Kings Langley garage meet

[Keith Clements]

Just some pics.

[Keith Clements]

Mike has come back saying solid copper gasket required.

[Keith Clements]

At the NEC I contacted the Hillman Imp club who put me in touch with the expert on Wills rings whom Richard Gane also knew. So a phone call on Monday when Harry came around helped me make some decisions.

1. WILLS RINGS should not be reused. So a new set will be required and so getting the right ones is the first challenge.
2. Since they will be at least £160 a set . I will try reusing the old ones for the initial commisioning of the engine.
3. The liner height should probably be flush and currently they are set to at least 20 thou. So a gasket will be required. I propose to use a copper gasket from a standard Jowett gasket which is 15 thou that surrounds the liner and then an additional sheet that surrounds the Wills ring. Imps use a plastic material and I have a supplier of this which might be used in any subsequent attempt.
4. The Wills rings start at 120 thou diameter and sit 60 thou proud and are then compressed to sit 20 thou proud. Thus the second layer of gasket helps keep the water from getting to the Wills ring.
5. Loctite SI 5660 will be used to seal copper gaskets and Hylomar will be used to cover the imperfections on the used Wills rings.
6. The Renault liners do not give much support to the gasket so either welding or fixing a support is probably required between liner and block to fill the gap left by the location flat.

7. Checking the liner height showed the block needed facing as there was 8 thou of variance. Studs were removed and block flattened with fine file and straight edge. Not the best way to do it but a subsequent rebuild may put the block on the mill.

[Keith Clements]

This is the Trelleborg info on the ring installation. All I have to do now is work out the three dimensions, but my 'gut' feel is that the thickness of the liner seal gasket needs to be about a quarter of the diameter of the ring. The problem is that the ring is now crushed and thus not round so I have to guess its original diameter and the depth of the groove in the liner, which presumably had the desired side clearance originally.

https://www.trelleborg.com/-/media/TSS- ... 17f21b70a1

and from the IMP site
https://www.imps4ever.info/tech/engine/ ... rings.html

[Forumadmin]

At 49 wd4 8ar
My phone number is in the front of any Jowetteer or 07973 850 842
From 10 till 17:00 but just come when you can.
Lunch at cafe or pub or snacks from Texaco (all within a couple of hundred yards) or bring your own.
Hopefully change pistons and liners in Amy's Javelin, and/or fix liner sinkage in another engine,
possibly get heads onto Wills ring engine when we get them back from flow test. Also will check out the valve timing on a couple of engines.
Or can you suggest or bring along your own subject for us to look at?

The dates are changeable to when you are able to come so just contact me to discuss. Some preference has been expressed for Wednesdays and Thursdays, others preferring Saturday. Sundays are out for now as I have car club events to go to do in the workshop.
Please contact me to say which day or days you would like to come.
Note that all the days following will have something on.

Wednesday 3rd
Saturday 6th
Wednesday 10th
Thursday 11th
Saturday 13th but only for those not going to the Reunion in Bradford.
Wednesday 17th
Thursday 18th

This was emailed to the 71 members on email who live within 50 miles. If they all come we may have a party!

[Nick Webster]

Just as a matter of interest, this weekend I had the chance to examine a prototype Triumph car engine, known as "Sabrina". This 2 lire four cylinder twin cam engine was was used in the 1959/60 Le man race cars and was being developed for use in the production TR4. A change of direction under new managers - Leyland - saw a switch to a fuel injected development an existing six cylinder. A few examples of the Sabrina engine survive. Of particular interest is the use of Cooper rings. At least the owner called them that but when I mentioned Wills rings he agreed that they were that too. My experience of Cooper rings is small, but in for use in industry I always understood Wills rings to be gas filled, whereas clearly Coopers are not. In fact, in the photo you can see the seam where the ring is folded over the filler material. Note also the retaining groove on the top of the liner. I did not measure it, but the ring sat proud of the liner. At the bottom end the liner had two rubber O rings, which I have described before and seems to me to be conventional practice with automotive diesel engines

Nick

[Keith Clements]

Investigation of the smoking Jav showed oil in the bores. No 3 had more coke in the head and oil in the bore but all were showing signs of either worn rings or pintel or balance pipe issue. It could also be worn valve guides which will be checked. The engine was ticking over beautifully before being taken out so there is not much wrong with it and unlikely to be pintel valve.

The vacuum was tested on the balance pipe.

