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What did you do with your TR4 today?

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jjtr4 john m
Penn's Landing, PA, USA   USA
Enjoyed the Autocross Post!

Here are some older "Kodak" prints from my TR at the Labor Day Porsche Corvette Challenge, Reading PA.1982. We got Drag $ Saturday Night and Runner UP Sunday Autocross behind a GT-1 Vette.

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Desert TR Avatar
Desert TR Gold Member Jim P
Albuquerque, New Mexico, USA   USA
After a false start and a carb re-rebuilt, finished setting up the idle, balance and mixture. I'll wait until everything is cold before locking in the accelerator linkage. Idle is at ~650, but it is well over 5,000 ft. altitude.

Jim

https://drive.google.com/open?id=0BwbdsZZu51jRa0JUVjNuU3FVZXM


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jjtr4 john m
Penn's Landing, PA, USA   USA
Not sure what you mean by "mixture" ?

Hi altitude, having less molecules of air per Ft^3 than sea-level, typically means a leaner mixture required "stoichiometrically" . Too lean pops and too rich misfires. I haven't tried one yet but thought I saw an exhaust gas O2 sensor advertised in Moss? We used to also spend a lot of time synching the TR4 SU's w/a "Unisyn" although some good mechanics can synch by ear. Re: acceleration, I thought the magic/(headache on ones in dis-repair) of SU's is the critical damping of the sliding dampers. Back to main mixture, I run top end and keep screwing the mixture leaner until 1st pop and then go out 1 flat richer. Then shut off and throw into neutral and coast down and pull plug(s) looking for toast color as affirmation. For idle mixture, hand held vacuum gauge to highest reading while adjust idle screw works real fine even w/my touchy 8,000 rpm hi-overlap cam motors.

Today's oxygenated, alcohol diluted, gasoline's also can play hockey with your tune if not fresh. They are hydroscopic e.g. absorb water from the air. I usually buy a few gallons of VP 110 leaded B4 a tune up. (May not be street legal in your jurisdiction)

Hope this helps! As fast as my TR is, I really enjoy the old Paul Newman Bob Sharp TR4 duels on YouTube with the stock motors. They still kept up w Jags etc.

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Desert TR Avatar
Desert TR Gold Member Jim P
Albuquerque, New Mexico, USA   USA
John,

Clearly by mixture I mean the fuel air ratio. In setting up the SU, this actually means the initial ratio. Partially for those that are less familiar with the workings of the SU carb, there is a needle attached to the base of the piston. The air flowing under the piston through the butterfly valve into the engine creates a lower pressure than that inside the dome surrounding the piston. This cause the piston to lift allowing air into the engine and lifting the needle with it. This needle is tapered and as the piston lifts it allows more fuel to enter the air stream through the fuel jet at the bottom. The shape of the taper is such that the same basic percentage of fuel is introduced into the higher air flow.
When setting up the SU, first the mixture is set to an initial set point near where it is correct. This is around two turns down from flush with the carb throat. The initial opening of the butterfly valve (or valves in a dual carb system) is set by the throttle screw. The air into each carb is measure using a manometer so that the minimum idle is achieved where the air flow into both carbs is the same (balanced). The link between the two carbs is eventually locked so that as the accelerator is pressed, the two butterfly valves open at the same time and by the same amount. This sets the idle and balance, but the mixture remains.
There are several methods of setting the mixture, but I use the piston lift method. With the engine running, the piston on one of the carbs is lifted ~ 1 mm. If the mixture is too rich (too much fuel) the engine rpm will increase. If it is too lean, (too much air) the engine rpm will drop and start to stall. If the mixture is correct, the rpm will momentarily increase and then settle back. Adjusting the jet down with the nut increase the ratio of fuel. Adjusting it up into the carb will decrease the amount of fuel. The mixture has to be individually set on each carb.
The fact I live at over 5,000 feet means the air pressure is less (~-22% here) and the partial pressure of oxygen is also less. If there is less oxygen, the amount of fuel has to be decreased as well. At some rpm level, there simply isn't enough energy being generated to keep the engine running smoothly. As you go high in altitude and less oxygen, the critical rpm increases. An engine that can run smoothly at sea level at 500 rpm, need to be set at a high idle at one mile.
O2 sensor are used to measure the amount of un-burned oxygen in the exhaust. (There is always some as an internal combustion engine isn't 100 % efficient.) The amount of oxygen in the exhaust can be used to dynamically adjust the amount of fuel introduced. This is the method used with fuel injection, but is difficult to pull off with a carb engine. I am attaching a downloadable link to a BL manual on setting and servicing SU HS carbs. It uses a method of setting mixture different than I described which I find less accurate. Either way, these methods are ones that most can do in their garage with few tools.

