Balancing Throttle Bodies

[smighall]

I've had my throttle bodies modified by Andy to have the bearings fitted and have put them back on the car. When i'm trying to balance them cyl 3 is only registering about 2.5 on my synchrometer with the idle sat at 900rpm where as 2 and 1 are already around the 7 mark.

Does that sound like there's an air leak or that i just need back off all of the balance screws and wind up the idle screw a bit more to get #3 in the right sort of ball park before i move on? I've already had to order some new balance springs as #4 doesn't actually close enough so is already sitting at 10cfm without anything pushing on the linkage, i can easily reduce this by lifting the linkage so hopefully new springs should help that one.

[smighall]

Yes started at cylinder 3 and it was really low on the synchrometer. To get it anywhere near 5-7 i think i'd have to really start opening the body up, so i'm thinking there must be an airleak on that cylinder potentially, I did try winding the idle up a bit but it was making very little difference to the CFM for #3 which seemed quite strange to me.

I refitted all the bodies with Powers gaskets that i've had sat on the shelf a while so hopefully they should be sealed properly.

I'll have another go once i get the new springs through, probably next weekend now.

Edited by smighall on Sunday 28th June 19:04

[smighall]

Did it again today and got them all pretty much spot on, although still need to replace the springs as the 4-5-6 cylinders won't go low enough as the springs have lost their strength i think.

One other question, I assume once setup you need to get it up to temperature and then reset the idle again?

[smighall]

Thanks,

and thanks for the PM too. The tip about using a drill bit to get them all mechanically balanced first really makes it a lot easier!

[smighall]

Finally took the Tuscan out for a run this morning and the difference is amazing! Really smooth all the way through the rev range, rock solid idle and no more flat spots.

I don't even think my bodies were too bad, certainly couldn't feel much play in them but with the bearings now in things just seem to be how they should be. Very happy and would definitely recommend Andy for getting the work done!