Marvel float level

[tcslr]

Rebuilding a 1931 marvel ( 10-796). The specification says the float level is to be 19/64” below top of bowl AND level. In order for it to be level across the entire float top, the only way would be to taper the top of the float material so that OR inset the float arm into the float.  Is this how it is to be done? Or when the dimension is met ( at end of the bowl) that elevation is the level comment. And there is a natural, inevitable taper. 
I think the latter is proper but would like input.

thanks in advance.

 

[hwellens]

May help?

 

[Str8-8-Dave]

14 hours ago, tcslr said:

The specification says the float level is to be 19/64” below top of bowl AND level.

I would argue simply setting the float in such a manner might not be exactly what you want to accomplish.  The real desired float level is that which has the maximum fuel level in the float bowl slightly below the height of the open end of the low-speed nozzles so the level is high enough that fuel is readily available to the nozzles under idle vacuum but just low enough to prevent fuel from being discharged from the low-speed nozzles due to gravity pressure working on the fuel in the bowl.  Be aware the old cork float is not as buoyant as it was when it was installed.  Be aware a plastic float, brass float, any float may have a slightly different buoyancy and therefore affect the fuel level in the bowl.  Make sure ALL the nozzle base gasket washers are present and do not leak.  Make certain the float valve does not leak.  The fuel level in the bowl is the key variable that has to be gotten right.  If your nozzle gaskets leak, if your float valve leaks the float will not properly control themaximum fuel level in the float bowl and too-rich idle mixture can be expected.

 

I hate nitrophyl plastic floats due to a fire I had because one absorbed fuel and sank, you can't buy virgin cork anymore, it is all recycled and glued and doesn't float.  So I made a float from solid 3/4" thick Balsa.  I took my carburetor apart to get an accurate measurement of low-speed nozzle height and transferred that measurement to the float bowl to determine maximum the fuel level that meets the level described above.  Then I installed the carburetor on the car and modified my float to get the fuel level just right in the bowl.  My car went from running slobbering rich at idle to running pretty clean at idle and as a side benefit the air valve adjustment has a much better defined happy setting.  

 

Conveniently you can measure low-speed nozzle height below the top of the bowl casting.  MAKE SURE the fiber gasket washers visible in the picture at the base of each nozzle is present and does not leak.  If they leak there will be puddled fuel on top of the nozzle plate that will be picked up as an extremely rich mixture.

 

Transfer the low-speed nozzle measurement inside the bowl and scribe a line to indicate the fuel level just below the low-speed nozzle height.

 

I fabricated a new float from solid balsa and thoroughly sealed it with SIG hot fuel proof model airplane dope.  NEVER try to 

adjust fuel level by bending that cast brass arm, it will surely break and send you on a hunt for an "unobtanium" replacement. 

 

Balsa by the way, when sealed so it does not absorb fuel, has a very slightly higher buoyancy than virgin cork.  You can't buy

virgin cork anymore, it's all reground recycled and glued and it won't float in fuel.

 

Make absolutely sure the float valve does not leak and adjust the float level by either changing the float dimensions slightly or using shim washers under the float valve body (preferred).

 

I didn't have correct shim washers to put under the float valve body so I wound up thickening the float slightly by adding a 1/16" thick balsa shim to the float and re-sealing it.

 

Again- washers under the float valve body are a better way and NEVER try to bend the brass float arm.

Edited January 23, 2022 by Str8-8-Dave
Arrange pictures, captions (see edit history)

[tcslr]

Dave,

thank you. Can you tell me what was the final thickness of your new balsa float? 
I’m gathering that you iterated the float level in operation. The scrubbed line is the internal maximum bowl level? 
 

then you installed the float and tried it? did you fab a new float between the iterative steps? 
Tom

[DGTryon]

I  Agree with the comments on Balsa float but GM use nitrophyl floats in production carburetors for years and I have never heard of it sinking,  It is a closed cell material and works great.  I use it in all of my old cars.  A couple of comments:

1.  The mechanical level in the Buick spec only applies to cork floats.  All other materials will be different.

2.  The only way to get an accurate fuel level setting is using fuel in the bowl at the inlet pressure on the car (if a vacuum tank it is just the head of fuel - about 1/4 psi.  I am using an electric pump at 1.5-2 psi.   Any pressures over that risk flooding since the needle and seat/float system are not designed for higher pressures.

