25 replies to this topic

[ACDodd]

Video call is £75/hour for consultations.

Ac

[timmy850]

I have a lean spot on gear changes, which I spotted with my lambda meter (via logged/recorded graphs). I didn´t know until know that this can be resolved with the dampers, so I wanted to look into that further.

Since Austria doesn´t have a dedicated SU tuning scene - unlike the UK it is rather hard to impossible to find someone, so I have to do it myself.

This is the only "construction site" that is left over, anything else I have fully under control...

I think the best thing to do in your case is contact AC Dodd and he can advise you on the right way to adjust your dampers. He does video calls for people in other countries.

Modifying dampers isn’t a common practice, so best to ask him directly

Edit: didn’t see you’d responded on the second page AC

Edited by timmy850, 21 August 2024 - 08:50 PM.

[timmy850]

I have a lean spot on gear changes, which I spotted with my lambda meter (via logged/recorded graphs). I didn´t know until know that this can be resolved with the dampers, so I wanted to look into that further.

Since Austria doesn´t have a dedicated SU tuning scene - unlike the UK it is rather hard to impossible to find someone, so I have to do it myself.

This is the only "construction site" that is left over, anything else I have fully under control...

Is the engine modified? If it is standard. do you have the correct dampers specified, which were AUC8114? Do you have the correct needles - GY for '62 - '63 or AN for '64? Do you have the correct springs - Blue in this case?

I too have a pair of HS2s with a weak spot on intial light accleration as identified by an A/F meter, but mine are on a modified 1098 so I may have to live with it, or just drive it harder, which seems to help a lot. I may play about with the pistons and washers in the future.

You shouldn’t have to live with a lean spot like that. The needles or oil can be changed or modified to make it drive properly

[Spider]

I get them however not to equally on initial throttle. One of them always rises faster.

 

There are a great many external infulencers outside of the Carbs for this, eg;-

 

Temperature differences between the carbs
Irregulaities in the Cam and / or Cylinder Head.
The way the exhaust flows
and a whole host of other factors

Choking down the balance pipe in the Manifold (if it's a factory item) can help with this, however,,,, I wouldn't be loosing too much sleep over it.

If you were to run the car on a rolling road, in particular, with the bonnet closed at a few different steady state cruising conditions, you'll almost certainly find the 'imbalance' will alternate between the carbs, largely due to temperature changes / differences between the carbs.

In regards to your flat spot, there could be a few reason for that, however while I did read that you don't want to run odd damper oils, as a starting point and to possibly guide you in a direction, try a heavier oil in the dampers, that will guide you if the issue is related to being under dampened in the carbs.

Check also the float level of each fuel bowl, but not by the usual method of removing the lid and measuring the up-turned float, but by measuring down each Jet to the fuel level in each of them.

The other thing that does occur with Nth/Sth engines is on hard starts from stationary, the front carb will tend to richen and the rear carb lean.
 

[PoolGuy]

Thank you Spider, that’s what this forum is all about, likeminded people sharing information.

[Cheeser]

https://mgaguru.com/...carbs/cb105.htm

I have messed with SU carbs for well over 50 years and have only ever used engine oil in the dampers. I am not suggesting that my engines were ever perfectly set up but I have never found the damper to have been a real problem. I currently run an inline 1360 with twin HS4s, about 100 bhp and have modified dampers as shown in the very interesting detail of the above link.

As in all things times move on although sometimes it goes round in a complete circle! I do believe that the likes of ACD and KC are currently some of the best in the A Series game so advice from them is worth listening to.

Good luck in getting your engine running well.

[woolfman]

Video call is £75/hour for consultations.

Ac

Hello AC,

 

thanks for your offer. Can this be booked on your website?

 

Cheers,

Wolf

 

[woolfman]

Thanks everyone for your answers, I will give it a try with different oil, maybe my engine oil has a different characteristc than whats needed although its a VR1 20w50.

[timmy850]

Just remember if you change the oil it will affect the rise and drop of the piston

If the rise is good, but the drop is slow then you’ll need to modify or change the damper

If you want to contact AC the best way is Facebook messenger

[ACDodd]

Contact through Facebook messenger.

Ac

[woolfman]

Contact through Facebook messenger.

Ac

Thanks!