Gunk Lead Substitute-Any Experience with It Good or Bad?

[Tom]

I picked up a bottle of "Gunk Lead Substitute" fuel additive from my local Auto Zone store a few weeks ago. Before using it I thought twice and decided to post here first to get input on whether it's helpful, harmful, or just a waste of money. The maker is Radiator Specialty Company of NC per the label. Any thoughts?

I always use Shell premium unleaded in my '64 Commander with its 259 ci engine to be on the safe side for its cleaning agents and for a little extra kick.

[StudeRich]

Probably won't hurt a thing, but the question is WHY?
I don't think it will help much, the lead substitutes in the Fuel are supposed to help, and if at your last Valve Job you used unleaded Valve Seats, it will not matter at all.

Also, unless you raised the Compression, it's only about 8.5 and should run OK on Regular, and quite well for certain, on mid range 89 Oct.

[maxpower1954]

In over 20 years of driving Studebaker V-8s, I've never had a problem using unleaded gas with NO lead additive, and that includes my R-2 GT Hawk which I've run pretty hard and fast for 25,000 miles - without valve seat inserts. And there is no extra kick using premium gas - the purpose of higher octane fuel is to avoid detonation (knock) in a high compression engine as Studerich sez. '64 Commander is a nice car, best of luck with it! Russ Farris

[trnstrtrk]

Since replacing several valves in my 64 GT Hawk in the late 80's following a trip using unleaded gas, I have added a bottle of lead additive with each fill up. No problems since then. Gunk is one of several brands that I have used. I do not use premium grade gas.

[Tom Bredehoft]

The theory is that the lead additive eventually coats the valve/valve seat interface and becomes a sort of lubricant. If an engine was run on straight leaded gas (before 1975), and is now being run on unleaded, with no valve grinds, it might be OK. If the valves have been ground, that cushion is gone and the valves will eventually destroy themselves, whether through heavy service or just continued service.

I use whatever lead additive I can find, and haven't driven far enough in 10 years to have any problem.

[jg61hawk]

I am a driver I guess in the sense that last year I drove form NJ to Gettysburg PA and the Hawk ran fine BUT it ran over 180 (closer to 210) coming home on the PA Pike. This year I literally today just returned from Rutland Vermont form NJ. This time I took a shot and added the GUNK Brand Lead SUBSTITUTE. Maybe it was a fluke but my car, my situaation, my trip the car ran 30 degrees cooler. The trip was much more enjoyable and I will never again travel a long trip without that stuff. HOWEVER, at the Rutland show I spoke with a guy who I respest and he said YES USE IT AS DIRECTED ONLY> too much will cause a build up and he said do not add it and let the car sit or it will separate from the gas. So my experience and my opinoion is I will use this product when and only when I am driving on a road trip. That's all I do not want to open a can a worms, but after two trips in excess of 250 miles one way in a Hawk I can say I believe this stuff lowered MY ENGINE TEMP BY 30 DEGREES.

[jg61hawk]

PS after driving that distance I anit fixin the spellin in the above post. Gewt it. Yeah I is tired and so is the Hwk, but the hwk is cool!

[David]

If you have a with a gas tank that has ever been sealed in the past with a system such as Gas tank RENU or similar marketed repair systems DIY coating systems you should never use lead additive in that tank. It will destroy the sealer coating.

[jg61hawk]

I just read what you posted and immediately sent the following to an engineer at RENU who I spoke to as I was restoring my car. I will post his response when I get it.
Dan,

We have communicated in the past about old cars and renu-

I have a 1961 Studebaker Hawk that has RENU. I was just posting that I believe Gunk Lead Substitute when added to the fuel lowed my engine temp.. Someone posted the following on the Studebaker Driver's Club Forum in response. Is this true?

"If you have a with a gas tank that has ever been sealed in the past with a system such as Gas tank RENU or similar marketed repair systems DIY coating systems you should never use lead additive in that tank. It will destroy the sealer coating."

[63 R2 Hawk]

Most of the so-called "lead additives" that I've seen are merely top oil additives. Not sure about Gunk but I think true TEL additives are not EPA allowed. If you have access to it, just run a half tank of 100LL avgas every 5-6 months.

[jackb]

I'd like to hear what an engineer has to say about your lower temps.....and just a musing....why did the Stude engineers believe 160-170 degrees was an optimum operating temp ?

[jg61hawk]

David why do you believe that this additive would destroy a RENU (trade mark) restored tank? I did speak with an engineer there and he is attempting to research the claim. I supplied him with the CAS #'s and information from the back of this product. He stated RENU has been in business 25 years and has NEVER had problem with the product dissolving or lifting. I tried putting the stuff on old paint, and old silk screened yard sign, and an old body panel. No lifting or break down of the paint. I can't see how it can hurt the RENU tank if it can't even lift marker from a yard sign. Please advise why you wrote that as I do have the RENU tank and am using this product. RENU engineering will get back to me but probably in several days. Thanks.

[Tom Bredehoft]

why did the Stude engineers believe 160-170 degrees....

In the 50s and before there were two kinds of anti-freeze. Ethylene Glycol and alcohol. If you had a 180 deg thermostat and ran alcohol as an anti-freeze, it would boil away quickly. With a 160 deg thermostat it would last a month or so.

[jg61hawk]

I heard back from the Gunk Manufacturers with the following quote:

Thank you for contacting RSC Chemical Solutions on this matter. I’m not sure why you were told that this product would cause harm in this situation, but I can assure you that it would not. Our team here takes every precaution when developing these products and this will not destroy the coating.

Regards

[63 R2 Hawk]

Years ago someone gave me a dozen or so bottles of Pyroil lead "substitute" so I was curious to see what the label said, if anything. Turns out it is basically kerosene. Note that these products are called lead SUBSTITUTE, not lead additive. As I mentioned before, most are just a "top oil" and should not have any affect on any tank that is intended for gasoline. The ethyl alcohol they adulterate gasoline with may be a whole different story, however.......