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Posted

So my 964 is nearing completion at GTR Motorsport , hoping to have it back come the end of the year. My favourite 911 has always been a 964 despite its parts bin suspension and unusual looks for me it was the best of old and new . The transition year if you will. I thought I'd share the build as many on here enjoy a shiny engine bits before they disappear into a case. Most of the stuff here is GT3 gubbins going in a 64 case . There are some 105mm pistons and liners to go in next . 

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Posted

Very nice DBS. But only half the story!

So, 964 case with GT3 crank & pump, Pauter rods & big pistons.

Which p&c's have you gone for and what capacity does it end up?

Have you decided on cams & top end yet?

Looks like a fun build.

Posted

The liners are from Capricorn and the pistons have been made by Carrillo. Have to think a bit left field with lemans style head sealing arrangements which I'll post when I'm done with the the top end dry build . Need to still do the cc'ing and piston to valve clearance checking ring gaps etc as the Carrillo's demand huge ring gaps due to the material they're made from. Skirts are shorter than jes but generally appear to be a better product. Not mad about the 3 piece oil control rings either. I'll post some photos come the assembly . You might have noticed the rs seals in the case as they don't fit in the same place as the standard liners. They are 4.0 l pistons with RSR cams 993 rs intake valves . Heads have been ported to match some itbs that have been in another build on here 🤪 but they might be married to a varioram intake . Ignition system might be COPs ala Robs 64. Aim is torque and lots of it 350bhp and 420nm is my plan . 

Hopefully ready for Xmas

 

 

Posted
6 minutes ago, ALEX P said:

Very nice :madjg:

What about the 'zorst?

That's a long way off. I'm hoping if finances allow a full cargraphics setup but it's getting silly now. 

Posted
9 minutes ago, Busybee said:

Sounds like it’ll be a monster! Good job 😎

I'm actually hoping for the opposite more a blend of the 2 but not easy with 2 port heads and fixed cams . Going to be a road car that I hopefully take to the Alps each year so I'm planning some modern heating and cooling arrangements , ditching the horrendous 964 Aircon system  for something lighter and more basic . 

Posted

Carrillo = CP pistons?

Anecdotally, I read someone on Pelican fitted the CP pistons, and is suffering a fair amount of oil consumption (can’t recall the cylinder). 

Would the ring gaps you’ve mentioned cause this? Or is it the particular oil rings?

Posted
2 minutes ago, SP72 said:

Carrillo = CP pistons?

Anecdotally, I read someone on Pelican fitted the CP pistons, and is suffering a fair amount of oil consumption (can’t recall the cylinder). 

Would the ring gaps you’ve mentioned cause this? Or is it the particular oil rings?

Combination of the  2 really . The ring gaps demanded by CP pistons albeit it's more critical on the top compression ring, the very fragile 3 piece oil control ring and the short skirt with no gudgeon pin offset can create issues. On JE s you can fit goetze rings as the dimensions are the same. The JE rings are Shyte too imo and I've had success by fitting the goetze ones . Use no oil at all on a couple of 64s I've built now. 

It's more the cold startup issues and piston slap from cold on the Cp pistons . Unfortunately there's not an ideal solution and the mahle stuff will always be the best for reliability oil consumption etc

Proprietary pistons are just that and unless your liners are perfectly round ie replated and honed  there's always the chance you'll get a puff of smoke with them from cold as the rings constantly move around in the bores at some point the gaps will be in a position that they align . 

That said from hot there should be little  oil consumption as the pistons expand and mitigate the cold clearance . 

 

Problem is there are limited piston and liner options in increased capacities and more exotic arrangements people want to explore. None of which can be warrantied without extensive rnd imho . 

Set of CP pistons are about 1500 quid landed but a a full mahle set of liners and pistons are a lot more than that so it really is up to what you want from an engine. I'd always suggest go stock or with whatever Porsche RNd as it was proven and works. Only reason I'm going this route is it's my own engine.

 

DBS

 

Posted

Thanks for that explanation.

I had the latest JE design fitted earlier this year, paired with Mahle cylinders. So far (not very!), so good in terms of piston slap and oil consumption on a 10w50 oil.

I’ll look forward to your updates 

Posted
49 minutes ago, PorscheApostle said:

Going to be a road car that I hopefully take to the Alps each year.

Car's gonna need more aero ;) :P

Posted
6 minutes ago, SP72 said:

Thanks for that explanation.

