TR4/4A Removing Oil Canister/Pressure Housing from Engine Block

[KVH]

On my 4A, I'm removing the oil canister and pressure housing to address a leak, and plan to reinstall immediately.

I removed three bolts and the oil pressure line--and the housing won't budge. I assume it's just the gasket fused to the block? Nothing else is holding it tight?

Also, about that oil pressure line, I'm not seeing a hole in the little stud that the oil line slides over, but I assume it's there somewhere--otherwise how could the pressure gauge work? Dumb question, I know, and maybe I need to look closer, but it's certainly not obvious to my nubby fingers reaching down there.

thx

 

[TR3driver]

3 bolts and a stud is what I remember. There is no hole in the stud, the oil flows around the outside of the stud between it and the housing. The copper washer between the banjo fitting and the housing should have a larger id as well, to allow for oil flow.

 

[KVH]

That's incredible. Does that mean that the stud is some special manufacture? How does oil bypass the threading? I only find one copper washer. Maybe I lost the other. Do you know the two sizes? Something tells me you do. Hate to order just a washer from Moss.

 

[Geo Hahn]

...Hate to order just a washer from Moss.

Call Ernie (no shipping charge) - if he doesn't have one he can get it pretty quick. If it is the same size as something common (like on an SU fuel pump or MG carb) then it is probably on the shelf.

 

[TR3driver]

An ordinary 5/16" copper washer should do fine, as they are always somewhat oversize for easy installation. If you want, you could open up the center (maybe even as separate notches) but I don't think it's really necessary. It just always struck me as amusing that the factory designated a special part just for that application.

If you've got a Harbor Freight nearby, they have an assortment of copper washers on sale for $5 at the moment (which is what I use)
https://www.harborfreight.com/80-piece-copper-washer-assortment-67526.html
Or I think I've seen individual copper washers in the specialty bolt drawers at Home Depot; but I couldn't find them on the web site just now so maybe I'm mistaken.

In a pinch, just leave the copper washer out and use some Hylomar between the surfaces.

The hole through the housing (and the banjo) is larger than the stud or its threads. So there is a gap there, even past the threads, large enough for a small amount of oil to flow. And it doesn't take much, we're only talking about the feed to the pressure gauge here. It only takes a few drops to move the needle, and since there isn't a steady flow, the pressure will always equalize eventually (as long as the gap doesn't close up with sludge).

 

[KVH]

I'm still amazed by the technology and it's simplicity. I'm picturing a white coated Brit explaining the stud thread/oil/bypass design to his colleagues circa 1952 (earlier I'm sure).