20 replies to this topic

[Daveontoast]

Yes, A and B are connected, it came that way from Burlen. So that connection weakens the mixture? I had no I idea what they were for so I left it that way. I’ll try plugging both connections and see is that helps. Maybe an AAM/AAB would be better then, as the engine runs fine at small throttle openings. It’s only when I get to 4K rpm or above that the engine seems to starve of fuel. Using the colourtune, I can see that making the mixture really rich at idle, the mixture stays rich (orange flame) up to 4K then turns blue, so it (sort of) fixes the issue. Where as if I have the mixture blue at idle, it’s stays blue until 4K, where the flame diminishes.

[Daveontoast]

*sorry, double post.

Edited by Daveontoast, 03 September 2020 - 02:32 PM.

[nicklouse]

Yes, A and B are connected, it came that way from Burlen. So that connection weakens the mixture? I had no I idea what they were for so I left it that way. I’ll try plugging both connections and see is that helps. Maybe an AAM/AAB would be better then, as the engine runs fine at small throttle openings. It’s only when I get to 4K rpm or above that the engine seems to starve of fuel. Using the colourtune, I can see that making the mixture really rich at idle, the mixture stays rich (orange flame) up to 4K then turns blue, so it (sort of) fixes the issue. Where as if I have the mixture blue at idle, it’s stays blue until 4K, where the flame diminishes.

not quite correct. A would have been connected to the vacuum advance. and B should be connected to the engine breathers. as standard.

[Daveontoast]

Mine definitely came with A and B already connected, haven’t touched the hose since it came boxed from Burlen. The connection for the vacuum advance is on top behind the dash pot, you can’t see it in that photo.

[Lplus]

 

Yes, A and B are connected, it came that way from Burlen. So that connection weakens the mixture? I had no I idea what they were for so I left it that way. I’ll try plugging both connections and see is that helps. Maybe an AAM/AAB would be better then, as the engine runs fine at small throttle openings. It’s only when I get to 4K rpm or above that the engine seems to starve of fuel. Using the colourtune, I can see that making the mixture really rich at idle, the mixture stays rich (orange flame) up to 4K then turns blue, so it (sort of) fixes the issue. Where as if I have the mixture blue at idle, it’s stays blue until 4K, where the flame diminishes.

not quite correct. A would have been connected to the vacuum advance. and B should be connected to the engine breathers. as standard.

 

The large pipe marked "to the rocker cover" is connected to the engine breathers.  The vacuum advance nipple is directly in front of the dashpot - only partially visible in the photograph beside the dashpot just to the left of the screwhead above the rocker cover pipe.

 

Please check out the thread on MMOC linked beneath the photo above.

Edited by Lplus, 03 September 2020 - 05:16 PM.

[Daveontoast]

Update, managed to fix the issue. I actually did a few things before running it so I’m not sure which actually fixed it or if it was a combination of them all. I put some ptfe tape around the threads of the banjo blanking bolt on the manifold, and I blocked off the two vacuum connectors on A and B in the picture. I also found a leak on the exhaust between the manifold and the middle section, I had an awkward time lining it all up as I’ve had to lean the engine forward slightly to fit the hif carb. After realigning it and put some exhaust sealant on, it gets up to 4K no problem. I’m still having to run it rich to stop it dying at idle, and it’s quite lumpy at low rpm, but I think that’s probably the sw5 cam.
Thanks again for all your help, much appreciated!