3.  I put small white dot of paint on the inside of the bowl when it is off the cars that is 3/4" below the top of the bowl.  When the car is running with the bowl cover off, you can see the actual fuel level.  It should not be any higher that that.

4.  Nitrophyl floats usually are not flat on the top when set correctly but as long as there is clearance around the float and clearance to the bowl cover, you should be good to go.

[Str8-8-Dave]

13 hours ago, DGTryon said:

I  Agree with the comments on Balsa float but GM use nitrophyl floats in production carburetors for years and I have never heard of it sinking,  It is a closed cell material and works great. 

Well- here's the story on my nitrophyl float in the Rochester 4MV Quadrajet on my then brand new 1969 GTO Ram Air IV automatic car, one of about 50 1969 GTO's out of the total 1969 production run with that engine and trans.  I started the car in my garage, heard a little dull pop, then it stalled and smoke started pouring out of the hood seams.  I managed to push it out of the garage and the neighbor came over with a powder extinguisher and put the fire out.  That was round one with the nitrophyl floats.  The second one sank in that same car about 18 months later on the way up I-75 to Gaylord MI.  There was no fire that time, just a slobbering rich running engine when I slowed the car down.  I managed to nurse the car another 40 miles to East Jordan MI to my great aunt and uncle's place.  Next day I borrowed my great uncles 64 Buick Special with a V6 and 3 on the tree and drove into the Pontiac GMC dealer in Charlevoix, bought another float.  I spent a very cold afternoon in a dirt floor garage rebuilding the 4MV and got it back on the car and running.  That was what happened to me back then and why I'm skitter-ish about nitrophyl.   I'm sure the chemistry has improved.

[Str8-8-Dave]

On 1/23/2022 at 9:08 PM, tcslr said:

Can you tell me what was the final thickness of your new balsa float? 

Hi Tom- I never measured the final thickness of the float but initially it was cut from 3/4" thick balsa and later had a 1/8" thick piece of balsa sheet to increase the thickness just enough to get the fuel level below my reference line inside the bowl of my carburetor. So it would have been close to 7/8" thick. 

[Bloo]

 

36 minutes ago, Str8-8-Dave said:

That was what happened to me back then and why I'm skitter-ish about nitrophyl.   I'm sure the chemistry has improved.

I doubt it, they're still nitrophyl.  I changed hundreds of bad ones in the 80s and 90s. They failed pretty reliably at 80k miles. The cars didn't usually catch on fire, but they would come in running horrible, smoking black, and with gas running out of all the discharge tubes at idle. GM had instructions on how to weigh the float, and I guess you were supposed to put "good" ones back in. The floats were such a failure prone part you couldn't really do that and expect the car to stay fixed.

 

[carbking]

We include new floats cut from nitrophyl in rebuilding kits that we make for carburetors that originally had cork floats.

 

Just one (there are several) reason why we promote telephone call orders rather than website orders is so that we can tell each customer buying one of these THAT THE FLOAT SHOULD BE SEALED AFTER INSTALLING THE FLOAT ARM! Long ago gave up on putting this in writing; too many folks don't read.

 

POR-15 or the dope used to coat the fabric used for flying model airplanes may be used to coat the floats.

 

We have also been suggesting the use of balsa to customers only wishing a float, not a complete kit, for probably 30 years.

 

Both the nitrophyl and balsa have a greater buoyancy than the original cork, so if the sealing holds, either is superior to the cork.

 

And Bloo, I have had NEW GM nitrophyl floats fail in a couple of weeks, depending on the ethanol content of the fuel being used by the customer. Weighing the floats was an absolute waste of time; just put in a new one.

 

I have always believed the sealing is what keeps the nitrophyl floats from failing. Guessing those that failed early had a defect in the exterior seal.

 

40 years ago, we had an American supplier of brass floats to replace the GM nitrophyl, but these are no longer available.

 

Jon.

Edited January 26, 2022 by carbking (see edit history)

[Str8-8-Dave]

1 hour ago, carbking said:

I have always believed the sealing is what keeps the nitrophyl floats from failing. Guessing those that failed early had a defect in the exterior seal.

