Massive Coolant Flooding - Cylinders And Sump

[PJGD]

Yet another way of understanding the issue is to use pressure sensitive or pressure indicating film; it is what the engine OEM's do to check for and confirm even gasket loading.

There are a number of companies that make these films, for example: https://www.sensorprod.com/surface-pres ... nitude.php and https://www.tekscan.com/applications/ga ... and-design

Torquing all the cylinder head nuts to the same value is convenient, but I imagine that to get an even loading around the combustion chamber, analysis may indicate the need for different torque values from one nut to the next.

[Mike Allfrey]

Thanks Philip and Keith,

This morning I received a reply from Bill Lock, explaining his 0.002 to 0.004-in. cylinder liner protrusion specification. On that basis and on a warm night's thinking, I decided to try the following procedure:

1. Check the gap for the fourth time, it was still 0.002-in.
2. Marked in white, one point of each hexagon on each of the cylinder head nuts, then made corresponding marks on the outer face of the cylinder head.
3. Using the reverse torque sequence, each nut was backed off by a quarter of a turn. This left the centre nuts in a firm finger tight situation.
4. The gap was measured and found to be a consistent 0.004-in. measured at the points suggested by Keith.
5. The nuts were then tightened back to their previous setting, with the same torque wrench as previously, in the order shown in the Maintenance Manual.
6. The gap was again measured and was found to be a consistent 0.002-in. at all places.

That activity tells me that we have the upper end of Bill's specification, when the nuts have been backed off, which in turn indicates that 0.002-in. has been lost since the engine was assembled with 0.006-in. prior to tightening the cylinder head in place. 0.002-in. I can handle that with comparative ease and, at present put it down to yield at the spacer washers and shims. The crankcase, when static, appears to be 'springy', but, what happens when the engine has warmed through and is running - I am not too sure!

We will be trialing a Bill Lock gasket with the settings the way they are at present. Should this action result in failure, then we have another crankcase to experiment further. I am hoping to put together a workshop day for Victorian JCCA members, once the Chinese Plague is well behind us!

One interesting point is that the old cylinder head gasket is still firmly 'glued' to the cylinder head face, However, a 0.006-in. feeler blade slides easily between the gasket and the swage-over combustion seal ring area, adjacent to the sparking plug. It was too hot in the workshop to continue investigating. More on that later.

The next point is to find a suitable gasket sealant. Loctite Master Gasket 515 tends to grow a bit much when cured. Any recommendations out there?

Will keep you informed,

Mike A.

[Keith Clements]

Usually 3 or more shims are required and usually they are a bit crinkled so they will settle. I think this may be the cause of many of the failures in the past. The assemblers did not tighten the head down without gasket to 20lbft after installing the shims and then checking the protrusion.

Yesterday I went through my collection of gaskets. I still have original new Payen Jupiter and Javelin gaskets and Hall new old stock. I took loads of pics but lost them in transfer to PC so will take again and post here. I took measurements and noted differences. I measured some of the many used gaskets that I have. I measured the thickness at four points on each liner ring and six points on the outside water jacket seal. This shows the amount of liner protrusion (perhaps with an adjustment for no load).

20201110_104249.jpg

Below you can see the used Payen over the top of the new NZ showing the copper liner seal protrusion into combustion space. I know one is the wrong way around!
It also shows the excellent seal this Payen managed.

20201110_104438.jpg

The used original Payen do seem to have delivered a perfect seal everywhere! They have a good copper seal to the steel back on the holes so do not rely on the gasket material which being asbestos is not water tight. Some of the grey material gaskets of which I have three or four types were poorly made. (Not the NZ ones). There is a great danger of seapage of water into the oil or the other way around as the grey material is prone to cracking or is broken during manufacture.
The latest NZ gaskets have a smaller diameter combustion chamber ring than the Payen which might intrude into the chamber. I will check on an original and a gas flowed head and against standard and my oversize Fiesta piston liners. Note the NZ does come in two sizes.

20201110_143313.jpg

The above shows the copper of the NZ showing below the superimposed Payen.

Many of the gaskets suffered from droop of the copper between the cylinders often resulting in cracking and was a contributary cause to failure. This is why I introduce a stainless steel support plate above the standard support tube at just below the liner protrusion height.

