madkaw

I stand by my statement 🙂

Well I did get another lid and have both short ears on there . I have my float sync tool and messed with float levels forever . I come up short- no matter what I try to get the correct height . I said time to try it . It seems the engine want at least 4 turns out to be happy . That also varies from start to start . I need to check the incoming fuel pressure to make sure it’s adequate or maybe too much . I do have my wideband working so I am shooting for about 13.5 at idle . . Did I say I hate carbs :-0

Just got off the phone with my car friend and PHD physics guy. His thought was as long as you had a reasonable amount of fuel in the float bowl, the Venturi will pull the fuel pass the jet fine . It’s more critical that the jet and needle are the same on both carbs than it is to get max amount of fuel in the bowl . I like the idea of the floats being more level , but it doesn’t add any more fuel to the bowl ( volume ) . I think getting the float needle to sit in the float tang properly is important too - especially with these flat tipped float needles

Very interesting read and right on target for I’m dealing with . I’m a little intimidated to boring holes in my SU’s , but might have to do that . I’m building a high performance engine for a customer and I can’t get the floats to comply . I’ve been at for days - literally . My floats are slammed against the lid to get proper level using a float sync. I can’t afford for this engine to go lean . Instead of a fancy slug I was thinking a coarse screw into the side of the float . Maybe a brass vs an aluminum would give me options as far as weight - even steel . Any thoughts on this approach ? I am using two short lids hoping I could duplicate my approach easier

Well it’s not my car or I would consider that option

Hey Cliff , if you have any pics of those tangs or maybe sketch out the shape of your tangs that worked . I’ve been at for days now and actually bought another set of SU’s so I had more floats to choose from . I got the front one nailed , but it’s seems whatever I do to the rear one comes up short .

So today I went for a pleasant 90 mile trip to meet with a fellow Z'er who had a crucial part for me . He said he found an extra float for a SU in his Weber stuff. Believing that the float was the issue I was happy to find one and try it out. So I noticed that the tang was longer on the replacement . I also noticed how flat the tang was compared to mine that was bent straight up it seems. I set it using the 'blow thru the needle and seat method. When I put fuel to it the fuel level actually stop rising and didn't overflow. It was too low so I proceeded to tweek it . And wouldn't you know it overflowed -SH!T So I made another adjustment . Long story short I come to realize that if I empty the bowl by completely draining it( usually when I remove the float sync tool) , the needle and seat had a harder time stopping the fuel then when there was fuel left in . I can only presume that the fast filling empty bowl made it harder for the valve to stop the incoming fuel. So I started making float changes by just removing the lid and leaving the float sync tool in place . I was able to get pretty close to the 23mm from the top of the lid. When I moved on to the front carb I saw another mangled float tang -ugh. To be continued

I've done a lot of playing around with timing since I have a programmable ecu. You should have most of your advance in by 3000rpm, but sometimes you might have to drag out the last few degrees beyond there. You can run quite a bit of vacuum advance especially when you can control it with this 123 ignition. I run 45 degrees of advance on my stroker in high vacuum/low KPA areas .

Probably the lack of use is the biggest culprit. Valve probably hung up and the rocker went off the rail. Worst thing you can do to these engines is to NOT use them. Just starting them up now and then is not enough. I'd put it back on and go thrash on it down a back road .

You can only manage 28 degrees total ? That seems quite low even for 10:1 and 92 octane . Serious amount of power left on the table .

Thank you for the link . I should have known that there would be an extensive discussion here on this site ! The idea of a float that is hitting the wall had come across my little brain while dicking with this . The float metal structure actually looks bent to one side . Maybe I will swap floats from front to back and see what happens . I don’t think I have any spares .

Hey guys , I guess I’ve been away from carbs too long and now I can’t work on them . A customers car that hasn’t really run yet since rebuild . Trying to set my float levels and using a float sync tool to help assist . The problem I’m having is that I have one carb that wants to be ole faithful . Even if I adjust it for a low fuel level it will eventually overfill. I am using a Holley Black fuel pump that is rated for 4-7 psi . I also installed a Mr Gasket inline fuel pressure regulator set at 2psi . I had an extra needle and seat laying around and swapped it out , no difference . The carbs were lightly rebuilt with new needle and seats from Z Therapy . Not sure what to try next. The front carb seems to be doing fine and holding a certain level. I was considering swapping parts from front to back and see if the problem follows . Any thoughts ?

Bizarre for sure . Laser temp gun to verify readings . Not sure what to suggest other than replacing the sender sensor to start

They won’t take calls - which sucks . They are usually good with replying to emails

Nice set up. The n42 pair is not my favorite for modification . I would definitely want flat tops for the block - but that’s all the mods needed there . The head is going to be a lot more work . The best solution to keep down time to a minimum is to have another head rebuilt and ready to go . I would source a higher quench head - p90, p79, mn47 . They will do better with pump gas . Or maybe just find a zx motor and use the block and head . As far as the cam - going big or go home .