1969 Tri Power Not Working
Thread Starter
Instructor
Joined: Dec 2016
Posts: 245
Likes: 132
From: Port Coquitlam BC
1969 Tri Power Not Working
Hi Folks:
I recently purchased an all original 69 Tri Power 427-400hp.
The car ran fairly well, and pulled hard through the rpm range, but the carbs leaked fuel, so I had them rebuilt by a local specialty shop that only does carb work.
They machined the sides of the main bodies, and base plates, drilled and installed bushings on the throttle shafts, etc. A lot of work, but they are the original date-coded carbs.
When i installed them on the car, they run well, idle better, and certainly don't leak any more.
The car runs well on the centre carb, but when I do a full throttle run, the engine revs to about 3500-4000 rpm, and then starts to miss, or bog real hard, and won't rev higher.
The guy at the carb shop suggested that the motor may not be making enough vacuum to open the outboard carbs, and that I should take a reading at a higher rpm under full throttle while driving. I have a hard time with this, since it ran "well" before the carb work was done.
The motor has a roller cam with .510 lift, 282 in, 288 exhaust, so a bunch bigger than stock.
At idle, the motor has 14" of vacuum in the manifold, so less than the generally accepted 17-22", but like I said before, it was fine prior to the work being done. The diaghrams for the secondaries sound to be working fine.
As there is no insurance on the car, I have not driven it on the street since buying the vacuum gauge, so will take a full throttle reading at the upper port of the centre carb, when I get a temporary permit.
I do not believe this is anything with ignition - unless there is a ridiculous coincidence.
Any suggestions on what could be causing this bogging/missing problem, since the carbs were re-built?
Cheers,
Rob
I recently purchased an all original 69 Tri Power 427-400hp.
The car ran fairly well, and pulled hard through the rpm range, but the carbs leaked fuel, so I had them rebuilt by a local specialty shop that only does carb work.
They machined the sides of the main bodies, and base plates, drilled and installed bushings on the throttle shafts, etc. A lot of work, but they are the original date-coded carbs.
When i installed them on the car, they run well, idle better, and certainly don't leak any more.
The car runs well on the centre carb, but when I do a full throttle run, the engine revs to about 3500-4000 rpm, and then starts to miss, or bog real hard, and won't rev higher.
The guy at the carb shop suggested that the motor may not be making enough vacuum to open the outboard carbs, and that I should take a reading at a higher rpm under full throttle while driving. I have a hard time with this, since it ran "well" before the carb work was done.
The motor has a roller cam with .510 lift, 282 in, 288 exhaust, so a bunch bigger than stock.
At idle, the motor has 14" of vacuum in the manifold, so less than the generally accepted 17-22", but like I said before, it was fine prior to the work being done. The diaghrams for the secondaries sound to be working fine.
As there is no insurance on the car, I have not driven it on the street since buying the vacuum gauge, so will take a full throttle reading at the upper port of the centre carb, when I get a temporary permit.
I do not believe this is anything with ignition - unless there is a ridiculous coincidence.
Any suggestions on what could be causing this bogging/missing problem, since the carbs were re-built?
Cheers,
Rob
Last edited by f1rob; Feb 12, 2017 at 02:48 AM. Reason: update
Thread Starter
Instructor
Joined: Dec 2016
Posts: 245
Likes: 132
From: Port Coquitlam BC
Thanks for your help!
Rob
