Tappet Leakage

AlanBartlett · Post by **AlanBartlett** » Thu Aug 30, 2007 8:22 am

I was wondering if you could shed some light on a tappet leakage Ive got, it seems to be leaking heavily from one side(passenger side) of the engine from the tappets, but not on the otherside, I thought the problem would go away once I put the tappet covers back on, put them on and it was still leaking, took it off applied a bit of hylomar on the tappet covers to seal them a little better, but still no luck. Ive taken the tappet covers off again and it appears to dripping puddles. I was wondering If anyone had any ideas?

Keith Andrews · Post by **Keith Andrews** » Thu Aug 30, 2007 8:29 pm

I assume u mean leaking out from under the tappet cover?
I made a gasket from approx 1mm gasket paper, with a hole in it for the hold down nut.
Cleaned both surfaces, and applied a little Locktite gasket maker to the tappet cover, and a very thin film of oil on the underside edge of the gasket.
Then tightened down only till just touching, leave for several hours then fully tighten...

Make sure u have the covers the right way up.

AlanBartlett · Post by **AlanBartlett** » Thu Aug 30, 2007 8:32 pm

I find out today looking very closely it moves as normal when the engine is running but as it moves it squirts/shoots out oil, at quite a rate i must say. Any ideas?

george garside · Post by **george garside** » Thu Aug 30, 2007 10:02 pm

Keith - the pre war tappets are completely different from the CC bradford but much the same as the CA & CB.i.e. each tappet & valve spring is covered by a separate 'tube' made in two halves & held together by bolts.

Alan. - First thought is to check the function of the crankcase breather valve which should , if working correctly result in a depression in the crankcase which should help keep oil where it belongs. Depression can be measured using a manometer connected to the the oil indicator tune by a rubber tube. 'lift' should be 12" using redex in the manometer (at tickover) don't know what this translates into on a modern vacuum guage.
Check that the small oil return hole in the breather valve housing is clear and that the diaphram is intact i.e. no broken off bits (should have 5 'wings' and that the stifening plate is doing what it is intended to do.

If crankcase depression ok check that tappets & valve guides are replaced correctly if they have been removed. top of tapet guides marked with file for top position/. inlet valve guide has small hole in cooar & this should be underneath.

george

AlanBartlett · Post by **AlanBartlett** » Thu Aug 30, 2007 10:10 pm

So I undo the the oil guage tube?, And check with a "manometer", check the reading at tickover, erm where is the breather valve located on the engine? is it the small hole that is on the actual tappet rod? Or is it something completely different?

george garside · Post by **george garside** » Thu Aug 30, 2007 10:33 pm

not the oil pressure guage tube but the tube that contains the oil level inicator. dont undo the tube just the screw cap. then if you have a spare screw cap drill a hole in the top of it & solder a bit of ? 1 eighth inch copper tube to it so that this can be connected to a manometer ( glass or plastic U tube as used in laboratories) or a vacuum guage - but I cant give you the correct reading in inches of mercury which is what vacuum guages read in.

Th breather valve is situated on the back of the timing case and has the breather pipe which passes down the outside of the crankcase sprouting out of it. It is held to the crankcase by a singe nut. remove this cover complete with breather pipe and you should find a star shaped diaphram supported by a smaller diameter star shaped plate. Probably also a lot of gunge if its not been dismantled for a long time. If it looks complete clean everything carefully including the small hole that leads back into the timing case. Also check that the breather pipe itself it not blocked - blow down or up it! If any of the 5 vanes of the diaphram are missing or damaged it must be replaced & I think the spares section have them in stock. The vanes must sit firmly on the holes they cover and be supported by the smaller star shaped plate. All will be revealed when you undo the nut and there will probably be a clip of somesort holding the breather pipe to the crankcase

The effective functioning of the breather valve is crucial to good running of the twin engine.

AlanBartlett · Post by **AlanBartlett** » Thu Aug 30, 2007 10:39 pm

Thanks George, I will have a tinker over the weekend and see whats going on, Another thing which is puzzling me is at the front of the crank case below the timing case is a bolt screwed into the crankcase, now Ive looked at the other engine which is in bits waiting for a rebuild at some stage, but it appears to be doing nothing other than just being there. Can you shed some light on this?

Tony Fearn · Post by **Tony Fearn** » Fri Aug 31, 2007 1:00 am

Alan.

As I thought and suggested, George would be able to itemise the necessary checks you need to do with respect to excessive oil leakage from the tappets.

Nevertheless, as promised, I looked up the relevant paragraphs in previous Jowett and Jowetteer (in italics) publications. These just back-up what he said.

June 1946:- Jowett Service Bulletin.

Breather valve-
The main cause of external oil leaks is a faulty breather valve. The breather is designed to act as a non-return valve, allowing displaced air to escape freely from the crankcase, but restricting the intake of air. This causes a depression in the crankcase, which can be tested by the use of a mercury (or latterly Redex, or today perhaps ordinary oil??) gauge coupled by rubber tube to the oil level indicator tube.

Lift should be 3/4" to 1" on tick-over, decreasing as r.p.m. increases. Care must be taken to see that the vanes of the diaphragm are effectively sealing the holes in the engine casting and are well-supported by the stiffening plate.

