Visit our Twitter feed for more great content
TRExp

TR6 Tech Forum

1974 TR6 hesitates above 55 mph (only under load)

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

67GT64008 Avatar
67GT64008 James D
Bainbridge Island, WA, USA   USA
1959 Triumph TR3A "Don't Know Her That Well, Yet!"
1967 Triumph GT6 MkI "Wolfhound"
Did the symptoms start after something was updated, or did the symptoms exist before you started changing components to address the issue? I don’t know anything about the TR6 fuel system, but I had similar symptoms in my GT6 one day, that started out-of-the-blue. After I chased fuel filters, timing, etc, I found that a spider had decided overnight to build a nest in the fuel tank vent line. A the car ran okay with less than a quarter tank, then I filled it up and it would run, but would stall when I put any demand on it. I evicted the spider and her nest,and all was back to normal. No air coming not the tank means fuel starvation at the carbs!

Jim

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Dudley1675 Avatar
Dudley1675 Dan Dudley
Douglas, MA, USA   USA
In reply to # 1595648 by poolboy That hose to your distributor's vacuum RETARD is activating the retard just when the centrifugal ADVANCE weights are trying to advance the timing,,,that's counterproductive.
The vacuum Advance module you asked about is manufactured by British Vacuum Units (BVU) and sold by various retailers including Moss...I have one.
With or without that 'modification' your timing will still advance adequately with the increasing rpms by the centrifugal advance weights within the body of the distributor housing.
BUT... the hose from YOUR rear carb to the retard module needs to be disconnected and either cap the nipple on the carb or hook the hose up to where it was meant to be,,,the EGR valve on the cylinder head.
IF you want to RETARD the ignition timing at idle as it originally was, that vacuum comes from a little larger nipple on the bottom of the front carb,,,,but if you are not using the Retard (and why would you ?) then at least see if you have a TIGHT fitting cap on the nipple in this picture.. There's a red straw as an indicator of it's location.

Thanks, I will check all this out and post if it helps, I plan on taking the TR6 out tomorrow before we get a snow storm here in Massachusetts on Tuesday.


Attachments:
20190210_161340.jpg    59.9 KB
20190210_161340.jpg

Dudley1675 Avatar
Dudley1675 Dan Dudley
Douglas, MA, USA   USA
In reply to # 1595666 by 67GT64008 Did the symptoms start after something was updated, or did the symptoms exist before you started changing components to address the issue? I don’t know anything about the TR6 fuel system, but I had similar symptoms in my GT6 one day, that started out-of-the-blue. After I chased fuel filters, timing, etc, I found that a spider had decided overnight to build a nest in the fuel tank vent line. A the car ran okay with less than a quarter tank, then I filled it up and it would run, but would stall when I put any demand on it. I evicted the spider and her nest,and all was back to normal. No air coming not the tank means fuel starvation at the carbs!

Jim

Hi Jim, I had a 1969? GT6+ back in the day, was in my 20's. Loved that car to death, sold it for pennies on the dollar so I could move to CA to experience SF in the early '70's. Always have regretted selling that car!

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Dudley1675 Avatar
Dudley1675 Dan Dudley
Douglas, MA, USA   USA
Anyway, the car came with this problem, the mods I've done have helped, but not solved the problem.

poolboy Avatar
poolboy Ken D
Sandy Hook, MS, USA   USA
In reply to # 1595675 by Dudley1675
In reply to # 1595648 by poolboy That hose to your distributor's vacuum RETARD is activating the retard just when the centrifugal ADVANCE weights are trying to advance the timing,,,that's counterproductive.
The vacuum Advance module you asked about is manufactured by British Vacuum Units (BVU) and sold by various retailers including Moss...I have one.
With or without that 'modification' your timing will still advance adequately with the increasing rpms by the centrifugal advance weights within the body of the distributor housing.
BUT... the hose from YOUR rear carb to the retard module needs to be disconnected and either cap the nipple on the carb or hook the hose up to where it was meant to be,,,the EGR valve on the cylinder head.
IF you want to RETARD the ignition timing at idle as it originally was, that vacuum comes from a little larger nipple on the bottom of the front carb,,,,but if you are not using the Retard (and why would you ?) then at least see if you have a TIGHT fitting cap on the nipple in this picture.. There's a red straw as an indicator of it's location.

Thanks, I will check all this out and post if it helps, I plan on taking the TR6 out tomorrow before we get a snow storm here in Massachusetts on Tuesday.

