Adam C

Curious whether any Stroker veteran has a breakdown on costs to build one.

We know the kit is roughly $7500 - what else is there? Assume a home install, not a mechanic deal. What do you farm out?

Adam C

Anyone?

blau928

One left kidney, one right index finger, two little toes, and scrapings from the foreskin of a wild rhino.. That of course is not including the surgeon's fee, the anasthesiologist, the big game hunter, nor the trip along the Zambese..

All in good jest of course...!!

Jim bailey - 928 International

OK just some off the top of my head comments ...approximate prices Moldex will make a crank for about $2,500 you specify sprint or endurance (number of counter weights) 3.75 inch stroke (95.5 mm)ask for Whitey 313-561-7676. You then need small block chevy rods ($800-2,000 )since the crank rod journals are chevy size 5.85 inch length or so. Next you need pistons many use the 104 mm 968 Mahle piston ($2,400 or so ) in an overbored and honed cylinder ($600 ) or you can have the block bored and plated with Nickasil ($1,000) which allows you to use aftermarket pistons like from J E Pistons etc. (maybe $800-1600 a set). So now you have crank,rods and pistons and a block bored and machined at the bottom of the cylinders for piston clearance. The basic components of a kit HOWEVER you need a gasket set $500 , main bearings $300 (modified for chevy oiling) ,chevy rod bearings ($10 ) probably want to do a valve job, t-belt ,water pump, hoses, knock sensors, plug wires etc. etc. etc. ...... Of course some head porting would be nice ,larger intakes , bigger cams ,exhaust modifications/ headers, aftermarket intake ,adjustable fuel pressure reg, maybe Motec Injection..... The price of the crank ,rods, and pistons is just the down payment, I wish it were not so because a well built stroker motor is quite a beast !

Adam C

Jim,

i really appreciate that. forget about the other upgrades - once you have all the aforementioned parts, is that really it?

Adam

Fastest928

Porsche went to an 8 counterweight crank to minimize case flex and crank fatigue due to the imbalance in a 6 counter wieght crank coupled with V8 harmonics.

Bob DeVore broke two 6 counter weight stroker crank engines due to block flex and crank fatigue failure. It was at high hp levels.

After building building more strokers than I care to think about, here is my simple advice if you are thinking about stroker engines.

There are three cost levels:

the cost to do it right the first time
the cost to fix it right if it was not doen right the first time
the cost of the fallen dream, if you cant afford the first two

Do it right, do it once....dont cut corners: remember, once done, you will have a new engine....new rubber, new sensors, new gaskets, new seals, etc.

Adam C

I'm thinking of something like putting together the sub assemblies I have sent out for work. Heads, etc.

So I am back to about $8-9K in hard costs parts wise. What else?

Adam

Adam C

Marc,

Makes sense,

What is the cost in your opinion to do it right?

To all:

THAT IS WHAT I AM FISHING FOR IN THIS THREAD.

blau928

20K

bcdavis

The actual number you are searching for, seems to be something people are unwilling to post.

Somewhere in the neighborhood of $20K.

But I also would like to know the final grand total of all the parts, labor, machining, rubber, sensors, etc...

Jim bailey - 928 International

I neglected to mention the very important step of balancing of a number of components which were not initially designed to be run together. Porsche in the product information manual simply stated "The crankshaft was revised and now features eight counterweights. Stroke is 85.9 MM (was 78.9mm)" with no mention of the benefits. Mark Anderson continues to race his original 6 counterweight crankshaft same crank he has always had. Like most things I believe there are a variety of opinions.

Fastest928

It all depends on the powerlevel you want to acheive...power = details = cost.

Example, to bore and hone to factory or better specifications requires extreme quality control over the process, deck plates plus other techniques....I know of no one who will bore and hone for $600...and keep the piston to wall AT .0008" +0/-.0001" measured at ambiant temp. It does not mean that the engine will not run or run reasonably well. But it will not make the extra power that is there for the taking....

Just a bunch of parts will make a decent stroker, but the paying attention ot the details will make power.

Engine building is like cooking...same component, different results.

Jim bailey - 928 International

The last new GTS engines from Porsche as I recall were listed at about $32,000 each so what is a new motor worth ? Especially a 6 liter or 6.4 liter ?

Jim bailey - 928 International

According to the Porsche spec books there are three tolerance groups of piston diameter nominally 99.980 , 99.990, and 100.00 each with a PLUS OR MINUS of .007 in addition the corresponding bore sizes are 100.00 ,100.010,and 100.020 again with a PLUS OR MINUS of .005 . So on any given day Porsche in one a single tolerance group could assemble a "small" 99.973 piston into a large 100.005 bore ...stacking the tolerances gives a Porsche acceptable spread of .005 plus .007 or .012 in the extreme. I am somewhat challenged by the math but Porsche seems to say a 99.98 average runs in a 100 mm average bore. So 100 minus 99.98 looks to me like .020 piston to wall but the 100 can be as small as 99.973 and the bore as large as 100.005 which gives a piston to bore of .032 ....Whoa the above mentioned .0008 piston to wall is but 2.5 % of the Porsche allowable maximum . Going the other way big 99.987 piston into a small 99.995 bore gives a MINIMUM allowable piston to wall of .008 ! would someone please check my math ? A .0008 piston to wall would seem to be one tenth of the allowable Porsche MINIMUM. Details,details......This is perhaps one example of where tighter is not better ...

Fastest928

Some GT makes 280 rwhp and some make 309 rwhp, some S4 make 265 rwph and some make 292 rwhp, some GTS' make 675 and some make 310 rwhp.

This is why some strokers make much more power thant others even though they use exactly the same components!

What would you rather have .....and engine built to factory or "proven" specs, or the parts just at the edge of out of spec? Take your pick

It is the difference between a C, B and an A....they are all passing grades!

Happy Holidays!