89 951 engine overhaul

[four0four]

I have given it some thought - it's a little of many things! This project was originally intended to be a major refresh of the engine internals + turbo + seals, which kinda exploded when I discovered cast rods.

Cost...isn't a huge driving issue...though more than doubling the block's machining cost isn't great, but the number of moving parts (proverbially!) in this project is. Take it as a combination of not really knowing what I'm doing, and being too stubborn/stupid to let someone else do it all. I'm sure it's a vastly better solution, but I don't see it as bringing any characteristics I *need* here.

I'd also like to be able to continue to convince myself I'll drive the car this year. If this was a longer term project, or I was building an engine to eventually drop in (and I won't count that out...) the block would already be crated up.

Plus, the Alusil concept tickles some part of my brain. It's quite clever, even if it's complicated and inferior after all



....Lets see if I still agree with this after another cup of coffee

[Tom]

If you want to stick with Alusil, I get that. A freshly hones alusil bore is pretty darn cool. But... choose your machine shop wisely! Consider my story.

Back in the mid-2000's, I took nice 968 block to a local machine shop that used to build lots of 944 turbo motors with success. They checked all the boxes for me insofar as they had a solid track record machining these specific motors with successful. So I dropped the block and pistons off, and the wait began. Turns out the guy who was into 944s previously had left, so the block sat and sat until finally, nearly a YEAR later, I told them I needed to pick up the block done or not. So they finished it alright. They ruined the front face with their EDS machine (and therefore the whole block) and put a deep score mark down every cylinder by doing something I never fully understood when they honed the block. The fact that the didn't even notice spoke volumes about the overall quality of the work.

Upset and frustrated, I found Scott Gomes on the other side of the country, about 2700 miles away. He was actively machining the 944 motors at the time with real success, so I called him. That was the first time I shipped a block via UPS in a cardboard box, and it was easy as pie. Because Scott was doing nothing but 944 stuff at the time, he turned everything around very quickly. I assembled the motor shortly after getting it all back from him and it's been running strong for nearly 15 years. So what's my point? Find someone who really knows what they are going with the 944 and don't worry about their location. Going local to save time or money sounds logical, but it often costs time and money in the long run. Just my two cents, yet again.

[chris white]

I’m surprised at that price quite, I used to get mine for significantly less….maybe inflation or supply and demand? If you are sill interested I could see if I can get you a better deal with the nikasil and piston combo. Btw - you have to have the pistons in order to get the nikasil done since the machine to match the pistons

[gruhsy]

Honing tolerance for Nikasil

https://www.millennium-tech.net/plating.php

[four0four]

Well, while I can appreciate that getting it plated is probably the optimal solution (minus that whole sulfur thing)...I think sticking with Alusil is more than good enough for my modest goals! If all hell breaks loose I'll surely come crawling back


I ordered some Molnar rods (...from some reseller...Molnar themselves are backordered at least another few months) and the 0.5mm oversize Mahle pistons linked in earlier.

Edit: Nope, Wossner rods. All the Molnars in stock at the moment are PCA legal weight...

Turbo is at Evergreen getting a rebuild and some minor upgrades.

Any thoughts on the oil pump o-ring? I'll get some pictures up later. Also, someone really gobbed the sealant on mine (...) - does heat break down 574?

Also curious if anyone has experience with the Wizard Cooling (I guess LR resells it?) oil cooler/radiator. I don't really want to put that tiny stock thing back in...So it's either that, or the big 3X+ LR cooler. Similar enough pricing.

[Tom]

Sounds like a solid plan to me. 99% of 944 Turbos have Alusil cylinders and do just fine. Figures crossed you find a shop that can do them right.

Not sure what you are asking about the oil pump o-ring, but for sure change it! After going to all this trouble to have a true rebuilt motor, I wouldn't even consider re-using any old seals or gaskets (or bearings)...

[gruhsy]

I have the wizard combo.

My car ran nice and cool. 160F on the highway.

That was with a 3.0L

Well, while I can appreciate that getting it plated is probably the optimal solution (minus that whole sulfur thing)...I think sticking with Alusil is more than good enough for my modest goals! If all hell breaks loose I'll surely come crawling back


I ordered some Molnar rods (...from some reseller...Molnar themselves are backordered at least another few months) and the 0.5mm oversize Mahle pistons linked in earlier.

Turbo is at Evergreen getting a rebuild and some minor upgrades.

Any thoughts on the oil pump o-ring? I'll get some pictures up later. Also, someone really gobbed the sealant on mine (...) - does heat break down 574?

Also curious if anyone has experience with the Wizard Cooling (I guess LR resells it?) oil cooler/radiator. I don't really want to put that tiny stock thing back in...So it's either that, or the big 3X+ LR cooler. Similar enough pricing.

[four0four]

Sounds like a solid plan to me. 99% of 944 Turbos have Alusil cylinders and do just fine. Figures crossed you find a shop that can do them right.

Here's hoping I'm not another cautionary tale!

Not sure what you are asking about the oil pump o-ring, but for sure change it! After going to all this trouble to have a true rebuilt motor, I wouldn't even consider re-using any old seals or gaskets (or bearings)...

Oh, shoot - I didn't post it here. The o-ring that sits between the washer and drive gear on the pump is relatively new (<3k mi). That said, it looks like it..wasn't thick enough? The washer rode mostly on the gear, and was worn away some at the point of contact. I guess it's possible the bolt was under-torqued, I'll have to calibrate the wrench before putting it on this time.


And yes, not really planning on re-using any of that! Except the gear. That thing's in fine shape.

[Latitude48]

I ordered some [rods]... and the 0.5mm oversize Mahle pistons linked in earlier.

Info on the LN Engineering site says the Mahle pistons are only intended for use with Alusil, but Millennium Tech says customers use them all the time with Nikasil. So, is the piston coating compatible with Nikasil but the rings are not, so if using with Nikasil one just needs to change the rings? Would be good to know for sure if anyone has information... paging Chris White

[four0four]

TBD if LN even has those pistons...Lots of things I've tried to order have resulted in "oh, actually we're out of stock"!

That said, every 951 rebuild thread eventually gets a "pictures from Charlie's shop" post, so here's mine!

k26_1.jpg (2.71 MiB) Viewed 1595 times

k26_2.jpg (2.88 MiB) Viewed 1595 times

Mine's the little guy

k26_3.jpg (4.49 MiB) Viewed 1595 times

Machine shop is busy til the 22nd, so kinda in a holding pattern there. Maybe I'll finally get around to picking up a blasting cabinet and doing some cleaning.