TR2/3/3A TR3 Carb Piston Damper Length

[RedTR3]

First of all, I want to thank all of you for your help in the last 6 months - I am not new to LBCs ( I had two MGs previously) but am new to TR. 6 Months ago I sold my MGB and acquired a nice 58 TR3.

My question now is In my H6 carbs I have 2 different types of pistons; one has a brass cap and is about 2-1/2" long and one has a plastic cap and is 3/16" longer. Does this make a difference?

BTW, the car runs well. It idles fast (1200 rpm) and I am trying to work on that but otherwise runs great.

Thanks, Tim

 

[Harry_Ward]

Actually don't know what effect the length would have on dampening if the plastic topped damper was in an earlier type carb. I also guess it would depend on if you had the AUC786 installed up to late 1958, or the AUC878 installed 1959 to TR4 #CT21470E SU type H6 carb, or a mismatched SU HS6 for a TR4 installed which is what the plastic top damper is listed for use in. The HS6 would require some fuel supply plumbing changes though. Maybe the PO did not want to spring for the more expensive brass damper or couldn't find one and installed it in an earlier type carb?
I notice the brass damper is still available through Moss P/N 370-745 which lists at 27.95 which is almost twice the cost of the plastic damper

 

[RedTR3]

Thanks, I forgot to mention that both carbs are labeled AUC786.

 

[startech47]

Check to see if the longer damper limits the lift of the piston. They pistons should have the same maximum lift. This should only effect operation at maximum speeds. Phil

 

[Camping57]

If they are both the 786 carbs, then I think they should both be using the brass cap damper piston. I am not sure if having the newer piston will have an effect as long as you adjust the oil level so that it starts damping at the proper point.
Startech has a good point about the possibility of it bottoming out at full lift.

 

[Geo Hahn]

That would bug me (one brass & one plastic) such that I think I would be trying to get a decent used brass one. Must be bunch collecting dust somewhere, on eof the used TR parts guys should be able to help.

Glad you're enjoying the '3.

 

[RedTR3]

Right, now that I know that I need the brass one I'll start looking for one - thanks!