Engine and Transmission Tech

Anyone had any experience with flat plane cranks in the rover engine?
Secondary vibrations are a problem but the stroke is so short. Ferrari et al do it but only on very small v8s.
Wha'd ya think?

Fred, save your $'s. Unless your running"Indy", very little to be gained,(neat sound/very few hp.). Now I think, if you run "180" hedders with a "180" crank=normal sounding ? I've read, in the lower rpm. ranges, their very hard, on the mains. If you need more Crank$haft, to handle the TA Mystery heads, you might consider,sbf or LS chev., for raw forgings. 2cents, roverman.

Hey Art, I'm not concerned about hp gains and I know about a lot of the pitfalls. If I use a flat plane crank then I can run my Lotus cams as is. If I use the stock crank then I need custom cams ground. Just trying to balance out the pros and cons of both.

Old post for historical purposes:

[forum.britishv8.org]

Greg

Forgive me, I just bought a "flat plane" crank...very, as in Modle T. Fred, why don't we make (8) cams, u-no volume ? I like aluminum. 1/3 the weight ? Less cost/more innovative ? roverman.

Buy directly one 4.5 AJP ;).

I'm thinkin, "Mike" is runnin one in his monster bore rally motor, but he's "still" Smokey Yunic on us. roverman.

Man you guys are killing me! The mystery motor has a 4.0 crank in it. The flat plane crank in a rover? The racers all used Crowler cranks except the UK rally guys. There was no need for anything radical plus rules dictated a stock configuration replacement could be used.

Hey guys I think I need to give you some more info.
I've built a 4.6 with a 98.5mm bore. with the stock stroke that gives me 4995 cc
I'm using that bore size because it lets me use the stock Lotus head gaskets that go with the 907 heads on the motor.
A flat plane crank would let me use lotus cams. The stock crank means that I have to get 4 custom cams made.
Either way its expensive.
I work on a lot of vehicles with 180 degree cranks and they sound great. My concern is the vibration. All of my experience is on very short stroke engines. I'm concerned about the 82mm and longer cranks shaking up the car too much.
Any input is appreciated
Cheers
Fred

Fred, At least, "Mike" dangled some pictures in front of us ! How bout ? Aluminum cams-not as goofy as it sounds. roverman.

Hey Art, This one just kind of happened and no pictures were taken yet. When it's ready for final assy. I'll snap some shots. I will be building another one with 912 heads and a 4.00" bore. I plan to document that one better.
In the meantime "How it's made".
I started with a 4.6 block. Bored the headbolt holes into the mains and threaded them for studs. Then I decked the block .750" and had aluminum plates made to match the lotus heads. These were sealed to the block and fastened with studs and countersunk allen nuts. Then the whole works was over bored for the new wet liners and decked. A step was made at the bottom to allow for an O ring to seal the liners to the block. The new plates use studs to fasten the lotus heads down.Oiling is by external lines in the valley but the next one can be done with drilled passages I think. The cams are mounted backwards and driven by belts from a jack shaft through cutouts in the bellhousing flange. The jack shaft is run through the original cam bore and extends out the rear of the block. A custom aluminum flywheel clears everything. The deck studs exit and re enter the block in several spots and I've sealed them with O rings, but it might be a problem down the road. The next one will be a little different. The intake is stock Dellorto manifolds into a central log with a TPI throttle body. Fuel and ign.on this one is SDS just because I have it. The next one is megasquirt. The only thing left is the crank issue and sealing the valley.
This engine is going into my Elite. The next one is for the TR8 if it fits ( it's WIIIIIDE! ) if not then into the Esprit.

Fred, perhaps you read our (7) pages of "hashing, 907 Lotusheads/Rover V8" ? Pete Ardema does similar kinds of head swaps, alot. He likes, hi-strength steel tubing for main shaft of cam, and individual lobes and journals slid into position and TIG welded, finish ground/all done ! Less weight/cost-more filling(oil). roverman.

Your lotus head imagineering is what got me to this site.
I've been doing this build off and on (mostly off ) for the last few years.
A little internet inquiry and voila! here we are.
I am considering the DIY cams but for two engines thats 64 lobes, even my cam grinding buddy thinks I've leapt over the cliff. I think I'd rather turn some from billet and get him to grind them for me. For a crank I've been looking at some 4cyl forgings that could be reground to fit or a custom billet unit that is huge coin. But what the heck it's only money, if I don't spend it my wife already has.
I wonder if that high strength tube and some steel discs could be turned into a crank. hmmmmmm.

Fred, don't even hmm. Welded 180 deg. crank = mega cracks. I suggest a chat with "Pete"- a savy guy. Good news is with modular lobes, you grind a whole bunch at once.Perhaps a "V block" fixture to index the lobes. Maybe buy your buddy a grinding wheel ,suitable for alum. ? roverman.

Art, I was thinking more along the lines of a pressed pin design. No welding and complicated enough to make a person fearful.

Hey Art, haven't spoken to Mr. Ardema for a few years now. Kinda let things set since the fire. He is a phenominal engineer and a very talented original thinker. I have thoroughly enjoyed every conversation that we have had.
I'm a little concerned about the aluminum cam thing. The weight advantage is minimal. Torsional rigidity for the available cross section is less than ideal. Lobe stability (ie molecular wave ) is questionable. Frictional compatability of the various surfaces involved is an issue. Stress over time failure (work hardening) is an unavoidable obstacle. Is there an available advantage that I am missing?
Cheers
Fred

1/3 the weight X 4 cams.No post heat teatment, proprietary hard anodize with TFE = 62rc and .45 coeff. of friction ? Not "thinkable" in a pushrod cam. Symeesed lobes with generous corner radii, same tensile as mild steel. First step would be a torsional deflection comparison test. roverman.