So that was good. I then tested ring gap which was bad on the worn ring at over 28 thou. Luckily I found a set of new 40 thou rings and these had a gap of only 7 thou. There was no wear in the bore with the gap remaining the same at top, middle and bottom.

Another possible cause was too much oil mist the other side of the piston so bearing clearances were checked with Plastiguage. See the short lengths of red plastic across the bearing surface. Squeezed out when the crankcase is torqued up.

I thought the centre camshaft bearing with 3 thou of gap to be too much but the book has a clearance of 7 thou.

The crankshaft mains were well within spec but I fitted new bearings to check on crank wear. All within spec and it is a standard unground shaft!

[PJGD]

FYI, Percy Wills of Bridgwater in Somerset invented the pressure charged Wills ring in 1931 and continued to develop it for decades later. It is formed as a hollow ring, then partially filled with sodium azide (NaN3), welded closed, and then heated to 350°C which decomposes the sodium azide which turns into Nitrogen gas at a pressure of around 600 psi in a stainless steel ring. The ring can be coated to improve its ability to seal against surface irregularities.

[Keith Clements]

Today's jobs were to check camshaft for wear and test out oil pump.
Cam journals 37.92, 37.93, 37.93 mm so wear was in casing, not the shaft.
Cam lobes. 31.88, 31.92, 31.94, 31.91, 31.92, 31.92, 31.94,31.91 so not much variation. Happy with that. Followers look good as well.
Crankshaft replaced with original bearings, and tie bolts torqued to 75 lbft. Checked freedom of movement after each torque setting. OK.but tightens as last one torqued up requiring about 30 lbft to turn. Frees up as more turns are done and it beds in. Also there is part of the rotation which requires less torque but, because the pistons are fitted, it is not easy to judge the cause.

Built up the test bed for the oil pump which was set to 50 psi and it should be 60 to 70. So relief valve adjusted. Noticed oil pump drive gear spray was blocked . So dismantled base and blew through with air gun. Now clear.

Checked brass worm gear which was badly worn. Clearly the blockage had been there for some time. Replaced with much less worn one.

The blockage was checked by turning the drive shaft counter clockwise with thumb over main outlet. Spray should come out of pin hole.
During pressure testing the outlet is connected to the pressure gauge and the spray defelcted downwards with an aluminium plate.
The unit is driven by a shaft that copies the offset drive of the distributor shaft. An electric drill is rotated in reverse up to 1000 rpm which simulates 2000 rpm of the engine.
Adjustment is quite critical easily reaching 120 psi if you go too far.

[Keith Clements]

Today's job was to clean pistons.
Old rings were extracted with the ring compressor.

then I made a tool to clean out the ring gaps as an old broken ring was not good enough. That, plus a brass wire brush, did the job. Then a clean in the parts washer and blow dry.

Then I fiited the rings. The 4 part third ring was assembled as per instructions. Then the second and top ring.

The con rod bolts were to be replaced with modified Unibrako Allen set screws. They had to be shortened and the top ground off so that it did not foul the liners.

[Keith Clements]

Having let the o rings and sealant cure on the balance pipe it was tested.

Then the pistons were fitted giving them a coating of graphite and oil.

If you click on picture and zoom in you can read the instructive notes on this diagnostic vacuum gauge.

[Keith Clements]

There was wear on the guides in one head but the other head was good. Looks like the good head was renewed as the gasket was different to the one on the other side.
Valves and seats look good which is one reason the car ran so well.
I do not think the wear on the guides significantly contributed to the smoke.

[Forumadmin]

The previous rebuild in 2007 of this engine is of course recorded on JowettTalk in a long topic viewtopic.php?p=1848#p1848
Luckily this has refreshed my memory but will need to link up what was discovered then and what was discovered this time. Surprisingly all the low oil pressure and overheating since have not worn the bearings.
Yes it would be nice to fully recondition everything whenever you rebuild an engine but that really is practically impossible as it basically means fitting all new parts. My mantra is ' if it ain't broke do not fix it' mainly because new parts often bring new problems.
I think I am going to run the engine on the test bed before refitting to the car. Mainly to see if the oil pump may be the cause of low oil pressure. I have one rebuilt with new gears which probably will deliver more volume than the old pump. Testing a pump for volume delivery is not going to be easy!
I would need a drill to drive at 300 rpm equivalent to idle speed and see what volume it can deliver whilst maintaining 50 psi.

[PJGD]

Keith, surely the ratio between crank speed and oil pump speed is 2:1 not 4:1?

[Forumadmin]

Yes corrected after I read the previous 2007 topic more thoroughly! Well spotted, Philip.