Another 2.8
 

Well, finally, after many many years have begun building an engine. Life just gets in the way sometimes... Work, got widowed, years pass, get married again... life :-).

So way back in the 2005 timeframe this was supposed to be a hot 2.0 to swap for the 4 banger that came in the 1967 912 I picked up while a post doc in new mexico.
Was going to be a 2.1 longstroke actually on R cams. My first (and supposed to be only, haha) splurge purchase was a set of titanium rods from Crower. Beautiful pieces. Those went onto an original RSR crank kindly sourced by BMEP from this board. Also found a set of straight cut gears while trolling the board :D. Remember that 'only one splurge piece bit'....

http://forums.pelicanparts.com/uploa...1480444101.jpg



Toss in a GT3 oil pump in a modified 68 aluminum case. Shuffle pins, the 'big' 1.5 mm squirters, oil mod, ect... including mounts for MFI welded on. Coated bearings too.

http://forums.pelicanparts.com/uploa...1480444460.jpg

Well, along the way there happened to be a set of LN 92 mm cylinders in the for sale section and not a week later, a set of 92 mm RSR Mahle pistons as well. I just watched both of these sit till I couldn't stand it, said F&*k the 2.0 and bought both. Kinda forgot they would have to go off and be re plated to actually fit eachother...duh.

This was my undoing... Cause now I just had to have RSR heads... and they are around, I just never had the luck to have cash while a set was for sale (at least those I could afford).

So Thankfully, Steve Weiner said he could fix all that with his magic CNC...along with the sickness of reducing rotational mass with DLC coated Ti wristpins. And that sets up another post cause I need to get pictures...

Two more pics... Rod and case:
http://forums.pelicanparts.com/uploa...1480445566.jpg


http://forums.pelicanparts.com/uploa...1480445650.jpg

More pics and chat after I take more pics :-)!

Wow, that's way down the slope. Really nice, a dream motor .

So, what stroke crank, 70mm?

I am guessing the case and heads had to be machined? Twin plugged? MFI? WOW.

Cant wait to see more pics.

344 total weight of the rod.......... WOW. By comparo a lightweight version Pauter chromoly steel rod for the 2.4 is 500.

That crank holding fixture in the top pic was making me actually nervous. Palpable relief seeing it nestled into the case in the subsequent pic!! Good luck w the build and look forward to seeing more; this looks fantastic.

So part of my quest on reducing rotational weight was the pesky shake the 2.8 RSRs had due to a harmonic problem that spit flywheels. My thought was to shed mass and shift the bad harmonic upwards away from actual operational speeds. So lighter is better :-).

However with respect to weight, I do realize that Ti has a cycle fatigue limit (lifetime)...so I didn't have crower go for the ultimate in lightness. I may have this incorrect, and Chris may be along to school me on my ignorant understanding, but like any material, if the induced stresses are below the critical energy, then that effect is suppressed. So in my discussion with the engineer, they did a comsol FEA and we 'set the mass of the rod' at a break even force to equate to 7000 rpm. In other words, made the rod beefy enough to try and minimize fatigue below that stress level. I figured that was a fair compromise between longevity and lightness.

So the pistons are Mahle 92 mm RSR. These are the older style that give you the ungodly compression with the 24-.7 stock 'small volume' heads. They have had the ring lands coated and the skirts. Gave the tops a quick polish. I still don't get how the thermal coatings are supposed to work given the thinness of the coating and thermal equilibrium...so I skipped that bit.

http://forums.pelicanparts.com/uploa...1480511012.jpg

Got a piston on the block with a standard 0.25 mm shim and got 1.12 mm (0.044")deck height. Its not as tight as some run, but given that there really isn't any true squish band to induce turbulence (there is a hefty chamfer on the head to fit the larger piston), I'm ok with it. Actually considering going to an .5 mm shim.

http://forums.pelicanparts.com/uploa...1480511362.jpg
http://forums.pelicanparts.com/uploa...1480511362.jpg

Static compression ratio should be somewhere around 11.5-11.75:1. I am going to use the greased rings, assemble the whole stack, rotate to TDC, and liquid measure the whole assembly method. Maybe this weekend if I am lucky.

