Hemi Build #3 -Boogie Woogie Woogie

[TT540]

I like the idea of testing the fuel pump to see if it pushes past the carb bowl needle/seat.

I have used such a valve from McMaster car with success as a fuel tank vent "blow off valve" for my Chevelle. I use two in parallel. One in, one out. This way, my tank burps when it's internal pressure if over +1psi or under -1psi (to suck air in).

https://www.mcmaster.com/#7757k42/=1cv7y3s

---------- Post added at 09:45 AM ---------- Previous post was at 09:40 AM ----------

and if you do not use this switch for your handbar, you're a homo:

https://www.amazon.com/dp/B00NZCAA6...pi&pd_rd_r=HC36S49NAMT7RHAJJHM5&pd_rd_w=zRlIw

Actually, it wont work. is only a SPST. but you would be the coolest kid on your block. There is a stripper pole version too.

 

[bob58o]

If the bowl is full and the return line is closed, the pump stalls.
If the bowl is empty and the return is closed, the pump will fill the bowl then slow and stall.
Never did the carb flood.

It sure is loud.

Not sure what this test proves. I think it shows proof of concept and tells me I should keep the return line open.

Super said no more oil and gas in the parking lot.
I said sure thing.

https://www.youtube.com/watch?v=F1TpAVtdP1Q&feature=youtu.be

 

[Whitetrashrocker]

Nice valve there TT540.
It's a one psi blow off valve.

Hey bobO did you put a pressure gauge on that pump and see how much it puts out and where it stalls at?

 

[bob58o]

Nice valve there TT540.
It's a one psi blow off valve.

Hey bobO did you put a pressure gauge on that pump and see how much it puts out and where it stalls at?

I did not.

 

[Whitetrashrocker]

:toetap05:
So dissapointed
:toetap05:
GAB fail
:toetap05:

 

[bob58o]

Nice valve there TT540.
It's a one psi blow off valve.

Is that not a check valve with a 1 psi cracking pressure?
I have these, but don't know the cracking pressure of them.
https://www.ebay.com/itm/Aluminium-...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649
With a cheap vacuum pump /gauge....
The needle moves a bit with the check valve installed on the end.
~.5" Hg? Maybe 0.25 psi? Probably not very accurate.
The needle doesn't flinch with no check valve, so it requires some pressure to crack it.

 

[Whitetrashrocker]

That's what it looks like to me.

---------- Post added at 05:32 PM ---------- Previous post was at 05:31 PM ----------

And cheap enough to try it!

 

[bob58o]

:toetap05:
So dissapointed
:toetap05:
GAB fail
:toetap05:

I ordered a pressure fitting and gauge.
I ordered a fitting with with barbs for 5/16" hose because I couldn't find one for 1/4 hose.
Gauge is 0-15 psi.
https://www.ebay.com/itm/391510083059
https://www.ebay.com/itm/Natural-Fu...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

Going to have to GAB the difference caused by using the 5/16" fitting vs the 1/4" line.
Does 56% increase in area mean a 56% decrease in pressure?

3.0 psi at the gauge = ~1.9 psi in the 1/4" line
2.5 psi at the gauge = ~1.6 psi in the line
2.0 psi at the gauge = ~1.3 psi in the line
1.5 psi at the gauge = ~1.0 psi in the line
1.0 psi at the gauge = ~0.6 psi in the line
0.5 psi at the gauge = ~0.3 psi in the line
?????

 

[Whitetrashrocker]

Umm. If I put a tire gauge on my tire it reads 32 psi( or what ever)

Now if I make a one inch hose to jump from tire to gauge it will still read 32 psi. Minus the volume to fill the hose.

Off a pump that fills the volume difference, the psi is still the same.

 

[bob58o]

Umm. If I put a tire gauge on my tire it reads 32 psi( or what ever)

Now if I make a one inch hose to jump from tire to gauge it will still read 32 psi. Minus the volume to fill the hose.

Off a pump that fills the volume difference, the psi is still the same.

Well as air flowing through a carburetor passes through the venturi, the diameter of the pipe reduces. The air speeds up. The pressure is lowered. The lower pressure is what causes fuel to be pushed up though the jet.

If the pressure of a fluid FLOWING THROUGH an open system didn't change with changes in pipe size, then carburetors wouldn't work.

And airplanes wouldn't fly.

When the pump stalls, it should read the same, then system is then like a closed system, like your tire.

 

[Xtreme Yard Karts]

Great thread! Lots of GAB�� but it's a great build. Can't wait to see it completed.

 

[bob58o]

Great thread! Lots of GAB�� but it's a great build. Can't wait to see it completed.

I'm a bit worried that my mods might have pushed pk HP to a higher RPM than I wanted. 1.2 Rocker on the intake, ported head, 28.5mm intake valve.

I'm relying on the short duration of the camshaft and the early intake valve closing to keep the Pk HP at a "Lowish" RPM.

I wanted pk HP around 5300 RPM.
Brad Hill suspected that this build might be making pk TQ at 5300 RPM, but doesn't have any experience with the 280 cam IIRC. Either way, it should make good power. I want to get it Dyno Tested. I think Brad Hill is in Illinois as well. All the cool kids are. LOL. Maybe he will let me bring him this for testing/tuning.

That would be fun. Or maybe Grant will let me ship my engine to him for some testing. Not sure how much that would cost to ship? $50 each way?

I suspect that before I could get this dyno tested, I would have to put the billet flywheel on this engine. Not sure dyno operators would be comfortable spinning the charging flywheel at 6.5k maybe 7.5k RPM.