It may not solve your problem, but it needs to be done regardless..because it's just not right.



ZS carb repairs
kencorsaw@aol.com

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR7 Drophead "The Great Pumpkin"
1980 Triumph TR8 "Wedgie"
In reply to # 1595686 by poolboy It may not solve your problem, but it needs to be done regardless..because it's just not right.

Dan:

Poolboy is spot on. That vacuum connection is pulling out your ignition advance just when you need it. It is a common error made when attempting to "improve" things. That will cause your timing to pull back and power to drop just when you need the power. Rerouting that line may not fix the entire problem, but there is no doubt that it will help.

Another contributor may be the fact that the correct vacuum fitting for the vacuum advance capsule on the bottom of the carb is uncapped, which will give you a significant vacuum leak. Poolboys photo shows where the vacuum capsule should be connected. The fitting on top of the rear carb is for the EGR valve, which is not connected to anything in your photo.

If correcting the vacuum line routing does not eliminate the problem, the next thing I would look at are the carb diaphragms. A pinhole or tear will cause the engine to hesitate under load.

Vance



1980 Platinum Metallic TR8, frame off restoration, complete.
1980 Vermilion TR7 Sprint replica, in progress.

Dudley1675 Avatar
Dudley1675 Dan Dudley
Douglas, MA, USA   USA
In reply to # 1595716 by Darth V8R
In reply to # 1595686 by poolboy It may not solve your problem, but it needs to be done regardless..because it's just not right.

Dan:

Poolboy is spot on. That vacuum connection is pulling out your ignition advance just when you need it. It is a common error made when attempting to "improve" things. That will cause your timing to pull back and power to drop just when you need the power. Rerouting that line may not fix the entire problem, but there is no doubt that it will help.

Another contributor may be the fact that the correct vacuum fitting for the vacuum advance capsule on the bottom of the carb is uncapped, which will give you a significant vacuum leak. Poolboys photo shows where the vacuum capsule should be connected. The fitting on top of the rear carb is for the EGR valve, which is not connected to anything in your photo.

If correcting the vacuum line routing does not eliminate the problem, the next thing I would look at are the carb diaphragms. A pinhole or tear will cause the engine to hesitate under load.

Vance

Thanks to you both for sharing your wisdom & photos! I will be making the mods 1st thing tomorrow morning & reporting back with the results.

tirebiter Jeff Garber
Dighton, MA, USA   USA
If you are still having problems I'm almost in your backyard, just East of providence. Worked on 100's of TR-6 engines since the 1970's. Email or PM me on here, if you want. I own a timing light and 15 minutes of looking/checking everything could save many posts.

Dudley1675 Avatar
Dudley1675 Dan Dudley
Douglas, MA, USA   USA
In reply to # 1595719 by Dudley1675
In reply to # 1595716 by Darth V8R
In reply to # 1595686 by poolboy It may not solve your problem, but it needs to be done regardless..because it's just not right.

Dan:

Poolboy is spot on. That vacuum connection is pulling out your ignition advance just when you need it. It is a common error made when attempting to "improve" things. That will cause your timing to pull back and power to drop just when you need the power. Rerouting that line may not fix the entire problem, but there is no doubt that it will help.

Another contributor may be the fact that the correct vacuum fitting for the vacuum advance capsule on the bottom of the carb is uncapped, which will give you a significant vacuum leak. Poolboys photo shows where the vacuum capsule should be connected. The fitting on top of the rear carb is for the EGR valve, which is not connected to anything in your photo.

If correcting the vacuum line routing does not eliminate the problem, the next thing I would look at are the carb diaphragms. A pinhole or tear will cause the engine to hesitate under load.

Vance

Thanks to you both for sharing your wisdom & photos! I will be making the mods 1st thing tomorrow morning & reporting back with the results.

