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TR4/4A old gas after sitting for a few years TR4a

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Mr. Brown, out of curiosity does that $160 you were quoted include coating the tank or just cleaning it? If it's just cleaning I agree that the price seems high. If the coating is included, I'd probably go for it.

I've coated three fuel tanks at home. All involve several stages of cleaning as mentioned. I've used the kits by Kreem and by POR-15. Of the two, I much prefer the POR kit as it doesn't use MEK for the solvent and leaves a metallic finish inside the tank... making it still look uncoated.
 
Thanks, I did alot of reading about the PoR kit and it sounds good.
Its hard to believe that it will really give the inside a cleaning to the bare metal though.
 
well, after hooking up a electronic fuel pump directly to the carb fuel line from a gas can, I was still not able to get it to start, fires quikly on starting fluid but its simply not getting gas. I am guessing the carbs have stuff in them even though they seem to have ben very recently rebuilt. I think the rusty sediment from the gas tank made it through since he had no inline fuel filter.
So, how far do I need to go, can I just drop the bowls and clean them all out and the jets or do I need more drastic measures? I had planned to send the carbs off for a rebuild before I saw my car not knowing they had been rebuilt.

Looks Like time to pull the tank and do the POR-15 treatment to it and then see what I can do to shoot fuel through the lines to flush them out.
 
a friend told me he used to put bb's in his old motorcycle gas tanks and shake them around to clean the inside. sounds good to me-I'm going to try it on my 73 that's been sitting
 
Hello Richard,
Did your car come from a dealer or an individual? Anyway two things to consider chemically speaking with fuels containing oxygenates like ethers (mtbe) and alcohols (ethanol/methanol). Both should (read might) be compatible in modern fuel systems where seals and gaskets are concerned, but can cause problems with composites like the cork gaskets often found in kits. They slowly dissolve the binder, which is impervious to gas but not to alcohols/ethers (which were probably used in the manufacturing process). This is usually the source of the 'varnish' effect. The other problem is that alcohols love to absorb water from the atmosphere. I don't think I need to add anything else. Good luck.
Tom Lains
 
Mr. Brown, whether you go with a POR kit or other tank lining, the process will be the same. The first step is to remove the varnish and deposits in the tank. POR recommends starting with their Marine Clean product. I perform one step before that. I put strong (water rinseable) paint stripper in the tank first. This will soften/loosen everything and make it easier for the Marine Clean to do its thing. The ball bearings mentioned above help. I use gravel, regular old grey crushed stones instead. After pouring the chemicals in the tank I add a couple of cups of stones, plug the openings and slosh everything around for a long time. Friends of mine have used old nuts and bolts, chains, BBs... almost everything. Whatever you choose, this added aggregate greatly improves the cleaning process. The tank lining is basically a paint and with all painting your results will depend on the quality of your prep work. Follow the instructions carefully and make sure the tank is clean, dry, and well etched prior to lining.

The SU and Stromberg carbs can both have problems with their float valves after they've been sitting and the SUs are susceptible to crud in the bottom of the bowls. Before you tear the carbs all the way apart, take a look at the float valves and make sure they're opening. Since you have an electric fuel pump this will be easy enough to test.
 
actually I looked in my books and not yet knowing enough about these carbs I do not know how to check the Float valve. Is there an easy way for you to explain?

thanks for your help.
 
Well, I don't know which carbs you have on a TR4 but I'll assume they're Strombergs like on my GT6. If so, you should be able to remove the air cleaners and find six screws securing the fuel bowl to the bottom of the carb. Remove these screws and wiggle/pry the fuel bowl down and off the jet. As it's probably been a while since the bowls were removed, plan on having to use some force to get them off/down. There is an o-ring between the outer body of the jet and the bowl and these stick over time. Once the bowl is off, the float will dangle and you'll be able (with an inspection mirror) to see the brass float valve screwed into the top half of the carb body. Remove it with a socket wrench or nut driver, clean it with carb cleaner in a can (and a cotton swab... no wires) and make sure the parts aren't stuck together. The traditional float valves have an insert with a conical rubber tip that may be stuck to the seat. Be careful not to drop this and loose it when you take the float bowl off. There are other types of valves that could be fitted (like Grose jets... that don't come apart). Fit a new o-ring when you put the bowl back on. This is just a regular buna(nitrile) o-ring that you can get from the hardware store. Take the bowl with you and find one with 1/16 cross-section that has an OD that's a little snug in the hole. You may also have to use gasket paper to make a new bowl gasket. Alternatively you can order these parts from your favorite source.

If you've got SUs the process is much easier. Remove the three slotted screws from the top of the float bowl, remove the cover with the float, remove and clean the valve. You'll be able to reuse the gasket if you're lucky.
 
I just learned that they were completely rebuilt a while back and have 6000 miles on them just like the engine so I probably don't wnat to do a complete rebuild. do any of you have the gross jets in your carbs, I was thinking while I am in there I might just install those.
 
Richard, if you are going to all the trouble and expense of overhauling your gas tank, now is the time to do the same with your gas lines. Personally I would vote for replacing them with new. Not sure about the TR4, but my TR6 lines are 5/16 steel, available at NAPA in stock straight pieces. Takes a bit of practice to properly bend steel lines but doable. And of course change all rubber connections using only the best available rubber fuel lines, around here that would be Gates. You can clean out old steel fuel lines with a long section of tach or speedo cable, I would still go with new. You will be amazed how badly these fuel lines will crap out over 40 years.
Also, a friend here at home is a gasoline jobber (Shell) and it would scare you to know that (at least around here) all gas stations get their product from the same refineries, regardless of what brand name it ends up being sold under. I only run the highest octane that I can get, usually around 93.


Bill
 
I have Gross Jets in the GT6 and the Mini. I am probably the exception, but one of the jets I bought was "bad" out of the box (never completely closed and would overfill the bowl) and had to be replaced. When they work, they work well. However, old gas can turn in to varnish as mentioned earlier and this can "glue" the balls in Gross Jets to their seats which blocks fuel flow.
 
When you get your tank out, have it cleaned ultrasonically, then etched and then polymercoated internally. A GOOD(reputable) rad shop who is used to dealing with heavy equipment (Cat) can do this.
 
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