Pittsburgher looking for HS8 L28 advice

D

Don Schmitz

New Forum User
Hi All,

I ran across Ali Khosravi on Facebook talking about L28s with big 2 inch SU carbs; he told me the experts were here!

I'm in the middle of a 'bucket list' L28 build:
  • N42 block, +1mm forged flat top pistons, balanced crank and rods, ARP rod bolts, BHJ balancer
  • P90 head, sent to Slovers to be rebuilt and ported, with a hot street cam from Web Cams (.488 lift, 240 degrees @.050 duration, 106 degree lobe center).
  • header and big exhaust
  • 'B' 5 speed and 4.11 gears
Wanted a motor that will pull hard and be dead-solid reliable (and make race car sounds) to 7000 RPM plus a bit of safety margin should I do something stupid. If I had unlimited funds I'd run Mikuni 44s, but wanted to see what the big SUs could do. I've been talking with a fellow at Birmingham Carbs who says he could find and rebuild a set for me about the cost of a Z-therapy rebuild on Hitachi carbs, but he is unsure about needles and springs and such to work with the L28.

Any and all information greatly appreciated!
Don
 
zbloke

zbloke

Club Member
I ran twin 2" SU's on my 240z for a number of years and rather than trying different needles I took my car to a rolling road and had the original needles the carbs came with reprofiled to suit the engines fueling requirements

The method used wasn't massively hi tech, a piece of 1/8" welding was wire inserted through a hole in a replacement piston damper screw on top, car ran up on the rollers, when the guy running the rollers gave me a signal I lent into the engine bay and scored a line on the welding wire with a small file

This line was measured and transferred to the needles and they were then 'profiled' with a file, the process was repeated until the guy running the rollers was happy there were no lean spots, the needles were then removed and polished in a lathe to clean up the file marks, a final run up on the rollers and done

Just my opinion, but I think this is a better method than trying different needles and possibly only getting close to what your engine really needs, especially if you're building something a bit special
 
D

Don Schmitz

New Forum User
zbloke said:
I ran twin 2" SU's on my 240z for a number of years and rather than trying different needles I took my car to a rolling road and had the original needles the carbs came with reprofiled to suit the engines fueling requirements
Click to expand...

Thanks, I will try to find someone here that can knows this procedure. Just finding someone who knows what an SU is is a bit of challenge!

Don
 
Farmer42

Farmer42

Club Member
If the cost of rebuilding SUs is the same as ZTherapy Hitachis then I would go with the Hitachis. SUs are dead simple to rebuild and you can get advice and parts from Burlen to do it yourself. The only difficulty is if you have to re-bush the throttle shafts. Burlen can do this for you as it is tricky. There is a thread on here talking through my HS6 rebuild and HS8s are no different apart from size. Burlen will advise on the best needles as they are probably going to be different from the SM or DX needles on a HS6. You will also need the jets to match.
 
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