Mike Simard

I did consider going with the Honda/Quad4 journal size but decided against it because I feel that some rod journal area, width and diameter, is desirable for an engine that will see varied conditions and stay together for a long time. If one day on the track I have momentary fuel starvation and a little detonation, I want the rod journals to be able to take whatever comes their way. Those used NASCAR rods for sale all over the place are tempting but they're wacky sizes, aside from the journal diameter they have narrower journals and smaller wrist pins. That may be fine for picking up a few horsepower from reduced drag in the controlled NASCAR environment they must survive for the limited time until they're replaced like clockwork but I believe those sizes would be risky in a sreet/track car, not so much the 48mm diameter but the widths.
The pistons will be J&E. I've had very good luck with JE custom pistons in the past, it should take 5 weeks for a set. The pistons are going to be ordered after the bores are finished honed and the combustion chamber milling is complete.

tommi nylund

If I live at The States and I have a need for Ti-rods, I would call to Don Pauter without thinking anything else. Just my opinion...

Eagles and others are forged and machined at China, but I think you all knew that already and took that in count when thinking rods....

About pin oiling....IMHO I think it´s bad....it steals oil from rod bearings..... I´m sure you know which is best when re-engineering these engines, but I would never use such rods in my own engines, and never been used.

-> Mike Simard: Which material you used to your sleeves? Nice project! Looking forward to see more!

I think I saw a pic of ribbed sleeves on this topic somewhere... It might be good idea, but actually it´s quite small amount of heat which transfers from the cylinders into water. (great example is a vw-boxer of one friend of mine, with water-cooled heads -> no need for cylinder cooling anymore)

PS. Erkka, I happened to be a cnc-machinist at a company which is involved into prower transmission and precision mechanic industry......so I have some 'home-field advantage' when it comes to producing transmission parts (not ssf though...)

Vilhuer

Suspected something like that based on your 9xxfin messages. Hope your shops rates are reasonable. We have few projects which could use some help.

tommi nylund

Actually.....the prices are one complete disaster......for 'outsider´s' project started from the scratch. As we have no production into presonal vehicles.... But everything can be solved, when something special is needed for special car.

slate blue

Mike I understand your reasons and I'm not being critical, the quad 4 which are the rods I'm using are the same width rods as what you have. So no difference there however I understand your point about widths as that has to do with the piston guided rods which won't be any good for the street. As to the pin size, Porsche recently reduced its pin size in the GT3 997 engine, I think it is now about 21 mm. 22mm or 0.866'' is a common size in Nascar but I went the more convential route of 0.927'' So again no difference as long as you are careful what you buy.

With the detonation issue, well that can destroy any engine, and the Tri Metal Clevite bearings are certainly harder than any 928 bearing. In assessing what rod to use I also thought about relevent weights, that is the piston and rod. Well my piston weighs a bit over 400 grams and the pin about 120 grams which is as light as the Honda factory uses to get to 9000 rpm in their street engines. So I figured that Honda builds some of the finest engines in the world, their technical resources are supurb and would be in the top five of all manufacturers.

So I think that I am not stepping outside any convential bounderies. Also the reduced bearing diameter should be stronger and stiffer than that of a larger diameter. It should also need less oil, this will be handy for me as I'm running piston squiters and my crank like yours will be drilled in a Chevy pattern and as such has less oil potentially for the thrust bearing.

The other thing I would like to impress on people who are about to start their stroker projects is the clearance and windage issues all strokers have. I reduced the stroke in mine to keep a respectable 1.75 to 1 rod to stroke and as such keep peak piston speed down, if you are going to no more than 6500 rpm and the car may also be a auto, the convential setup is probably best but in a manual I would definately go the way I have, as it is more revs friendly. I would say that your setup would allow you to reduce the stroke while maintaining a capacity of 6.5 litres. This big bore will unshroud the valves and allow even better flow. Truelly a monster!

Cheers Greg

P.S what piston material are you going to use 2618a or 4032?

Mike Simard

The Moldex crank arrived! Their 16 week projected delivery was very accurate. It's a very nice piece with lovely radii and finishes. The oiling is nicely done too.

BC

Can you take a closeup of the radiused holes for the rod journals?

Vilhuer

**** Looks much better than mine.

Mike Simard

Here's the journal oil holes but forget those, look at the radius at the journal! Getting a nice radius when grinding is very important for strength and takes some effort to get right.
Sterling, the center of the crank isn't drilled, Erkka's pic should be the same as mine, we ordered our cranks within days of each other but they like him better so he got his sooner.

BC

Any updates Mike?

Mike Simard

It's been insanity, I just spent many hours working on some elaborate block reinforcements that provide clamping force at angles, anchoring at the center of the block. It uses some complex machined parts that I would never make again, too much work. Now that that's finished I want to try something simple to strengthen the bottom end that would be practical to duplicate so that's going on now.
One thing I feel is important and often overlooked by engine builders is the design of head and main studs. Most studs, even ARP, are round sticks cut to length with threads rolled. The smallest area will be where the stretching occurs so that will be the minor diameter of the threads not engaged. A stud that has un undercut body of slightly less than thread minor diameter will distribute the stretching more evenly and over a greater distance. IMHO that's very important. I hypothesize that many cases of damaged threads, head and block damage and possibly main cap walk are caused by studs with no undercut to allow movement. I suspect that in the case of a main cap, the stud will be hammered by detonation at some point and the shock will be focused on the minor diameter of the exposed threads thereby permantly deforming them and relaxing the clamping force whereas an undercut stud would have had more area available for stretching without deforming. I used to use standard ARP head studs and always wondered how good they can be if the thread is the only place for stretching and the whole idea of retorquing head studs after some runtime means that somethin is moving, a proper stud should have a very long distance to reach it's tension, like say 1mm or so, why should a stud need to retorqued? The engine and gasket couldn't possibly change that much but yet I've installed ARP studs that didn't need retorquing after some runtime but then I go to the track and then after that they can accept retorquing, so what happened if not the stud permanatly deforming from the hard use?
So anyway, now I'm making head and main studs. They are a similar material and heat treat to what ARP uses (if they don't relax the heat treating for ease of production) and will have rolled threads but undercut bodies and threads held to the closest fit to the Porsche block. It seems crazy to go about making studs but I feel it's very important.

6.0-928S

That crank looks sweet Mike!
Have you considered Raceware for your studs? That's what I'm using & I'm quite satisfied with their quality.
Hammer

BC

Well, maybe make a few sets and make your cost back. The issue is alot of the people making the bigger engines, or at least assembling the parts (me), are using the 89 heads (well, me), and the studs for the heads need to be just a bit longer as the 89 heads have thicker boses and some more material in different areas. Its for this reason I would only build an engine (that will see large combustion pressures) with 89 heads if I had the chance.

I have ARP head studs, but they are supposed to be a bit longer. Maybe I should measure them.

BC

So what you are saying is that where there is no need for threads, you will make sure the stud is smooth there?

Mike Simard

Here's a CAD drawing of what I have in mind, a reduced diameter section for stretching, like a rod bolt.


Hammer, what do the Raceware studs look like?