So you ask, WTF am I going to do with that compression ratio... the logic is that is static. The cams are a bit weird. They were Shrick steel cams equal to GE100s. Mr. Douguty was kind enough to regrind them to 3.8 RSR specs but on 102 lobe centers to better suit the smaller displacement. The idea is to have enough overlap to have a workable dynamic compression ratio a part throttle/lower engine speeds where turbulence is low and possibility of detonation is high. The hope is to be able to run on premium pump gas for three seasons and require mixing an extender for the hotter summer months (VP or toluene, I am a chemist :D). Long term I would very much like to go EFI using the Porsche DFI injectors in the stock MFI injector location and run liquid propane injection. Its 110 octane rating, but it is temperature sensitive, so that is inject the liquid bit. Get a nice cool down from the latent heat of vaporization....but that is way up the road. Have to get it on the road first!


http://forums.pelicanparts.com/uploa...1480511838.jpg
http://forums.pelicanparts.com/uploa...1480511838.jpg

A few extraneous notes...
1. Since this is an early case, it doesn't have a thrust bearing on the IS shaft. It locates by using the helical thrust of the gear set balanced by oil pressure on a shim set plate. I wasn't happy with the float that was possible due to not having the helical thrust due to the straight cut gears... so did machine a cylinder of aluminum that fit inside the coupler between the IS and the oil pump to hard set the rearward travel. Its trapped inside, so it can't go anywhere and there is no relative motion, so that was my solution. I just wasn't happy with having the chains do all the locating.

2. I went with Curel T for the case halves rather the well used Loctite. Mostly this is because I have used Curel T for all my bikes over the years and I have not had any trouble with it. The devil you know...

3. I left off the O-rings from the thru bolts upon assembly. Got everything bolted and torqued quickly, then went back and added the washers later, one at a time, using lots of krytox so they can seat properly.

4. Went with AN to metric fittings for all the oil lines. The AN stuff seems to be a bit more robust to frequent assembly/disassembly than the choline stuff due to the threads being a bit more coarse.

5. Everything is getting redline assembly lube!

That's about it for now...

Next post... Steve Weiners CNC magic!

James:
Funny you say that :-). I made that to go in the vise, but that was down stairs and it was a pain. So I just clamped it to the table. What you cant see is that it is actually over the main beam that runs under the top. Its like 2x4 in size, so although it looks bad, it wasn't going anywhere. I gave it a good shake to be sure and it didn't budge when I was torqueing the rod bolts...

:) Can't wait to see those heads.

Ask and ye shall receive :D!

So here is what can be done with a multi axis CNC...Steve was also very kind and went extra on the intake valve... Its actually a cut down intake from the 3.0. So its not the true RSR size, but its the biggest that can fit in the tighter valve angle of the smaller motors heads.

Steve tells me that his ports almost flow to the same extent as the 2.8 RSR heads, but aren't 43 mm drain pipes. They are actually oblong, 39 wide, 41 mm tall. Interestingly the bulk of the meat removed is from the roof. You can actually see spots on the floor that were stock (not touched by the CNC). Steve told me that makes a big difference getting the air around the coroner. In addition, I figure the smaller port volume will make a big improvement in actually having a midrange :eek:.

http://forums.pelicanparts.com/uploa...1480514729.jpg
http://forums.pelicanparts.com/uploa...1480514729.jpg

Just to be clear, I went 'crazy' mostly because having driven an 2.0S I didn't think it was enough. I guess it is from too many two strokes in my youth (All yamahas: DS6s, RDs, and RZs). When I say enough, it is more about how the power hits than how much. I don't have any issue with something I have to 'baby' driving. My only requirement is that it has to idle well. No stalling. If I stall it off the clutch, that's my problem and part of the fun.

Lastly, for now, is the rockers. Going with the lash cap type. Had them redone by electric chrome and grind. I need to chase up some rocker shafts, but not quite sure yet what to go with. Optimal would seem to be the nitride shafts, but they are hard to find anymore. There is just no room to have a bushing in the solid rockers. The stock might be too soft. That said, I have heard wonders about Gibbs motor oils and running steel cams on stock rockers with no issues.

I could DLC the stock rockers, but then the wear would be on the hard to get rocker rather than the easier to find shaft. Or could have both pieces DLC coated and not worry about it.

http://forums.pelicanparts.com/uploa...1480515595.jpg

And that's where things stand at the moment. Would very much like to have a long block by the new year, but there are so many odds and ends to get thanks to building from pieces parts rather than starting with a complete motor.

Only other goodies (suppliers) I can think of are JB racing for the AN fittings and Supertec for their head studs and 906 cooling tin...and not least pelican parts for all the odds and ends like miscellaneous studs and extra bits you don't get piecemeal that eat your wallet :D.

Lastly will be the intake. Would like to go with one of the repro high butterfly units, but that aint gonna happen at $6k... so I snagged a cheap set of T MFI TBs to cut up... ahem... 'port' to the heads. Since the meat is out of the top of the head from the CNC work, lots of metal will need to come out of the intake to match. I figured I will match the bottoms, then send off to someone to open up and install bigger throttle plates. Would like to then top that with fiberglass intake trumpets for a 911R look to go with the inline 6 MFI unit (rather than the side by side).