 

[Xtreme Yard Karts]

I'm a bit worried that my mods might have pushed pk HP to a higher RPM than I wanted. 1.2 Rocker on the intake, ported head, 28.5mm intake valve.

I'm relying on the short duration of the camshaft and the early intake valve closing to keep the Pk HP at a "Lowish" RPM.

I wanted pk HP around 5300 RPM.
Brad Hill suspected that this build might be making pk TQ at 5300 RPM, but doesn't have any experience with the 280 cam IIRC. Either way, it should make good power. I want to get it Dyno Tested. I think Brad Hill is in Illinois as well. All the cool kids are. LOL. Maybe he will let me bring him this for testing/tuning.

That would be fun. Or maybe Grant will let me ship my engine to him for some testing. Not sure how much that would cost to ship? $50 each way?

I suspect that before I could get this dyno tested, I would have to put the billet flywheel on this engine. Not sure dyno operators would be comfortable spinning the charging flywheel at 6.5k maybe 7.5k RPM.

I wouldn't sweat that too much though. If all the improvements you did raised average HP and torque, the peak means very little anyway. Every one these engines ever made would make way more power than their governed level of power, but they do they job they were designed to do. If your engine peaks higher than you wanted, but does everything better up to your target RPM, you still accomplished your goal.

Your trick now is to tune the drivetrain to make it stay in your desired range.

 

[bob58o]

I wouldn't sweat that too much though. If all the improvements you did raised average HP and torque, the peak means very little anyway. Every one these engines ever made would make way more power than their governed level of power, but they do they job they were designed to do. If your engine peaks higher than you wanted, but does everything better up to your target RPM, you still accomplished your goal.

Your trick now is to tune the drivetrain to make it stay in your desired range.

Luckily there are only a few things to tune on a TAV-2.

Driver unit weight pack, which partially controls engagement RPM.

Driver unit springs, which are supposed to control engagement - but will also change shift RPM (along with the weights).

Driven unit spring, which controls shift RPM.

Driven unit preload hole, which controls shift RPM.

I can't easily change the helix angle, which controls the rate of the shift.



I have a TAV-2 kit with 7" Driven Unit, springs and weights for a few different engagement settings, a stock Driven spring and a yellow one (for higher RPM shift). However, I think the bike I plan on using has a JS for the driven unit (so I possibly won't need the backplate).

I may put this engine and TC on my current minibike and tune the main jet and TC, but I honestly haven't even tuned the main jet on that engine yet, nor have I given it WOT. I'm slacking.


Once I start testing that...
I'll just have to watch a tachometer and a speedometer.

When accelerating and RPMs stop climbing, but MPH's continue to do so... I will have found the shift point and will adjust from there.

Painted the backplate that I may not use, but I was lazy with my taping. Specially on parts that won’t be seen.

 

[bob58o]

what are best options for sealing threads on gasoline fittings.
I have this high temp thread sealant from Permatex. Supposed to be solvent resistant.

Heard Aviation Form-a-Gasket No. 3 is better?

I’ve never used the yellow tape stuff.

Any other options?

Where would you like your testing done Whiskey Tango Romeo?
At the carb? At the Pump? In the return line?

Reads 2 psi at the carb when it stalls.
https://www.youtube.com/watch?v=cKP2COVGhAY&feature=youtu.be

 

[Randy H]

^
Nothing. A proper NPTF fitting needs nothing.

Pipe dope if you're a contractor.

 

[Whitetrashrocker]

Anywhere in the pressure side of the pump there, BobO.

If the pump is stalling at 2 psi I think your fine not using a pressure relief valve. The float should hold that back. If you were above 5 psi then I would look into a relief valve.


As for fittings use AN!
Kidding. Rubber hose and Barb fittings should suffice. A clamp will help. Why the threaded fittings? If they are pipe thread they should seal them selves. Or do they have a flange seat?

---------- Post added at 07:53 AM ---------- Previous post was at 07:48 AM ----------

And make sure the rubber hose is rated for gas. Vacuum tube will dissolve and leave your carb full of junk.

 

[bob58o]

Anywhere in the pressure side of the pump there, BobO.

If the pump is stalling at 2 psi I think your fine not using a pressure relief valve. The float should hold that back. If you were above 5 psi then I would look into a relief valve.


As for fittings use AN!
Kidding. Rubber hose and Barb fittings should suffice. A clamp will help. Why the threaded fittings? If they are pipe thread they should seal them selves. Or do they have a flange seat?

---------- Post added at 07:53 AM ---------- Previous post was at 07:48 AM ----------

And make sure the rubber hose is rated for gas. Vacuum tube will dissolve and leave your carb full of junk.

Some of the NPT fittings are as follows...
Pressure Gauge, NPT x Barb fittings in tank for vent and return line,....

The tank petcock has and o-ring seal...

The rest of the stuff is barb fittings.

I got a spool of this for my fuel line...
https://www.ebay.com/itm/1-4-X-25-F...401084001145?_trksid=p2385738.m4383.l4275.c10

1/4" X 25 FOOT BLACK RUBBER FUEL LINE HOSE BIODIESEL E85 GAS Made in USA

 

[Whitetrashrocker]

Your vent and return lines are on the top of the tank. I wouldn't worry too much about sealing those. And you probably want to use Barbed fittings on anything that you might have to remove in the future.

 

[KartFab]

what are best options for sealing threads on gasoline fittings.
I have this high temp thread sealant from Permatex. Supposed to be solvent resistant.

I have something similiar from loctite looks like the same tube (small white tube). PTFE based. I put it on my gas tank fittings no leaks and governor holes that i put a bolt in, no leaks and they dont come undone.