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SU carb synchrometer

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SU carb synchrometer
#1
rggavmge Avatar
rggavmge roy gavilan
Williamsburg, VA, USA   USA
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1974 MG MGB MkIII "Ruby"
I have been searching for a HS4 SU carb synchrometer air flow meter that fits. Every one I look at measure a 40mm(1.57"winking smiley to 55mm intake hole. The SU carb intake measures 1&3/8 inches. Do they make one of the following synchrometers that will fit a SU carb.
SU carb synchrometer

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Re: SU carb synchrometer
#2
dickmoritz Avatar
dickmoritz Platinum Member Dick Moritz
Philly 'burbs, PA, USA   USA
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For decades I have enjoyed success using a Uni-Syn... See here: https://www.amazon.com/Edelbrock-4025-Carburetor-Balancing-Instrument/dp/B00062YC2E

Dick


Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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Re: SU carb synchrometer
#3
barry s Avatar
barry s Barry Stoll
Alexandria, VA, USA   USA
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1972 MG MGB GT
1974 MG MGB
1976 Triumph TR6
1980 MG MGB
If the hole in the Unison, or whatever, is larger than that in the carb venturi, there is no problem so long as a good seal is achievable with the remaining casting on the carb face. Eor that matter, if the device hole was smaller than the carb venturi, there should still be no problem in balancing at idle, unless it so restricts the air flow that carb starves.

If you get a Synchrometer, there is no issue as the device fits into the venturi. I now prefer the Synchrometer to all other balance devices because of its stability regardless of rpms.

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Re: SU carb synchrometer
#4
benhutcherson Avatar
benhutcherson Ben Hutcherson
Maryville(St. Louis), IL, USA   USA
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1970 MG MGB
1974 Austin Marina
At least on the Uni-syn, the diameter of the hole really isn't an issue. The back plate on mine is a bit concave and covered with a sort of foam that allow it to make a good seal.

In fact, the only real issue I have is that it will stall(or nearly stall) the engine if it's too far off center, but that's an easy fix.

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Re: SU carb synchrometer
#5
barry s Avatar
barry s Barry Stoll
Alexandria, VA, USA   USA
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1972 MG MGB GT
1974 MG MGB
1976 Triumph TR6
1980 MG MGB
Roy - I just reread your initial post and clicked the link that you included. I now realize that you were actually devoting your inquiry to a "Synchrometer", what I now advocate.

I just grabbed a carb off the shelf and held the Synchrometer to it. Indeed, the collar rests on the face of the carb without penetrating into the venturi. This is not an issue however. The collar is a quite pliable, somewhat sticky rubber which provides a good seal against the casting. Getting it centered is also straight-forward. On my SU equipped '80B, the brake booster prevents holding the Synchrometer collar directly against the face of the rear carb. For it I use a PVC right angle coupling on the carb and insert the Synchrometer into the other end. Works very well.

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Re: SU carb synchrometer
#6
ghnl Avatar
ghnl Eric Russell
Mebane, NC, USA   USA
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1961 MG MGA "Calvin"
I have the SK Synchrometer. The nose is tapered so it fits the 1 1/2" carbs fine. On my MGA I made a right angle adapter (using a 90* plastic plumbing fitting) because there isn't enough room to fit the synchrometer straight in. I forget if that was the case with then MGB but I don't think it was.

That said, the only reason I have the synchrometer is to synch the four carbs on my motorcycle. It really isn't needed for the MG's. I use the small kit that has a pair of pointers that fit into the dashpot pistons. these allow you to synch the carbs and check the mixture. And you needn't remove the air cleaners to do so. I have checked my results with the synchrometer and always found it to be spot on after using the dashpot pointer method. (I could never get them synched with the 'listen using a hose' method.)




Eric Russell ~ Mebane, NC
1961 MGA #61, 1981 Alfa Romeo GTV6, 1984 Alfa Romeo Spider, 1991 Honda ST1100

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Re: SU carb synchrometer
#7
LowCarbs Thomas W
Boston, MA, USA   USA
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1977 MG MGB
Just want to offer one other alternative, and it's free: by the very nature of SU carbs, they already have a piston that shows you airflow by how high it is. So at idle, with the air filters removed, just compare the height of the pistons, and if it appears as though they are not exactly the same height, you can adjust one carb's throttle stop screw appropriately until you get them even in height (just like you would do with a carb sync tool).

It does take a little practice - you want to get your eyes about as low as you can while still having a clear shot over the fender to see both pistons. And try to look straight into each carb as you compare. Keeping as straight of an angle as possible reduces parallax and makes your judgement a little more accurate.

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Re: SU carb synchrometer
#8
Tar Trekka Avatar
Tar Trekka Ross H
Sydney, NSW, Australia   AUS
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1968 MG MGB MkII "Miss B"
HI Roy,

There is a "Synchrometer Adapter" that fits to the inlet of Synchrometer & it's shown in the Information I emailed to you a few days ago.

