Wietse
Well-Known Member
Is the standard filter after the fuel pump??
Bit confused now.
Bit confused now.
Holley 750 carb adjustment
- Thread starter Wietse
- Start date
miller
Well-Known Member
Not sure who your asking. If on mine, filters for two carbs, between pump and carbs.
Wietse
Well-Known Member
Well, i assumed the standard fuel filter will be located before the fuel pump to protect the pump as well.
But now i am in doubt if the fuel filter sits on the suction or discharge line on my car, i am away from home for a few more days so i cannot check it at the moment.
If it is installed on the suction line of the pump it does not matter if the pick-up suction screen in the tank is installed or not because all mechanical components are covered.
But now i am in doubt if the fuel filter sits on the suction or discharge line on my car, i am away from home for a few more days so i cannot check it at the moment.
If it is installed on the suction line of the pump it does not matter if the pick-up suction screen in the tank is installed or not because all mechanical components are covered.
Cornpatch MO
Well-Known Member
Then why do all automakers have a screen or filter on the pick-up?............................MO
Wietse
Well-Known Member
At least here in the Netherlands, if your fuel tank is clean it will stay clean.
Never reported that any fuel station has dirty fuel with "large debris" as everything is filtered several times during transport.
So with a clean fuel tank i am not scared of leaving the "sock" off and regularly replace the fuel filter in the engine bay.
Then again, this happened to me now, but most likely i will never face problems again with the fuel supply.
Once i will replace the pick-up on the tank i will know how my tank will look like inside.
Never reported that any fuel station has dirty fuel with "large debris" as everything is filtered several times during transport.
So with a clean fuel tank i am not scared of leaving the "sock" off and regularly replace the fuel filter in the engine bay.
Then again, this happened to me now, but most likely i will never face problems again with the fuel supply.
Once i will replace the pick-up on the tank i will know how my tank will look like inside.
miller
Well-Known Member
Difference between old, and new. Newer ones, all I've seen have those high dollar inline filters, outside the tank, probably with the pump inside the tank.
Older, yeah, but not installing junk from China, like you find today. And gas was a little different. Sure, had to decide, not take the chance.
With the junk you had in your filter, I suspect if you look 'inside' your tank, you will find more...and the pick-up filter pretty much gone.
Wietse
Well-Known Member
Yeah, if the pick-up comes with a stainless steel mesh for example i would put some faith in it.
Most likely i will find a lot of debris in the tank, time to clean then.
Will keep you posted.
Most likely i will find a lot of debris in the tank, time to clean then.
Will keep you posted.
Wietse
Well-Known Member
Well, back home and got some stuff done in the afternoon.
I've received my stuff from Summit Racing incl. a stroboscope and a new vacuum gauge.
-Installed new spark plugs (NGK XR5/3332), 1 step hotter to the previous ones. (NGK BP6S)
-Checked ignition timing and vacuum.
I've found an Initial timing of 12 Deg, and found the mechanical advance is set to 21 Deg, so 33 Deg total.
Mechanical advance starts to pick up around 1250 RPM is fully advanced around 2500 rpm.
Intake vacuum was at 5 Hg at idle @ 700 rpm.
One major thing to note is that i am using RON 98 pump gas! (could be 97 as well, normally things are not as advertised)
After my professional
adjustments of timing, carb idle adjustment screws and idle i came to this:
Initial advance: 18 Deg.
Total advance: 39 Deg.
Vacuum 8 Hg, idle @ 800
One major thing noted was that the exhaust gas did not stink as before, it was overly rich i guess.
During a test drive i noted at higher rpm a rattling sound (hard ticking), now as i am a noob not sure if that noise was engine knocking but i did not go that far again.
Guess next step is to re-adjust the initial timing to 16 Deg and try again?
After all that noisy jobs with my face on the engine trying to see the balancer advance scale i will make a start on sorting out the electric wiring for the ignition to make sure everything gets a clean 12 Volt supply
I've received my stuff from Summit Racing incl. a stroboscope and a new vacuum gauge.
