Vaseline or Hylomar?

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mojo
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Vaseline or Hylomar?

Post by mojo »

I'm not going to admit where I heard this advice, but I'm led to believe that for most ordinary gasket applications (engine oil and coolant), a layer of petroleum jelly is as effective a "dressing" as the fancy gasket compounds such as Hylomar Blue.

Can anyone confirm or refute that from personal experience?

The reason why I want to use Vaseline rather than Hylomar is not because I'm too cheapskate to buy the latter - I already have a tube of it on the shelf. The problem I have is that there is a good chance I'll have to take it apart again a short time later, and Hylomar and similar compounds tend to adhere so well that you cannot re-use the gasket - you have to tear it to pieces to get the two surfaces apart. On small parts that may just be inconvenient, but for bigger stuff such as oil pans it can be quite expensive, as well as a time waster while you wait for (or make) a new gasket.

So - any real-world experience on this would be appreciated before I put my sump pan back on later today...
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DaveT
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Re: Vaseline or Hylomar?

Post by DaveT »

It all depends on the cleanliness and localised flatness of the joint surfaces. If you have any pitting or bruising then use hylomar and accept the issues of re- using gaskets and cleaning up. Otherwise there is the (sometimes significant) benefit of a higher chance of a good seal first time when using hylomar. Don’t put too much hylomar on the joint, it will squeeze out and can cause oil way blockages etc if you are unlucky.

If I was paying for your time, I would want you to use hylomar. If I was doing the job for myself, it would be 50/50 and in some applications (eg rocker covers) I use hylomar or silicon RTV on one side and grease on the other side - that way the gasket should stick in place when you separate the joint next time.

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mojo
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Re: Vaseline or Hylomar?

Post by mojo »

Thanks Dave - that makes sense. In this case I should probably use Hylomar on the flange of the block, and grease on the sump pan (which is brand new and so clean, uncorroded metal). Which means that when I have to take it off again it will (hopefully) stay attached to the block. And yes - I try to limit the amount I use to avoid Hylomar worms in the internals!
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Kevin Birch
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Re: Vaseline or Hylomar?

Post by Kevin Birch »

I use Wellseal, none drying, but twice the price of Hylomar, it is twice the price for a reason, as it is better. I believe Rolls Royce developed it and a Lotus twincam guru swears by it and a good quality RTV used in different areas.
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mojo
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Re: Vaseline or Hylomar?

Post by mojo »

That's odd - I was led to believe that Hylomar (which is non-drying) was developed for Rolls Royce!

But anyway, the job is done, except for the fact that I seem to have 2 bolts too few. Not sure how that happened...
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Re: Vaseline or Hylomar?

Post by johnw »

Rolls Royce developed lots of things for their aircraft engines in the 20s and 30s, including the actual type of steel, many steel and aluminium alloys now commonly in use today, with alloys even developed and tweaked for particular applications. By definition no experience with sealants or gaskets existed for those new materials, so they would have needed to develop those too. Developing a single reliable engine that took land, sea and air world speed records simultaneously was the result. I have heard the Hylomar comment before.

Manufacturers today have an easy life being able to choose a material alloy from a catalogue, find it's ISO number, and pump the details into a Solidworks model, then order a sample part machined from the spec, and select the sealant from a Loctite catalogue!

I have a few sealants on the shelf depending on the material, surface finish, and fluid type and temperature range. Many joints you can get away with just the gasket, and reuse that. Once you put sealant on a paper gasket I generally find it is toast afterwards if you then try and reuse it. Loctite and 3M also have good ranges of products.

These reusable rubber like sump, transmission pan and rocker cover gaskets are interesting. I have never used those, do they really work and not need any sealants etc?

Vaseline is useful as it is not a good insulator so can be use on contacts, battery terminals etc. I am a fan now of silicone grease and silicone oil, now available on ebay, amazon etc. This can be used on rubber seals around lights as it is not oil based and generally safe on rubber and lenses, where petrolium based products would attack the rubber and plastic over time.

I recently rebuilt a 1970s Bosch fuel injection distributor, and found that no sealant and the original steel shim gasket worked fine. Others online that have used a sealant, seem to get more problems as a sealant product adds another point of failure if it is not used properly.
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Wolfgang
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Re: Vaseline or Hylomar?

Post by Wolfgang »

The Rolls Royce products had been developed due to restrictions for aircrafts and Hylomar had no application for these affordings and regulations. In principle these products are based on the same ingredients and consistence like Hylomar but able to withstand higher temperatures.

Hylomar is useful for the gaskets of the oil pan, the valve cover, but also for connectors for oil and also hot water if you're using a dry sump system.

Having a cork gasket which is only broken on a single part put there some Hylomar on - it will work.

To apply it all parts must be clean, free of oil and rust.

Using it in a carburetor is not to be recommended because it's never getting hardened as needed and there is always the risk that Hylomar is getting in the thin channels and then blocking the carb - please use always original gasket sets.

Put as less as possible on the parts to be put together - not on the gasket. When trying to get the parts and the gasket away, warm them a little bit and hope for the best while working very slowly - then it may work, but no guarantee.

There are many other products on the market, but in principle the same recipe - heat and oil resistant silicone based components.

Vaseline is a good alternative, but since being a natural product it hardens and shrinks - so you have to renew it in periodical times.

I use Hylomar now since around 30 years - and have been always satisfied.
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Wolfgang
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Re: Vaseline or Hylomar?

Post by Wolfgang »

Thanks for your PM, VFK44

I tried to reply, but up to now the PM is only in the Outbox. You're absolutely right it has to be named sump. My maternal language is german, and in this language swamp and sump has the same 'name' We're not having different wording between natural swamp (please don't fill in there Hylomar - the frogs will die :( ) and the dry sump of a car (mostly racing cars) to improve the greasing system.
I always try to be as good as possible - in cars and wording - but sorry I'm not perfect :lol: :lol: :lol:
Please correct it for my - thanks a lot.

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Re: Vaseline or Hylomar?

Post by VFK44 »

I have changed "swamp" to "sump". Very different in English, as you said. You have a very good command of the English language apart from that!
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johnw
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Re: Vaseline or Hylomar?

Post by johnw »

Wolfgang wrote: Fri Aug 27, 2021 5:38 am Using it in a carburetor is not to be recommended because it's never getting hardened as needed and there is always the risk that Hylomar is getting in the thin channels and then blocking the carb - please use always original gasket sets.
Is there anything that will work on carbs and fuel systems? Something getting in a carb fuel channel is nothing like as bad as getting silicon in an oil way, as happened when a historic Honda Six small CC bike was rebuilt by a brit who stuffed the oil ways up with silicone and wrote off the engine.
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DaveT
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Re: Vaseline or Hylomar?

Post by DaveT »

Re fuel system sealants, I have been given a very small quantity of sealant to use when refitting the 541 type fuel reserve solenoid assembly after having them rebuilt (at great cost) so there must be something on the market that is considered suitable.
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Wolfgang
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Re: Vaseline or Hylomar?

Post by Wolfgang »

products from Liqui Moly, Loctite and Elring are available for reasonable price, applicable on the gaskets between fuel reservoir and carburetor main housing, as well between the gasket sealing the inlet between carb and carburetor bridge. Doing this the carb must be completely free of oil and fuel. Before applying the surface has to be completely clean and plane and grinded ( I use grinding paper 60/80/100 to get a relatively raw surface that gasket or sealing paste has the chance to adapt and 'sit in')
The grinding 'sand' please don't get away with compressed air, clean it manually with WD40. Then afterwards measure it with a precision steal lineal if it's as plane as possible.
Having done that apply the paste, has to be a complete ring. Use as little as possible of the paste, should be max 0,2mm in diameter for the carb fuel reservoirs, an 0,5 mm for the main gasket. Let it dry out for about 5 minutes then apply the gasket, get the parts together. Then fix it with around 70-80% of the recommended torque, wait for the time recommended by the producer then fix it to 100% torque. Then wait for minimum 48 hours. Then check the torque again, start the engine (perhaps you need some start pilot).
The inner gaskets and rubber rings there is only the possibility to replace.

If the carb is oily (may happen when standing still over the winter) clean it with paper and WD 40, for the nozzles you may use ear cleaning sticks.

But be careful this is only refurbishing not really repairing.

If we do it for customers (or our race cars) we use a complete repair gasket set, then putting the needles and nozzles in an ultrasonic cleaner, afterwards measuring the vacuum on a test bank.

carbs have to be adjusted in periods and also adapted to to outside temperature (summer/winter), use the screws Lean/fat on every side (only a quarter to the left or right until the engine sounds good and is not trembling, correct the base revs -all to be done when he is warm) If you have the corresponding measurement equipment check CO (3,5+ is ok with our oldtimers despite technical inspection and the green parties are telling something different) and CHG should be about 6-7)

The rest are test stints, if you feel he is not aggressive enough or fuel stinking get the screws quarterwise back to lean, if he is coughing or having misfire go also quarterwise to fat.

I hope this small description will help. The carb is -even looking easy- the most complex part of the engine.

If the car is not running well other reasons may be spark plugs (most often), the cables from the distributor to the spark plugs, the distributor, the coil. the fuel filter, the fuel pump.

Hope this helps
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Wolfgang
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