Tony

Jay..with the time its gonna take me to get this little project underway and then completed, the Topic will be around for a while I think..or atleast tangents of it!
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Normy

I think I read someplace...

[probably here!]

That due to the stresses involved, some 5.0 blocks are fine at 100 MM bore, but if they are bored to 104 mm, then cracks become evident. Perhaps this is because the walls become too thin and some blocks [due to gentle drivers] are not cracked while many develop or have developed cracks already.

So...the alternative is "sleeving" the engine- removing the original cast aluminum barrels and installing steel barrels.

OK...my question again: If you sleeve this engine, just how big can you go, bore wise?

And is 95.25 MM the biggest the crank can go?

Normy!
'85 S2 5 Speed

show'n'go

[quote]Originally posted by marc@DEVEK:<strong>The best we can do on a 4.7 is a 6.0 l, there is a 5.7 running in canada</strong><hr></blockquote>
Marc, I take it that this "Canadian" 5.7 liter is a stock bore-sized 4.7 liter with a 95.25mm stroker crank and short connecting rods ??? What pistons/compression ratio does this engine build have ???
While I certainly do not know *every* Canadian 928 owner, this is the very first I have heard about this car/engine/owner.... and am most curious....
WHO IS IT ???
If you don't want to publish this info, PLEASE have the owner contact me via email at:
showngo@telusplanet.net
Thanks in advance, I'm looking forward to talking to this fellow Canadian 928 enthusiast !!!

Brad
'78 <a href="http://www.p-caronline.com/directory/showngo/" target="_blank">928 euro</a> 5 speed
928 Owners Club

slate blue

Hi Brad, to expand further on the conrods, firstly the 5.85 inch v 5.70 inch means that in metric about 4mm which I would say would have to be the maximum. I do know of 1 stroker motor down here that had 5.70 inch rods but I don't know what pistons were used.

I see your 5.7 liter question and the only way that would work economically would be if the shorter chevy rods had a bigger small end and then you could bore out the Porsche piston. Otherwise you would need to change pistons or have customs rods, expensive which ever way you look at it.

Also there is a crankshaft maker down here who is currently making a stroker crank for a client. It's made of 4340 billet and has 8 counter weights. I will find out the weight from them later when it's made. As you know I was going to have one made from EN26, Scat won't use this material as it is too hard on the equipment.

I put my crank on hold as I'm developing my headers and variable back pressure exhaust. That will be ready this year by the way. The headers will be ceramically coated inside and out. I will try to make them equal length, but as we know space is at a premium in that engine bay. I see that others advertise their headers as equal length but every photo I have seen shows they are not. Have you any input on this?
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Fastest928

Unless mistaken, all DEVEK cranks are Interlloy EN26.

Marc
DEVEK

Normy

Marc-

For fun [I doubt I will do this- my car is too fast for me as it is!!], do you happen to remember the details of the Canadian 5.7 liter engine? What pistons and which connecting rods did he/she use?

-It occurs to me that rod ratio in the 928 is pretty good. What effect does the increased stroke have on the shape of the torque curve?

Normy-
'85 S2 5 Speed

slate blue

Well it is indeed good to know Marc that your cranks are made from EN26, because the Scat cranks are not. That by the way comes from Scat themselves. All the best.
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Fastest928

I do not think that Tom changed materials....that is Tom Leib, president and CTO at SCAT...and did not inform his customers. I will ask..he may have switched suppliers but kept the same material specification.

We check hardness at various points and perform a few other checks to ensure compliance and so far, the material is the same, within 1-2 Rc points as all previous orders. When visiting and checking the raw billets, they have the right color code on them...but then again??

Greg, what is your last name and I will ask Tom if he knows you or remembers the conversation. You did speak to Tom correct?

How is the 200 mph quest going? Where do you plan to run this speed, I sure would like to be there.

Marc

slate blue

Hi Marc and thanks for responding to my post. I did write the person's name who I spoke to down but I am unable to locate it at present but it wouldn't have been the president as I just rung in.

What I can tell you is that I was told it was 4340 and not EN26 as you are probably aware EN26 is about 30% stronger than 4340. It is very tough on the tools and as such Scat said they use 4340 as it suffient in most cases, and it probably is too by the way.

