Tim Murphy

6.1 Liter Stroker Short Block For Sale

Here are some of the details:

• Mahle forged pistons, 101.6 mm, 9.1:1 compression
• Carillo H-Beam rods with Carr bolts
• Moldex Crank, 8 counter weights, drilled, 94 mm stroke
• 89 block with custom support rings on upper cylinders
• Completely assembled short block

There are three main reasons for selling:

1. We tested this exact setup on a supercharged car and it had WAY too much torque low end. In my opinion today, supercharging a stroker motor is not the right combination for a drivable street car.
2. We are testing a new setup for high HP/ high boost that looks promising, although it is a little on the labor intensive side and expensive (as far as the prototype goes), but this is the direction we are going.
3. HERE IS THE DISCLAIMER: When the first engine was assembled there appeared to be some galling of the “Iron Ferocoat” coating on the Mahle pistons. We contacted Mahle and they assured us that they have tested this coating and it works perfectly fine and was designed to run in an alusil bore. There was some second guessing going on with respect to the finishing procedure for the final hone so we changed it a little on my engine build. The engine was assembled and everything went very smooth with nothing suspect at all about compatibility. After 7000 miles on the first engine it was disassembled and we found a lot of scuffing on the cylinders and piston skirts. Without the evidence of the first engine at 7000 miles I would not have ever thought there might be a potential problem with this engine. I cannot guarantee that this engine will have longevity in its current state. It might work perfectly fine in a non-boosted application and run forever, but I could not guarantee that. I have not contacted Mahle to get their opinion because I am focused in another direction and don’t want to invest any more time on this project.

I easily have $10k in this engine, not to mention all the hours. I am asking $7500 (obo) which is way less than the cost of the parts alone.

If you are interested in this engine, please PM me and we can discuss this in as much detail as you would like.

BC

When Tim means "We" he means him and basically the best mind in Performance 928 motors in the country today, public or private (and he's not on the web, so don't look)

slate blue

First of all Tim I'm very sorry to see this problem, it can often be a very hard path to thread when modify cars and engines in particular. I also have a set of Mahle pistons that have the Ferroprint coating, they have not been installed as yet. Could you tell me what material the piston is made from? Is it 2618a or 4032?

Cheers Greg

IcemanG17

Tim
What kind of low end torque did a S/C stroker make? Do you have any dyno sheets? I would guess a stroker twin screw would have ALOT of low end torque...but a vortech would has less low and more top end? Kind of the best of both worlds?

drnick

thats a bargain... i wonder what the new direction is?

FlyingDog

Big bore, stock stroke, high revs, if you read H-P's posts.

SwayBar

...and wet-sleeves: https://rennlist.com/forums/928-forum/239222-110mm-bore-928-engine-project-plans-for-a-7-4-liter-in-the-works.html

And there is a thread somewhere with pictures of the parts of the engine Tim is selling.

Okay, found it quick: http://members.rennlist.com/pageauto/stroker.htm

Herr-Kuhn

Tim...Have you built anything with a Nikasil bore yet? It seems to have proven very reliable thus for for me. I'm assembling a 4.7 Euro with 2618s and Nikasil bores for my brother right now...Callaway 4 is getting a full upgrade. I looked into the Mahle route, but they are hard to deal with and don't really want to talk unless you have large orders to place. They are one of only a few in the country that can do the treatment for the Alusil...but Swain Coatings claims to have a piston coating that is applied to the pistons such that they can be run on straight Alusil. My experiecne with Swain has been excellent.

That is serious coin you have in the bottom end...

drnick

you could bolt a euro top end on to that and increase the compression to something respectable and simply run it till it smoked like chernoble then you could re-use the rods and crank in something else!

BC

WHoa John! Are you keeping this from us? Who did you speak to there? Are you saying they said thier PC-9 would work?

Herr-Kuhn

Yes...I was going to use the PC9, but I am staying with Nikasil...because anythign with 100K plus will be out of round anyway. I know lindsey built a 951 with the PC9 and it was supposed to be running fine...also some guys at EBS were working with a guy that was going the same route. I believe the guy's name is Richard...he worked with me on the thermal coating on my manifolds....great stuff.

BC

So Aluminum forged pistons (JE, Arias) + PC-9 is working without wearing off and gauling on an alusil bore?

mark kibort

hmmm, could the Holbert racer use a 6 liter upgrade?
even at 9:1 vs 10:1, maybe we could use a thinner head gasket.
mk

mspiegle

mark, this one's for you

drnick

go back to the euro 2v heads to add compression