-Installed new spark plugs (NGK XR5/3332), 1 step hotter to the previous ones. (NGK BP6S)
-Checked ignition timing and vacuum.
I've found an Initial timing of 12 Deg, and found the mechanical advance is set to 21 Deg, so 33 Deg total.
Mechanical advance starts to pick up around 1250 RPM is fully advanced around 2500 rpm.
Intake vacuum was at 5 Hg at idle @ 700 rpm.
One major thing to note is that i am using RON 98 pump gas! (could be 97 as well, normally things are not as advertised)
After my professional
adjustments of timing, carb idle adjustment screws and idle i came to this:Initial advance: 18 Deg.
Total advance: 39 Deg.
Vacuum 8 Hg, idle @ 800
One major thing noted was that the exhaust gas did not stink as before, it was overly rich i guess.
During a test drive i noted at higher rpm a rattling sound (hard ticking), now as i am a noob not sure if that noise was engine knocking but i did not go that far again.
Guess next step is to re-adjust the initial timing to 16 Deg and try again?
After all that noisy jobs with my face on the engine trying to see the balancer advance scale i will make a start on sorting out the electric wiring for the ignition to make sure everything gets a clean 12 Volt supply
Wietse
Well-Known Member
Got the 12 Volt supply wire replaced for the ignition, and also put a jumper wire between the plugs of the ballast resistor.
Now everything gets a proper 12 Volt supply.
Also installed a new 14" x 3" air filter.
I readjusted the Initial timing back to 16 Deg but looks like the "engine dying" issue kicks in more earlier.
A bit of hitting it hard and that's it, again it just goes down and after a bit of light throttle it gets back on it's feet again.
Makes me wonder if i should retard the timing instead?
Any opinions? Otherwise tomorrow i will try and set the Initial timing for 10 Deg and see how that works out.
According me, with high octane fuel, more aggressive cam and higher compression ratio (not sure how much) i should be advancing the timing?
It does idle very well, starts easy and drives good at cruising speeds.
Now everything gets a proper 12 Volt supply.
Also installed a new 14" x 3" air filter.
I readjusted the Initial timing back to 16 Deg but looks like the "engine dying" issue kicks in more earlier.
A bit of hitting it hard and that's it, again it just goes down and after a bit of light throttle it gets back on it's feet again.
Makes me wonder if i should retard the timing instead?
Any opinions? Otherwise tomorrow i will try and set the Initial timing for 10 Deg and see how that works out.
According me, with high octane fuel, more aggressive cam and higher compression ratio (not sure how much) i should be advancing the timing?
It does idle very well, starts easy and drives good at cruising speeds.
Last edited:
Wietse
Well-Known Member
I've got a new fuel pump, fuel pick up and new hoses and clamps lying here.
Maybe replace them first i guess.
It could not be because of the new spark plugs? I've gapped them @ 0.0375" and they are 1 step hotter type (5).
Is it possible to pull the fuel pick up assembly from the fuel tank without removing the tank from underneath the car?
Maybe replace them first i guess.
It could not be because of the new spark plugs? I've gapped them @ 0.0375" and they are 1 step hotter type (5).
Is it possible to pull the fuel pick up assembly from the fuel tank without removing the tank from underneath the car?
Wietse
Well-Known Member
Tank is still at 3/4 full so guess i will pump out some fuel and drive it low.
Thinking about the timing settings, it really felt good at 18 Deg compared to 16, which kinda made it more sluggish.
Guess when the shop installed it they left the mechanical advance internals standard, so the blue (max.21 Deg) bushing and the 2 heavy grey springs. That's whats in there from the box.
If that's the case the mech. advance ramp-up time will be very slow, in that case up to 4000 rpm, weird thing is i did not see it go any higher above 3000 compared to 2700-2800 rpm so i guessed that will be the max mech. advance. (see below link for the installation instructions, there is a "timing curve from factory" that shows the standard settings)
http://documents.msdperformance.com/8387.pdf
Thinking about the timing settings, it really felt good at 18 Deg compared to 16, which kinda made it more sluggish.
