944S rally car engine teardown results - advice needed

[Remi]

Hi all

I have been discussing my build in another thread, but this part needs its own.

I have recently pulled the engine from my 87 944s rally car, and was thinking to build a second motor while my longer, bigger build goes on - so I was curious on what the group thinks I could get away with reuseing for a short lived (year or so) stock rebuild... and what to toss out. I have my opinions but this is my first build of any m44 so I'm not an expert.

I'm also turning this into two builds, in a way.

Because I don't want to miss a season of events, the plans are to actually take my stock reciprocating parts and put them in another block with fresh wear parts, put it back in with the current head (which was rebuilt 10 years ago) and then take my time building quite a hot m44.40 with the original block. (I don't really care if the build uses the original block, this is more about not wasting perfectly good parts if I can avoid it).

So, I'm seeking advice on the wear and tear you see below, in two contexts.

The first question is - should I bother refinishing this block (convert to nikasil) for the a big build. I think it's fine, but want second opinions.

the second question is - any concerns seen by the experts if I was to reuse the pistons, rods and crank in a new block, and are there any gotchas or issues in putting 16v S bits into a different 2.5 block, either 8v or turbo whatever I can get my hands on here.

I did take quite a lot of pictures, so enjoy the thread and I look forward to any experienced advice here













































This is the main reason i'm after advice. Cylinder #1 has a barcode ... it's the only cylinder with this. I'm not really sure if this is a common way to fail for these bores, I don't recall anyone mentioning it before. It's odd because it's not aligned with the thrust surface so I do wonder about potential crank play having caused this... but then why only Cyl #1?



The rest look like this, immaculate.





Oil pan had remnants of the oil pickup seal in it



swollen seal starting to disintigrate






The #2 rod journal does have some light lines on it. Enough to catch with a fingernail, but I think this will polish out easily.



Another view of the #2 surface


the rest looked good to me






two of the rod bearings looked like this but two of them...



looked like this.




rod bearing cap for 2



cap 1




cap 3



cap 4




Piston skirt for cylinder 1 has some gouges for sure. Not sure if this is going to be a big problem to reuse for the second engine or not, as it does only go up to the halfway mark or so. Thoughts?



Annoyingly someone replaced an oil pump bolt with a non-oem quality bolt at some point, it rusted to all hell and broke off. Got the rest out without damage to the block thankfully.






Farther away view of the bores






the bastard cylinder



Finally, as a thank you for reading this far - a picture of the car ripping backroads with another *fairly quick* Porsche in the background

[michaelmount123]

Hello Remi,

Your 944S engine has served its time and all photos indicate a complete rebuild is necessary. Anything short of a complete build will result in disappointment in power and longevity. Why shortcut your rebuild with a less than complete job and live with it while a "good" engine is being prepared? Do the good build now.

Your cylinders are screaming for a Nikasil coating and fresh hone, and your 10 year old cylinder head will need a complete reconditioning including valve guides. Your pistons are beat; ring grooves will be worn and will not be able to support a good ring seal. Your bearings are shot and (all) need to be replaced. Rods need to be reconditioned, crank needs to be measured for size and straight, then polished. Oh, consider a 3L crank for 2.8L. You'll love it.

Do you "good" engine build with your reusable components. Nikasil the block, have a set of pistons made to use 964 (Nikasil compatible) rings, make sure the compression is up to at least 2.5S specs, put a Web cam in it, have someone good recondition the head, use Glyco main and balance shaft bearings, ACL performance rod bearings, reinforce your oil pick-up tube. Talk to John at Vitesse Racing about a MAF conversion and a proper tune.

This engine will serve you well and avoid any delay in enjoying more power and big grins. If you agree and have more questions, ask away.
MM

[Remi]

Thanks - I should clarify. I am not cutting any corners, in fact the opposite - I have meant to have two engines for some time, so I can build one while using the other.

As this is a car that sees quite a lot of events (both competitive and non competitive) and trips every few weeks during 10 months of the year the point of the second motor is to have two engines so that I can keep hitting events off the back of one while building the other.

The proper build will take at least a few months, likely longer. I'd like to take my time with that proper build, and not rush it.

So that makes now a good time to build a second, stock engine and reuse what parts I can

So I thought I'd post here and see if I may have enough life left in some of these oily bits to just put in another block.

I wouldn't use these pistons, rods and crank in the new build - but if I can build a spare motor that runs alright with them, why not. I hate having downtime with the car, and I put a lot of miles on it, so I've wanted a second motor for a while anyway.

I was just curious if the experts think I could get through the season on this stuff, assuming I source a decent block, put new rings, bearings and seals on it, and bolt it back up.

End of the day I won't miss a year of events, life is too short - so I need another engine in the meantime.

