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I may need a carb chamber & piston

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AUSMHLY

AUSMHLY

Yoda
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Hello all,
I am having some problems with my HD8 carburetors.
After a very good cleaning, I found that one of the pistons went into the chamber and got stuck. In trying to pull it back out, it scored both the chamber and the side of the piston. After some sanding with 2000 grit, I got it back to smooth and back together. Now the piston moves and seems like a tight fit, but maybe the tolerance is off?

I put everything back together with the help of my Healey mechanic. We also replace the points in the distributor with Pertronix .

My mechanic is not happy with the way the carbs are running and I too notice it. He is not sure if they need more adjusting or if my bad in scoreing the inside of the chamber.

What to do?
Maybe replace the one chamber and piston?
If so, where can I get one.
Or maybe send mine out to someone or the entire carb set up, as in the entire both units?

Also I notice when starting the car, it does not start as quickly as with points. With points it used to turn 2-3 times and start. With Pertronix, I turns 7-8 times before starting. And sometimes after 3-4 times turning over, when I turn the key back to on position the car starts. I did not know it was going to start, so I was going to do it again. Know what I mean? You think it isn't going to start so you turn the key back, then the car starts.

OK, guys, I'm sitting down.
Roger
 
Hello Roger,

did you possibly mix up the pistons and dashpots? What you describe is very rare unless there was fome foreign body caught in there.
If you cannot get the piston to move smoothly, (and ideally the two should have the same time when you do a drop test) then you need to source a replacement piston and matching dashpot. Second hand should be fine as generally these items do not wear unless mal treated (such as using abrasives to clean them).

Alec
 
On the carbs, go here & check XII. "Vacuum Drop Tests" & XIII "Suction Chambers & Pistons"
https://www.jcna.com/library/tech/tech0006.html
Note that the two carbs "should be" pretty well matched for "drop timing".

On the starting issue, maybe not related to the points or Pertronix. The key switch is supposed to make a connection to BOTH the starter solenoid AND the ignition coil when the switch is in the start position. When the key is released from start to run, only the circuit to the coil is maintained.

It's not uncommon for the key switch contacts to fail so that the coil is not energized when the switch is in the start position, but only in the run position. So - if you get the engine spinning & it's still spinning when you release the start, the switch run contact energizes the coil & it starts.

Check for voltage at the coil while the switch is held in the start position. It "could" be an intermittent condition also.
D
PS - Alec has a good point about the two sets of parts being mixed.
D
 
roger, sorry to hear of your problem, not having your carb. in my hands it sounds as if the "needle" part # 16 in the moss catl. is mis-aligned, if you intend to send them out for rebuild i can with great confidence recommend joe curto (718) 762-7878 or https://www.joecurto.com /bcforum/images/%%GRAEMLIN_URL%%/savewave.gif
 
Hi Dave, Good comment. We cautioned him to do one at a time when he first over hauled the carbs. What I think I may be hearing now is the usual result when the bells are polished. If a simple cleaning and/or part change {Needle} won't correct the problem, I suggest another carb be obtained and rebuilt.---Fwiw--Keoke
 
Thanks all for your comments.
I did head the concerns when I cleaned and polished them.
I did make sure not to mix them up.
Maybe the bell got warped?
Maybe that's the reason when I put the piston in, it stuck?
And when trying to take it back out, it scored both the bell and the piston.

So if needed, anyone know where I can get a replacement?
 
Hi Roge, You might put a flag up on E-bay for a rebuildable one. There was a set that went very cheep recently.---Keoke
 
Hi Roge,
The reference I gave you above tells how to correct dents, warpage, if it isn't too great. You don't have much to lose.

On a two carb setup it's worth spending some time to get the drop timing the same on the two carbs. Also matching the spring rates.
D
 
Question?
Isn't it important when replacing the chamber (bell) onto the carb that the orientation be the same as when it was removed. In other words not shifted 90 or 180 degrees. Even if the bells didn't get switched, perhaps they are oriented wrong.
 
Hi Shorn,
I believe the bell tabs will only line up one way, solving the orientation situation. Good question.
 
Roger,
Sorry to hear you are having a problem with your carbs. I hope you can get it straightened out without too much trouble/$$.
Ed
/bcforum/images/%%GRAEMLIN_URL%%/frown.gif
 
I concur; all the ones I've had apart can only be assembled in one (1) orientation.

What is that tidbit about "spinning" the pistons in the chambers prior to assembly? I suppose it could confirm them being uniformly round.
 
Roger, If you have not been able to sort out your problems, Bill Bolton might be able to help you with some used components. I believe he is tricarb@aol.com or you might try Joe Curto. I had him rebuild my HD8 carbs. https://www.joecurto.com/

Joe has also been very helpful when I have called him about trying other needles for my Bugeye SUs.

Good luck.

Lin
 
You didn't get any junk in the vent holes on the side of the chamber, did you? What did you use to free the piston that scared them so badly? Did you creat heat when pollishing them on a buffing wheel? You did such a beautiful job on them.
 
Hi guys, thanks for taking interest and offering your help.
Car was running good. I removed the carbs, cleaned/polished them. My mechanic came over and we replaced any parts that need be. He put them back on the car, installed the Pertonix and he mentioned it should not be this hard to get them insink.

I don't know if it's the carbs, the Pertonix or the distributor needs adjustment.

I took the two bells and pistons off tonight. Did the drop test and finding I may not be doing it right. I can not get a consistant count on each. I've tryied swaping the pistons and doesn't seem to make much difference. I will bring them to the mechanic and have him show me the proper way to do the drop. Then I should know if they are the problem, or move to the distributor.

Process of elimination.
Interesting thing about this go around of what the heck is wrong. I'm not upset or frustrated. What's up with that?
Maybe I've been Healeytized. You own a Healey, it owns you.
 
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