Guess when the shop installed it they left the mechanical advance internals standard, so the blue (max.21 Deg) bushing and the 2 heavy grey springs. That's whats in there from the box.
If that's the case the mech. advance ramp-up time will be very slow, in that case up to 4000 rpm, weird thing is i did not see it go any higher above 3000 compared to 2700-2800 rpm so i guessed that will be the max mech. advance. (see below link for the installation instructions, there is a "timing curve from factory" that shows the standard settings)
http://documents.msdperformance.com/8387.pdf
Wietse
Well-Known Member
Guess tomorrow i will start on the fuel pump replacement and hoses and put back the Initial timing to 18 Deg.
If it does the trick i will drive the fuel tank empty and replace the fuel pick-up and clean out the tank.
The new pick-up i bought has a plastic screen sitting on the suction pipe, although it does look fragile i think i will leave it on for now, guessing it will survive fuel as that's where it is made for.
Just checked the float sender as well and give a signal from 11 Ohms (full) and 72 Ohms (empty) which looks according specs. (Spectra Premium brand)
If it does the trick i will drive the fuel tank empty and replace the fuel pick-up and clean out the tank.
The new pick-up i bought has a plastic screen sitting on the suction pipe, although it does look fragile i think i will leave it on for now, guessing it will survive fuel as that's where it is made for.
Just checked the float sender as well and give a signal from 11 Ohms (full) and 72 Ohms (empty) which looks according specs. (Spectra Premium brand)
oldbee
Well-Known Member
Wellll I put a Spectra in mine last summer & it shows 1/2 full on gauge, you could get lucky or I have more problems to solve. Good luck, I don't trust anything anymore, although I have to say mine has original fuel gauge. And I worry about it more and more as time goes on!
Wietse
Well-Known Member
If i fill up the tank to the brim the gauge shows 3/4 full, when i just bought the car i remember it showed full once after filling up the tank.
I replaced most electronics of the dash just before that, hopefully this new sender will fix it.
Maybe yours got a bad contact somewhere increasing the ohm reading on the gauge?
I replaced most electronics of the dash just before that, hopefully this new sender will fix it.
Maybe yours got a bad contact somewhere increasing the ohm reading on the gauge?
Wietse
Well-Known Member
First off i set the timing again at 18* initial advance and played around with the idle mixture screws.
The best i could get it at was 9-9.5 Hg vacuum with the air filter off.
After installing the filter and start again the engine won't idle and dies.
1 thing i forgot was to check the vacuum with the tranny in Drive and then the vacuum drops to 5-5.5 Hg.
Thinking about it, this will open the 6.5 power valve as well which to me is not good right?
I bought a Holley trick kit (37-1539) to rebuild the carb, in here are 5.5 and 3.5 power valves as well.
As i am not able to get the vacuum high, probably because of the cam, i am wondering should i install the 5.5 power valve when i rebuild it?
I will go now and replace the fuel pump and the fuel hoses in that area to eliminate a bad fuel pump for the "engine dying" issue.
The best i could get it at was 9-9.5 Hg vacuum with the air filter off.
After installing the filter and start again the engine won't idle and dies.
1 thing i forgot was to check the vacuum with the tranny in Drive and then the vacuum drops to 5-5.5 Hg.
Thinking about it, this will open the 6.5 power valve as well which to me is not good right?
I bought a Holley trick kit (37-1539) to rebuild the carb, in here are 5.5 and 3.5 power valves as well.
As i am not able to get the vacuum high, probably because of the cam, i am wondering should i install the 5.5 power valve when i rebuild it?
I will go now and replace the fuel pump and the fuel hoses in that area to eliminate a bad fuel pump for the "engine dying" issue.
Similar threads