Hope that clarifies this situation

at any rate, it sounds like your opinion on this is that no, those pistons, rods, crank aren't worth reusing.

[Remi]

Hello Remi,

Your 944S engine has served its time and all photos indicate a complete rebuild is necessary. Anything short of a complete build will result in disappointment in power and longevity. Why shortcut your rebuild with a less than complete job and live with it while a "good" engine is being prepared? Do the good build now.

Your cylinders are screaming for a Nikasil coating and fresh hone, and your 10 year old cylinder head will need a complete reconditioning including valve guides. Your pistons are beat; ring grooves will be worn and will not be able to support a good ring seal. Your bearings are shot and (all) need to be replaced. Rods need to be reconditioned, crank needs to be measured for size and straight, then polished. Oh, consider a 3L crank for 2.8L. You'll love it.

Do you "good" engine build with your reusable components. Nikasil the block, have a set of pistons made to use 964 (Nikasil compatible) rings, make sure the compression is up to at least 2.5S specs, put a Web cam in it, have someone good recondition the head, use Glyco main and balance shaft bearings, ACL performance rod bearings, reinforce your oil pick-up tube. Talk to John at Vitesse Racing about a MAF conversion and a proper tune.

This engine will serve you well and avoid any delay in enjoying more power and big grins. If you agree and have more questions, ask away.
MM

So after looking around a few weeks, I'm having a hell of a time even finding a decent late block, and am changing my mind on my plan.

I am going the route you think makes sense here, Michael - just building this block now.

I've talked to a couple people in the community about their wait times with various parts and can say that the stuff that will take the most time is all stuff I can do as 'part two' of the build. Things like converting to stand alone and getting a specialist to really tune it in with a built head, ITBs, a web cam, and some other goodies - that stuff can all wait for this winter but I realized there's no reason i can't just build the core engine for that build now, use it for the year on my current fuel management, and then step up that build after the season ends. The only real limitation it imposes is it does mean I should stick to stock compression but truthfully, with our poor quality gas in Canada, especially in remote areas where Rally events often take me, the stock 2.5 S compression of 10.9:1 is probably about as high as I want to go anyway.

Doing it this way does risk that with turnaround times on the block and pistons, I may miss an event or two which stinks, but I've made backup plans.

I still prefer this plan to my last one, as this way I can still make events, but don't sacrifice anything for the big build, and won't be wasting time on a second build.

So the new plan is...

A fresh nikasil coated block and a set of JE pistons to match (stock 2.5 S compression, 964 rings...)
have my current head checked for any issues at a local place,
Replace my oil pickup tube
reinstall everything with good bearings and all new seals and enjoy the year.

So, I'm going to reach out to Millennium technologies this week to start the build.

The next thing I'll need to do in preparation for the return of that block is order my piston.

So, I could use advice on piston dimensions. I'll plan to use 964 rings, I'm keeping my factory bore size and compression.

[icb]

Any update on this?

[944m3]

Remi, just messaged you. I have a complete S2 engine I’m ready to sell if you are still interested in getting a new block.

[Remi]

Any update on this?

Yes - I'm going to build a 'new' engine.

I've ordered a new block (new old stock still exists for the late 2.5 blocks!) and the head is with Michael for some massaging. I'll build it for a high compression street motor running a web racing cam and soon I'll reach out to Lance Hayward to see if he wants to make me an ITB setup later this year. The car will run standalone, with the lightest reciprocating parts that will stand up to the modest power goals, and be built into a street machine designed to sing at high RPM.

I keep saying this in various posts, but I will start a build thread for my car, just haven't had time to sit down and post the 5 years of photos and tell the story yet... one day though.

Remi, just messaged you. I have a complete S2 engine I’m ready to sell if you are still interested in getting a new block.

Very interesting - responded.

[stitch2k1]

I'll reach out to Lance Hayward to see if he wants to make me an ITB setup later this year.

Danst in the UK also makes ITB kits, and a priced much better.

The car will run standalone,

What ECU?

[Remi]

I'll reach out to Lance Hayward to see if he wants to make me an ITB setup later this year.

Danst in the UK also makes ITB kits, and a priced much better.

The car will run standalone,

What ECU?

It's good to know if there is another supplier, but Lance Hayward is in the next city over from where I live, so I'm going to go with him for a combination of supporting a local business and because it will be easy to just go pick them up.

For ECU: Haven't decided yet. I'm going to reach out to the local tuner that's been recommended to me by a good Porsche indy that I do events with, I want them to tune the car and will go with whatever ECU they like to use because ultimately it's the tune that makes the car. They do a lot of 911's and 928's so I trust their experience to select one. If that wasn't the case, VEMS and Link have both been recommended to me. Link is appealing because of their integrated PDM addon and I'm thinking about adopting a PDM to replace the common faulty relays and simplify the body electrics.