Vapor lock

[Todd138]

Does anyone have a good trick to stop vapor lock?

[Rob P]

Is this on that nice new (used) series truck you just got?

I am thinking to move the fuel line away from the area it is overheating in, or try wrapping it in aluminum foil to reflect away the heat or change from steel gas line to a rubber line.

You could change to an electric fuel pump and a regulator up at the carb with a return line running back to the tank thereby moving more fuel and lessening the chance of boiling gasoline.

Not sure if any of this is applicable at all. I am personally fighting with OBDII codes at the moment.

[siiirhd88]

X2 to what Rob said....

I find the newer fuel with methanol is more likely to cause vapor lock due to a lower boiling point.

Installing a fuel filter with a return line just before the carb should help greatly, by having a constant flow of cooler fuel right up to the carb, and also by having a place for any pressure to relieve to after engine shutdown, when the fuel in the carb bowl can flash. I haven't had the problem since installing the return line and filter.

I also found that my original mechanical fuel pump was supplying fuel at too low a pressure, and ended up installing an aftermarket spare. It is still a mechanical fuel pump, but doesn't have the sediment bowl.

When my 109 would vapor lock I would have vent the vapor by removing the fuel line from the carb and then use the fuel pump priming handle to pump some fuel into a small jar.

Bob

[Todd138]

I reran the fuel line away from the engine, covered it in heat resistant sleeve. But I think my pump has seen better days and the truck still wants to sputter and run like itsout of fuel when I stop after driving more then 10 mins.
I did some more reserch and I have a Holley electric fuel pump with a regulator and a fuel pressure gauge on the way. I'm just going to bypass the mechanical pump. Any Ideas or thoughts? how should i plug up the old pump or should I take it off and make a plate that bolts on.
Cheers

[Rob P]

I've seen block plates before but not on LR engines. I'd say remove the old pump and block off the hole but I am not sure on LR engines if that is OK or not. Not sure what the pump drives off of and if it will affect anything else.

I had a high pressure Holly rotary gear pump on an Isuzu pickup. It made 45 psi of pressure as the Isuzu used port injection instead of low pressure TBI injection. Anyway, it was noisey as hell. I called the shop and asked about the noise and they told me it was normal. I was constantly being told by onlookers that there was something wrong with my truck.

[Ken Heaton]

I did some more reserch and I have a Holley electric fuel pump with a regulator and a fuel pressure gauge on the way. I'm just going to bypass the mechanical pump. Any Ideas or thoughts? how should i plug up the old pump or should I take it off and make a plate that bolts on.
Cheers
I am going the same route, I have mounted a Mallory Low Pressure/Flow fuel pump on the frame right near the tank. I have removed the mechanical pump and am planning to make a plate that bolts up to the engine block. I don't think this will affect the operation of the engine in any way as the mechanical pump just ran off the cam shaft( I think anyway, I will have to look at a drawing of the engine, if I can find one) I plan to mount the pressure regulator on the plate where the old mechanical pump was located. I have to add an extra port in the fuel tank for the return line ( I bought an aftermarket tank[heavy duty] that does not have a second port for a vent line like the older tank). I have a Weber carburator that only has 2.5 psi fuel pressure, so I will have to adjust the regulator very low.

How does this sound? Any thoughts? Does anyone have any pictures of an installation?:confused:

[siiirhd88]

You just need to make a blank plate to cover the fuel pump hole. There are no problems running without the mecanical pump in place, you could even leave it there, but it could be a later source of an oil leak or mechanical failure.

The fuel filter with the return is, I think, for a Chrysler application. The filter was bought at an Auto Zone type store, after looking at the various filters on the rack. It has 5/16" nipples in and out, with a 1/4" nipple for the return line. I placed the filter just before the carb, and ran a 1/4" steel line from the filter to a short hose connected to the steel return line. I ran the return line parallel to the supply line along the top of the right frame rail to near the fuel pump, and then up along the bulkhead.

I had the second hole on the fuel tank, covered with a blank plate. I removed the blank plate, drilled and tapped a hole for 1/8" pipe thread and used a 1/8" pipe to 1/4" tubing compression 90 degree fitting to attach the return line. Some plates are too thin, so you might have to fab one up.

Ken, your heavy duty tank might be thick enough to drill and tap..... maybe.
I don't know how well a 'T' would work on the suction side of the pump...

I had repeated problems with the diagphram type "tapa tapa tapa" electric pumps on the wife's 109, especially in cold weather. I finally went with a Holley rotary style pump and have had no problems since. Your results might vary..

