26 replies to this topic

[ACDodd]

https://youtu.be/rck8uPyaZKw

Ac

[ACDodd]

And use this as a guide to set starting point for dashpot oil/damper configuration,

https://youtu.be/ne0XWw4-9Tg

Ac

[Omnomsan]

Those are great videos! I'll need to dial things in, but also wanted to followup.

 

I drove around last night until my tanks were nearly dry, then fueled up with fresh premium grade fuel (93 octane in the US, 99 I think in UK) and it runs just like it did before my oil change. So I must have had garbage fuel! That said, I've ordered a new damper LZX2085 from Minispares to replace my LZX1509 that came with the HIF44 from new, so when that arrives I'll be working to dial in the correct oil, then pick a needle to start polishing.

 

Question for you ACDodd, how do you determine the correct positions to polish on the needle? I've got my AFR, but I'm not sure how you're able to see which spot of the needle is at the point that needs adjustment for a given RPM. 

In either case, beautiful videos and many thanks for your help! I'll get a video of a drive soon to show off the new running characteristics :)

[ACDodd]

I use years of experience, and provide training for those who want to learn.

But people pay for the information I have so that would not be received well if I was to disclose this type of information on an open forum.

Sorry,

Ac

[Omnomsan]

Oh I perfectly understand and respect your for that! We'll see how my new damper and my efforts following your videos goes, then I may be in touch :)

[Omnomsan]

Aaaand it's bogging lean to 20-21 today upon light acceleration like you would do to slowly start moving, and if I'm not careful, it will stall. Anything past slight throttle responds fine and doesn't bog. I let it warm up fully.

 

I'm going to run through the HIF44 setup like your videos suggest and go from there. Damper should be here soon. I might delete my Filter King Regulator to see if that's the issue. I can see fine rust powder in the bottom of the glass bowl, and my main fuel tank has some rust patches inside that need addressing, though it's not rusted through. It shouldn't be a tank pickup filter issue though since I have twin tanks and the RH tank is new, so even if I had an obstructed pickup filter in the main tank, it would pull fine from the secondary. However, it makes me think that the rust is affecting my electric fuel pump internals and prefilter, but I should be able to check that easily with an inline fuel pressure gauge.

 

I'll dig and report back.

[Omnomsan]

throttle shaft seals were sitting unevenly, reseated them.

 

adjusted idle screw and butterfly valve (mine has the sprung bypass valve) since it showed a little too much light around the edges (wasn't perfectly centered), spaced to 18thou and adjusted choke until arrow lined up

 

float height was ~4-5mm below straight edge, so adjusted float height to ~1mm gap under straight edge

 

dashpot and damper with LZX1509 and 80w90 compresses with laygear in ~1 second vs 3-4 seconds as you demonstrated in your video. New damper LZX2085 arrives tuesday, so I'll retest then and find the right oil to suit

 

put it back on the car and its running the same. aside from the damper, I'm starting to suspect electrical...

[ACDodd]

Now you need to work on the calibration, that where needle modification come in.

Ac

[cal844]

Sounds like a visit to an AC Dodd trained specialist is what's needed 😉

[Omnomsan]

Little update.

 

Electrical

I examined the electrics and found that my loom should have an integrated ballast resistor wire. However, the readings from my 1.4ohm coil were ~12v instead of the expected 6-9v with a ballast ignition, so I've upgraded to a 3ohm coil to suit the non-ballast ignition. The new coil is a PerTronix 40511 3ohm coil. I also swapped plugs to BPR6ES from 7s. Colder plugs I've read can lead to sputtering, so we'll see what the running characteristics are like with slightly hotter plugs. Hopefully no run-on, though I doubt I'll see that with premium fuel.

 

Carb Adjustments

I got my new LZX2085 and what a difference it makes. That in conjunction with 20w SU oil makes for a consistent 3.5-4 second compression rate when using the laygear (which is right around 3lbs, the same weight as the MED flywheel puller tensioning bolt come to find out). It was still climbing lean while holding steady at a given rpm when using 80w90, and again with 20w but with the red spring, so I swapped from red spring back to yellow spring and my AFR values are now consistent, the revs are smooth, and I don't have anymore sputtering.

 

Next steps, following the SU carb manual, is to measure the different heights of the needle using a stick in the damper tube with graduated markings. Using those markings to identify the needle profile at the top of the jet, I should be able to polish each section at the correct location down toward the tip and gradually tiptoe toward proper AFR at each rev range. If I've gotten that wrong, I'll gladly pay AC Dodd for a lesson on proper needle profiling :)

 

Hopefully this thread is helpful toward anyone else running into similar issues!

[Omnomsan]

Sounds like a visit to an AC Dodd trained specialist is what's needed

 

Don't I wish! It would be fairly expensive to fly AC over to Dallas to tune my Mini lol!

[Mini Manannán]

Try the technique in this link from one of your fellow Americans: http://www.turbomini...p=vt&tid=159683