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tahoe healey

tahoe healey

Yoda
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Well, I went on that nice winter ride yesterday which was great. When I first warmed her up and tried to drive with the choke operating, I got several "back fires" which seemed to be at the exhaust manifold /down pipe area. As she got warm and I could remove the choke everything was fine. Why up front and not at the tail pipe? What could be the probable cause (too rich carbs of course)? Could it be a leak in the exhaust system (new stainless, with new exhaust manifold) or leak in the carbs?
Interesting side note: I put a bra on the front and it has a screen mesh over the grill. I think it helped the engine run warmer cause I got to 140 - 150 range. Usual winter driving was 120. Air was 25 to 30 degrees(f). I hope this will not be a problem in the summer.
 
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I put a bra on the front and it has a screen mesh over the grill. I think it helped the engine run warmer cause I got to 140 - 150 range. Usual winter driving was 120. Air was 25 to 30 degrees(f). I hope this will not be a problem in the summer.

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I bought a bra for my car and found that it raised temperatures about 10 degrees due to reduced air flow. I cut the mesh away.
 
Michael, if you are out running in 30 degree ambient temperature a 10 degree increase in running temp would be a bonus.Agreed, in the summer it would be undesireable.---Keoke
 
Well TH, I don't think you have much to worry about.It sounds like that even though you were running with choke it just was not enough while she was still warming up.-FWIW---Keoke /ubbthreads/images/graemlins/driving.gif
 
TH,
I don't know if it applies to your car, but the older Healeys with the temperature pickup in the radiator do not give a true indication of engine temperature when things are cold. (The temp sending unit was moved from the radiator to the engine somewhere around mid 1958.) If the thermostat is closed, the temp in the engine can be well above the temp in the radiator & the gage will read the low radiator temp. In your part of the country, in winter, it is likely that the thermostat is closed most of the time. (only open for brief periods) The thermostat opens a bit, cold water from the radiator goes in & the thermostat immediately closes again.

As others have said, the backfires are likely to be carburetor spit back, a symptom of lean mixtures. You should be able to drive with the chokes partially engaged until the engine fully warms up.
D
 
WellTH, Its a bit like Dave said, Either let her warm up a bit more and run with less choke or you will require more choke if she is below 160 degrees.If you want to speed up the warm up put a towel over the front of the radiator and let it get good and warm then run with just a little choke.-FWIW---Keoke /ubbthreads/images/graemlins/driving.gif
 
Tahoe, you are not alone, I have similar problems with cold starts, I conked out at the start of a roundabout last Saturday and caused a few headaches until I restarted it, however a quick burn down the local motorway solved the problem temporarily. I guess that I should check the tappets, they rattle a bit(ALWAYS HAVE SINCE I BOUGHT THE CAR 2 YEARS AGO)and tune the carbs again, it does not tick over properly even when warm.

/ubbthreads/images/graemlins/cheers.gif /ubbthreads/images/graemlins/england.gif Bob
 
Me too. I find that it's taking me about 10 minutes of warm up to avoid the misfiring. Even when the engine is idling well, with choke off, as soon as I try to take off it starts again. I lose power and sometimes stall. It seems like it take way too long to warm up. After I've driven about a half mile, I'm fine.

Scott
 
SHG, just keep a bit of choke on until she gets warm and you won't have the problem-FWIW---Keoke
 
Keoke, I do, but it takes forever. I'm warming her up with the choke out for 10 minutes or more. Cold weather, longer. And it's never clear when she's warm enough. When I think I'm set to go, and go down the end of the drive, boom. I keep thinking I'm going to blow the pistons through the block. (I know, but it's paranoia). Plus, I'm feeling all good about the world, driving my Healey, looking like a middle aged jerk pretending to be young and free ;-) and this blows the whole feel good thing. Personally, I blame the mechanic for screwing up the SU carbs. It's better than having no one to blame. And since I pay him, he's happy to take the blame.

Scott
 
I didn't realise this was a problem.
My Midget does the same in the cold, takes a good ten, fifteen minutes to drive 'explosionless' with no choke.
So I just blocked off some of the radiator with a piece of cardboard and now she warms up much quicker without running hot. On warmer winter days I fold back a bit more cardboard to expose more radiator.
It's what we do in Sweden, and it seems to work well here too.
Simple if not altogether pukka.
 
Well I guess I should share a Swedish secret with you guys that live in the cold climates SHG/Rulle7 and others.Being an old Volvo lover too when I purchased a 444 saloon I found a window shade mounted in front of the radiator,yes a window shade /ubbthreads/images/graemlins/confused.gif. Attached to the window shade was a chain that ran to a tube soldered to the top of the radiator and then entered into the drivers compartment. When ever the engine temp could not be maintained you simply pulled on a lever that raised the window shade and blocked off the cooling air.This unique set up kept the SU's from coughing while driving and allowed short time warm ups.When you "pulled its chain" it made a bit of racket to be sure /ubbthreads/images/graemlins/lol.gif but it didn't cough while driving in the cold.-Bob's Your Uncle.Merry Chrismas, and Happy new year to all,My regards---Keoke /ubbthreads/images/graemlins/driving.gif /ubbthreads/images/graemlins/patriot.gif
 
You could always richen the main jets by a few flats to improve cold running. I suspect that long warm up time is often a symptom of lean jetting.
D
 
Aint got no flats /ubbthreads/images/graemlins/laugh.gif, Like I told Skip turn the fast Idle screws down about 1/2 turn does the same thing Dave.--Keoke
 
Keoke,
My error, you are correct, the HD8's which were the original discussion, have a jet adjusting screw instead of the nut. Will you ever forgive me?
D
 
Please excuse my ignorence but why does a lean mixture cause these explosions? My logic would say an excessive amount of fuel (over rich) would "explode" easier.
 
TH,
A lean mixture can burn so slowly that it is still burning a bit when the intake valve starts to open for the next cycle. This ignites the mixture in the intake manifold. The situation is made worse if the ignition timing is retarded.
D
 
/ubbthreads/images/graemlins/savewave.gif Oh I guess You are forgiven Dave since you gave TH such a good explanation on rich and lean. I was going to suggest the Pan of gasoline and a match experiment. /ubbthreads/images/graemlins/laugh.gif---Keoke
 
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