Setting my SU carbs

[sydney.wedgehead]

Wow - this thread has grown since I last looked!

Phil, I live at Northbridge, so am not far from Chatswood. I am happy to come and help you set a tune - let me know if this would be helpful.

Note, I haven't worked with wax stat jets. If you decide to replace them you should be able to get trad jets and matching needles online or from Midel at Lakemba.

Owen

[UKPhilTR7]

Hi Owen,

Lol it sure has grown. It is all down to my sheer lack of knowledge and inexperience on the carbs. However, the guys have been a great help and now I feel confident enough to have a look. I will be getting some bits and then looking at doing it. So with delivery it could take a bit. Thanks for the offer though, I will for sure keep in mind 

I think I will be looking at replacing the old wax jets I have to the red ones that Stag76 showed in the picture. Along with that a needle change sounds in order.

Cheers for the offer of help, I really appreciate it and will for sure contact you.

Phil

[UKPhilTR7]

One thing that I have thought is that lead 1 and four are aligned with the mark on the pulley. Lead one being by the fan (first from the front) and lead 4 next to the bulkhead.

However, looking at the firing order it should be 1, 3, 4, 2. However, it looks like mine could be 1, 3, 2, 4 or 1, 2, 3, 4. Late here so I cannot check it out but if I am looking at this right, I bet this is not helping.

[Stag76]

Hi Phil,
It's 1-3-4-2, anti-clockwise on the distributor cap.
If it was wired incorrectly, it would be running really badly...missing, backfiring etc.
WaxStat jets don't seem to be as troublesome here in Australia as their reputation suggests
they should be, maybe due to the temperature range not being as severe.
If Owen can come over, extra knowledge is always a big help.

[UKPhilTR7]

Hi Stag76,
She seems to be running OK, but now and then when I turn the car off she does run for a second or two. That is helpful as I was going to ask about the dizzy direction. So on the block is it 1-2-3-4 from the fan?

[FI Spyder]

If you are talking about spark plug position (not firing order), yes.

[sydney.wedgehead]

Phil,

What fuel octane rating are you using? My rebuilt Sprint (with a 10.5:1 static CR) runs-on severely using anything less than premium 97 RON and it is better to stall the engine in 5th with foot on the brake than to just switch it off and expect it to shutdown gracefully.

That being said, engine run-on (dieseling), can occur due to a variety of other conditions. Getting your timing set correctly and ensuring you have good ignition is a prerequisite to carburetor calibration. You need to be certain that the ignition system is top-notch before spending time on the fueling, and vice-versa.

Cheers,
Owen

[FI Spyder]

Not sure if it's on your car as off hand I'm not sure what year it was available and it's my understanding you had a mixture of N/A and UK cars sent to Australia but my Yellow TCT has a run on valve whereby when the engine is turned off the anti run on valve opens dumping a lot of fresh air into the intake manifold thereby creating such a large lean condition that it doesn't run on (diesel).

[UKPhilTR7]

I only ever put premium in here these days. Was thinking about the ultimate but decided that premium would be the better option she only runs on now and then and only slightly.

I have the carb tuner on order and will order the balancer too.

Owen I will pm you and have a chat as the option of help is a great one.

[kippy]

Just another complication , but an important one in response to some of the posts in this thread in regard timing as part of the tuning.
My Tr7 has the Delco Remy distributor with an AccuSpark electronic conversion with the vacuum advance set to 10 degBTDC at idle which is all very well for idle but what you really need is to determine total advance of ignition at around 2500 + revs of around 30deg . You will need to purchase a timing light like this one and with a little YouTube tuition they are not difficult to operate successfully.
http://www.ebay.com.au/itm/Innova-Digit ... SwTM5YwafQ

With time / age and corrosion gunk inside the distributor I found i was not getting anywhere near the total advance at revs with the mechanical advance that is required for best performance so as a quick fix set the timing much more advance at idle of 16deg +. To clean the distributor advance mechanism is not difficult although the whole thing needs to be dismantled which does sound imposing The hardest part of that whole job is getting the nuts done up on the distributor holding down bolts. Fine finger motor control with more articulations than is normal would be a help in this job.
Not meant to hijack the thread but setting the SU's as part of the tune up really is just one thing required along with the valve clearances, correct timing, setting of points if you have them etc. as already mentioned by others.

Michael

[Stag76]

Hi Stag 76.
About time you took a little drive to the east.

Hi Phil,
Sorry, I missed that post.
I'm in Parkes at the moment, then have to go to Charters Towers, so it will be late April/early May
before I get a chance...will call you in a few weeks.

[UKPhilTR7]

Hi Owen,

Thanks for that, I look forward to chatting.
As yet, I am still waiting for the bits to get here, so there is no rush my side

[sydney.wedgehead]

Hi Phil,

No problem, just let me know when you want to connect.

I'm pretty useless with mobile phones (keeping it charged and close to hand) so a pm here or an email to sydney.wedgehead@gmail.com. may be quicker to elicit reply than txt/sms.

Cheers,
Owen

[UKPhilTR7]

Some good news to report. Last week I got the balancer and colourtun and over the weekend I set about using them. Well the balancer first.

When I put the carb balancer on, I took it the carb 1 was the one by the fan, to match the ignition lead 1. Gosh they were out. Carb 1 was on 8 and carb 2 was on 4.

I just did a quick balance (without the linkage of) and got them both to around 5. Since then I have noticed that there is no black soot out the back of the exhaust on startup. She is running at about 1000 rpm, but I will work to get that down on the next balance without the linkage. Now she pulls off smooth and does not judder.

Last night I used the colourtune on spark plug 1 and 4 and they were virtually perfect, a nice blue glow.

I will take the linkage off hopefully over the weekend and try to get the revs down to about 800. When using the balancer I did notice that carb 1 (by the fan) could be turned clockwise to increase the revs, but not anti clockwise to lower the revs. The second carb (by the bulkhead) could be turned both ways and this resulted in the revs going up and down. To lower carb 1 I had to turn carb 2 down and then carb 1 would go down. I took this as due to the linkage still being connected.

On carb 2 (with the colourtune) I did notice that every 10 seconds or so, the car would sound like she missed a beat and the blue glow would turn to a yellowish glow for a millisecond. Then the car would pick up again and the blue glow would return. Any ideas guys?

[Hasbeen]

Great stuff, you are getting there. That business of one carb controlling the other is pretty usual.

One thing, in the manual it tells you to give the thing a rev every minute while tuning, to clear the plugs & system.

From memory it was to 2500 RPM for 30 seconds, but it is a while since I looked at the manual.

You definitely do have to regularly clear the thing, or the tuning will not be right.

I have never got an SU carb 7 to run nicely continually under about 750 RPM. It is even higher since I fitted the air conditioning.

Hasbeen