Jim bailey - 928 International

Sleeves are used so you can use inexpensive custom aftermarket pistons or to "save" a block too badly scored to cleanup with an overbore. The process of boring out the existing cylinder large enough to press in a steel sleeve of a thickness sufficient enough to be strong means removing much of the aluminum of the cylinder yet it is that remaining cylinder which must support the sleeve. Yet in the process most want to make the motor as big as possible. The old chevy Vega engine used the same alusil material for the blocks at a time when few knew what that meant so thousands of them were sleeved.

slate blue

Carl I will have 280 degree duration cams, with solid lifters and Ti retainers, the valve train should be able handle 7500 rpm. I think I will also coat the lift with DLC. I should at this point be at 100 hp per liter. The engine is a 5 liter Gt motor as standard. It will be dry sumped and balanced. It wil have either 38 or 39 mm intake valves with the standard exhaust valves. A custom 3 inch thin stainless exhaust with variable back pressure. Also a custom set of headers built by yours truelly as no RHD headers are available of the shelf. I would love to be able to achieve 200 mph or 320 kph just for the records sake with a 5 liter essentially all Porsche engine. I just dont know about the bolts on those rods.

Cheers Greg

Carl Fausett

Greg - that sounds like a first-class beautiful build up.

More money than I am going to spend!

I'd recommend you get Pauter rods tech support on the phone, tell them what you are doing, ask them for design/application advice. You are in rare air with that, they can help.

I'd also chat with the Mark Anderson, Joe Fan, Kim Crumb, and others that have 7200 RPM red lines (or higher) and ask them what they did, and how they like it. I do not know where Mark Kibort shifts - he also may be a good source and he is an willing Rennlist advise-giver.

Carl Fausett

Here are some pics of my balanced crank and harmonic dampener.
Just thought they might be interesting to you guys that are reading this thread about balancing...

The engine shop was pretty impressed by the stock 928 balance. They commented "it was really close to perfect alrerady" They said the same thing about the harmonic balancer - and if you look at the amount of material they removed from it, you can see they weren't kidding! That balancer was within .1 gram of right on!

Note the photos of the crank.... the balancer adds a little here, takes away a little there... just like balancing a tire, they use weights at 2 or 3 positions to net the desired effect at a point in space they cannot touch. Example: they cannot add weight to the main journal or c-rod journals... but if that is where you need to adjust the weight, they move out in 3 directions and adjust the weight out there for the same effect.

The finished, balanced, and polished crank photo is on the bottom.

Fastest928

Carl,
"As to steel sleeving an aluminum block - not much rocket-science there..." Absolutely right, EXCEPT, the Reynolds 390 is not the typical aluminum alloy used in aluminum blocks. The traditional material is usually 356/357 casting alloy with a property call % ELONGATION, usually rated at 2-3%. Reynolds 390 elongation is generally referenced as "0"%.

That means that it does not stretch wtih failing well. In laymans terms, it does not stretch to allow sufficient squeeze to seat a steel sleeve over a wide temp range.

Draw the curves with the the choosen nterference fits and the two CTE and see where the sleeve will crack the block when cold and get loose when hot ... lots of fun.

Porsche and Mahle did experiments in the mid 90 with steel sleeves for refurbishment, but the experiments failed for reasons I was unable to extract.

Best of luck,
Marc

Carl Fausett

Marc - well researched. Looks like I could have my hands full! We'll see how she does.

I am working with a couple suppliers to find a block-filler for the top of the block (not the bottom) compatable with aluminum expansion rates. The idea being to bolt a milling plate on the top of one bank of cylinders, flip the motor on an engine stand so that those 4 cylinders point straight down, then use an epoxy-type (not grout type) block filler to create a webbing at the top of the cylinders.

Of course, later when it is hard, you use a head gasket as a template and drill water passageways into the epoxy filler.

Anyway, that's my plan. Your thoughts?

BC

My thoughts are it would break up and fall down to where normal block filler is -at the bottom of the towers.

TexasDude74

I'm new to this board and still researching the 928. I plan on building a supercharged, sleeved 6 liter stroker myself next spring. Sean Hyland motorsports has built several 1000-1500HP cobra engines. They recommend sticking with the stock bore. They heat the block in an oven to 300 degrees and freeze the sleeves with liquid nitrogen before assembly. But the cobra is a different engine. It still seems there has to be a way to sleeve the 928 engine so it will survive at 20 psi!

John Speake

Greg,
Are you retaining the MAF or using a MAP sensor ?

slate blue

Hi Carl, thanks for your response, I also thank you for your candor. Those Pauter rods look great but from memory they are about $2 k that is too much for rods, I think I would have the Porsche rods moded so to accept Top class ARP bolts. I know Mark doesn't rev the engine too much so I don't think he can help there.

I will dry sump and re-route the oiling in the crank. I think as far as the heads go, Ti retainers and light solid lifters will get me too 7500 rpm certainly they have very similar numbers at 7250 rpm. The thing with the cams is that you really don't know exactly where the power peaks will be, it is just an educated guess. Also the cams have a wide lobe separation angle as they are 86.5 model cams. So this helps with the idle. I'm planning on quite high compression to try a take some of the cammieness out. The new BMW V10 has 12 to 1. We have 98 octane here in Oz. I will use 11 to 1 as a minimum.

I think the bottom end as far as mass forces go wouldn't be a problem if either the rods were changed or the pistons were lighter. I don't really want to do either. This is where the costs start to really get out of control and I will say that I don't have the cash for that anymore.

Hi John I plan on using a Motec M800 it can use both MAF and certainly MAP which is what Motec reccomemd as they say the big cam mucks up the MAF readings. So I will take their advice and use MAP. Do you have any differing opinions? I also plan on adapting an electronic throttle from a GM or Ford vehicle as it will work with Motec's traction control system. This tied in with the PSD should make a very tractable car.

Cheers Greg

John Speake

Hi Greg,
Any overlap on the cams with mess up the MAF readings at ilde, so a MAP is best. If your cams aren't too radical, then you could used the standard MAF and remap the LH ECU. My EPROM emulator will be available in the next couple of months. Have you already purchased the Motec ?

It would be quite a bit of work to build up the maps for the Motec.

slate blue

Hi John no I haven't already purchased the Motec, but the current computers are the ones form the euro 1984 engine or the m28/22. In Australia this engine didn't run the 02 sensor. The s3 and s4 engine of course did, I was planning to adapt a 02 sensor for the Motec. They recommend it. What do you think? Also the Motec has a traction control device built in, what can I do in this regard?

Thanks Greg

John Speake

Hi Greg,
You would have to upgrade to the 87 and later LH/EZK, to be able to use the EPROM emulator I have.

This would give you the knock sensor functionality. But no traction control option...

How much overlap is there on your cams ?

slate blue

Hi John the intake opens at 30 degrees before TDC and closes 70 degrees ABDC
The exhaust cam, which I am planning to reduce by 10 degrees, is as follows
Opens 70 degrees BBDC and closes 30 degrees ATDC these measurements are total cam duration. Piper are the grinders, lift is almost 11 mm on the intake and 10 mm on the exhaust. With the lifts, there will be no problem on the exhaust as far as a coil bind issue but will need to investigate further about the intake. I really dont care for big lifts. I could reduce the lift to 10.5 mm and be sure and safe.

Thanks for taking an interest.

Cheers Greg

Lagavulin

Greg, do you know what the specs are at 1mm lift per the Porsche Workshop Manuals? If so, then we'd have a good idea what Piper did to the cams with respect to stock. How about at 0.050" lift?

I'm sure you already know, higher than stock max RPMs is big bucks in more ways than one.