The crankshaft manufacturer in Australia who was going to make the crank for me also said when he was at a trade show the Scat rep said the same to him also. Also Marc if you go through the Scat catalog I don't think I saw any reference to EN26 but many references to 4340. So if they are using EN26 it would be by special order I would think. Is that another difference between your cranks and others? By the way EN30B is not available in this country.

You could probably get your cranks made up cheaper in this country as our dollar is worth only 54c to yours. The fellow who was going to do mine makes up cranks for his Top Fueler, I would suggest a price wholesale of, well I'll leave that for a private email but only if your interested.

Now to my car, out of interest have you seen my car? Engine mods, We'll before your stockmarket started to crash and every dodgy accountant had their hand in my pocket. I could have afforded to build that motor, I was going to build a variocam 6.5 liter.

Parts are a lot cheaper here so I put a budget of $15,000 USD on it and that also included a Motec too. My aim was 585 hp. The problem with the 928 Gt profiles is that they are still pretty tame and I was going to run the 968 profiles or profiles with just a little more in duration. I was going to get them made up here in billet but as you probably know getting that gear ground is a bit tricky. Porsche were prepared to help technically also. The reason I planned to use a bigger profile and Variocam was that my car is an auto as such I needed a relatively smooth idle but I wanted more topend. If you look at your dyno sheets your motor has an abundance of torque but hp drops earlier than you would like I would have thought. Your thoughts?

So what I have decided to do, is this, I am currently making up headers for the 928 (The headers will be ceramic coated inside and out) as I have discussed this before with Susan. (Since you can't supply headers for RHD vehicles) I have to make my own. This will be completed in the next two months, also my variable backpressure exhaust which is similar to what is used on Diablos will be fitted to a custom 2.5 inch stainless system. I am making jigs for all these components and will be able to supply commercially so if you interested please email me.

I'll leave it there for now as I'm probably putting everybody to sleep. All the best.


<img src="graemlins/yltype.gif" border="0" alt="[typing]" /> <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" /> <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

BC

I wanted to resurect this thread. Didn't I read some where that a there is now, or always was, a company that will do a one-off crank for like 2200 dollars? Anyone remember reading that like I did?

Tom. M

Hey Brendan,

Yep saw that. It was Don Hanson who posted the info on the email list and on our pacnw 928 list. I'll dig up the info and post it here if I can find it.

It is nice to know that we can get one crank without having to wait for a batch order...

later,
Tom
midlman@rennlist.net
89GT
87S4 (almost sold)...

Jim bailey - 928 International

Moldex crankshafts (313 ) - 561 - 7676 in Michigan . They have made many cranks for 928s including some of the very first . Price sounds about right , they build them one at a time (no minimum order quantity ) . I believe they are doing one NOW ........You must tell them exactly what you want and they will make it .......they will NOT design a crank for you . I think Don Hanson is getting one for his new motor . Mike Avitt (San Diego racer) ordered one . Mark Anderson has used their crank since his very first "stroker" engine ....SAME CRANK . I also believe that the Bob Devore (founder of Devek) used the Moldex Crank in his big engines . They do a lot of prototype work for major auto manufacturers and your order may take a bit longer than the initial estimate depending on who pulls rank and gets in front of your order ........... they have to take care of their " big " customers .

BC

So I have a standard crank. Can I just send them the crank and say "Make this XX.XX stroke with a Journal to accept a Chevy Rod?

May as well post this here:

We can all get Chevy Rods for between 400-600 (new Eagle, used carillo), and Pistons will be 400-600. Well, if I do some fuzzy math, using the price breaks that come from being able to use rings, rod bearings, etc, and the fact that I would have to pay someone 500-700 dollars to get correct oiling on the standard crank, we come out ahead with a stroker crank - if the price for the crank is 2200-2300.

Jim bailey - 928 International

Brendan that is correct and you get a 6 counterweight crank ...send them a GTS and it has 8 counterweights . The 8 counter weight is heavier but both will need balancing with heavy metal since the original counter weights are designed for the standard stroke , standard rod , standard piston ....all of which change .

BC

Hmm. Very temping. 6.6L with a 106mm bore? Add...maybe...18psi?

Oh my god. Did I just say in my head "I wonder what the gas mileage is?"

I didn't, did I? I've been away too long men.