[Spridgets] [___Spridgets] fuel delivery issue

John O'Brien banjojohn at cox.net
Mon Apr 19 21:17:53 MDT 2010


  _____  

From: Shop at " Just Brits " [mailto:shop at justbrits.com] 
Sent: Sunday, April 18, 2010 6:57 PM
To: John O'Brien
Subject: Re: [___Spridgets] fuel delivery issue

 

<< Heat shield and spacer are in place. >>

OK, good John.

<< I have headers installed, but they are wrapped with header insulation
wrap. >>

NOT good !!!  Headers WILL disintegrate before you UN-seeing eyes -:) !!!
It is due to the "heat cycles" of the pipes and WATER
forming = RUST !!  "Jet-Hot" or similar strongly recommended!!  I've heard
that and will probably fix this one day.

<< Timing has been checked and is spot on. >>

How do you know ??

 I set it with a timing light. To spec.  (don't remember what the spec is
now, but I set it to manual spec. at specified idle speed and it holds
steady. 



<< I have the Pertronix electronic ignition, so it holds very consistent. >>

"Holding" is one thing; being "correct" is another.  I don't have
one of their Instruction Sheets but IIRC timing changes by something like 15
- 30 degrees !!

<< One thing I changed this spring was to remove the water pump mounted fan.
I have a custom built aluminum radiator, with a front mounted electric fan.
Engine temp holds right in the middle of normal with this set-up, (gauge
needle straight down) so I don't think the engine is running too hot. >>

You can get [for around $10 - $15] a Heat Temp 'gun' that is accurate enough
for what you need;  my suggestion is that not only do you get one but check
all around the block.

<< Could be that the water pump mounted fan was moving enough air around the
carbs to keep them cooler. >>

"Could" be.

<< Maybe the float bowls are getting too hot during extended idle. >>

Well my 1st question would be WHY "extended idle" times ??  maybe because
heat is coming off the headers with little air movement to move it away when
sitting still.  Heat rising to the carbs.

<< I covered the fuel line and pressure gauge with insulation wrap. >>

FTTB, I supposed good for 'testing'.

<< Maybe I could wrap the float bowls to see what happens. >>

Can't hurt for sure !!   

Can you see water flowing with radiator cap off ?? Not really, because the
custom radiator has an offset filler neck, but I am confident coolant is
flowing.
Was block "boiled out" when it was rebuilt ??  I bought the engine freshly
rebuilt maybe 7-8 years ago.  I can't say for sure but  don't think the
engine is getting too hot.
Do you have a thermostat ??  MANDATORY or at least a
"blanking disc".  Yes.  I'm running a 160 degree thermostat.  Aluminum
radiator has a front mounted electric fan.  Engine temp gauge shows it comes
up to temperature and then holds at mid-point of normal range (needle on
gauge pointing straight down)
What pressure Radiator Cap ??  7 lbs.
What engine block ??  1275
What carb[s] ?? SU HS2 twins 
What fuel pump ?? aftermarket Mr. Gasket brand electronic fuel pump.

Guess dats enough to start -:)-:)-:) !!!

Me


More information about the Spridgets mailing list