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MG MGA - SU Damper Upgrade?

Can / Should the piston in the oil dashpot be modified to the later (shortened) type?. I recall reading that this was made to improve acceleration. The change was signified by a small stamped "o" on the face of the brass hex below the small vent hole.

I'm looking for information on, and the dimensions of the shortened piston.

Thanks,
Doug
D Sjostrom

Doug,
Mine have the "O" stamped on the top, towards the center from the vent hole. Length of the shaft from the bottom of the top threads is 2 & 55/64"
Distance from the bottom of the top threads to the top of the collar that the brass slug slides on is 2 & 1/8" Distance from the underside of the top of the brass collar to the circlip is 1/2"
Hope this helps-- p.s. I didn't know that there were shorter ones...
/ gil
gil

Gil,
I'm after the exact length of the little brass sleeve (piston) that is captive between the washers. The eatly version was noticeably longer. I assume its function is to slow the reaction of the dashpot thereby prolonging unnecessarily the "accellerator pump" function of the dashpot.
Thanks,
Doug
D Sjostrom

Gil,
Yours are the later shortened type.
Doug
D Sjostrom

Doug,
Interestingly enough, I have one of each..... The shorter one (the one with the "O") measures .3081 inch.
The longer one measures .3766 inch.
Guess I should cut one down. What do you think? -grind them??
/ gil
gil

Doug,
Forgot to tell you that the overall length of the new type is longer than the old ones. If you will send me your E-mail address, I will scan them side by side and send you the picture.
/ gil
hcgilbert1@comcast.net
gil

Doug,
This is getting curioser and curioser. According to the Moss catalogue, the 1500 engine did not have the vent hole, and the 1600/1622 engine did have the vent hole.
I have one with no vent hole and no "O" with the longer plunger.
The other one has a longer overall length, it has the vent hole and is stamped with the "O" and has the short plunger.
/ gil
gil

On the mga twin cam the the brass sleeve on the damper rod was shortened at the bottom from 0.378 inches to 0.308 inches and the cap stamped with an "O".
I have placed the MGA Twin Cam Service Bulletin (in PDF format) on the Internet at:

http://www.angelfire.com/amiga/mga/index.html

The SU must have an air vent in the damper cap OR an internal air vent in the web of the bellhousing, BUT NOT BOTH.

Mick
Mick Anderson

Gil
I suspect that sometime in the past one of the the carbs was replaced with the wrong one. I wonder if it makes any difference in how your car runs.
Kris
Kris Sorensen

Thanks Gil & Mick!
Doug
D Sjostrom

This thread was discussed between 29/04/2005 and 30/04/2005

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