Temperatures in small engines?

[rogerf]

Hallo folks
l've often wondered what the temperatures are in a running air cooled small engine. It would be helpful to have some idea of this before selecting a material to use for gasket making when it's not practical to use a manufactured gasket for some reason.

I doubt I'd try making a cylinder head gasket these days, but I do remember making a cylinder head gasket for a small car from sheet copper years ago. That one worked fine after a de-coke and was even used a few times with the application of a kerosene blow lamp to re-anneal it after each use.

I'm looking for typical temperatures found at places such as inlet, exhaust manifold, oil pan, and overhead valve cover.

Can someone give me an idea of these temps or where to find them? Mr Google seems to turn up plenty for water cooled engines, but precious little for small air cooled engines.

Looking forward to some clues!

Roger

[KE4AVB]

Whenever I can I stick with the manufactured gaskets as labor cost to make a gasket from scratch is just too much for most to consider nowadays; unless, it an one time deal in an emergency case.

[Skywatcher]

Hi Roger

One could get an infrared temperature gun and actually measure temperatures of an engine running under full load. However, the materials that manufacturers make their gaskets from can give an indication. OHV valve cover gaskets are often rubber or cork, so fairly cool (still too hot to touch though). Sump or crankcase, intake and side valve cover gaskets are usually paper which can stand higher temperatures than cork or rubber.

Head and exhaust gaskets are usually graphite or pressed metal to contain the combustion pressures of the power stroke and the heat of the exhaust port indicating temperatures are getting very close to the combustion point of paper 451ºF (230º). If you do need to create your own gaskets for various reasons, NAPA stores carry or can order in bulk gasket material including graphite head gasket material. I had to make a new head gasket for a 1947 Wisconsin Type A-B engine a few years back. The engine is still run a couple of times a year at old tractor and farm machinery shows.

Back when the average shop rate was $20.00 an hour and manufactured intake gaskets were $3.00 each plus freight, one could spend 5 minutes making a gasket and still be ahead of the game. Now that shop rates are $50.00+ and after market gaskets retail at 95¢ each from a packet of 10, unless you can make a gasket in 50 seconds or less, it's just not worth it. All the best,

Sky

[rogerf]

Hi Sky

Thanks for that - it gives me something to work on in the future, and next time I'm visiting our daughter in the USA I'll pay a visit to NAPA. She has an Autozone near and I guess they might be worth a try as well.

Unfortunately the auto supply places near to us here seem only to have a limited range of these materials. I had quite a task to replace my small supply of paper gasket material recently, although I'll keep on trying! I have noticed that those infrared temperature gauges and for that matter thermocouple devices are getting very inexpensive

I only make a gasket if I can't easily buy one, or if I'm caught out over a holiday or else some emergency situation, but I do like to have the material available as a back up in case of need. When you need it it's too late to go looking to buy as the material itself is harder to find than most of the gaskets I need!

Cheers,
Roger

[okie]

Hello Roger
Something to take in to account is the ambient temperature. In Oklahoma in the summer time (100+F) it get hot to the point the engine starts to slowdown. I stop and let it cool, and me also, before continuing. No problems in the spring or fall of the year

Travis

[rogerf]

Hi okie

We get it pretty hot here in Australia as well - summer temperature can easily get to 35C and 40C is a scorcher of which we get a few or week of them at a time. It's those days when I have been known to weaken and reach for a bottle of cold amber fluid

Cheers,
Roger

[okie]

Hi okie

We get it pretty hot here in Australia as well - summer temperature can easily get to 35C and 40C is a scorcher of which we get a few or week of them at a time. It's those days when I have been known to weaken and reach for a bottle of cold amber fluid

Cheers,
Roger

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