylinder model. We wanted to do an M3 but couldn't find anything cheap enough to be worth potentially completely ruining. We spent 6 months designing it, that design work helped my brother get a job where he is now working for a very well known diesel engine Manufacturer.

We liked driving the 328is so much before we tore it apart that it has convinced us to sell our e39 M5. We are looking to pick up either an e36 M3 or a second gen JCW Mini.

This is the Briggs and Stratton that we did the research on. It was gen 3 of the rotary valve work that started as our senior design project back in 2013.

**milKt** · 08-16-2016, 06:26 AM

Idle hands...

**Moron95M3** · 08-16-2016, 07:56 AM

very cool! I love the briggs. You could always put the 328 head onto an S52 if you get your hands on an M?

(also an ME that grew up racing w/briggs karts - much praise for your work!).

**drjames** · 08-16-2016, 11:09 AM

Just did some reading on rotary valve engines. U guys a insane. Well done!!!!!!!

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**jalopi** · 08-16-2016, 12:25 PM

on one hand, i think this is really cool. the design seems to let you use a crazy domed piston for gnarly compression with no risk of hitting the valves. you can turn higher RPMs without risk of valve float. i assume the amount of air each port can flow is pretty good

on the other hand, i just don't think a m50 with OE pistons can really take advantage of this new head. you'd need to be turning some crazy RPMs running very high compression for this to make sense. at least in my head anyway

out of curiosity, i do have a couple questions, if you don't mind answering them that is

* did you weigh the assembly before installation? i'm torn as to whether i think this is lighter/same/heavier in weight compared to the stock head. if it wasn't for those big bronze seals and that crazy gearbox/transmission thing coming off the timing chain i'd say lighter, but with those i dunno

* what kind of clearance is there between the valve and the seal surface? is that where all of the combustion gasses are sealed? i imagine fitment would need to be pretty tight to do so. or is there some blowby that gets stopped at the valve journals?

also, gotta love the mcmaster baggie chipguard

**pizzaman09** · 08-16-2016, 08:14 PM

Originally Posted by Moron95M3

very cool! I love the briggs. You could always put the 328 head onto an S52 if you get your hands on an M?

(also an ME that grew up racing w/briggs karts - much praise for your work!).

The briggs were fun. The engine you see in the video is actually a 1950s vintage Briggs Model N that we had laying around in our basement. Our rotary valve head would bolt directly to an S52 as far as we know. We were initially going to build an M42 318ti but talked ourselves out of the 4 cylinder.

Originally Posted by drjames

Just did some reading on rotary valve engines. U guys a insane. Well done!!!!!!!

Subbed

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Insane is correct.

Originally Posted by jalopi

on one hand, i think this is really cool. the design seems to let you use a crazy domed piston for gnarly compression with no risk of hitting the valves. you can turn higher RPMs without risk of valve float. i assume the amount of air each port can flow is pretty good

on the other hand, i just don't think a m50 with OE pistons can really take advantage of this new head. you'd need to be turning some crazy RPMs running very high compression for this to make sense. at least in my head anyway

out of curiosity, i do have a couple questions, if you don't mind answering them that is

* did you weigh the assembly before installation? i'm torn as to whether i think this is lighter/same/heavier in weight compared to the stock head. if it wasn't for those big bronze seals and that crazy gearbox/transmission thing coming off the timing chain i'd say lighter, but with those i dunno

* what kind of clearance is there between the valve and the seal surface? is that where all of the combustion gasses are sealed? i imagine fitment would need to be pretty tight to do so. or is there some blowby that gets stopped at the valve journals?

also, gotta love the mcmaster baggie chipguard

Due to some choices in geometry we have actually lowered the compression ratio just slightly. However much to your suggestions you can do some crazy things, the first rotary valve we built for our senior design project was a 16:1 compression ratio. Indeed you can run much higher rpms with the rotary valve due to the lack of reciprocating mass and thus no valve float. Unfortunately the M52 engine's crank shaft apparently the harmonic balancer breaks at 7200 rpm. We suspect the weight is very similar in the end of the day. If we were starting with a clean slate engine and didn't have to start with the stock timing chain drive, we could have made the head much lighter. It could be even lighter if we had tried the cross flow type valve as opposed to an axial flow valve since a cross flow valve would just require two valves running parallel to the cam shaft. We think the rotary valve head we have built is around 125 to 150 lbs. We don't really know. That would include the exhaust headers which are stock.

The sealing surfaces between the seal and the valve has been lapped to size with valve grinding compound. It probably started at 0.001" to 0.003" and has likely worn in to be tighter. The drip feed oil we have takes care of compression issues if the gaps are too large. There is also coolant flowing around the seals to keep them from getting too hot and expanding.

Many Mcmaster baggies have been sacrificed for this project...