refresh951

Tonight I was reviewing costs so I decided to put a list together to estimate cost to build a 3.1L hybrid stroker . The costs are based on actual costs from my builds. The costs assume you currently have a 2.5L with usual mods (M Tune, Tial, ect). Turbo and clutch may need to be addressed and these costs are not included.

3L Crank 485
Rods 388
Pistons 372
Rings 157
Rod Bearings w Coating 99
Main Bearings 210
Seal Kit 350
Cometic HG 110
ARP Head Studs 195
Iron Sleeves 114
Clean Block 100
Install Sleeves 480
Deck Block 120
Offset Grind 275
Balance Assy 240

Total Cost $3695

eman930

How did you get a 3L crank for $485? I always see them for like $1000-1500.... Also do you have any info or pics on how they do the offset grinding on the crank? I'd just like to learn more as I've never seen it done

refresh951

Watch, wait, and pounce!

URG8RB8

Add lucky to that list, 3.0L crank in good shape very rare under a grand.

refresh951

Test fitted the crank tonight. As I looked at it, I started to worry that the rod bolts were going to hit the cradle but they cleared with a minimum of 0.08" clearance. Crank is nice and straight.

Crank scrapper is a perfect fit. The scrapper was for a 2.5L and it had pretty big gaps at the rod slots on the 2.85L due to the small Mitsu rods but with the extra stroke it is perfect.

refresh951

I found a few in the $700-$800 range. I found this crank on Ebay.

blown 944

small journal FTW

URG8RB8

Strange, I have the mobile app with permanent search or saved search with alerts that sends me E-mail with all new listings for porsche 3.0L crankshaft. Have not seen one under a grand lately. Maybe it is not working, but just did manual search and could not find one either. Anybody that has a straight one and wants to sell for your price let me know or even higher.

refresh951

Ya, I do not see any either. It was a couple months ago when I was looking. At that time I thought there might be a run on these cranks and maybe that happened.

refresh951

Great post by Michael Mount about crank prep:

https://rennlist.com/forums/9160722-post9.html

My crank has .0015 max runout. This was the best we could do without grinding the mains. I am going to go with it as I want see the results. I have no intention of running over 6400 rpm due to rod ratio considerations and some other ideas to be discussed later.

michaelmount123

I enjoyed reading through this thread. Great to see the hot-rodding activity with the 944. Good work! I have just a couple of suggestions that may help, and a couple of questions:

- Use a 944S2 harmonic balancer on this long stroke engine. The 968 unit is a pulley only, and is not a harmonic balancer.

- Crank straightening should not be a problem for any experienced crank grinder. Using one that runs out .0015 will likely not be a problem, but the runout really should have been addressed before you got it back.

- A cheap and very effective cam upgrade for the 951 is an early 944 NA camshaft. Try it; you'll like it.

- Are you running balance shafts?

- Is your crank guy nitriding the crank after offset grinding? It certainly should be (Google it).

Best of luck!

blown 944

Michael,

First off I'd just like to say thank you for the information you initially provided to me verifying that my stroker build could be done.

Obviously this isnt my build, but Shawn's first stroker build was a copy of mine and this was my next step as well. Shawn just beat me to it .

I am not too sure if I'll end up going to the bigger stroke yet since my current engine is making plenty of power. However, I am glad that Shawn is going forward so I can see the results.

I don't want to overstep by answering for him, but I will say that these are all proof of concept builds, so nitriding has not been done. I am now confident and will have my next crank done in California by your guy.

Anyway, I just wanted to personally thank you while you were logged on.

blown 944

Oh and I think you mean the late NA cam as the early is the same as the turbo cam

refresh951

Michael,

Thanks so much for your input on this build. I really appreciate the work you have shared on the forum.

Yes, running balance shafts and as Sid stated no nitriding on this build. I have researched this quite a bit and am aware of the benefits.

refresh951

I would not say 0.0015" max runout is "high". 0.001" max would certainly be better. Do a search on Google and you will see typical max runouts. Max acceptable runout is closely tied to crank flexibility. With the small journals, the crank will be more flexible than the OEM crank. I am pretty confident this will be fine given that this is not a track motor.