I think Jon is spot on on the sealing.  If you ever sawed a GM float you will discover a big difference between the color of the outer skin and the core because the GM floats had some kind of sealing operation.  Unfortunately, it wasn't consistent, and as Jon was indicating by suggesting it should be sealed after assembly to the float arm, if it is not entirely sealed it can and probably will absorb fuel, become heavy and sink.

[Str8-8-Dave]

This is a long sad side note about my 1969 GTO.  I bought the car brand new from Rinke Pontiac in Warren, MI.  My 18yr old age and gas station job didn't pass muster with the loan company so I got my mother to co-sign the loan with the proviso if I ever got to where I couldn't make a payment the car would be sold.  I shopped carefully at a couple of other dealers before ordering the car.  Every dealer in town had "The Judge" with it's tacky rear spoiler, fender decals and the 366 hp oval port Ram Air III engine.

Red Holman Pontiac in Westland, MI, 2 miles from home had a red Judge in stock and offered to remove the spoiler, bondo the holes in the decklid and remove the fender decals.   None of the local dealers had or wanted to order a Ram Air IV car.  Rinke Pontiac was the nearest dealer I could find that would take a deposit and order the car I wanted.

 

I ordered a 1969 Ram Air IV GTO optioned as follows:

Verdoro Green

Black vinyl top

Black bucket seat interior

Console

Ram Air IV engine package

TH 400 automatic

Safe-T-Trak 3.90 limited slip axle

Power steering

Power brakes

Retractable headlights

Rallye gauge pack

AM/FM stereo radio 

 

I waited 8 weeks for the car to be delivered to Rinke.  It finally arrived and after my mother got out of her teaching job for the day I drove her to Warren for the delivery.  I should have known the car was a jinx that day.   We took a short test drive up and down busy Van Dyke Avenue in rush hour traffic and I knew immediately something was wrong with the brakes.  The car was sluggish on takeoff and as soon as you lifted your foot it slowed to a stop.  The service manager drove the car and tried to fluff it off as just being new.  I said no- fix it.  He rummaged around and found a new vacuum booster, then proceeded to lean over the bare fender of my new car with a GM tie clasp rubbing on the new paint.  I made him put a fender cover on the car.  He did get the new booster on, we tried it and it cured the brake problem.  Papers were signed and we drove back to Westland.  

 

All was good for a few days except there was a 2-inch-long crease in the hood sheet metal right in my line of sight.  It looked like someone slammed the hood down on a tooI left under the hood.  I made a body shop appointment and they dollied the crease out and spotted in the paint, but it was yellow, stood out like a sore thumb.  My complaint led to an encounter with the field service rep who told Rinke Pontiac to paint the kid's hood all one color.  A few days later I picked up the car.  Now the paint matched but it fish-eyed along the brushed stainless hood molding.  I decided to cut my losses and drove the car home.

 

The car had quite a bit of exhaust growl coming from under the hood.  One day I pulled it into a service bay at the Sunoco station I worked at and ran the car with the hood up and discovered there were no less that 5 exhaust manifold bolts missing.  I rounded up the correct bolts and installed them and the engine room got much quieter.  

 

I hated the cheap corporate console shifter and conned a buddy into swapping the nice Hurst Dual Gate shifter out his 1968 GTO in trade for my corporate shifter and a little cash.  I did the work on both cars and they both worked well when I was done.  I drove the car carefully, broke it in properly and thought I was on top of the world at age 18.  In the late fall of 1969 I garaged the car, put it up on jack stands, changed oil and filter and covered it with a soft cotton car cover for the winter.  By that time I had required a 1962 Ford Galaxie with a 292 Y-block V8 to drive for the winter months.  The GTO didn't move until spring of 1970.  Then I let the car down off the stands, removed the distributor and used a speeder wrench and 3/8" socket to turn the oil pump and primed the oiling system before I started the car.  During the spring a few modifications were made to the car.  A Hurst Line-Loc was added to the front brake circuit. Heat riser passages in the intake manifold were blocked off.  Resonators were replaced with straight exhaust pipes.  Air Lift bags were installed in the rear coil springs.  The TH400 got a firm shift treatment.  The rear axle got a set of 4.88-1 gears and in a later experiment a 3.23 gearset was tried.  The 4.88 setup was really good to wake up the car's drag strip performance.  With the automatic trans and free flowing RA IV round port heads the car was sluggish off the line, not making really good power until the revs got up to 3,500 or so but then the car was limited to 55-60mph which made expressway duty a pain.  The car could definitely keep up with traffic with the 3.23 setup.  

