View Full Version : Oil for the SU H6 carbs

04-13-2012, 04:08 PM
Afternoon, i'm rapidly getting to the point that I will be able to try to start my car. It is a 1960 3A post 60000 car. Carbs have been rebuilt. My question is how much oil to I put in them the damping chambers?
Can't get a difinitive answer from the literature that I have, which is a bunch. So I am turning to the forum.
The carbs are SU H6's.

Any ideas and thoughts will be greatly apreciated.


Mickey Richaud
04-13-2012, 04:15 PM
HOO-BOY! You're gonna get as many answers to this one as you would if you ask what weight oil to use! Some of us geezers and near-geezers will remember the saying, "As many as Carter has pills!"

Anyway, here's the best advice I've found:

SU Page (https://www.jetlink.net/~okayfine/su/damper.html)


04-13-2012, 04:45 PM

Moss catalogs have a diagram showing how high to fill the dampers. Just to the top of the collar in the neck, and no higher or it will leak and doesn't help at all.

As for type, most of the people I talk to use Marvel Mystery Oil. Or... 3-in-1 20 weight oil.

04-13-2012, 05:03 PM
As long as you can feel the resistance when inserting the damper, there is "enough" oil. Too much oil will quickly get sucked through the vent and burned harmlessly.

The earlier versions of the owners manual said to fill to a higher level every 3,000 miles; but I believe the high level was so the excess could slowly seep down between the polished guide rod and the bearing inside the dome, to lubricate the bearing. Later versions had a lower level.

The grade of oil is by no means critical, practically anything will work well enough. The owner's manual says to use the same grade of (single weight) oil as recommended for the engine sump, which would be roughly 20W in the winter and 30 in the summer (for TN). I ran straight 20 weight year-round in the 3A, but I may move up to 30 weight on the TR3.