The oil return hole in the engine casting below the diaphragm must be free from obstruction. Clear this hole as well as the other two oil drain holes -( timing case, and crankcase rear cover plate) with a long wire, not a nail or pin which might drop through.

Oil leak from tappets.
This is usually caused by a faulty breather, but if persistent after breather has been verified, tappet requires attention.

For 1933-39 models, plug up one hole in camshaft end of tappet with brass wire and turn guide so that feed hole is at top. Machine inside face of guide dead square, creating a scraping edge which assists in preventing oil leak. (Last item is a last resort in my opinion - Tony.)

I think these tappet holes are visible when the tappet is at full extension.

The small nut on the front lower face of the exterior of the engine casting holds a guide bolt with a hole through the diameter of its head within the engine cavity. Through this hole, which must be vertical, runs the oil level indicator wire attached to a cork float in the engine and which pops up through the oil level indicator tube next to the oil filler on top of the engine when there is oil in the sump.

Tony.

AlanBartlett · Post by **AlanBartlett** » Fri Aug 31, 2007 7:15 am

Aha, seems simple enough to check/clean aslong as it isnt damaged, but the thing I'm always worried about is taking these things apart and then not being able to get them back togther.

That would explain why the front bolt isnt doing anthing, as when I looked down the dipstick hole ther was no dipstick, got a torch looked down still no, so I thought as its not ther I'll get a long thin rod to stick down ther to experiment with oil level, well it wasnt long enough and my hand slipped.....Oops. Luckily I had a small magnitic screwdriver which was able to pull it out, first attempt guess what I found, the dip stick only to have been a little mangled as I guess it has come astray from its float, and secondly I also found the rod I dropped down there.

ian Howell · Post by **ian Howell** » Fri Aug 31, 2007 12:58 pm

Tony: - This also goes some way to answering one of my earlier queries - 'How long is a dipstick?'

"The small nut on the front lower face of the exterior of the engine casting holds a guide bolt with a hole through the diameter of its head within the engine cavity. Through this hole, which must be vertical, runs the oil level indicator wire".

I will now check this small nut and see if I can 'feel' the hole for the dipstick. I have previously managed to pull the dipstick up by pushing a small bore plastic tube over it then pulling gently. The dipstick does move but is too stiff to 'float'. I have assumed that the float was sticky with gungy oil residue, but this gives me a new approach.

As usual: -

AlanBartlett · Post by **AlanBartlett** » Fri Aug 31, 2007 2:31 pm

Hi Ian, I have a fully assembled float/dip stick I could measure it and give you a rough idea if you need it, this assembly is part of the engine I found in pieces the original engine.

ian Howell · Post by **ian Howell** » Fri Aug 31, 2007 3:26 pm

Hi Alan: -

As I am sure you are aware, I have been watching your progress - and occasionally shoving in my 'haporth - for some time. It is good to make 'direct' contact as it were.

Many thanks for your kind offer. Originally the dipstick was jammed in the 'down' position, so I couldn't see it, but NOW it appears to be all there (but a bit rusty at the top) but as it does not move freely it doesn't indicate the oil level.

I am hoping that Tony's notes have given me a clue as to why it doesn't move. We shall see . .

One other small point: roughly how far does the dipstick extend from the tube when the sump is full?

AlanBartlett · Post by **AlanBartlett** » Fri Aug 31, 2007 7:31 pm

This is what the leaky tappet is doing at the moment this is before Ive cleaned and checked the pressure valve, although a quick glance at the bottom of the tube (I'm getting to fat to fit under that exahaust) and I see a dirty grubby clogged tube full of grunge. Tomorow I will get it out of the garage and then I will have more access to analyse, check, and clean.

A video of the leaky tappet, sorry its short but my torch ran out, and takes an age to recharge. If you look you can see it clearly spurting out.

http://uk.youtube.com/watch?v=pSlzM45fqaA

Tony Fearn · Post by **Tony Fearn** » Fri Aug 31, 2007 8:32 pm

Nice one Alan, there must be some excess pressure somewhere. Stuff a clean lint-free rag down the oil filler hole when you're cleaning the breather to stop gunge falling into the sump.

I hope it is only the breather and down tube that need a clean.

George: The reference I had for lift on the manometer showed 3/4" to 1", but your reference was 12". Which is correct?

Ian: Hope the notes on the oil level wire steady bolt does some good. I was thinking about the length of the piano-type wire which acts as the oil level indicator. It's quite a few years since I had my hands in the bowels of M.E.'s engine, but I remember that the rectangular cork float to which the wire is attached is about 3/4-1" thick and that the upstand of the wire originates from about half way on this thickness. This might stimulate the 'little grey cells' into surmising how long the wire should be if no-one has actually measured it, especially if you start with an empty sump and take note of the 'capacities' in the instruction book.

There again, a quick call to I.P. (on hol at the moment) might result in a definitive answer without resorting to all this palaver.

Tony.

AlanBartlett · Post by **AlanBartlett** » Fri Aug 31, 2007 8:41 pm

Is it possible to just have a dip stick type thing, say a long piece of wire (like piano wire) with indicators of the oil level, so say it I refilled the engine with oil and took a measurement from fresh type of thing with a piece of wire the length from the bottom the dipstick hole( the bottom of the sump) and then mark it and then keep that as a rough mesurement then if the oil fall below the that mark then it would need to be topped up?

Do you get my ramblings?