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Re: 2.8L N/A 318hp Build Recipe
Posted: Wed May 03, 2023 5:30 pm
by Tom
michaelmount123 wrote: Wed May 03, 2023 3:29 pm
Cruise98 wrote: Wed May 03, 2023 8:50 am
I am curious about the details on the Darton flanged sleeves. I just had a block sleeved, and it was a failure. We had a "D" chunk come out of cylinder 1, and there were small cracks at the crank web to cylinder interface. The flange was only supported at the top since the cylinder was bored all the way to the crank web.
So sorry about your failure. How much press did the sleeve have? I hear about way to many failures with sleeving these blocks. It's really not rocket science, just attention to detail.
- It's fine to bore all the way down a cylinder if you're using flanged sleeves. The flange locates and secures the sleeve at the top of the block, rather than the bottom. Works fine.
- Press on the sleeve is .001-.002" / .025-.050mm.
- Make sure the sleeve is pressed all the way down to the machined step. When the block is heated (in a hot spray washer, for example), the sleeve will pop up as the block cools. The last process in sleeving is usually to resurface the deck, and if the sleeve has popped up it will drop when the head is torqued - no more head seal.
- If there's interest, I can provide a PN for the Darton sleeves that I use for the 944.
I remember Garrity back in the day struggling to sleeve these blocks. He had an amazing shop and was a great guy, but for reasons I'm not sure he ever sorted out (or cared to admit), he had lots of head-sealing issues.
@chris white seems to have sorted it out with his Darton MID sleeves. Is that the same sleeve you use? I think it's like any complex skill. Once you have it mastered, it's easy (for you).
Re: 2.8L N/A 318hp Build Recipe
Posted: Wed May 03, 2023 7:50 pm
by Cruise98
We used the i 943 sleeves, with 0 - .001 interference at 100 degrees temperature delta. The flange was decked with the block. Because of the way his Rottler machine works, the crank girdle was not in place until the final hone to size. The d chunk from #1 was probably a crack that only showed up after machining. I always thought the sleeves were too thick and left very little aluminum. They were way too long so he turned them down in a lathe.
The MID sleeves they list for the 2.5 block would not work with 100mm pistons, and they are three times the cost. I wanted to fix the car and didn't want to wait for custom pistons. So, now I wait for another block to be sleeved!
Re: 2.8L N/A 318hp Build Recipe
Posted: Wed May 03, 2023 8:00 pm
by Cruise98
Yes, I would like a Darton part # and any dimensions on the boring/counter boring, depth, flange step OD etc. I do not want to turn this into a thread about my sleeve project, but maybe it will help others.
Thanks for being willing to pass on your knowledge and experience.
Re: 2.8L N/A 318hp Build Recipe
Posted: Thu May 04, 2023 5:14 am
by chris white
its also very important to chamfer the top edge of the block cylinder - the darton sleeves have a very slight radius from the top edge to the outside of the bore. If you don't chamfer the block the sleeve may not seat correctly and recess into the block after a bunch of heat cycles / stress.
Re: 2.8L N/A 318hp Build Recipe
Posted: Thu May 04, 2023 6:13 am
by gruhsy
Has anyone here ever tried the aluminum sleeves from Millennium Technologies?
I’ve only seen a photo from LN Engineering with what I assume are from Millennium.
Re: 2.8L N/A 318hp Build Recipe
Posted: Thu May 04, 2023 3:39 pm
by michaelmount123
Here are the Darton sleeves I've used:
100-110
100-111 (bigger bore)
100-3135
100-9003
Darton has many that will work. Note Chris White's comment above.
Re: 2.8L N/A 318hp Build Recipe
Posted: Thu May 04, 2023 3:53 pm
by michaelmount123
Re: 2.8L N/A 318hp Build Recipe
Posted: Thu May 04, 2023 6:57 pm
by 333pg333
Hi Michael. Glad you're still inspired enough to continue to contribute to the 944 platform. Also good to see a few others in this forum. I'm wondering if you want us to raise questions or add our own experiences to this post or create our own? I might start my own so as to not impede yours. I'll move it over to the 944 turbo forum.
Re: 2.8L N/A 318hp Build Recipe
Posted: Thu May 04, 2023 7:55 pm
by blueline
@333pg333
Would be great to have more input from as many contributors as possible - questions, experiences, insight and more. Thanks for joining in!
And yes, I would definitely suggest starting a new topic (as you mentioned) in the 944 Turbo sub forum if that's where it best fits.
Re: 2.8L N/A 318hp Build Recipe
Posted: Fri May 05, 2023 3:10 pm
by Motosport
Fantastic thread and a very interesting topic..
Seeing how a 2.5 944 engine can make 318 HP with an increase in capacity and some careful engine work, I would be very curious to know what Michael's approach would be with a 968 engine? What would be some beneficial upgrades and engine work (within reason) to get a 968 engine up to the same power figure in NA form, if possible?
I would imagine that many of the experiences from a 944 engine upgrade could also apply to the 3 liter engines, and perhaps Michael has some ideas of the most worthwhile upgrades for trackday/fast street purpose?
Thanks, Alex