Jim

https://drive.google.com/open?id=0BwbdsZZu51jRVHdlVENUZjJLSTA



Edited 2 time(s). Last edit at 2017-06-19 05:21 PM by Desert TR.

davecutter Avatar
davecutter Silver Member Dave Cutter
Fox Island, Washington, USA   USA
1963 Triumph TR4 "Angus"
In reply to # 1464476 by jjtr4 Here are some older "Kodak" prints from my TR at the Labor Day Porsche Corvette Challenge, Reading PA.1982.

John, great picture of your TR4 at speed in a turn! Just returned from our annual fishing trip on Rock Creek in western Montana, time to get back in the garage.

jjtr4 john m
Penn's Landing, PA, USA   USA
Thanks Dave!

gozto11 Avatar
gozto11 Todd Bermudez
Cincinnati, Ohio, USA   USA
Since the old starter broke inside the bell housing, I was forced to swap in an overdrive box...and the new starter pictured below

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davecutter Avatar
davecutter Silver Member Dave Cutter
Fox Island, Washington, USA   USA
1963 Triumph TR4 "Angus"
In reply to # 1473540 by gozto11 Since the old starter broke inside the bell housing, I was forced to swap in an overdrive box...and the new starter pictured below

Did same a few months ago. Cranks over stronger and you probably lose 10 lbs replacing the original Lucas unit!

BL50 Avatar
BL50 Silver Member Brian Leslie
Grosse Pointe, Michigan, USA   USA
Finally making some progress ... second coat of primer. Getting excited now!



Edited 1 time(s). Last edit at 2017-08-07 06:47 PM by BL50.

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jjtr4 john m
Penn's Landing, PA, USA   USA
Looks nice! Gr8 spray booth too!

Tommys4 Platinum Member Thomas G
Ojai, Calif., USA   USA
showing our cars racing, thought I would add mine. This is my car in it's hay day.

everyone have a great day........... TMG


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jjtr4 john m
Penn's Landing, PA, USA   USA
Nice! Thx for sharing it!

Perdido Avatar
Perdido Gold Member Rut Rutledge
Tuscaloosa, Alabama, USA   USA
I decided to tackle installation of the inner and outer waist seals and was really apprehensive about this project. I made a tool to hold and install the clips, but the metal was a little too thick to get between the door glass and waist seal so I dropped the window glass stop and removed the 6 bolts that hold the front and rear window channels. This gave me enough room to install the clips and was really quite easy...it took about 5 minutes per door after the glass was out of the way.
Rut

Fictioneer Avatar
Fictioneer Doug Hirt
Colorado Springs, CO, USA   USA
Hi Rut,
It appears that if one has the door completely disassembled for repair and painting, then the best time to install these seals is before one reassembles the innards. I will keep this in mind.
Doug



"Mr. Filby, do you think he'll ever return?"
"One cannot choose but wonder. You see . . . he has all the time in the world!"

Perdido Avatar
Perdido Gold Member Rut Rutledge
Tuscaloosa, Alabama, USA   USA
In reply to # 1485551 by Fictioneer Hi Rut,
It appears that if one has the door completely disassembled for repair and painting, then the best time to install these seals is before one reassembles the innards. I will keep this in mind.
Doug

Doug,
The guts need to be in the door, glass and all, just loose so you can work around it better.
Rut

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