Bob

[Todd138]

Ken, my main problem was the fuel pump was in direct contact with the engine, and that is the heat source, if you run the regulator attched to the mounting plate which is attached to the engine, fuel will still get heat from the engine. Just my though.

Bob i'm confused about the return line, what do I need it for?

maybe the rover could be my winter ski vehicle........

[siiirhd88]

The return line allows the fuel pump to supply a constant flow of fuel back to the tank, which helps prevent the fuel from overheating and flashing to vapor. For any fuel that would flash, the pressure created gets vented back to the tank and not into the carb where it can push the fuel thru the jets. When you shutdown the engine, the heat can soak into the carb and boil off the fuel in the carb bowl. Without the vent on the filter, the only place the fuel can go is out the jets..... I have no vapor lock issues with my 109 using a mechanical fuel pump and return filter.

The wife's V8 109 is quite warm under the bonnet, and I found the fuel in the Holley 4V carb fuel bowls would percolate in traffic during hot weather. This would cause a flooding condition with black smoke, etc. The condition improved after I installed an aluminum heat shield and a phenolic spacer, but was eliminated by using the return filter.

It gets a bit more complicated if you have dual fuel tanks, as the return is usually to only one tank. My 109 has one underseat tank and the larger rear station wagon tank, with a marine style manual fuel selector valve. I have the return running to the underseat tank, which is the tank I run until low. I then select the rear tank and run it until the underseat tank nears full from the return and then select that tank. No real problem as both tanks have their own fuel gauge. The wife's V8 109 has three tanks, each with its own Holley electric fuel pump, check valve, and fuel gauge. It normally runs on the right underseat tank which the return line feeds, and the other tanks are selected by operating the switch for its own fuel pump. One of these days I plan on installing a triple tank electric fuel selector valve, which has provision for individual return lines.

Bob

[Todd138]

That sound simple enough, do you remember the part number or brand of filter?

[siiirhd88]

No, I don't recall the part number, as I just buy them by sight. I'll stop by the auto parts store and find one.

Bob

[Ken Heaton]

Ken, my main problem was the fuel pump was in direct contact with the engine, and that is the heat source, if you run the regulator attched to the mounting plate which is attached to the engine, fuel will still get heat from the engine. Just my though.


Good point, my thinking was that was the cool side of the engine and being mounted low on the block the temperature was probably OK. But maybe not. Perhaps I can mount the pressure regulator on the frame. I will have a look tonight. Also, the pressure regulator has a return line built in on the bottom of the body.

[Todd138]

I just got my holley in the mail today. and the regulator does have have to "out" holes and one "in". I'm kind of confused won't that just pump into the carb and back into the tank? How is that going to help if I have gases in the bowl. Man I think i'm confusing myself now.
Good point, my thinking was that was the cool side of the engine and being mounted low on the block the temperature was probably OK. But maybe not. Perhaps I can mount the pressure regulator on the frame. I will have a look tonight. Also, the pressure regulator has a return line built in on the bottom of the body.

[Ken Heaton]

Is there a diagram with the regulator? One of the ports should be marked "Bypass", that is the one that returns to the fuel tank. The regulator limits the fuel pressure to the set point, sends whatever the amount is needed for the engine to the carburetor and returns any excess back to the tank through the bypass.

[Todd138]

Ken, I found out I have the normal regulator, the two out holes are for two carbs. I would have to order the bypass return regulator. But I decided to keep the reg. I have and run the filter return instead.

[Ken Heaton]

Sounds like that should work.

[Todd138]

I drove the series to work today after doing all the work this weekend, and it's about 5 miles to work. when I got about 4 miles I was at a stop light and it started to idle very low again like it use to. I pulled the choke half way and it idled normal. Does this sound like it's running lean after it gets completly warmed up?

[Ken Heaton]

Try adjusting your fast idle speed, what type of carburetor do you have on the Series? Now that you have the fuel pump fixed you can go on and fine tune the engine.

[Todd138]

I have a weber, I really can't find a straight forward awnser to tuning it.

[galen211]

I used to have the same problem on that truck when it has a Zenith and it was a vacuum hose that kept falling off.

Now with a pertonix and weber that thing should run well. Personally I hate the weber but that's another story.

[Todd138]

Yeah I have a gut feeling it could be the vacuum advance rubber connects. I just don't understand why after the engine gets hot, other then the rubber is more flexable. I never liked webers but after dumping a bunch of money already into the thing i'm not buying another carb.