 

The next calamity was a summer 1970 vacation drive to a Lewiston MI cabin owned by a co-worker at a later place of employment, Gad-A-Boat, in Livonia, MI, where I took a job repairing outboard motors.  Everything was fine as we drove up I-75 but then we exited and got onto County Rd. 612, a two lane blacktop road that led into Lewiston.  By the time we got there it was pitch black dark and I didn't pay much attention to a sign that just said "Loose gravel ahead".  As soon as I hit the loose gravel I could hear it hitting the bottom of the car so I slowed to about 30mph.  30 minutes later we pulled into the yard at the rental cottage.  I got out of the car and there was tar and pea gravel up to the mirror on the side of the car.  I spent the 2 weekend days at the cottage soaking the tar and gravel off the body with kerosene saturated rags.  That poor car's undercarriage was loaded with tar and pea gravel.  I spent a good week with the car on stands getting as much of that off the car as I could reach.

 

In the fall, just before I was going to put the car away for winter I made the mistake of leaving the car parked in an empty church parking lot to go on a field trip with a youth group.  When we returned that night my car's driver door was caved in and there was a note under the wiper from a very apologetic church secretary who backed her Mercury Cougar into the side of the car.  The car went back to Red Holman and the door got re-skinned and painted a not real close match to the rest of the paint.   Eventually the car went back in the garage for the winter.

 

It was when I started the car for the first time in spring of 1971 that we had the big fire.  The nitrophyl float was the culprit- it became saturated with fuel and couldn't close the float valve.  The car started and I was just about to back it out of the garage when it popped, stumbled and died.  I tried to re-start to no avail, then noticed white smoke coming out of the gap between the hood and fenders.  I managed to push the car out of the garage which probably saved the garage.  The neighbor across the street was in his front yard and I hollered at him that I had a car fire.  He grabbed a dry chemical extinguisher and put the fire out.  My beautiful engine compartment looked like a bomb hit it, vacuum hoses and foam ram air hood gasket, wiring, all burnt to a crisp and white powder everywhere.  The insurance company had the car towed to the dealer and it was gone for quite awhile while they re-wired it, re-plumbed it, replaced the carburetor and air cleaner assembly and re-painted the hood.

The insurance company paid for everything except the cause which they defined as the carburetor.  That cost me about 500 of my dollars.  They gave the carburetor back to me and I took it apart, removed the float and put it in a jar of gasoline where it promptly sunk.

 

Then one day I noticed the car was dripping oil.  Hoist inspection revealed a stress crack in the oil pan just above the oil drain plug.  Off to the Pontiac dealer for some warranty work.  Red Holman Pontiac tried to blow me off saying I hit something and broke the oil pan.  That wasn't likely, the crack was just above the front cross member and factory paint was undisturbed at the crack.  So we had another Pontiac field rep encounter.  He took one look and told Red Holman to put an oil pan on the car, he had several more cracked oil pans in his office.   A couple of days later I drove to the dealer to pick the car up.  It wasn't quite ready when I got there, still on a hoist and curiously dripping green anti-freeze.   I inquired why that was and was informed when they got the oil pan off the car they found quite a few of the white nylon camshaft timing gear teeth laying in the pan.  So they tore the water pump off, opened the timing cover and replaced the timing gears with heavy duty steel gears and a good Cloyes roller chain.  For once I thought I was gonna make out with some dealer service.  Little did I know what was coming next.

 

