weber fuel pressure question

simon84 · Post by **simon84** » Thu Jan 03, 2008 9:39 pm

I'm trying to get all set up for a weber conversion. I have the carb, adapter and short air filter.
I saw on here that the weber needs 3-3.5 lbs. Can anyone confirm this?
The stock fuel pump supposedly puts out 7 lbs, but may be lower.
There is a Holley fuel pressure regulater on sale at the local parts place but it is 4.5-9 lbs.
Anyone know if 4.5 lbs would be acceptable?
So I'm thinking of trying to get a pressure guage first to see what pressure I've got. I could also use it with the regulator later.
Ay suggestions on where to get a pressure guage?
Thanks

takza · Post by **takza** » Fri Jan 04, 2008 5:38 am

There is always HarborFreight...I have one...only use the vac gauge so far.

Post by **Petros** » Fri Jan 04, 2008 2:40 pm

I have not done the weber conversion, but I understand sometimes the weber will work without the regulator, but other times it will not. The float valve apparently is not designed for the higher pressures as the stock carb, it will not close off and leak fuel everywhere. It can cause the engine to flood and stall out. A larger float or bigger needle valve may have allowed it to use higher pressures reliably.

Most I understand have put in a simple fuel regulator, they are not very expensive. The question is if the lower cost 4.5 psi regulator (which will likely work fine) be worth the risk of having to buy and install a lower pressure one later if it does not work. I think not. See if they can get you one that adjusts lower for the same price. Otherwise pay the extra, I do not recall they cost much.

Good luck.

keith · Post by **keith** » Fri Jan 04, 2008 6:40 pm

I have never had a leak problem with our Weber. I put a pressure gauge on the fuel line and found that the fuel pressure was only 2.5 to 4 psi with a year old autozone fuel pump.

The Weber has a steel needle. Most carburetors have a rubber tipped needle. A Vitron needle is available for the Weber for a lot less than the cost of a pressure regulator. At the same time, you could drop the float level so there is less fuel in the bowl, it will work a little better that way. Less fuel sloshing around.

The Weber comes with instructions for adjust ing the float level for a range of driving conditions.

splatterdog · Post by **splatterdog** » Sat Jan 05, 2008 9:09 am

On my webbered 86 I have a holley low pressure reg(1-4 psi)with a gauge mounted to it. I can bottom the screw out and still only hit 3 psi max. I would still verify your pressure if you decide to go without a reg.

Viton tipped needle is always a better choice in my book. Both mine will be getting one before next summer. In higher temps(80 deg f +) both tend to spill over when parked hot. The hotter fuel system vapors push past the steel needle just enough to load up the engine a bit and start hard if its restarted before the fuel puddle in the intake manifold evaporates. Lowering the float helped but didn't eliminate the problem for me.

simon84 · Post by **simon84** » Sat Jan 05, 2008 11:33 pm

I got the 1-4 psi regulator, gauge, fuel line and some fittings today. Will be working on the install soon.
Wish me luck!

Snax · Post by **Snax** » Sun Jan 06, 2008 9:31 am

Good luck!

You'll spend more time taking crap off than putting it back on.

simon84 · Post by **simon84** » Mon Jan 07, 2008 9:25 pm

So before I started the weber install, I thought I'd set the valve lash since they were clicking a little. I set them as per my manual, 0.008 intake, 0.012 exhaust. Wouldn't start! They seemed to need quite a bit of adjusting to get them to that setting, about a full turn. So I decided to loosen them off a little to see if it would help. So I turned each valve adjuster back a quarter turn. Still wouldn't run. After I did that about 4 times I got it to run. Idles high (about 1800) and a bit rough.
So now I'm wondering what the deal is.
Any ideas on how to know that they are good? It is a 4ac replaced motor. I'm not sure if the guy that put the 4ac did a rebuild and could have done anything weird with the valves. I have replaced the head gasket already so I'm already a bit suspicious since it was supposedly only 10k since the 4ac install.
I'd like to have this sorted out before I do the carb.
Any help would be much appreciated.

takza · Post by **takza** » Tue Jan 08, 2008 2:54 am

I don't think you had the engine in the right position when you adjusted them. I had to mark the manual so I could keep it straight. And I tested each rocker to be sure it was loose some to verify the right cam position. Though you might not be able to do that now.

simon84 · Post by **simon84** » Tue Jan 08, 2008 9:44 am

I did use a screwdriver in the spark plug hole to check TDC on cylinder 1. So I think I had things at the right position.

keith · Post by **keith** » Tue Jan 08, 2008 6:05 pm

simon84 wrote:I did use a screwdriver in the spark plug hole to check TDC on cylinder 1. So I think I had things at the right position.

#1 and #4 are both at TDC at the same time, #2 and #3 would be at BDC when 1 & 4 are TDC. WHen 1 is TDC for the compression stroke, # 4 is TDC for exhaust.

Pop your distributor cap off, turn the engine till the timing mark is TDC and the rotor is pointed in the direction of the #1 sparkplug wire would be with the cap on. Now, from the front of the engine adjust the first two valves, then skip one, adjust one, skip one, adjust one.

Rotate the engine 360Ã‚Â° and follow the same pattern but from the rear of the engine.

#1 TDC E I i E e I i e

#4 TDC e i I e E i I E

Adjust bold

simon84 · Post by **simon84** » Sun Jan 27, 2008 1:13 am

I was away in the backcountry on an avalanche course and I finally got back to working on the tercel. I redid the valve adjustment tonight and it's purring nicely now. I reallized that the problem last time was that I had neglected to plug in two sparkplug leads on my first attempt to start it. I quickly remedied that but it wouldn't run. I guess I must have flooded it. I just assumed it had something to do with the valves.
Always more fun to do something twice!
So I'm finally ready to do the weber conversion!
Of course it's supposed to cool down to the -20's (celsius) this week.

shogun · Post by **shogun** » Mon Jan 28, 2008 7:01 pm

redline weber sold me one that pushes 4.5 psi and said it was the one needed for the dgv application

simon84 · Post by **simon84** » Fri Feb 01, 2008 12:02 am

Tonight I finished installing the new weber and fired it up. Running at a slow idle and the fuel pressure guage is reading quite low, around 1psi. But a fitting on the pressure regulator is leaking fuel. I think I need to get some teflon tape in the fitting threads. Apparently you can get fuel resistant tape.
Any other way to seal a fitting?
Once that's sorted, I'll set the mixture, idle, etc. and post some pics.

Typrus · Post by **Typrus** » Sun Feb 03, 2008 4:14 pm

Carter manufactures a high-flow pump that pushes out something like 5PSI. $90 last I looked I think. It'd probably be well worth it.

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