I had the latest JE design fitted earlier this year, paired with Mahle cylinders. So far (not very!), so good in terms of piston slap and oil consumption on a 10w50 oil.

I’ll look forward to your updates 

I've actually got both pistons Je's and Carrillo's in this capacity as this is effectively a test bed for others I might need to build in the future. I'll post pictures once I get round to  fitting the pistons for comparison.  Incidentally when I stripped this one after fitting mahle liners in the 3.8 capacity plus jes I found the gudgeon pins ie (actually the pins) demonstrated a fair bit of wear after 10k miles. That was the previous build . 

Posted
30 minutes ago, ALEX P said:

Car's gonna need more aero ;) :P

😁 this type of aero kit should sort it

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thanks for posting up progress, I'm following this build with much interest

Posted

Bit tame that aero WC 😜 Make a great snow plough with just a few tweaks 

And @PorscheApostle. You know it’s gonna be a monster 🐲😂 350hp, 420Nm. Are you lightening the car significantly? 

Posted
50 minutes ago, World Citizen said:

😁 this type of aero kit should sort it

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thanks for posting up progress, I'm following this build with much interest

Lol. I'm thinking maybe a bit of that yes. 

 

45 minutes ago, Busybee said:

Bit tame that aero WC 😜 Make a great snow plough with just a few tweaks 

And @PorscheApostle. You know it’s gonna be a monster 🐲😂 350hp, 420Nm. Are you lightening the car significantly? 

It's got a lot of carbon , doors , bonnet , bumpers , roof and wings . It has an integrated ruf style cage too.  So it should be lighter 😲

Posted
28 minutes ago, PorscheApostle said:

 It's got a lot of carbon , doors , bonnet , bumpers , roof and wings . It has an integrated ruf style cage too.  So it should be lighter 😲

High carbon diet is good for the weight, any pictures of the cage and who did you get to do the fabrication work

Posted

Sounds like a really good project! Regarding pistons, why not use Capricorn pistons and barrels? Also would it not be better to use offset gudgeon pins and make them handed specifically for each bank?

Posted
31 minutes ago, ras62 said:

Sounds like a really good project! Regarding pistons, why not use Capricorn pistons and barrels? Also would it not be better to use offset gudgeon pins and make them handed specifically for each bank?

Yes and yes . But I had these for sometime now and this was before Capricorn were doing their own pistons. Oddly enough mahle offset their pistons in some really odd arrangements. Like a 3.2 Carrera for instance . If you get the opportunity have a look at a set which are symmetrically offset on an asymmetrical piston crown. very odd. Carrillo will do you a piston to whatever spec you want it just gets more expensive. 

Posted

Standard pistons in the 964 are offset, one bank the offset works with the engine rotation while the other works 'against' rotation. You can rotate the pistons 180 deg on one bank as the crowns are near symetrical and this helps the motor spin up quicker and gains a little extra power. 

Posted
3 hours ago, ras62 said:

Standard pistons in the 964 are offset, one bank the offset works with the engine rotation while the other works 'against' rotation. You can rotate the pistons 180 deg on one bank as the crowns are near symetrical and this helps the motor spin up quicker and gains a little extra power. 

Lol. I'm fully aware of the concept of the offset but my point was the irony of the offset on a single plug piston such as a 3.2 Carrera which has (if you have built one before humps for the flame swirl) it is however offset symmetrically which means the RHS bank is offset wrongly as apposed to it's lower left and upper right thrust. I have done this with Motorsport pistons with the same offset flipped them around and machined the pockets for the intake valves for the intake valve timing and  overlap clearance . The concept of the offset is to reduce piston slap. The reason I haven't done this with my CP pistons is I already have them and do not wish to buy new ones. 

The point being Porsche did not flip them from factory.

 

 

Posted

So for instance here are some Motorsport pistons mahle that have been machined to take advantage of the offset. The compression ratio is high on these so machining the valve pocket had little effect on the CR. 

Next is a set of 964 pistons which are also offset but symmetrical in the crown so flipping them is possible . The E represent Einlass or intake in German hence the orientation.

 

Last set are 3.2 Carrera which to my surprise were also offset but cannot be flipped for obvious reasons.

My point being the offset is wrongly installed by Porsche on 4,5,6 giving no advantage to that bank. 

DBS

 

 

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Posted

The offset also lowers the forces on the crank/rods so maybe Porsche were more interested in this rather than chase a small performance gain on the 964. On the 3.2 as you say that wasn't possible due to the crown shape. What material are the Carillo pistons and how is the clearance to the barrel?

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