Apollo Tank Drain Plug

[Brucey]

I've recently had a 2nd hand Aollo tank re welded and gussets added around the oil inlet and outlet pipes. I also had to get the guy who repaired it to remove the drain plug as it was too tight for me to do (even out of the car and held in a vice!)

 

I've been told that CC do not fit any washer or seal to the drain plug, hence the reason they are usually so tight.

 

It has been suggested that I wrap PTFE tape around the thread, but I'm a bit nervous about bits of tape ending up in the tank as there is a lot of clearance in the thread and the tape would need to be wrapped around several times.

 

I've pumped the tank up to 15psi to test the repairs for leaks. They seem o.k, but I can't get a good seal on the drain plug. I've made sure both faces are clean and burr free, tried a similar metal/rubber sealing washer as used on the oil pipes (hydraulic sealing washer I think) and tried a fibre washer. They all produce air bubbles on my compression test.

 

I will try a rubber O ring next, which should seal o.k., but I'm a bit worried it will either degrade with hot oil or swell and make it impossible to remove the drain plug later.

 

I could also use a dab of instant gaskit around the flange.

 

Any one else had the same problem and found the best solution or know why CC don't fit some form of seal?

 

The guy who repaired the tank did a fantastic job. He also said he could make an improved version for around £90 to £100 if they were ordered in batches of 10. He would make the main body from 2mm or 2.5mm aluminium tube.

[Richard Price]

Brucey,

An "O" ring is very likely to blow out, unless the is a suitable groove to retain it.

You'll be fine with PTFE tape. Wrap more towards the end of the thread at the head end.

 

Testing for leaks at 15psi is will not match engine running pressure where you may see greater than 6 BAR on a cold engine (thats more like 90psi!)

[Mick Day]

There should be a dowty washer between drain plug & tank.

[Brucey]

Richard,

There is a slight groove in the plug, but ptfe tape may be safer as it is unlikely to expand on contact with hot oil.

 

With a vent at the top and a 1mm thick ally body, I very much doubt the Apollo tank side of the system will see 90psi. Surely the 6 bar is between the pump and bearings etc, where as the Apollo must be on the return run.

 

Mick,

What's a Dowty Washer? I've tried a fibre washer and a steel washer with a rubber insert around the ID.

[Frying Pan]

A Dowty washer is the one you have tried - metal washer with a rubber insert

 

See some pictures of the build here. 9000 miles completed!

[Richard Price]

Brucey,

The Apollo does see ALL of the engine oil pressure.

It is connected via a sandwitch plate onto the oil filter housing.

The oil is drawn from the sump into the pump, out to the apollo tank, through the oil filter, and then back into the main oil ways.

See here

[Brucey]

Richard,

 

Cripes , I don't even like pumping my steel compressor tank upto 90 psi let alone an ally pot I can crush with my fingers ❗ Maybe I'm just a whimp 😬

 

I still can't quite see how 90 psi is achieved with a breather pipe going into the Rocker Cover though . I wouldn't like to take the oil filler cap off with the engine running if there is 90 psi in there.

 

I'll give he PTFE tape another go. I will also skim the drain plug mating face in the lathe.

 

Would fitting a rubber strip inside the clamping jubilee clip help prevent the pot spinning?

 

Bruce.

[Richard Price]

I still can't quite see how 90 psi is achieved with a breather pipe going into the Rocker Cover though

The hole in the adaptor for the breather at the top is tiny, If I recall correctly, around 0.5mm diameter. Air passes quite easily, but the oil, being thicker creates significant back pressure.

[Nov-07]

Well, I can tell you that if you start the engine, as I accidentally did the other day, without the breather in place on top of the Apollo tank, the fountain of oil rises 2ft above the tank Someone will now be able to work out the pressure required to do that 😬

 

[dave1968]

Brucey

 

see here for infor on apollo drain plug removal, recommendation here is to use liquid gasket on the face of the plug but not the thread. no mention of PTFE tape....

 

http://www.alcester-racing-sevens.com/oil-change_pt__1.htm

 

Dave

[SLR No.77]

That's the method Miles uses then, but is only one of a possible number of alternatives! Having mistakedly used Hylomar on one occasion to seal the sump, and then finding out how much blocks the pick-up pipe when it breaks away 😳 I would use an alternative - ie. PTFE tape works fine

 

If Caterham now use a dowty seal it is only recently (last couple of years?) - there's been this same discussion previously!

 

Stu.

 

[SLR No.77]

More info on a previous thread here

 

Stu.

 

[dave1968]

stu, ta for that, its useful to know, im about to do an oil chnage and had assumed liquid gasket was the accepted method for this so nice to know there are other options

 

Dave

[mav]

My 5 year old system had a washer on for the forst couple of changes, but then went for a service at Caterham and they threw the washer away and never replaced it. I use nothing to seal mine and it does not leak, and is not so tight as I can't get it undone when I need to.

[SLR No.77]

Aaahhhhhh, your the owner with the one that seals ok 😬

 

Stu.

[Brucey]

Thanks for all your comments

 

I've got it to pass my air leak test at 40psi

 

I turned a small step on the drain plug and fitted a Dowty washer. I think the biggest problem is that the ally around the drain plug has a circular groove/score in it. The Dowty washer seems to have sealed this o.k.

 

Does anyone use a 1 way valve on their vent pipe to the rocker cover to prevent oil draining back into the sump with the engine off? Are they worth it and where is the best/cheapest place to get them from?

 

Bruce.