Ken, i've been reading the weber does not have a high idle. I'll have to look closely at it after work

[galen211]

I should clarify. The weber is a good carb and that particular one is like 1 year old.

But they are gas hogs and off-road do not perform as well as the Zenith. The Zenith has bigger problems till you correct it.

[Ken Heaton]

Ken, i've been reading the weber does not have a high idle. I'll have to look closely at it after work

Todd,

Go to this link:

www.carburetion.com/weber/adjust.htm

It explains the idle speed adjustment procedure.

[Ken Heaton]

I should clarify. The weber is a good carb and that particular one is like 1 year old.

But they are gas hogs and off-road do not perform as well as the Zenith. The Zenith has bigger problems till you correct it.

So far I am not a fan of the Weber either, I have looked into this problem and have been told that the old Rochester carb that was on Chevy trucks in the mid 1950s is the best carb for the Series engines. I have been trying to find one but it is like trying to find a needle in a haystack as they have not been made in decades.

British Pacific sells them for like $300 and I think you have to buy an adapter which is also expensive.

[Todd138]

Ken,Thanks for the link. Yeah my series funds have crapped out. so i'm stickin with this weber. but thanks for the info on the Roch.

[Todd138]

Ah i'm at the point that i'm just happy this carb keeps the series on the road. Went to get it inspected today, they just scratched their heads, 1976 land rover isn't even in the all mighty inspection book, so he had to hand type it in. then the same guy that asked me what kind of truck it was, then told me there is no such thing as a 2.25 engine.

But they are gas hogs and off-road do not perform as well as the Zenith. The Zenith has bigger problems till you correct it.[/QUOTE]

[siiirhd88]

I am currently running a Rochester B carb on my 109. I seem to like it the best as it has good power but it does consume more fuel. I can go to a smaller jet, and might do so in the future. The jets on the Rochester are higher up as compared to the Weber, and are less prone to clogging with dirt. Even with a fuel filter before the fuel pump, and two between the fuel pump and carb my Weber would get clogged juts. It was too inconsistant in operation, not knowing if it would idle or stall from one stop to another. It would seem to behave for a few weeks and then be nothing but problems for a while. I never had a good Zenith, but with the Weber the 109 did get 17 mpg on the highway in overdrive. I think I get 11 mpg around town with the Rochester.

The Weber and Zenith both use an aluminum 90 degree adapter between the carb and intake manifold, as their carb mounting holes are sideways, not fore and aft. No adapter is needed to mount the typical Rochester, as it will bolt directly to the intake manifold studs, keeping the phenolic insulator. The carb bolt holes might need to be slightly elongated as on my carb due to the manifold stud spacing being slightly long. The Rochester carb itself is taller than the Zenith and Weber, and I needed to slightly trim the bottom of the air cleaner hose to carb adapter and shorten the carb to adapter rubber coupling to prevent the hose to carb adapter from rubbing on the bottom of the bonnet.

The carbs seem turn up on ebay often, and I think there are a few on there now. The later ones have an automatic choke, which I would think could cause later problems. Since they were made with various bore sizes and mounting bolt distances, picking the right one sight unseen could be a concern. The preferred carb has the smallest bore possible. I think most of these carbs need to push up on the linkage to open the throttle, like the Rover Solex carb, and not down to open as on the Weber and Zenith. If swapping from a Weber or Zenith, you will need to find the Solex linkage or fab something up. I do know of one Rochester on a Series that pushes up to open the throttle. It had to be bolted onto the aluminum carb to intake 90 degree adapter to operate, which made it too tall for the bonnet to close....

I found my carb on a spare engine I had.... The rebuild kit, which does not include jets, was $17.00 at NAPA. I have not found a good source for jets, but the jet size is the same as a numbered drill bit size so the jet opening can just be soldered and then redrilled to a smaller size.

Hope this helps,
Bob

[Todd138]

:D After my vapor lock fix, i've still had a low idle sometimes when I'm at a light, and it seemed to happend more when I was stopped up hill. After weeks of trying to figure out this phantom low idle, I parked the rover after a long drive today left it running (low idle) and started tugging and grabbing things under the hood and as soon as I pushed the carb towards the bulkhead the truck started to idle normal.........what I had was a loose carb, right at the base of the carb the 2 nuts were loose. It makes complete sense now!:D

[Rob P]

Sounds kinda like when my old Geo Tracker had a loose ground wire running from the block to the frame, cause all kinds of havoc. Found it by accident while scratching my head cussing.