Black Betty - Part 3 Engine rebuild
01-25-2013, 03:57 PM
#271
Drifting
Thread Starter
An interesting question has been posed and I'm fascinated to learn the answers - I have every faith in Nick and his reasons for all things.
NB:Gents pls be aware; I am just a middle man between readers and Nick. Please kindly underestimate me in my transmission of info and not Nick's capabilities.
Thanks for the words gents.
NB:Gents pls be aware; I am just a middle man between readers and Nick. Please kindly underestimate me in my transmission of info and not Nick's capabilities.
You are right Frank. When we first designed the 9m 3.82 litre race engine I think we built it twice to check potential design issues and twice again to even out production tolerances through the engine. Always makes me smile when a customer questions the 100 hours on a race engine project, proudly telling me that "every man and his dog knows that a 911 engine only takes 40 hours to build".
Oh how we love the internet.....
Oh how we love the internet.....
Frank I think that nick has done really well with your build and as a armchair watcher on this epic build if that's the only thing that's pop up so far I think you have nothing to fear as he's taking great care & attention to your engine and it must be very time consuming making a monster engine like this & a lot of skill/talent but that's the best thing with the aircooled engine & people like nick there always pushing the envolope even after all these years this engine has been around...it will be epic when it's done but you know that already...
01-30-2013, 01:08 PM
#272
Drifting
Thread Starter
Update:
From my understanding.
Because the pistons are Mahle items the pockets can't be ground as it would reduce their 5mm tolerance.
Result we are now about to have another cam made up to do the job - no additional cost all part of R&D included.
Wiring loom all made up. ECU ready to go.
Brackets etc for the flat slides are coming along very nicely as is the intake plenum.
We are aiming toward a deadline of end Feb/ very early March.
I forgot to ask why we had a 1mm valve clearance issue in the first place - I'll find out soon.
01-30-2013, 02:37 PM
#274
Three Wheelin'
Hi Frank,
Good valves clearance is probably to prevent the valves touching the piston in case of over reving (from the back wheels as you probably have a REV limiter set according to cam spec))
from my experience typical setting is around a minimum 2 mm Inlet and 2,5 mm exhaust with a squish band at a minimum of between 0.6 to 0.8 , valve clearance is often measured by fitting plasticine in the valve pockets, and squish band by placing cuts of 1mm diameter wire lead placed with grease all around the piston edge , rotating the engine will crush the lead and create a print on the plasticine that can be measured; after removing the head...
I imagine no piston would be a straight fit to a special high lift cam, you would probably always have to modifiy them unless you have greater clearance, but the performance...
Good valves clearance is probably to prevent the valves touching the piston in case of over reving (from the back wheels as you probably have a REV limiter set according to cam spec))
from my experience typical setting is around a minimum 2 mm Inlet and 2,5 mm exhaust with a squish band at a minimum of between 0.6 to 0.8 , valve clearance is often measured by fitting plasticine in the valve pockets, and squish band by placing cuts of 1mm diameter wire lead placed with grease all around the piston edge , rotating the engine will crush the lead and create a print on the plasticine that can be measured; after removing the head...
I imagine no piston would be a straight fit to a special high lift cam, you would probably always have to modifiy them unless you have greater clearance, but the performance...
01-30-2013, 03:11 PM
#277
Drifting
Thread Starter
I'm feeling nervous! I'd like it back in my hands 4 weeks from now...
Allowing me enough time for shake down miles and some car prep pre SPA...
01-30-2013, 04:16 PM
#278
Nordschleife Master
If all else fails when you set off for Spa; pack 12 litres of black gold, a filter, a pan and book the good Doctor for a post 'run in' oil change in the pit box!
01-30-2013, 05:28 PM
#280
Drifting
Thread Starter
After a whole year without her - I think I would cry. 
I think I may - have the good Doc's number on speed dial always.
Yeah...
Yeah...
01-30-2013, 06:16 PM
#282
Drifting
Thread Starter
My simple logic would be that there isn't a Mahle piston that would match the custom cam... More aggressive than RSR...
Normally Nick would use another piston brand that can be ground. But I chose the Mahle ones for reliability and he doesn't wanna bring them out of spec from my amateur understanding. What you think?
I'm gonna give him a bell tomorrow - I didn't have time to ask my questions...
PS. How's the car???!
01-31-2013, 02:27 AM
#283
Three Wheelin'
Hi Frank,
Thanks for sharing all your engine info,
My car is find thank you , just done geo and corner weigh ...
Will try to fit next week 993 inner tie rods & outers with rose joints and fit spacers by measuring bump steer....I hope it's going to work...I will post results and try to take pictures...
Thanks for sharing all your engine info,
My car is find thank you , just done geo and corner weigh ...
Will try to fit next week 993 inner tie rods & outers with rose joints and fit spacers by measuring bump steer....I hope it's going to work...I will post results and try to take pictures...
01-31-2013, 03:01 AM
#284
Professor of Pending Projects
Rennlist Member
Rennlist Member
Sometimes I reflect on what my 964 would look and perform like if I had dedicated all my budget to it and not to buying other cars... sigh...
This is a great thread... keep going.
This is a great thread... keep going.
01-31-2013, 03:25 AM
#285
Burning Brakes
I'm feeling nervous! I'd like it back in my hands 4 weeks from now...
Allowing me enough time for shake down miles and some car prep pre SPA...
Allowing me enough time for shake down miles and some car prep pre SPA...
The plan is, that i got my rebuild engine/car back in first week of march (if the snow/winter in gone here around munich). Than i`ve to make at least 1000km slowly before "flat out".... I tought that`s no doable without any stress and the risk of hurting the new engine...
On the other hand - munich to spa is round about 600km. When i do some miles here around munich i could drive to spa, do an oilchange there an go to the track
regards