20201110_105019.jpg

20201110_105202.jpg

20201110_105213.jpg

Note the Payen is Copper/asbestos/steel with the steel being swaged to form the liner seal. This I have seen rust in some engines caused by prolonged storage after a short engine start.

20201110_104927.jpg

20201110_105259_001.jpg

The Hall gasket is copper/asbestos/copper so is better for an infrequently used engine although the copper might suffer in a high performance or lean mixture engine.

I also have a pair of solid aluminium gaskets. On the whole they look good but might suffer electrolitic corrosion.

[Keith Clements]

Payen good used Jupiter Gasket
min .0532 max .0552 on liner
min .058 max .060 on aly face
From this I would deduce a 5 thou protrusion under load.

20201109_145240.jpg

20201109_145159.jpg

Payen original unused Jupiter
.058 min .060 max
From this I would deduce there is little pressure on all but the liner.

Halls unused Javelin
.070 liner The swage gives double thickness copper.
.062 face

New NZ .080 

[Andrew Henshall]

I decided to try the following procedure:

1. Check the gap for the fourth time, it was still 0.002-in.
2. Marked in white, one point of each hexagon on each of the cylinder head nuts, then made corresponding marks on the outer face of the cylinder head.
3. Using the reverse torque sequence, each nut was backed off by a quarter of a turn. This left the centre nuts in a firm finger tight situation.
4. The gap was measured and found to be a consistent 0.004-in. measured at the points suggested by Keith.
5. The nuts were then tightened back to their previous setting, with the same torque wrench as previously, in the order shown in the Maintenance Manual.
6. The gap was again measured and was found to be a consistent 0.002-in. at all places.

Mike,
Initially I was very surprised that the gap between the head & the crankcase increased from 0.002" to 0.004" when you backed off the nuts by a ¼-turn, until I worked out that a ¼-turn on a 3/8" BSF (20 tpi) thread is actually 0.0125". Of course there is also the change in the extension of the 3/8" diameter head studs to allow for, which would reduce the 0.0125" somewhat. Although you confirmed that the centre nuts are still finger tight, unless you measure the re-tightening torque you really don't know what has happened - the head could actually now be "free" on the studs and no longer contacting one of the liners - i.e. it is now sitting 0.002" clear of the liner! The ten head studs could resist the head misaligning to the crankcase if there is no clamping force on a liner.

Yesterday I was thinking about whether the No.1 liner could be sitting in the crankcase at a slightly different angle to its mate in that bank. This could result in the gasket blowing in No.1 with the witness marks you see on the sealing ring. Hence my question about "wiggling" the liners, and although you advised that you could not feel any lateral movement in the liners, perhaps it is small enough that you need a dial indicator to measure it.

I looked up the diametric clearance for a G7/h6 neat sliding fit on a 3-3/16" diameter liner spigot, which based on nominal sizes would be 0.0016" . Then I did the geometry to work out what the maximum angle from square the liner could achieve with this clearance in a spigot that is 3-1/8" long = 0.03 degrees. Thus, when wiggled from side to side it could move through a total of 0.06 degrees. If we assume that when you "wiggle" it the liner is pivoting about the face where it sits on the bottom copper seal, then the top face of the liner at the head gasket is 2.5" away, and so it could move laterally through 0.0025" in total. Using the same 0.06° angle across a liner land with a mean diameter of 3.1" means that the nominal longitudinal error caused by this angle at the land face might be 0.0032" . These calculations are based on my assumption of the liner fit in the crankcase, and on nominal sizes for the liner spigot & crankcase bore with a G7/h6 neat sliding fit, and so the condition on Phil's engine could be worse than this, or it might be better than this. A 0.0032" reduction in "crush" on the sealing ring on one side is probably enough to cause a head gasket failure.

Perhaps my assumptions are wrong, or my simple geometry is an incorrect analysis of the liner fit in the crankcase, so please send feedback so that I can put this out of my head!

On the question of which head gasket sealant to use, JCCA & JCC member John Walker says he has always used "Permertex Blue" on all the crankcase mating surfaces, and "Power Plu"s (which is the same as the old "Gasket Goo") on the tops of the liners. He also does the same between the head and the gasket as you did on the crankcase side using Permertex Blue.

