I was in the middle of installing a new Sunny master cylinder on my kb10 yesterday when I realised the pushrod between the master cylinder and the brake pedal is shorter than it needs to be.

When I realised this, I vaugly remember that there is a pushrod change required to make the system work.

Can someone tell me if its the sunny pushrod rquired, or can I rob one from any other model?? Or can you buy these new from a brake place etc. ???

Thanks.

Yep. I agree. I don't see any reason to leave a rough finish to the exhaust port. The slipprier the better in my opinion (not that I have much experience here).

The reason the inlets are left rough is to discorage laminar airflow. 'Laminar' airflow is when the airflow tends to have infinetly thin layers of different air speeds. Like a river with its fast flowing centre and slower, almost stagnant edge flow.

Laminar flow will result in more airflowing through the port, but the bad side is the slow moving air (read vapour) near the port walls will result in the fuel particales clumping together and either forming drops of fuel or will 'wet' the port walls. This clumping effect results in slower and less complete combustion.

One of the pioneers of laminar flow is the WW2 P-51 Mustang. Its wings were specially designed to take advantage of reduced drag of laminar flow. The airfoils (wing section) were designed to maintain favourable pressure gradients up to 0.5C That means the airflow starts laminar, as it always does, then will sustain this until half way across the wing before it becomes turbulent flow (the opposite to laminar). At this point aero drag increases approx 10 fold.

However, it was found that in the 'production' version of the wing, the lack of smoothness caused an early trip into turbulent flow - somewhere around the 15-20% mark. Now, if you have ever seen a mustang wing up close, you will see it is made from sheet aluminium which is either polished or painted. The polished winged mustangs are beautiful and are like smooth mirrors, and these are the slightly quicker planes.

The point is that laminar flow is very delicate and the slightest roughness is enough to cause turbulent flow. Ie: the satin look is enough.

Aarhh!!
200 kph and you lost your tailshaft !!! I hope it was the rear connection. I've also wondered what would happen if one lost the front connection. Some sort of pole-vaulting action I'd imagine !!

Thanks for the tips so far everyone - even though there is some difference of opinion. Thats life I guess!!

I'll be sure to drop into Bunnings tonight and check out this Ozito router. I'm particularly curious to see the shape of it without the parts you must detach, just to see how difficult it is to get into those hard to reach places.

The comment about the emery paper is interesting too!! I'll make sure I give it a go!! I thought that HSS cutting bits with course teeth would have been the prefered tip though...Oh well - horses for courses I guess.

Well its about time I tooled up (properly this time) and ported another head for the race car. But there's so many options now.

I was just curious on everyones opinions, experiences and knowledge on the relevent tooling...ie brands makes models on die grinders, electric or pneumatic ??? Cutting tips: Which one were the most useful?? part no's??

ok-doky.
Got a pic then ??!!
I like the type that has almost a straight passage from carby to inlet. Unlike the redline manifold, in which the two passages from each carby approach each other very quickly then run parallel into the head.
Is this the manifold you raced with recently??
PM me your phone number and I'll ring you when its convenient for you.
Daniel.

Jeff, the twin webber manifold: what type is it ?? I'll need one for my other KB10.

I'd be very interested, depending on type and whether its original or ported.

Daniel.

Haha...YEAH!!! Mick & I have been talking about that for ages !!! We we're real disappointed not to make Bathurst last month. I've got the pics though - looks like a blast!!

10sec R-Fast ??!!?!?! Whats going on?? Ru getting slower or is Benny getting quicker??

We're busy designing our next engine at the moment. Might even make a little downforce thingy for the boot if I get time. Next year will be a very busy year for us both (off the track) and we fear we may not be able to make every supersprint in the championship. So maybe a 6-hour is what we should be aiming at!! Its at my fav track too!! You've just gotta love those fast, smooth sweeping corners at EC.

Whats the rules, costs, dates, etc and whats a respectible lap time for the 6-hour ??

I might be, depends on price.
But I'm not interested in turbos! just efi and throttle bodies.

I agree with you Freak!
I just done some number crunching. I hope I've got this right...

200HP out of an A15 bored to 79mm requires something like:
1) BMEP = 200psi at 8100 rpm
2) BMEP = 210psi at 7700 rpm

strength issues aside, these BMEP's are definately possible but to get them at those rpms will require some serious porting and compression.

I'm still a believer!!!