Crower Ti rods
 

Hi,I have used the Crower Ti rods for years and they make a great product.I have a set in my short stroke 2.8 built on a 76 Turbo case.66 x 95mm bore with 132mm length for a 2 to 1 rod/stroke ratio.Keep on posting.My 2.8 runs to 9300 and I added a dowel to help secure the flywheel to the crank.Fred

I love that intake port. really outstanding.

The intake valve, about what size were you able to get it at from 49mm? And were the seats changed or just cut as wide as possible to fit the altered 49mm intake valve?

Will you be using a V94 or equivalent space cam in the MFI pump?

That port size will actually be streetable with something like a DC60 cam, so don't think you can't street this rig one day. The only motor of this type of build I've driven before (which actually inspired me to build one myself) had 41mm intake ports with about a DC60 equivalent cam and was quite tame, but it revved to kingdom come :D


I'm guessing you're shooting for around 300bhp+ at the crank, and from what I'm seeing that looks entirely possible. Great build. I'm actually doing an identical build but am not as far along as you are!

I don't think the propane is the way to go. LPG will clog up those DFI injectors, and the high pressure fuel pump you need to install for them (3,600psi for the gasoline, 36,000 for diesel). I think the spray pattern won't be that great for an MFI location.

I'd suggest you run E85 or methanol instead to take advantage of the latent heat of vaporization while using more conventional components.

That said, the company I currently work for has a sister brand in Italy called BRC that races a rally car in the Italian championship powered by an LDI system (liquid direct injection of propane using the super high pressure to keep it liquid all the way to the injectors). But those pumps and injectors are stock gasoline components as far as I know so it's anyone's guess how long they will last with LPG. Not sure if the LPG is better here or there in terms of heavy ends.

Propane also doesn't have enough lubricity to keep the high pressure pumps alive.

One more opinion here about fuel. :)

Stay FAR FAR away from Methanol at all costs. Nasty stuff that eats Nikasil cylinders as well as dilutes the oil very badly. Hygroscopic as hell too, and there is nothing good about the effects of that. Just not worth it at all.

E85 is only for fuel delivery systems that are all setup and configured for that stuff. This means a plastic or SS tank, SS lines, Viton hoses, fuel pumps with Viton seals, and E85-compatible injectors and other hardware.

In the long run, race gas is FAR cheaper to use due to the consequences of using the above. BTDT. :)

Tadd - if using a standard diameter clutch, just torque the flywheel bolts to 150 lbs/ft with a little (quite little) bit of red Loctite applied so it can't get between the crank end and the flywheel mating part, and you will have no flywheel shedding troubles. Especially if you keep the revs down to 7,000, which I suspect will be way below where your torque curve will suggest upshifting.

Propane n cars
 

Awesome feedback, thank you all! Awesome info!

I am a huge propane fan, so hearing other fuel thoughts and having a discussion is really great. We are having a nice wave of low gas prices but I think that will eventually come to an end...

IMHO the advantages to propane are:
1. Super clean burning. It is a simple hydrocarbon with no hetro-atom (N, S, O, ect) functional groups. Unlike methanol or ethanol you don't get nasty side products like formaldehyde out the exhaust. Also it doesn't leave heavy combustion byproducts in the oil. Look at any forklift. Oil needs to be replaced due to wearing out rather than from contamination.

2. Reasonable storage. Since it stored under pressure, it doesn't spoil since nothing can vaporize away. Plus it liquefies, so you get great storage (800:1 expansion ratio), and does so at reasonable pressures/temperatures. Standard propane tanks are burst tested at only 350 psi IIRC. This is very doable pressure compared to to methane which does not liquefy with just pressure and needs 10k psi storage solutions to store the gas (or special cryogenic if you want liquid). The other darling is hydrogen which has the same issues. Propane tanks are also one hell of a lot stronger than a sheet metal gas tank current found on standard gasoline cars...

3. Propane has been a motor fuel for a long time and it is the only alternative fuel that already has a large full scale distribution infrastructure in place.

4. Propane can equal the usable energy density of gasoline. If the motor is built for propane (read high CR), you can achieve energy use parity. Even though propane has less energy per gram, because of its 110 octane rating, you can harvest more of the stored energy.

5. Propane antique cars are exempt from emissions testing because they are so clean. At least this was the case 15 years ago.

6. Propane can be generated via water gas shift reactions. This way out there, but we could take CO2 from the air and mix with water at high heat and have a closed carbon cycle for our transportation industry.

The only 'con' to propane is that the octane rating is temperature dependent. For manufacturers that have sold propane vehicles in the past, they have set the engine to the worst case use scenarios. For example International Harvester had propane trucks as an option in the 80s. Just incase someone had their truck stuck in a field, and working it hard to unstick, they set the CR at 8:1. Worst case use. So it got really poor mileage and didn't sell for squat. This can be avoided by utilizing liquid propane (LPG) vs gaseous propane (as the bulk of most propane fuel systems utilize).

LPG utilizes the latent heat of vaporization to keep the charge cool and maintain that high octane rating vs gaseous systems that pre-warm the liquid to vapor before use.

Siemens worked extensively with LPG in the late 80s early 90s. They did all sorts of wear testing because propane has no lubricity. Gasoline is low, but propane is even less. Anyways, from what I have read from their work, the only issue with utilizing a stock EFI injector is that they would split from the elevated pressure as they were only designed for 150 psi use. If the propane was chilled to lower the vapor pressure, stock injectors worked great. Anyways they did a run of re-engineered injectors to deal with increased pressure. They are findable, but hens teeth today. You think lash cap rockers are hard to come by, LOL!

The other issue for a LPG system that costs to much, and thus has hindered for general application, is the pump. As stated, propane has zero lubricity. This means a pump made from very hard materials. Pumps are typically several thousand. Since propane generates its own pressure with temperature (phase diagram), you need to pressurize 50 to 100 psi above whatever temperature you think your engine bay will be at to ensure liquid delivery to the injectors. There are two ways to do this... pressurize by heating the propane tank and letting the phase diagram do its thing naturally, or add a pump. To avoid the expensive gear drive pump, I would like to side step this by using a hydraulic accumulator and just use a small air compressor to pump up the system. Use two accumulators to swap back in forth during refills. Then utilize a regular forklift (43#) aluminum tank or two in the frunk. Although not as much volume as a conformal tank, you could then use a propane service. Say two tanks in the car, two empties at home along with two full ones ready to swap in. Last time I did the math a forklift service worked out to about $1.50 a gallon.

If you have a reference flieger on the 'gumming up' with propane, I would love to see it. I have never, ever heard of such behavior with propane. As for the DFI, I had considered them because they are operationally rated way over any pressure that would be required for propane. As for the spray pattern, I agree it would be less than Ideal, but it will vaporize anyway in the 'hot' head... unless maybe you are driving in Minot ND in the dead of winter. Had a buddy send me a pic of a coffee cup of liquid propane because it was -44F there! Yikes.

Love to hear others thoughts on this as this is a personal passion of mine...

t

Steve:
Thanks for the heads up on methanol. Do you know what the failure mode is with the Nickel coating? Having had several discussions with a Millennium engineer, the only issue that I know of with Nickasil is sulfur which chemically reacts with the nickel. Thus nickasil has not been used with diesels till recently due to the new low sulfur fuels.

I have seen the nickasil coating 'delaminate' (for lack of a better term... maybe lift?) from the surface due to a pin hole that allowed water to get underneath and react with the base aluminum forming an aluminum oxide layer that the lifted the nickel coating...

Walt:
Using an aluminum flywheel. I forget who makes it. Currently have a lightly used 5.5' dual plate tilton clutch that came with the flywheel. However, they are not very 'streetable' so I have been eyeballing tiltons 5.5" 'rally' clutch which I'm told can tolerate a bit more slippage than the metallic ones.

I will take your suggestion and add the extra ft-lbs. Got new bolts anyways... I tend to consider flywheel bolts as disposable since they take a beating in shock loads.

Firstly, I misunderstood you. I thought you were going to use propane like water-methanol injection rather than the primary fuel.

Propane is great, the problem is that what is commercially available is not just propane- it is liquified petroleum gas and has a good amount of other species in it just like gasoline. The problem are the "heavy ends" like paraffins which get left behind and will clog your regulators and injectors over time.

With the direct injection system the pumps were wearing out because of the lack of lubricity. That would be the high pressure 250 bar mechanical pump driven by the camshaft. I don't know if the DFI injectors will give enough flow rate if you use a normal low pressure pump since the orifices (orifi?) are so small and made for 3600 to 36000 psi.

With methanol they normally add a bit of oil like 2 stroke oil if I understand correctly to deal with the lack of lubricity. The unwanted species can be minimized by running closed loop at stoichiometric.

http://www.brc.it/en/auto-ad-iniezione-diretta-di-gpl-allo-stato-liquido.asp

Tadd,

Regarding the rocker shafts, check with chris_seven here on the forums and he should be able to give you some good feedback. I believe he has his own design of shaft that he uses with the original style un-bushed forged rockers.

Flywheel
 

Hi Tadd,I worked on factory 3.0 RSR & 2.8 and they would shed the flywheel.We would lap the flywheel on with valve grinding compound & check with Prussian blue for a perfect fit.Then use 2.0 flywheel bolts which are a little longer & torque to 110 ft.lbs.with light oil.A 4mm dowel pin does not hurt either to affix the flywheel to the crank.But with a missed shift good luck god bless.Put a paint mark on the bolts to see if there is flexing.I run my 2.8 to 9300 with a 3.5 lb.aluminum flywheel and have no problems.Fred