16valver

My buddy has a 951S short block thats clogging up his garage. He's throwing it in with some other parts I'm buying from him so it can come clog up my garage.

Anyway, I have yet to tear it down or even have a good look at it for that matter. I know it was a #2 failure and that the #2 cylinder wall has scoring. The extent of that scoring will be exposed upon teardown.

What I'm curious about is how many of those parts are likely or not likely to be in good enough shape to re-use without extensive machining.

Thats not to say I'm against machining.

Is it likely that I'll need to have the crankshaft re-done + oversized bearings? Block taken down to get rid of scoring and then nikasil coated? Nikasil coat the pistons to make up the difference?

I'm just curious about the amount of work it will take to bring this thing back from the dead. Theres a positive displacement roots supercharger thats also hanging out in my garage... This is a project I've wanted to go after for quite a while.

Arominus

Its a couple thou to redo it properly. Personally i'd take the 2.5 block you have in your car now (its the same as the 951S block) and get lower compression pistons and make the supercharger happen that way. Did you even put on that s2 intake yet?

V2Rocket

i tore down a 951 motor with a spun #2. most of the parts were OK still, the crank took most of the damage. #2 journal is 0.6mm smaller than any other...good candidate to offset grind

Van

The intake and exhaust manifolds are probably good.

odurandina

he's not kidding.

although you could also throw the dme, 3 good connecting rods, starter and serpentine parts/accessories in to the parts bin.

blown 944

If the block and crank are damaged, it's not worth doing the machine work to them. You'd be better off using good NA parts.

The pistons and rods may be ok. I doubt the rods are better than your NA parts. You'll need to check which tolerance group the pistons and block are.

Or sleeve the block and stroke the crank. That's what I'd do

16valver

Ok cool, thats about what I expected.

Are the crank shafts on the turbo's and NA's the same? Plan B for all of this is to pick up another engine with a good block, good crank and let the magic happen. I still won't know for a little while but I'd guess at this point that piecing something together is probably the more financially sound option.

Aronimus, its coming together but I'm having to wait on a couple pieces that porsche's hose supplier needs to make more of. I don't think the supercharger is going to go into the car I have now. What I'd like to do is build up a 2.5 16v SC engine and then buy a turbo shell later on down the road.

I'll see what other parts are still on the engine. Head is gone but the cam tower is still there. Intake and exhaust are probably gone. Should be plenty in store for the parts bin. We'll see.

Arominus

Why buy a turbo shell? Your car is already wired for the 16v motor and won't have all of the extra heat shielding to ditch. Just build what you have. Turbo nose/fenders and bigger brakes would be cheaper and easier on what you have vs swapping everything over to a new shell. Was your car wrecked? Keep in mind that the actual structure of the car is the same between an na and a turbo. It's just the fenders, nose cone/rear splitter and brakes that would be the real differences.

16valver

I've definitely thought about that. A lot. No its not wrecked, its my daily driver!! That option is still not off the table but I've learned that my car budget works better for long term projects. I've put a lot of thought into buying a cheap daily driving car and putting the S away for a while to do this project but A) I can't stand driving around in boring eco box cars and B) If I ended up with a daily that I actually liked it'd get a bunch of money dumped into it. Building something up and making it work with a shell just seems like a project I'd feel better about taking my time on. Plus I'll have another porsche to drive in the meantime!!

Then again, none of this is set in stone. I'll very soon be able to strip down the 951S engine and see whats what. I'll look forward to crunching some numbers on Frankenstein build vs machine work build vs using whats already in the S.

blown 944

The cranks are the same.

Might want to grab those parts from him to do a mock up for brackets, pulleys, etc.

When you get ready to do the 16v sc work, please remember rouge tuning for your tune using MAF and map, and dnovak for your intake.

It will make your life much easier, trust me .

Doing a SC project is fun, I've done it. Have fun.

16valver

Yes I intend to get as many misc parts for the engine possible. I actually did have Rouge in mind.

Its slightly off topic but please feel free to elaborate on dnovak (a member on here I'm assuming?) The intake is the one thing that scares me. The blower in question is an eaton m62 off of an xterra (if that means something).

I wish more people would do SC builds. What became of yours? Was it a 16v? Was it awesome? Do you have a build thread I can drool over?

BikePilot

FWIW nikasil is a fairly thick coating so it shouldn't be an issue to get the bore back to stock size without trying to coat the pistons to make them fatter (not real sure that'd even work). If there are deep gouges they can be welded, then bore, then nikasil. Very common thing to do after blowing up a racebike or ski. Also JE and most piston mfg's will do custom pistons for reasonable money. Also common with bike projects I've messed with. I imagine they could do the same for your project. Minimum order is usually 4 IIRC, which is a pain on a v2 bike, but will work out nicely in the porsche.

blown 944

Dave has flanges for the 16v head already water jet cut, and can build a custom intake for you. Your intake is magnesium and cannot be welded to an aluminum plenum.

I used an M90 off of a super coupe. The M62 is too small IMO.
If you search "lil mule" on here and pelican you should have hours of reading.

I ultimately sold it to focus on my black car, which is now going to be a 16v high HP turbo setup (my first 16v build)

It made very close to 300 rwhp in the end. I ran over 105 in the quarter up here before adding the intercooler.

16valver

Yeah I wasn't planing to have anything to do with the stupid magnesium intake. Hate those things. My plan was to take the spare one I have and cut off the flange to have a machine shop make me an aluminum copy of it. Then go from there. When the time comes I'll hit your guy up for sure. The part that concerns me is getting things blueprinted so that it all lines up. I'll be getting rid of the AC and running the alternator in the low spot to make it all a bit easier.

This is good to know. I'll take what I've got to a local shop and see what they want to do for me for what price. I have a potential NA engine that I could buy as well so it'll come together either way.

Arominus

You know, the mag intakes usually pull threads because they are mistreated. IE, seating the fuel rail into the injectors using the fuel rail bolts instead of pre assembling the rail/injector, then seating it by hand in the intake and then installing the bolts once the rail mount is flush against the intake.... I almost made the same mistake, but caught myself. Since then i have done it the correct way and have had no issues.