After getting the car back all was well for awhile, then I began to notice a slight knocking sound at idle, faint, but there.  As summer progressed the noise got a little bit louder, then seemed to stabilize.  By this time the car had about 15,000 miles on it.  Around Thanksgiving that year I decided to visit my dad's aunt and uncle in East Jordan, MI.  The weather was nice when I left with the GTO but as approached Grayling it began to snow.  So much for keeping the car a summer-only affair, I pressed on to Gaylord where I would turn west on M-32 to go to East Jordan.  When I slowed on the exit the car began to run rough and stumble.  I had a really bad feeling in the pit of my stomach but using a two foot approach, one on the gas, one on the brake I got around the corner onto M-32 and kept going.  About an hour later I arrived in East Jordan and parked the car right in front of the one stall garage at the end of my great aunt and uncle's driveway.  The next day as I recall was sunny and about 5 degrees, above zero, not below at least.  I raised the hood on the Pontiac and tore the Quadrajet off, carried into the dirt floor garage and took it apart under the light of a table lamp connected by several dime-store extension cords to the house, there was no electricity or lights in the garage.  Sure enough the float was laying on the bottom of the bowl patiently waiting to be changed.  I obliged it by driving great uncle Howard Taft's 64 Buick Special with a V6 and 3 on the tree into Charlevoix to the Pontiac GMC dealer and bought another float.  Later that day when the car rumbled to life and settled to a nice 1000rpm idle I thought I had done something.  The following Sunday I was on the road home to Westland, in a snowstorm with a car with summer street tires and way too much power.  I got fed up with following the car in front of me that was doing a solid 30mph about a mile before the Grand Blanc exit.  I signaled and pulled out to pass and when I checked the outside rear view mirrors I saw white puffs of smoke I thought were coming from the exhaust pipes, looked down at the oil pressure gauge which was bouncing off zero, reached up and killed the ignition.  I just barely coasted up the Grand Blanc exit and turned into the discount gas station at the top of the hill.  I raised the hood ad EVERYTHING was dripping with oil.  I didn't even have pay phone money on me but after hearing my story the station attendant called a wrecker for me.  The wrecker showed up and towed the car with me in the truck's passenger seat to Superior Pontiac/Cadillac in Grand Blanc.  We got there just before the service department was going to close for the day.  The dealership had me sign a work order, paid Captain Hook and pushed the car onto a hoist and raised the car.  The mechanic produced a pocket knife and cut the belts off the crankshaft pulley, reached up and grabbed the pulley and rotated it back and forth a good 20-30 degrees producing a nice CLANK CLANK, looked at me and said "I think I found the problem."  I called my mother and she drove 50 miles in a snowstorm and picked me up and took me home.    A few days later I was summoned by the dealer to come got the car.  The failure explained the dull knock.  Red Holman Pontiac's service guy must have forgotten what he was doing and failed to torque the damper wheel bolt that attaches the damper wheel to the crankshaft.  The knock was an ever-increasing clearance between the key slot in the cast iron damper and the hard drive key that keyed the damper to the steel crank.  Over time the damper wheel keyway wore to a ramp shape and finally the seal flange on the rear of the damper exploded throwing shards of iron into the oil pan and ripping out the oil seal in the timing cover.   The mechanic at Superior explained that he would have preferred to replace the oil pump after a failure like that but Pontiac couldn't supply replacement because it was unique to RA IV engines, no other Pontiac engine used it.  So the mechanic at Superior took the pump off, tore it apart and cleaned and inspected it and decided to re-use it. As it turned out the oil pump had a piece of debris in the pressure relief valve.  When cold the car started and pegged the 130psi oil pressure gauge and stayed there until the oil warmed up.  I learned the hard way oil filters didn't like the arrangement, one burst on the car and a couple others deformed under pressure.

 

In December of 1972 I landed a job at Ford Research & Engineering in Dearborn, MI in a brand new 8 million dollar Climate Control HVAC lab.  In spring of 1973 I traded the GTO in at Hines Park Lincoln/Mercury on a used 1971 Lincoln Mark III.  I didn't get much for the GTO and lost track of it immediately.  Between the fact the car was constantly beset with problems and the fact it was an outcast in the Ford parking lot I couldn't wait to get shed of it.  In retrospect I should have kept the car, I've seen only one RA IV automatic car sell at a Barrett Jackson auction north of $250k.  I paid just north of $4k for the car new.   

 

 

  

 

[carbking]

Dave - the whole problem is you bought the wrong color, it should have been yellow!

 

GM bought the phenolic floats from Rogers Corp. The molds were coated with the sealant, which was not always perfectly uniform. I think Rogers changed the composition of the sealant 7 or 8 times from about 1966 to about 1980 trying to keep up the changes in fuel composition.

 

Jon

[Str8-8-Dave]

17 hours ago, carbking said:

I think Rogers changed the composition of the sealant 7 or 8 times from about 1966 to about 1980 trying to keep up the changes in fuel composition.

I can believe that, the government chemists can't leave fuel alone it seems.  When I was a boater the hot rivet according to Boat US was the government was out to raise the ethanol content to 15-20% for all pump gas.  

 

I queried on Nitrophyl plastic trying to find a chemical patent or chemical mfg co specifications that would state clearly what Nitrophyl is and is not including cell structure.  All I could find was Rogers articles stating the stuff is closed cell, won't absorb fuel and in general is the best invention since sliced bread.  Looked like a sales campaign to me...

[32buick67]

Dave and Jon, you make great missionaries because I became a convert this week.

After researching Rogers as a top mainstream supplier of nitrophyl their specs list nitrophyl compatibility with ethanol as good and fair, but not excellent) and quite a few SAE and Japanese white papers on the harm of ethanol on certain polymers like raw cut and unsealed nitrophyl, and after I replaced my nitrophyl float with a balsa float, I am never using nitrophyl in my car.

The prior ran 87 octane for 20yrs, but I only run non-oxy (no ethanol).

 

My nitrophyl float was cut and not sealed, and now it barely floats and is leaving small powdery crumbs on white paper, which is the exact failure mode according to the 'experts'...ethanol causes the closed cells to embrittle and fail, allowing saturation and hence sinking.

 

Here is some info, you on the forum should be the judge...

 

Edited January 28, 2022 by 32buick67 (see edit history)

[32buick67]

Edited January 28, 2022 by 32buick67 (see edit history)

[tcslr]

Mr 32buick67, I like the photo. Can you confirm if that is a scrib mark on the bowl? And can you tell me what was the final thickness of that balsa float?

. Thanks 

[32buick67]

Below are pics of my new balsa float thickness.

It is not yet coated with sig supercoat butyrate dope (will be this weekend), so maybe plan on a few more mils added to the thickness dimension.

 

I have not yet finalized the float elevation vs the idle jet elevation, so I dont yet have any scribe marks like Dave, but based on the attached elevation diagram, I am can see that I must get the float below the idle jet elevation.

NEVER adjust float elevation by bending the float arm. Use shims or gaskets, refer to the comments from the pros on this forum about elevation adjustments to avoid leaky Marvel carbs.

 

Lmk if you need more pics or dims...my car is now out of commission while I and others try to figure out venturi spacer block designs for the old inefficient Marvel updraft carb.

 

Until then, I have an expensive paperweight to admire...

 

 

 

 

[32buick67]

We are trying to invent this in 2022 from modern durable materials with compatible 1920s-30s performance...Mr. Bernoulli would be proud...

[32buick67]

It is finished.

[tcslr]

How many coats did you apply?

[32buick67]

I don't know if this is ok or good enough, but I applied 4-5 thick coats.

Balsa is buoyant alone, but it absorbed a lot of the SIG sealant, especially on the end grains, so I kept re-applying until the finished product was shiny and smooth.

I hope this was correct.

 

My work is probably overdone, but maybe Dave or Jon or others will weigh-in on their thoughts on # coats.

This float is now very buoyant, the SIG sealant is amazing!

 

I bought a 1x2x12 piece of balsa from Hobby Lobby for $6 to trim to fit, and it is working well.

[Brian_Heil]

I have recently had four in depth telephone conversations with Buick owners asking me about Nitrophyl floats.  Turns out these calls could all be traced back to this post and the callers reading it and then calling me. 
 

Did GM have an issue 50 years ago when Nitrophyl was launched?  Sounds like it.  
 

Is the issue relevant to the Nitrophyl commercially available today?  No. 
 

Thousands, and I do mean thousands of Model T and Model A Ford owners are running Nitrophyl and have been with no issues.  I asked a Ford forum expert to confirm.  He did.  We, early Buick Brothers, are a drop in the bucket compared to the number of Ford owners out there. 
 

After fighting a losing battle with the who-knows-how-old cork float in my Marvel, I upgraded to Nitrophyl and it still looks and operates like new. I’m going on 3 years.  Nothing compared to the 99 years the Marvel has been operating but, a data point. 
 

Can you make your float out of other materials besides Nitrophyl if you so choose?  Be my guest.  And, be careful, depending on the density of the material chosen, and if required, coating, and number of coats, you can have too heavy a float. 

[Str8-8-Dave]

So to answer some questions here- I put 2 coats of Sig sealer on my float to start with, the second was done after assembly to the float arm to assure fuel does not find a leak there.  Balsa has a slightly higher buoyancy than pure virgin cork, you can't buy pure virgin cork anymore, it's all glued re-grind and does not float well if at all.  

 

Regarding the nitrophyl conundrum I had one major disaster with the original nitrophyl float which was parts in assembly of the original Rochester 4MV Quadra Jet carburetor on my then 1 year old 1969 Ram Air IV GTO which did catch fire and would have burned to the ground except a neighbor across the street rushed over with a 5lb dry chem extinguisher and put the fire out.  It ruined the pristine engine compartment on a car that I have seen sell for 250k today.  A year and a half later I had the float sink in the replacement fire from the first go round and limped the car to some relatives and replaced the float in their dirt floor garage in zero degree weather.  I have no doubt the nitrophyl material in today's floats is a petter product but I'm not the only one who is skeptical about it.  Jon (Carbking) is also skeptical and tells folks who buy his kits that contain a nitrophyl float to coat it with either Sig hot fuel proof dope or POR fuel tank sealer before putting the float in service.  

[Brian_Heil]

Here's a link to the Snyder's material used.

 

Not a conducive shape to carve a Marvel float from, but enough material to make 2.  You throw away more than you end up with when done.  Standing it on end, cut in half top to bottom and then go from there.

 

The point being, every side of the final shape has seen your saw blade or file and none of the mold skin is left.  No idea who their supplier is.

 

https://www.snydersantiqueauto.com/product.htm?pid=982542&cat=41842

[Brian_Heil]

I also respect holding an 'automotive grudge'.

 

Shell Fire and Ice motor oil had some issue back in the late 70s.  I was in college and broke but still changed my oil and filter.  Some bad product got out and I got some of it.  Shell admitted the issue some time later but did nothing for me.  Last Shell fuel or oil product I ever purchased. 

 

I drive by a car dealership in my home town every other day.  They hosed me back in 1983 and that was their last nickel from me.

[carbking]

When I still restoring carbs, I used 2 coats of POR-15 clear on Nitrophyl, with a 24 hour air-dry between coats, and 24 hour air-dry prior to using the float.

 

No one ever complained. This does NOT mean there were no failures, only that no one ever complained.

 

On Rochester Q-jets in the 1980's, I had several NEW genuine GM Nitrophyl floats fail within 3 WEEKS! Most LOCALLY, the rest in carbs sold in Colorado, with a lone exception in the state of Washington. This is embarrassing for a restorer! I finally quite using Nitrophyl floats in Q-Jets, as I then had a supplier with brass floats made in the USA (no, I do not still have that source)!

 

For decades, I have thought the only constant in this, is there are NO constants. I think the float coatings are failing IN SOME LOCATIONS because of the fuel. Fuel sold in central Missouri is horrible, not as bad as the panther-xxxx sold in Colorado, but still horrible!

 

Other non-constants:

 

Cork - original model T floats seem to have been natural cork, as were the floats used in Johnson Cadillac carbs. Natural cork seems to not be effected by today's fuel. Some of the Marvel floats were natural cork, others were laminated natural cork, and coated with orange shellac. Modern fuel will cut orange shellac like a hot knife goes through butter!

 

BUT I HAVE BEEN UNABLE TO BUY NATURAL CORK FOR DECADES!!!

 

The cork I CAN buy is "recombined cork". In other words, cork shavings from the companies that CAN buy natural cork are ground, and pressed together, like the pressed wood that is much cheaper than plywood. RECOMBINED CORK WILL NOT FLOAT. I guess the binder (glue) used in the recombination process is heavier than the cork.

 

What I am attempting to point out is that just because one (or a lot) of folks DON'T have problems in their location, is no sign that the same stuff will work for anyone else somewhere else (I have never seen a volcano in Missouri - guess volcanoes do not exist   )

 

Too often, folks read the contents of a thread, and then assume that the contents are always true; but it does not work that way.

 

One item many may find amusing is that the sale rep for the manufacturer of the Nitrophyl told me that the Nitrophyl was "closed cellular" (each individual cell of air was sealed) and the Nitrophyl would NOT leak because of this design!

 

One last comment: supposedly, Nitrophyl is formaldehyde-based; the particles released by machining are not good for your lungs, so if you machine this stuff, wear a mask!

 

Jon