View Full Version : Front Engine Oil Galley Plug

Tim Tucker
11-24-2012, 05:15 PM
I am working on my TR4 engine. The engine had blow by (#4 cyl) and a major leak at the front where the galley and front motor plate join. I built this motor in 1985. Had new piston/liners (86 mm), 20 under mains and 10 under pins, original cam and lifters, re-bushed rockers and new rocker shaft, new timing gears and chain. Maybe 10k miles since. I replaced the head gasket (leaking) in 1998 using Permatex Indian Head instead of the Permatex spray head gasket dressing I had used in 1985. The damage had already been done to #4 liner. This car sits a lot. Bottom line: I need to repair #4 liner and this leak on the engine front.

It appears that the oil galley plug that was installed in 1985 (block boiled) leaks. I immediately had a VERY significant leak in that area. Can the front motor plate gasket overcome this plug leaking? Did I simply fail to make a good seal on the front motor plate? Take a look at the pictures before and after cleaning. Where can these plugs be found? Google didn't really help me. I would like to start with this seal being rather leak free.

to me it looks like the top of the plug was leaking. The bottom (clean) picture shows a gap. What would you guys do?
lots more big pictures here: https://s902.beta.photobucket.com/user/tidentenn/library/TR4/TR4%20Engine%20Project

11-24-2012, 05:21 PM
Change the plug if you know it is leaking - that's a high pressure galley so I wouldn't count on the front plate holding back anything. Roadster factory has them, pretty cheap too. PN #PU1404, you'll get a stick of 3 for less than $5. If you don't want to go with aluminum, you can buy a set plug, don't recall the thread offhand but can probably dig out the info for you.

11-24-2012, 05:24 PM
just checked out the pics, looks good! Is that a little valve recession going on with #1?

Tim Tucker
11-24-2012, 05:49 PM
Thanks for the reply and for letting me know the TRF part number. I'll check #1 cylinder. I'm unsure whether to lap the valves and maybe replace springs. The car ran great. The oil leak and blow prompted the tear down. Just curious: should original valve springs be declared "bad" and replace?

11-24-2012, 08:53 PM
IMO, if the plug was already leaking, just tap out the hole for a suitable pipe plug. As noted, no way is the paper gasket going to hold against full oil pressure.

Certainly can't hurt to check the springs for installed force, but if they are original, the chances are very good that they have sagged over the years. I'd inspect the seats and leave them alone if they are clearly good (bright shiny line all around); lap them if they are blackened or pitted anywhere. If you don't lap them, put the valves back in the same holes.

Check the liner protrusion carefully, all 4 liners, on both sides of the block. Even with new components, you may find that the protrusion is too low in places. I spent years fighting head gasket problems before I finally figured out that one side was way low on my engine. Oddly enough, that has been true on two engines in a row now; I guess the factory was a bit sloppy with the machining. As a band-aid repair, I soldered a ring of copper wire to the gasket around each cylinder, which seems to work well. Eventually of course I'll do it right, but the band-aid approach worked for over 10 years (and probably 100,000 miles) in the TR3A and was still working fine when it got wrecked.


Tim Tucker
11-25-2012, 02:14 PM
Thanks for the great replies! I truly appreciate it.

I took the head apart today. Glad I did. The seats and valves look good, but need lapping. The guides are still good and rather tight.

The springs are another matter. The free length of the inner spring (middle spring on the exhaust valves) is ~1.79 on all 8 springs. That's .1" short of the factory spec of 1.88-1.9" (from Bently)! Looks like I'll be replacing the springs.

Any opinion on the best spring set to use? Are all of the major suppliers equal for the spring?

I added a bunch of PICs to the photobucket link, and here a pic of one of the cylinders:

Tim Tucker
12-13-2012, 09:14 PM
I removed the front galley plug tonight. The bore it came out of is threaded. I expected to find a smooth bore that would allow the seals I got from TRF with 3 concentric rings to seal. I will try and get a photo tomorrow and measure threads per inch. I would truly appreciate any experience you guys have dealing with this plug. I have never done this task. It seems rather simple, but the threads have me baffled.

Many thanks,

12-14-2012, 09:25 AM

From my notes my understanding is that the hole is tapped for 5/8-18. The aluminum stick TRF sells is actually 3 plugs, you basically cut them apart and grind flush. Thread sealant is needed, it is not a pipe thread. If the aluminum stick looks too fragile, then you can get a socket set screw of the same thread and use instead, McMaster Carr or others will have them. Or just start with a bolt and chop the head off. Only other caution I've seen is don't have the plug too deep as it can block off a port in the galley.


Tim Tucker
12-14-2012, 10:07 AM

A thousand thanks for the information and advice! I think I'll go with the setscrew or bolt. NO WAY I want this to leak again. Thanks for the advice.

Don Elliott
12-14-2012, 03:29 PM
Since you have the head apart, why not have an engine re-build shop put in inserts to run on lead free gas? I had my shop put in 4 exhaust valve seat insert rings in 2000 and have had no issues since then driving over 66,000 miles in my 1958 TR3A. I supplied 8 new valve guides and 8 valves (in 2000, the engine had 124,000 miles on it from new). He skimmed the head and ground all the valves and seats as per spec.

Tim Tucker
12-14-2012, 09:19 PM
The head was re-worked in 1985. I was told with unleaded OK parts. It has 26k miles on it. I plan on putting in new exhaust valves. The car ran fine. The reason for the tear down was the oil leak and the blow by from #4 cylinder (leaking head gasket (coolant into bore) and too much sitting). Plus, I just really wanted a winter project.

Did final clean on the block and head today. Installed the TRF supplied threaded oil galley plug. I don't see how this could leak: