blau928

Thanks,

Dema I spoke about, is Dema Elgin of Elgin Cams in Santa Rosa, who does all the stuff you listed, and has a few custom grinds for the 928 already.... It seems like Jim M may have sent the cams to Santa Rosa.... I know Elgin also did the cams in Kibort's Car etc..

Thanks again for jogging my memory...! I'm getting old and forgetful

slate blue

Where have you been Richard? I have seen you post here for years?

Cheers

Greg

blau928

Hi Greg,

I have been building engines for my boat and having fun with my Ducatis..!

Here's something you might like, as it's from Australia.. I now have a Motec M8 with full datalog and dual WB..! (Not yet in the car, waiting on a redone milspec harness, and my spare motor to show up before I pull the old one..) Well over 300K miles, and I promised myself I'd do a rebuild once I got to 300k..

Just got back to the 928 after I had a disaster with my machinist ruining a bunch of my SC parts..

Anyway, good to be back..

PS.. the new spec motor on the rebuild calls for 2.0 rod journals and a call to moldex...

Dennis K

Hi Richard -

Long time no see! Glad to see your project is continuing.

Jim Morton is doing the thrust bearing mod in-house these days. He's on the 3rd generation of this mod and it has evolved into quite an elegant solution. You can see the final product in this thread:
https://rennlist.com/forums/928-foru...e-cam-mod.html

I also took some pics recently while he was machining an S3 cam in preparation for the new collar:

Hilton

That blue PVC tape looks familiar

slate blue

Hi Richard, glad your having fun, way to go In case you missed it I had a stroker crank made with a 90 mm stroke and the Honda rod journal size of 1.888" or 48 mm. I have also investigated offset grinding our standard crank down to the BMW journal of 47 mm. With the 104 mm pistons I have that makes around 5.7 liters if that idea is of interest. I am going to get Carrillo to custom make the rods for that one. It should be a lot cheaper and still make a strong performing engine.

Below is the Moldex Honda, which is designed for higher than standard revs, peak power hopefully around 7,500 with the redline at 8,000 rpm, what you lose with capacity you more than make up with higher RPMs as it is just a air pump in the end. (as long as its a manual)




The next pic is part of my display cabinet, the crank there is not chromed but fully polished to relieve any stress risers, this even includes the oil galleries. I was going to a do a post but time has been preventing me. I have an idea about reduced main journal sizes, one to recycle minorly damaged thrust bearing failure blocks, two for high rpms, above 8,000 rpm reduced journal sizes help the oiling situation. This is the amount of overlap you have when there is 90 mm stroke and honda journals are employed along with 2.3" mains.

It also makes the crank quite light, with other measures a 90 mm stroker crank should be around 22 pounds (10 kgs) lighter than a GTS or normal stroker crank. (None of this of course applies if you are using an auto, it is pointless in that case or if you don't want or can't for various reasons turn it very fast).

I am looking at using 2.3" main journals with the honda journals on any other work. It is not just weight there is power there too, there is also research out there that shows that the 8 counter weight crank has a power advantage as well.



People have said to me that depending on how far you want to push the envelop you may need to look outside normal 928 crank suppliers, I am open minded. Is your project still supercharging? I am working on in my spare time a set of 4V heads that I hope will flow over 400 cfm of air @ 28" Most Nascar stuff is at the 420 to 430 cfm level and we know the power they produce.

Greg

blau928

Hi Greg,

Congrats on the crank..! That gives me more ideas...!!! I had planned a 3.78"/96.52mm stroke with a 4.31"/109.47mm bore in a sleeved block to give 7.3 Liters.. If I went to a 3.85" stroke, things could get more interesting indeed.. I'll need custom pistons anyway, and rods I have found matched sets in at 6.0" with a Chevy common pin size of .927.... The big end of the rod was planned at 2.0" to keep parts availability cost down.. By the way, rod specs All NASCAR stuff..

I know of someone who has done Honda 4v heads that flow 400CFM, and their motors do 137% VE Normally Aspirated... The honda head is similar to the 32V 928, and I am looking for specs on head dimensions to send to this guy to see if he can perform his magic.. He has a SC Honda with a mildly ported head that lays down 400 WHP from 2.0L.. Well, Big Block Chevys with 7.4L can do 1000HP.. I have also seen a BBC with 565CI lay down 1000HP/TQ Normally aspirated with a 4 Barrel Carb.. I almost fell over until I looked closely at the valve train, cam spec, and head chamber shape etc...

I hear a lot of talk about total flow, and peak flow on heads, and cam guys talking a lot about lift. Well, I would like to know what ramp rates they are using in their modified stuff, and I also want lower spring pressures on the valve, and a rounder nose profile, and the maximum lift to be less than .550.

Anyway, once the heads are specced, I can then jiggle the pistons and rods accordingly, and then I will have the crank cut. Crank is last due to the bobweight info needed to cut the crank. At least I want to have it done this way, as I want the motor internally balanced, and YES, I want 8 counterweights too..!!! That way, the counterweights can be smaller, and closer to the crank centerline, and no mallory needed.!!

So, lots to do, but I'm not doing this to make $$$ so hobbying is like that as you know..

Those NASCAR motors make 800 HP, and use really nice stuff, and the heads flow 400+ CFM, as they would need to.. (My off the cuff measure for theoretical HP on a V8 is 2 X CFM per head).. As they used the 2.0" rod journal, I thought they have to be strong enough if made properly.. Besides, some Small Block Chevy guys, and Honda guys have made as much, and more than I plan to do, and still have the motor in good shape..

You wouldn't happen to have head/valve/ V stem/ V Angle/ Port size etc. dimensions in your files, would you..?

In addition, I will have to cut my hood open, or use a carbon, or fiberglass hood. I redesigned the Supercharger system just a bit, (injector blocks flipped for better valve angle to hit the back of the intake valve) and the setup will be very difficult to fit otherwise.. Shouldn't be too much higher than the regular hood though. I envision a bulge like the new M3's....

This winter will be fun, or I will have many more grey hairs from doing this stuff and learning "MOTEC" speak...!

Great to hear about your progress..! Keep up the good work...!

Cheers,

blau928

Oh, BTW, about crank suppliers, I woud love to have a Chambon crank, but they cost a king's ransom, and I am not funding a cup team..!

I am exploring a semi auto 6 speed that can withstand 1100 lb/Ft though.. I didn't just say that, did I..? I must be getting old and senile, who makes such stuff anyway..?

blau928

Hi Dennis..!

Long time, yes..! I think the last time I saw you was at the RM Auction in MRY during historics week/Concours D'Elegance a few years ago..!

Good to hear from you too..! Seems like lots of stuff is happening in the928 world, which I think is great..!

Thanks for the update on the cam.. How's your car running..? Still talk to Marc and Susan..? Wonder how they are doing as well..? Sheesh, it hass been a while....

mark kibort

Great shots Dennis!

Yep, there are a few ways to do the mod on the S3 cams, but Dema didnt want to weld it. actually the original idea was from Todd back east, to make a collar and then only weld the collar to itself, and not subject the heat to the cam. it was straightened after the mod anyway, due to it being impossible to really not subject the cam from the indirect heat from any welding.
anyway, the bearing area is widened which removes the existing collar and then a new collar has to be installed in the area where there is nothing machined normally. the collar can be two piece as dema did on mine, and then sandwitched on the cam which might have a set of cuts made to fit the collar (flats or something) then , the two pieces are welded together at a seam. Or, in Dennis' case, the collar is welded to the cam, spot welded somehow.

the ends being cut off is a minor mod.

slate blue

By Blau 928

Hi Richard a few little things that might help you, I have some concerns about the amount of torque you mention, that is Veyron type power and will require massive engineering and cost. Basically you will need to change the whole drivetrain, to me that is not that practical and will take a massive amount of time too.

I did have a look at a Ferrari 6 speed gearbox, they are very strong and heavy but if you can believe this they offset the input shaft. So that stopped me from buying it but even that box wont take that much torque. There is an article in Forza with a supercharged 599 and that is as powerful as I think anybody needs, it is quicker to 100 mph than a Mclaren F1. So the Ferrari gearbox can certainly take a lot of power but no for us.

As for the cranks, this one has plenty of heavy metal, many hundreds of dollars of the stuff.

The heavy metal makes the crank lighter and the bob weight is only 1500 grams. You are right Chambon make nice cranks, how much are they? Meynard MCT do some nice ones too. I still like the American suppliers.


By Blau928
Now as to those Honda heads, I think they are either testing at 50" or they are telling you stories. I don't believe 400 cfm Honda heads are possible unless they are the Indy heads which are pure race heads. If you want you can ask him the valve sizes as it the max flow rate that has been achieved is 114 cfm per sq" of valve area, a standard Honda bore would be around 90 mm and the valves would be around 37 mm, so something is wrong there somewhere.

Most stuff is tested at 28". Velocity is also a key power driver and one without the other doesn't mean much. To achieve that 137% efficiency the air has to be traveling extremely fast. Which means the induction is extremely straight!

What is your desired RPM level with your motor? Also with the cams given you are forcing the air in I wouldn't be going with such high lifts. Too much hassle and potentially higher wear rates. Colin or Lizard931 is having some billet cams made just for this purpose, higher lift than standard but with a wide LSA and quite a reasonable price too, I would definately contact him as this is a great time and money saver. You can choose your own profile too I believe.

As to my 4v heads, that adventure is just starting, so nothing is tied down, I would be keeping the 928 4v port the same size especially given the forced induction, no need to be bigger. As to the valves for yourself probably 39 mm on the intake and 35 mm on the exhaust. This will allow you to clean up the seat bowl area. Given the forced induction I would look at inconel exhaust valves.

I also bought some nice piston pins, Del West and the material is C-350, look it up, sensational material, it is what they use in the Top Fuellers. These pins are also mirror polished on the inside! That is for the same reason as the crank is polished, to avoid stress risers. The Diamond Like Carbon is "DLC star" by Baekarts in the U.K.


With a forced engine you will need very strong pins, that is the reason the Top Fuellers use this material. They are in the $700 to $1000 range depending on who makes them. You can use a lesser material and the only penalty is weight, they just have to make them thicker. If you are not using a lot of revs like me that should be a good compromise.

Greg

blau928

Hi Greg,

Thanks much for the tips, I appreciate the input.

As far as the heads go, I believe Larry Widmer, as he designed and built some very interesting stuff indeed. He is an honest guy, check out his stuff here..

http://www.theoldone.com/

Lots to look at.. I do not want high lift cams, I want good ramp rates, and a rounder profile to keep the spring pressures low.

After looking at his work and charts, let me know what you think. I think he's been on it for a long time, and has the motors to validate his results.. The site has all the data, including flow rates etc. tested at 28in water..

In addition, it is as you say, not a pure flow number, but the blend of flow, volume, and speed of the air mass into the cylinder, and also the swirl effect in the chamber and charge stratification and placement to give the VE he is getting...

He (Widmer) also does not reccommend very high lift cams, same as Dema Elgin...

About the gearboxes, they can be found here...

http://www.weismann.net/

Transmission guys..

They have not gtten back to me with cost yet, but have a look.. I got to them through my boating contacts, as many of us are breaking drives up, down and sideways. In addition, they did the original trans for the Mc Laren F1 and a few other cars that make big power.. Take look at the 360 Modena with a blown 7Liter Big Block with 1000lb/ft they did as well as the Gale banks Truck and some of the race winning cars they have made boxes for. In addition, look at the marine Drive, as they compare to a Mercury Speedmaster 6, which is what many big power boats use making 1100 lb/Ft.. Some of the race boats I know make 1200 lb/Ft with 1400 HP, and run WOT for an hour or more... Kinda like a big Nascar motor with two superchargers.. The 565 I saw does it NA 1000/1000 on pump gas, and idles at 800 Rpm like a kitten..

Anyway, I plan on using Nascar pins from del west or another good Mfr. Carrillo or Oliver Rods (Carrillo's are easier to get), Moldex Crank, and pistons may come from JE, or another mfr, and I plan to send them to swain tech in scottsville NY for coating..

I had a chat with some guys from Aston Martin this summer at the 1-77 West Coast press release party (what a car that 1-77 is wow!, Should I post a pic..?), they also said the DBS paddle shift has a similar gearbox as the 599 (Graziano) I also spoke to some Ferrari guys, and the Bugatti Factory rep, (DSG Audi based) all about the same time, and then started looking around at what could be done on the lower cost end, and I figured I would ask Weismann and see what they say..

The graziano boxes cant take that kind of TQ load, and I don't think I can fit a 4L80E Hydramatic box in a 928..... So, the search is on....

My redline is to be capped at 7500, with an 8K upper limit.. Hell, if it goes as planned, the thing will be too scary to drive over 6K in 4th with the auto box, and the 2.2 rear end anyway...... The other thing about the M8 Motec, is that I can limit the boost with a solenoid to control the Blow off valve, or the bypass valve, or even limit the pulley size of the SC to control the TQ output until I get a solution that allows the thing to really run well.

I am aiming for a torque table, and I know I am at the upper limits of the stock gearbox, and can possibly break it etc. However, I will try to use my better judgement and tune the motor to not break too much stuff.. (I have a spare gearbox , and am waiting for my spare motor to show up anyday now)

The LSA for the cam planned is exactly 114 Deg for idle and civility... Cam lift not over .550, and considering duration based on head analysis... I also have room in the pistons to make good valve releifs, However, it depends on the head analysis.. I could also go with shorter rods than 6.0 if needed etc.

Chambon makes moldex look cheap. In addition, they are busy cutting cranks for Nascar, and other big fun racing teams. Meynard also great stuff, and same with them.. I'm just a guy tinkering in his garage, Moldex is fine for me...! Mike Simard's crank looks very good, and it is a 3.7" stroker Moldex and i didn't think it had mallory, but it had knife edged counterweights... Aerofoil counterweights would be nice, but who wants to pay for that...!

Lots of options to consider, but I guess it's part of the fun.. Oh, I saw Colin's post, and his pricing seems good if I get to pick my grind, I'll send him a note and see what he says... I'm curious about the ramp rates....

I actually have an idea for a hydraulic lifter I want to check out, it could improve the tent airflow (widen it, and make it rounder, and have less friction using stock cams.... Then again, maybe it's a dud..)


Cheers,

ptuomov

If you email Dema Elgin about 928 cams, he will direct you to Jim Morton. They are working together on these.

slate blue

Well Richard I didn't know that Weisman designed the McLaren gearbox, they have some nice stuff, that is going to be an absolute fortune, I would like to be proven wrong there. I have a similar clutch to what the McLaren F1 uses, it should provide light pedal pressure while holding high torque levels.

As to Graziano, I don't believe they make the Ferrari box, I am pretty sure that ZF make it. The same basic box in its various forms dates back to the 456 GT to the 599. As I said great box but bloody offset input shaft. Also the other difficulty is the high mounted input shaft in the 928, so it makes things a bit difficult. Maybe the Aston box might fit? Staying with ZF means that the half shafts will bolt up like on the Ferrari.

With regard to the oldone website, well there is a lot there to digest. I couldn't find the 400 cfm figure, I did find 349 cfm but it was sketchy on the details of the valve sizes etc. Not saying a number like that is impossible but it is very high. However while there is some questionable stuff I saw, like 8000 g piston force, well if something can run at that level it certainly wont run for long, maybe a quarter mile? Nascar stuff is just over 5000 g. Basically there is a lot of knowledge being shared there and it appears to be of high quality. I don't really know Hondas but they are a high performance engine that is for sure.

In regard to revs, with a long stroke around 3.8" regardless of piston and rod weight the piston speed will be the same as a Nascar engine at 8,000 rpm, I think on longevity grounds the max redline should be more like 7,500 rpm and normal limit at 7,000 rpm. The high G forces can produce high wear on the journals and bearings, I have seen this first hand and I am coming from it in a way that I would approach my engine, I don't want regular rebuilds.

When I spoke to the crank maker that made the polished crank, they said they don't know how Moldex do it for the price, I put forward probably the depressed Detroit economy keep the prices down. As I have a Moldex crank I of course am a bit favourable to them. I have heard Richard of broken Moldex cranks, I can't remember what broke them. I good damper is key and I may make the ATI hub so that an off the shelf damper can be purchased.

My Moldex crank didn't need any heavy metal, I could have used heavy metal to bring the weight down, I will probably do that next time. As to crank design, their seems to be to be many variations. Those variations change the design of the counter weights, given I will have a dry sump and I believe Mike does too.

I think a crank running in a vacuum has greatly reduced losses anyway probably small gains they are looking for. The polish on the crank is also related to windage issues. It has no knife edging at all, go figure, I think it is the same reason they have been dlc coating rods. On rods btw I would not put Oliver in the same catergory as Carrillo Lentz, Arrow or Pankl, they are good but their products are not found in F1 or Nascar Le Mans or Supercar racing so I suspect their R&D is not at the same level as the majors.

Carrillo does a lot of R&D and they were I believe the leader in bearingless rods. Also in regard to rod sizes, 2" rod journal sizes are not used in Nascar anymore, probably not for up to 10 years, the Honda and BMW journals are stronger and have better hoop strength so they distort less and also offer friction advantages due to less bearing speed and need less oil.

I don't know how much Chambon cranks cost, (most cranks are in the 3,500 to $5000 range with some over $10K) they are now part of Capricorn and they also own Perfect bore, so pretty high rollers. BTW the maker of the polished crank always do a study on the application their cranks are used in to make sure they can take it. They are happy to make 928 cranks too, they are more expensive. They did tell me don't confuse weight with strength, that can be deceptive, this surprised me at least a little bit.

I would like to know exactly what the material that Moldex use, there is so much secrecy among crank makers. If you speak to them can you ask please, I suspect it is 4340, just a guess.

Regards

Greg

docmirror

funny how threads morph.