HD8 damper with Brass or plastic cap?

[AUSMHLY]

My 64 BJ8 HD8 carburetors dampers have a plastic cap. My friends 66 BJ8 HD8 have brass caps. Why do the same carburetors have different caps? Which is correct?
Stock photos from Moss.

 

[gonzo]

i understood HS6 (BJ-7s) and HD 8 (BJ-8s) carbs require plastic-capped dampers. On the brass ones installed on your friend's HD8 carbs, do the plungers offer any resistance? Too much or too little resistance will impact performance as described in your
earlier post. GONZO

 

[red57]

The stem of the damper is just a press fit into the cap - and will fit either cap.

Obviously they are different damper stems for HD6 vs HD8 because the different diameter means a different length damper stem but you can swap the caps.

My HD8s had plastic caps and I replaced them with brass caps because I think they look better. BJ8 stock HD8 should have plastic caps.

Dave

The other thing to look for is venting - they have to vent and some SUs have internal venting in the dashpot with no vent hole in the cap but others have no internal venting in the dashpot and require a vent hole in the cap.

 

[Keoke]

My 64 BJ8 HD8 carburetors dampers have a plastic cap. My friends 66 BJ8 HD8 have brass caps. Why do the same carburetors have different caps? Which is correct?
Stock photos from Moss.
View attachment 58305View attachment 58306

II have personally never seen it happen but have seen and read of cases that happened , so I use the brass caps because they do not allow the shaft to penetrate the cap.

 

[John Turney]

The PO of my HD8s apparently had a shaft come through the cap. He glued a dime to the top of each cap.

 

[tahoe healey]

Years ago I had a shaft blow through the black plastic cap so I purchased the brass. I found no difference between them. However, I went back to the plastic as I've been trying to maintain the originality of my BJ8. I carry the brass ones with the spares I carry in case I blow another plastic one on the road. They are both vented.

 

[gonzo]

The PO of my HD8s apparently had a shaft come through the cap. He glued a dime to the cop of each cap.

Yeah, that's what the PO did to mine too, but with a copper coin of foreign denomination. I liked the personal touch applied here enough that I would consider reproducing it with some other exotic coin that fits.

 

[Patrick67BJ8]

II have personally never seen it happen but have seen and read of cases that happened , so I use the brass caps because they do not allow the shaft to penetrate the cap.

The only time I’ve seen it happen was when there was a big hickup on a Carb. Carb backfire.

 

[dougie]

The only time I’ve seen it happen was when there was a big hickup on a Carb. Carb backfire.

I had 2 of the 3 plastic top caps break while racing on my SU HD8's, so I switched to brass about 8 years ago with no issues.