NineMeister

Engine strip continues:

-nick

Do I spy some rod bearing scuffs? Do you come across many stock engines that have significant bearing wear?

Glad to see you back on the forum, I always enjoy your posts.

NineMeister

The big end bearings are always the first items to suffer from oil contamination, number 3 big end in particular since this is supplied from the journal nearest to the flywheel end of the crank which in turn is fed from #1 main bearing (thrust) which is also the first bearing fed from the main oil gallery.

Thanks for the kind words, since our move it's been a traumatic 12 months at Ninemeister, but now it's feeling good to get back doing things that I enjoy, like sharing our work experiences with like-minded enthusiasts. I'll do my best to keep it up!

NineMeister

Bottom end going together.

Stock 964 crank plus 9m RSR connecting rods. The stock rods are 15% heavier than the 9m RSR, helped by the narrow little end bearing of the RSR rod which means that we can also use the 10% lighter 993 piston. The target for this engine is to spin up quickly, so saving 150g from each piston/rod assembly will have a huge impact on acceleration.

Boydrsr

Oh I am very much liking this one. Great Job.

Navaros911

Those rods look great to my eyes

Vandit

15% weight reduction on those spinning internals, that's awesome.

NineMeister

Thanks.

We now have four different connecting rods in production:
9mR-RSR 964 crank to 993 piston (as seen in photo), 127.0mm centres, 23mm pins
9mR-GTS GT3 crank to 993 piston, 127mm crs, 23mm pin
9mR-GTR GT3 crank to 9m Race piston, 132mm crs, 22mm pin
9mR-SCS SC 3.0 crank to 993 piston, 130mm crs, 23mm pin (can also be used on a GT3 crank with special piston)

The SCS rod is an interesting unit, designed it for a special build 911SC engine. By using a 100mm 993 piston on the short stroke 70.4mm crank you have a 3320cc motor running a nice 10.2:1 CR with the perfect crown design to make the most of a twin plug cylinder head.

NineMeister

993 pistons & cylinders now fitted. These were donated from a 40,000 mile 993 engine that I bought and rebuilt as a 9m 3.82 Race engine some time ago, being saved for a suitable good cause ever since!

Will post photos of the body soon.....

-nick

Are the 993 piston crowns different from the 964? Better design? What kind of application would you use the short-stroke 3.3? Sounds interesting.

NineMeister

For starters the 993 piston weighs 592g, the 964 piston 660g, so the first big saving is with the reciprocating mass. The weight saving of the piston comes from piston bosses that are closer together with a narrower little end of the con rod, hence the piston pin is also shorter, stiffer and lighter. The top section of the piston is also thinner. The intruder (crown) design is similar although the CR is around 2 points higher with the 993 piston due to a shallower dish.



The SC connecting rod is a spin-off from an engine which we are assisting developing for a business client in Europe. We needed a large capacity 3 litre, so by re-machining a stock 1989 964 cylinder it can be converted to a 105mm spigot, machine-to-fit 100mm bore upgrade package for the SC block. Combine that with a 993 piston and you have an over square 3.32 which we can make work with a suitable high velocity cylinder head. Then we add the low pressure turbo.....

ALEX P

Colin, by machining the cylinders therefore reducing the wall thickness have you ever come across problems with the bore going out of shape i.e. oval? and as a result blowby and poor leakdown figures?

Con rods look the business by the way

NineMeister

Good question.
The machining required is down at the bottom of the cylinder, where it locates into the block, hence the upper bore area within the stroke of the rings is not affected. Down at the bottom the stock 964 100mm cylinder has a 107mm spigot which would have to be machined down to 105mm for this SC engine. This is directly comparable to the aftermarket Mahle slip-fit 3.8 conversions for the 964/993 which have a 102mm bore and 107mm spigot. There are also recognised 100/105 3.5 conversion kits available for the 3.2 and 3.3 911/930 engines so I am confident that we would not have an issue for this development engine.

Glad you like the rods!
First set in test this week in a 3.8 litre 964 street engine, first pull on the dyno was 341hp with more to come.

NineMeister

Cylinder head time. With the 964 engine, unless the money is there to fit 9m Billet Heads reworking the heads is a no-brainer on the 964 head due to the significant performance benefits found from careful reshaping work around the seats and guide areas. In this case even though it was my own engine I wanted to see how far I could go without breaking the bank, hence there were no other options than to don my protective gear and get out the porting tools. That said, if there is one job that I have to psyche myself up before tackling it's cylinder head porting - when cutting the ports with a tungsten burr the aluminium shavings just about get everywhere, even wearing boots they manage to find their way into your socks!

Please don't ask me what port shape is required or how it's done, if you want to know go buy a die grinder, some burrs, a spare set of heads to play with and a flow bench to measure the results.....

NineMeister

Once cleaned, Mark was immediately on the task of lapping the valves and fitting the 9m Sport valve springs with titanium retainers.

Two things to note with the heads.
The 964 head is cast with a ceramic port liner and over time the ceramic liners have a tendency to crack under the exhaust valve guide boss. The one shown has a crack propagating all the way through to the port exit but since the liner cannot be replaced you have to accept this minor flaw. As long as there are not chunks missing the heads will be safe to use.
Also you will note that I have not refinished the intake port away from the valve guide boss, the surface finish of the casting deliberately left "unsmooth" to promote fuel atomisation (amongst other things).