Took the TR6 out today and drove it hard, my problem is 99.8% fixed! I was only able to get it to cough 3 or 4 times. It happened at a slightly different point with the vacume lines plugged. I could do a full throttle acceleration up hill with no problems, lots of power with no hiccups. However, after taking my foot off the peddle momentarily during full acceleration and reaccelerating it would momentarily buck, but only one or two times, I was able to duplicate this one more time. Previously, it would have messed up repeatedly so many times I probably would have lost count. Next I plan on getting a timing light and learning how to calibrate the carbs. Thanks to all for your very helpful comments and advice. Photos of capped off vacume lines attached. �


Attachments:
20190211_161253.jpg    63.3 KB
20190211_161253.jpg

20190211_160736.jpg    34.9 KB
Sign In or Register to view this photo
20190211_160550.jpg    41.5 KB
Sign In or Register to view this photo
20190211_160533.jpg    41.4 KB
Sign In or Register to view this photo
poolboy Avatar
poolboy Ken D
Sandy Hook, MS, USA   USA
Please!!! eye rolling smiley That's no way to plug the nipple on the bottom of that carb....There (can be anywhere from 17 to 20 inches of Mercury vacuum force sucking thru that nipple...more when you downshift....
The one on top isn't as strong....but please do it right. and don't worry about the nipple on the distributor....there's no vacuum there...it's just a hole...but someone who doesn't know better will probably point to it and tell you "You got a vacuum leak there, pal" so maybe you should cap it, just get something more appropriate....Roach clip...give me break.hot smiley
Go to AutoZone and get some "emission plugs"



ZS carb repairs
kencorsaw@aol.com

Dudley1675 Avatar
Dudley1675 Dan Dudley
Douglas, MA, USA   USA
In reply to # 1595997 by poolboy Please!!! eye rolling smiley That's no way to plug the nipple on the bottom of that carb....There (can be anywhere from 17 to 20 inches of Mercury vacuum force sucking thru that nipple...more when you downshift....
The one on top isn't as strong....but please do it right. and don't worry about the nipple on the distributor....there's no vacuum there...it's just a hole...but someone who doesn't know better will probably point to it and tell you "You got a vacuum leak there, pal" so maybe you should cap it, just get something more appropriate....Roach clip...give me break.hot smiley
Go to AutoZone and get some "emission plugs"
Will do, but the hose is not only closed with a "roach" clip, I put some crazy glue in the open end 1st then a pair of vice grips. After the glue dried I put the clip on it for good measure! � thanks again! �it!

zinteck Avatar
zinteck Silver Member David Zinteck
Syracuse, NY, USA   USA
1966 Chevrolet Corvair "Yenko Stinger"
1973 Triumph GT6 MkIII
Dan:

Lots of good advise here.

Your problem reminded me of the exact same problem I had , twice

Your need to check the distributor points and set the point dwell.

You also need to check the condition of the coil. The coil could have an inertial short or current loss

Dudley1675 Avatar
Dudley1675 Dan Dudley
Douglas, MA, USA   USA
In reply to # 1596009 by zinteck Dan:

Lots of good advise here.

Your problem reminded me of the exact same problem I had , twice

Your need to check the distributor points and set the point dwell.

You also need to check the condition of the coil. The coil could have an inertial short or current loss
I agree, this site is fantastic! So many people wanting share their knowledge & help newbie's like me smiling smiley I am running an electron ignition with a new matching Flamethrower coil. So, hopefully I am all set there at least. Still need to check the timing and balance & tune the carbs.



Edited 1 time(s). Last edit at 2019-02-11 07:04 PM by Dudley1675.

LFMTR4 Avatar
LFMTR4 Lou Mijares
Scottsboro, AL, USA   USA
smileys with beer spinning smiley sticking its tongue out smileys with beer. You just couldn’t make this up if you tried.

In reply to # 1596005 by Dudley1675
In reply to # 1595997 by poolboy Please!!! eye rolling smiley That's no way to plug the nipple on the bottom of that carb.......Roach clip...give me break.
Will do, but the hose is not only closed with a "roach" clip, I put some crazy glue in the open end 1st then a pair of vice grips. After the glue dried I put the clip on it for good measure! � thanks again! �it!

Dudley1675 Avatar
Dudley1675 Dan Dudley
Douglas, MA, USA   USA
In reply to # 1596021 by LFMTR4 smileys with beer spinning smiley sticking its tongue out smileys with beer. You just couldn’t make this up if you tried.

In reply to # 1596005 by Dudley1675
In reply to # 1595997 by poolboy Please!!! eye rolling smiley That's no way to plug the nipple on the bottom of that carb.......Roach clip...give me break.
Will do, but the hose is not only closed with a "roach" clip, I put some crazy glue in the open end 1st then a pair of vice grips. After the glue dried I put the clip on it for good measure! � thanks again! �it!
Life is good, then you... crazy glue smiling smiley


Attachments:
8-Second-Triumph-TR6.jpg    34.5 KB
8-Second-Triumph-TR6.jpg

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster