Making my own gasket?

[Capt. Rodbone]

I have twin Ford Lehman 120 engines. Long story but I’m going to have to tap drill the injector oil sump drain plug opening because of a prior owner retrofitting an elbow with a peacock on the end to make for easy draining. I get why they wanted to because they are hard to reach and almost impossible to get something under there to catch the oil. To do this I’m going to take the JABSCO raw water pump loose to drop it down enough to get the tap in place to do its job. I’m probably going to need a new gasket at that point. Doubt it comes off looking like one I can resume.
We are doing the great Loop and are in a fairly remote area. I suspect I can source some material at an Auto ports store nearby. Any guidance on what I should get? I’m assuming they will have some and further assuming there are different choices?
Thanks in advance for thoughts and suggestions.

 

[Comodave]

I would call Brian at American Diesel and ask him. He may be able to ship one to you or advise on the material to buy to make your own. 804-435-3107

 

[luna]

If you need a gasket to seal the water pump's mounting flange to the engine block and this gasket is to resist engine oil, then a paper based gasket, depending on thickness, would be my choice.

My local automotive chain store stocks Fel-Pro's Karropak sheet gasket which is actually made in the UK by Jointline, here is their Fluid Resistance Chart.

https://jointine.co.uk/wp-content/uploads/2024/08/Fluid-Resistance-Chart.pdf

Fel-Pro simply markets Jointline's product under the name Karropak in order to imply that it is a Fel-Pro product.

I normally stock a bit of Karropak and some cork sheet to make my own gaskets as its easy, quick and cheap to do so.
Karropak is easy to drill or punch the holes in and then cut the gasket outline.

Your local auto shop likely carries Karropak as well. Just be careful that whatever thickness you use is close to the original gasket's thickness.

 

[Nick F]

My boat had this connection made using a banjo fitting. The male part of the fitting had the right thread so that modifying the injector pump body was not necessary. Motorcycle stores are a good source for banjo type fittings.

I would be very hesitant to do metal cutting on the injector pump for fear of particles getting into the wrong place.

 

[Lepke]

Any thin cardboard, like a cereal box will work as a gasket for a pump. The old gasket may not tear and just need sealer. Even if it tears, gasket sealer will make it tight again.
If you have a flexible sealer like silicone, you usually can clean the surfaces and use the sealer alone. Many racing engines use silicone instead of gaskets except in high pressure areas like the head to block.

 

[psneeld]

The problem with water pumps is a really good gasket that is too thick or too thin can be an issue. One won't seal and the other will drag the impeller and may slowly damage it.

An old time commercial fishing engineer told me when in a pinch to use a paper bag. You don't even have to be neat except for the bolt holes if they are close to the edges of the pump.

You just cut or rip a piece out of the paper bag, put it over the impeller opening, smear a finger of engine oil on the paper around the hole, place the cover against it with one starter hole, carefully making the other holes and hand tightening the bolts. Snug up the rest of the bolts to torque. The oil helps preserve the paper and getting it off the next impeller change. The paper up against the impeller gets wet, rips cleanly around the hole and gets pumped out as it gets chewed up.

I tried it once and it worked great. I noticed that some of the newer gaskets were as thin as decent computer printer paper. So I took a factory gasket and copied it a bunch of times, cut them out and punched the bolt/machine screw holes. Kept a half dozen aboard in a plastic CD case in case I needed a spare or got a impeller without a gasket in the box/bag. If you don't have a gasket to xerox, use the metal cover.