Very good info!!!!
-----Original Message-----
From: T. S. White [mailto:tswrace@pacbell.net]
Sent: Wednesday, September 21, 2005 8:22 AM
To: Mclean, John R
Cc: mgb-v8
Subject: Re: Cured a problem.
For all of you that responded I will detail the process. When I first
installed the new engine I worked for days trying to get the fuel
mixture right. My headers were getting red hot at idle. I thought this
indicated a lean condition but if I increased the jet size on my Holley
600 the headers would get even hotter. I was measuring temps with a
lazer thermometer. Also, if I increased the jet size the plugs would
load up after a few minutes at idle. I settled on size 56 primary jets.
The engine would run OK on the 56 jets and the engine temperature was
stable at about 195 degrees. Anytime in traffic would drive the temp up
over 200. The heat coming off the headers would make the passenger
compartment uncomfortable at low speeds.
I had a problem with the fuel preasure during the above process. I
would adjust the preasure at 5 1/2 pounds at idle. After taking the car
for a drive the fuel preasure guage would read 0 - 2 lbs of preasure. I
would re-adjust the fuel preasure to 5 1/2 lbs. After the re-adjustment
when I started the car cold the fuel preasure guage would read 9 - 10
lbs. After it got hot it read 5 - 6 lbs.
I called the Holley Tech Line. They said that the liquid filled fuel
pressure guage I was using had problems working in high heat
environments. They recommended that I switch to the non-liquid filled
guage. I switched guages and adjusted my fuel preasure to 5 1/2 lbs.
The engine immediately relaxed. I reset the carb fuel bowl level at
this point for the new fuel pressure. I left the size 56 jets in the
primaries. However, the operating temp remained the same. Holly also
said they would have my engine on size 58 primary jets.
Last weekend I was adjusting my valves and decided to look at the plugs.
I installed new plugs about 600 miles ago. The plugs looked good in
general but the electrode was still too white for my taste. An
indication the engine was lean. On a hunch that the previous problems
with header temps were a result of the fuel pressure problem I increased
the size of my primary jets to a 57. The engine immediately relaxed
again. I re-tuned the carb for the new jets. The engine operating
temperature dropped 10 degrees. The headers cooled off considerably.
The engine will idle for an extended period before the plugs begin to
load up.
For reference my engine is a 289 Ford bored and stroked to 306. It has
a 10:1 compression ratio. The heads are ported and polished. It has 1
5/8" custom headers.
It is on stands now as I prep for Triumphest but I can't wait to get it
off stands and drive it with the new jets.
Best Regards,
Tom
///
/// mgb-v8@autox.team.net mailing list
/// Send admin requests to majordomo@autox.team.net
/// Send list postings to mgb-v8@autox.team.net
/// Edit your replies! If they include this trailer, they will NOT be sent.
///
|