The Correct one for HS4 is the Short Squat one on the LEFT on Page 1 & it fits into the Carby Throat.

That's the one I use & it works perfectly.

Ross H.

Any day above the ground is a great day, especially "Driving Miss B".


Any day above the ground is a great day, especially "Driving Miss B".



Edited 1 time(s). Last edit at 2016-08-30 06:46 PM by Tar Trekka.

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Re: SU carb synchrometer
#9
ozieagle Avatar
ozieagle Gold Member Herb Adler
Geelong Victoria, Australia   AUS
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1958 Wolseley 1500 "Wooly"
1966 MG MGB "Bl**dy B"
1995 Toyota Highlander "Hi Ace Van"
2022 MG ZS
Don't bother with external devices, use the SU carbs themselves.

This article includes a description of how to.

Herb


Questions about prostate cancer? Click here to join the discussion


Attachments:
SU idiot guide.PDF    1.5 MB

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Re: SU carb synchrometer
#10
rocannon Avatar
rocannon Gold Member rocannon L
Comanche County, OK, USA   USA
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1967 MG MGB GT "GT From Hell"
I use pointers too. thumbs up
Has the added advantage of showing if the pistons raise/lower in sync, and if by the same amount.

In reply to # 3344255 by ghnl I have the SK Synchrometer. The nose is tapered so it fits the 1 1/2" carbs fine. On my MGA I made a right angle adapter (using a 90* plastic plumbing fitting) because there isn't enough room to fit the synchrometer straight in. I forget if that was the case with then MGB but I don't think it was.

That said, the only reason I have the synchrometer is to synch the four carbs on my motorcycle. It really isn't needed for the MG's. I use the small kit that has a pair of pointers that fit into the dashpot pistons. these allow you to synch the carbs and check the mixture. And you needn't remove the air cleaners to do so. I have checked my results with the synchrometer and always found it to be spot on after using the dashpot pointer method. (I could never get them synched with the 'listen using a hose' method.)



Pogo is right.
—————————————————————-
The power of reasons is an illusion. The belief will not change when the reasons are defeated. The causality is reversed. People believe the reasons because they believe in the conclusion.

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Re: SU carb synchrometer
#11
britguy324 Avatar
britguy324 Brian Caskey
Fresno, CA, USA   USA
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1968 Dodge Dart
1969 MG Midget MkIII
1973 MG MGB
Pointers? Details/photos please.

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#12
stevenstrange Steven Strange (Disabled) (Disabled)
Disabled Account, Antarctica   ATA
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Post has been removed by the administrator due to violation of the Terms of Service.

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Re: SU carb synchrometer
#13
Tar Trekka Avatar
Tar Trekka Ross H
Sydney, NSW, Australia   AUS
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1968 MG MGB MkII "Miss B"
Hi there,

Attached is the Instructions which came with my "Synchrometer".

This may answer your questions about the device.

Ross H.

Any day above the ground is a great day, especially "Driving Miss B".


Any day above the ground is a great day, especially "Driving Miss B".


Attachments:
SYNCHROMETER PAGE 1.pdf    1.04 MB

SYNCHROMETER PAGE 2.pdf    929.2 KB
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SYNCHROMETER PAGE 3.pdf    990.6 KB
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SYNCHROMETER PAGE 4.pdf    891 KB
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Re: SU carb synchrometer
#14
rocannon Avatar
rocannon Gold Member rocannon L
Comanche County, OK, USA   USA
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1967 MG MGB GT "GT From Hell"
http://www.mgexp.com/phorum/read.php?1,3189429

See post #5.

In reply to # 3344426 by britguy324 Pointers? Details/photos please.


Pogo is right.
—————————————————————-
The power of reasons is an illusion. The belief will not change when the reasons are defeated. The causality is reversed. People believe the reasons because they believe in the conclusion.

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Re: SU carb synchrometer
#15
trmgb Avatar
trmgb todd martinez
littleton, CO, USA   USA
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1975 MG MGB MkIII
1998 Toyota Tacoma 4WD
In reply to # 3344257 by LowCarbs Just want to offer one other alternative, and it's free: by the very nature of SU carbs, they already have a piston that shows you airflow by how high it is. So at idle, with the air filters removed, just compare the height of the pistons, and if it appears as though they are not exactly the same height, you can adjust one carb's throttle stop screw appropriately until you get them even in height (just like you would do with a carb sync tool).

It does take a little practice - you want to get your eyes about as low as you can while still having a clear shot over the fender to see both pistons. And try to look straight into each carb as you compare. Keeping as straight of an angle as possible reduces parallax and makes your judgement a little more accurate.

I like this ,I will give it a try... Ok here goes
Try a db meter on your phone . I like this way too


72 engine, hif carbs, black od, rest of car stock

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