Tommy,
Thanks! I tried all sorts of dash-pot oil, the Mobil 1 0W-??? seems to work
the best, I've got a bottle in the cabinet just for that. The distributor
recurve is interesting. I tried setting it at the stock position and it was
a dog, so I just started adjusting until it ran better. Now it's nowhere
near where it should be, but it goes like heck, and I don't have any
detonation or pinging, so I marked the spot with paint and haven't touched
it since. I read the pipe stuff with great interest, but decided to go with
the stub stack, and it has worked very well.
To Biff, David, Peter and all who offered help yesterday - thanks very
much!! I dug into it last night for the first time in a year, and soon
began to remember everything I tried before. To recap - The float bowl is
level with the ground. It was not to begin with, as the HS-4 in the MGB
sits as quite an angle and the float bowl was offset to correct for this. I
found my old MGB book and confirmed this, the carbs were angled and the
float bowls were level with the ground. I must have known this back then,
because I had managed to break that little tab that holds the float bowl in
one position, so it is adjustable now, and I've had it level with the ground
for some time now.....apparently my memory is fading, 'cause I rushed home
last night thinking I had the answer, then realized I'd already tried that,
and apparently somewhat forcefully at that! The new HS-4 came with a
plastic float attached with a pivot, and the car would die relatively easily
when I hit the brakes (I retried that last night, just to be sure, and yep,
it died easily upon braking or hard turning - also tried different
orientations of the hinge, more or less the same result). Joe Curdo in New
York sold me a bronze float that is not attached to anything and an older
style float bowl cover with a switch in the top, and that helped quite a bit
(I've been running it about a year and a half). At the specified float
height, it helped some, and when I later adjusted it as high as I could
without having fuel come out the other pipe or leak from the bowl seal, it
helped quite a bit. But I'm at the limit of the adjustment for obvious
safety reasons, and on hard braking, it still stalls, particularly down hill
braking! As I mentioned yesterday, I tried both the left and right carbs
(since I had new ones of each), no difference.
I'm kind of out of ideas (much as I was a year ago). I do have two HIF4s
out of the '73 MGB (it rotted away badly from snow salt before I got it, and
when the engine died, there wasn't enough of the car left to justify saving
it), but I know they need rebuilding. Maybe I should try to rebuild one of
these carbs and try it instead? It was just such a pain getting the jet
right, and the car runs great now, except for this one little problem, I've
been reluctant to go at it again. What do you guys think?
I'll be at home most of today, please send any ideas to the
mueller944@cs.com address. Oh, and I screwed up on the oil viscosity
yesterday, the Mobil 1 I've used so successfully and is so recommended by
the Porsche folks is 15W-50. Sorry about that. One Lister that has cars in
Europe, Florida and Puerto Rico, says the Mobil 1 0W-40 they have in Europe
sure looks an awful lot like the 15W50 they sell over here, he thinks it's
the same stuff, just different packaging to meet various testing
requirements. Thanks!!
Bob Mueller
'74 MG Midget
-----Original Message-----
From Tommy_Samuels at markivauto.com [mailto:Tommy_Samuels@markivauto.com]
Sent: Friday, January 04, 2002 7:32 AM
To: RMueller@grumobile.uscg.mil
Subject: re:Weird Carb Problem
I don't know if you got this yesterday
I got an undeliverable message
I was rambling when I wrote this yesterday and had about 20 interuuptions
The biggest difference was finding the right viscosity for the dashpot oil
When you start to modify the carbs to improve airflow, everything else needs
to
be tweaked a little
I don't know if you have a vacuum or mechanical advance distributor, but if
it's
a vaccum advance unit the curve will be wrong now.
This may or may not be significant, I don't know what other engine mods you
have
I serious about the addition of the ram pipe though. Re read the induction
and
carb tuning sections in Vizard.
That's horsepower you can have almost for free
Good luck
Tommy
---------------------- Forwarded by Tommy Samuels/MARKIVAUTO/US on
01/04/2002
08:24 AM ---------------------------
Tommy Samuels
01/03/2002 03:17 PM
To: RMueller@grumobile.uscg.mil
cc:
Subject: re:Weird Carb Problem
I'm running a single HS2 on my 67 sprite w/ a metro manifold and I modified
the
carb per Vizard instructions.
A couple of things to pay attention to.
1. The float bowl angle is wrong w/ the Mtero manifold. I had to file off
the
"ear" on the float bowl so I could change the angle and get it level
2. Make sure the fuel filters and carb passages are clean. You're flowing
all
the fuel thru 1 carb now instead of 2
3. I had to change dashpot oil to keep it from leaning out to much and dying
when I came off the throttle. Once I got the viscosity right, it was much
happier
If you have access to a rolling road dyno, book the time and fine tune your
needle as described in the carb mods section of Vizard
If you haven't added a ram pipe, do it. You're gonna LOVE the difference
(Embedded image moved to file: pic09285.pcx)
These numbers were circulated a while back and are the length (inches) from
the
combustion chamber to the end of the ram pipe
I have mine tuned for maximum ram @ just under 4000 rpm
When you nail the throttle it really goes
I'll never go back to dual SU's
Tommy
70B
67 Sprite
69 Sprite
/// unsubscribe/change address requests to majordomo@autox.team.net or try
/// http://www.team.net/mailman/listinfo
/// Archives at http://www.team.net/cgi-bin/wilma/spridgets
|