Amazon: Amazon Estate Rolling Project

[Burdekin]

If there was a manual for tuning the B20 that would make life much easier, do XYZ and you will get ABC power. But there isn't so will see how things go. There will be a bit of a restriction remaining at the bend in the manifold so hopefully that will help keep the mixture in the head when the valve closes as Derek suggested. But the inlet manifold outlet will be slightly smaller than the inlet for the head, this will allow flow better into the head and create a little turbulance for the mixture and as suggested help keep the mixture in the head also when the valve shuts. I hope to do a dyno at the end of my build and if I can get a hold of another inlet manifold will hopefully do a comparison.

[Burdekin]

That's the inlet manifold porting finished. Happy how it's turned out and the sizing differences between each one is only slight. I still need to give the flange faces a slight tidy up and will give the manifold a paint. The runner exits are 39mm.

Also a pic of one of the carbs after it was cleaned in the ultrasonic cleaning bath at work for 1 1/2hrs. It came up okay but I'll give it a clean with white spirit, wee polish and oil the steel parts. Darren is going to send the head up tomorrow so hopefully it will arrive on Saturday and I'll do some porting on that. The plan was to do the carbs but after the port and polish we still need to get the valve guides in so the head takes priority. The engine build starts on the 3rd of June so need to get everything sorted by then and have the engine ready to be assembled.

[940_Turbo]

Are you not using the fire rings twixt manifold and head?

[Burdekin]

Hi Peter,

Just the standard gasket with an E head and the ali inlet manifold so no step in the intake ports if that is what you mean?

[tdz840]

Mitch
I think Peter was referring to the small rings which fit in the step between head and manifold on the inlet side. I dont have any pics to hand but have some spare somewhere which I can show installed in a head.
I believe you are highlighting the small ridge between the manifolds/heads/carbs meaning in direction of flow the upstream outlet should be smaller than downstream inlet (but only slightly).
Have you pegged the head; that is install small pegs which locate in tight fitting holes in the manifolds and ensures when your checking the material you remove from the head/mainfold you also locate both in the same positions. The provide no securing function only location whilst you fettle the head
Russ

[Burdekin]

Thanks Russ. The E head doesn't have the rings. Darren was in the machine shop and they said they have a good guy who ports heads so he's going to do it for me. Been doing the carbs today, most of the time spent is getting the carb spotless. Will post some pics tomorrow night.

[Burdekin]

I did up my twin carbs on the weekend, first time I've rebuilt SU carbs. The job involved lots of cleaning and buffing mainly. I thought they looked good but still look a little scruffy in the close up pics. One annoying thing was that the new spindles don't come with a drilled end for the linkage adaptor, so I had to drill the holes. It was a bit tricky as I have only a bench drill at work I could use and getting the angle spot on was a bit of a pain. One is spot on and the other is a little out so not sure if I can adjust the linkage to accommodate or whether it needs doing again. You can see what I'm talking about in the last two pics. The linkage adaptor should be horizontal, one is and the other is a little high. Does anyone know if you can just but the spindles with the hole drilled in the end for the linkage?

I set the float clearance to just over 3mm and centred the needle in the jet. I've attached a pic showing the needle in the jet tube housing and how it looks off centre but the tube is also off. So all you need to do is loosen the tube nut a little, slide in the jet and move the tube until the piston slides down with a nice clunk at the bottom, then just tighten the nut and assemble the jet. Check that it stills slides down with a nice clunk and Bobs your uncle. The little bearings that attach to the bottom of the arm connected to the jet could come out of their housing meaning when the arm tried to pull or push the jet it seemed to drop out of alignment. So I took the arms off two other SU carbs I have and used them. However some bright spark had twisted one of the arms for some reason, so I straightened it and it fitted spot on and the throttle and jet work perfect. So don't try and twist the arm to fit, the way it is made is correct.

[Derek UK]

How are the new spindles in the old bushes? Did you get lucky and find that only the spindles had worn?

[Burdekin]

Hi Derek,

Yes got luck, they've either been rebushed before or are the later models that came already bushed. The spindles were worn on one half mainly so probably would have passed air causing problems at idle but no movement with the new spindles so that is a lucky result.

[Burdekin]

Just off the phone to the resto guy and the bodywork is finished and he’s primed the car. He’s not sure about the colour that he's got so my Mrs, the chief mechanic and me are going to drive up tonight to check it out, very exciting and he hasn’t mucked about it doing the body work as he really only started 3 weeks ago.

Darren (mainly Darren) and I have rebuilt the engine, just waiting on longer push rods to be delivered from KG as the ones I had were too short by 4mm. I will finish the engine this weekend as long as the push rods are done and will paint it all up.

Will post pics and give a better update on everything soon.