Permatex Blue is a actually range of sealants which include an RTV Silicone Gasket Maker and a medium strength threadlocker. I know that John uses a silicone product in many places on his engines, so I assume he's talking about Permertex Blue RTV Silicone Gasket Maker. I can't find anything about "Power Plus" and although I did hear mention of "Gasket Goo" years ago, I've never used it.

Like you Mike, I was taught never to use silicone sealants in engines, and so instead I've always used Permatex Aviation Form-A-Gasket No. 3 Sealant Liquid successfully on all the engines that I have rebuilt. Permatex Aviation Form-A-Gasket No. 3 is a slow-drying, non-hardening sealant approved for use in aviation as well as automotive applications that resists petrol, oil and grease. Temperature range -65°F to 400°F (-54°C to 204°C) It is a very thick dark brown/black coloured liquid.

The advantage of Permatex Aviation Form-A-Gasket No. 3 over Permatex Form-A-Gasket No. 1 is that No. 1 is a fast-drying, hard-setting sealant designed for sealing rigid joints where permanent assembly is desired, whereas No. 3 is a non-hardening sealant and so it retains the ability to accommodate movement due to thermal effects, etc, and still seal the joint. Comments please?

Cheers,

Andrew

[Andrew Henshall]

Rather than working with my theoretical figures based on assumptions, this afternoon I decided I should do a few measurements and share them with you for your entertainment!

I took one half of my Series III crankcase and randomly selected one bore where the liner spigot fits & cleaned it. I selected one liner at random out of the set that I plan to refit to this crankcase and cleaned the spigot. I then took the following measurements:

Liner spigot OD: 3.1866" (using my 2 - 6" Starrett micrometer)
Crankcase bore ID: 3.1880" (using a bore gauge and the same 2 - 6" Starrett micrometer)

Calculated Diametric clearance = 0.0014"

I then installed the liner in the crankcase dry (& without any bottom seals) and "wiggled" it sideways; I could see that it was moving so I fitted a dial indicator gauge and measured the horizontal movement of the liner relative to the crankcase: 0.002".

I then repositioned the dial indicator and measured the vertical movement of the liner sealing flange as I "wiggled" the liner sideways: 0.0015"

These figures are smaller than the theoretical numbers in my previous post, but I have selected one crankcase at random, and selected one of its four bores at random, and selected one liner at random - there must be variation from part to part. For instance, the bore in the crankcase has a diameter specification of 3.1880 – 3.1895", and so my crankcase is right at smaller end of the tolerance.

I think that this exercise confirms that a liner can sit at an angle in the crankcase and that the consequential impact on the "crush" on the head gasket sealing ring is of a magnitude that is significant when compared to the liner protrusion that Mike has measured of 0.002". I guess it is possible for one liner to be at an angle relative to the other liner, and for the gasket to seal nicely on one liner but not seal perfectly on the other liner.

Is this phenomenon the cause of the head gasket failure; who knows.

More for you to think about!

Andrew

[PJGD]

Andrew,
I would be surprised if liner slop in the crankcase was a significant problem, but if it is then there would be definite merit in assembling the cylinder head with the bore axis vertical so that the liner sits flat on its seat without slop. This orientation is not normally easy to achieve and impossible with the engine in the car, however it is very easy and convenient if you build a rotating engine stand similar to the one that I described here: https://jowett.net/forum/download/file. ... &mode=view

[Andrew Henshall]

Hi Philip, I'm inclined to agree with you on the question of the fit of the liners in the crankcase, however what if you had a crankcase with a bore at maximum tolerance of 3.1895"? With my liner spigot OD of 3.1866" this results in a diametric clearance of 0.0029", which is starting to sound significant, and it increases the angle that a liner can sit in the crankcase greatly. The angular movement of the liner in the crankcase when you "wiggled" it sideways would be quite noticeable. The effect would be to double the lateral movement of the top of the liner to 0.004", and the corresponding vertical movement of the liner sealing flange to 0.003" as you "wiggle" the liner sideways.

Knowing how meticulous Mike Allfrey is when he sets the liner protrusion to specification on every engine that he assembles, and the care he takes to ensure that the heads are tightened down exactly to specification, I'm looking for something that is not currently being controlled in the assembly process that has caused these three head gasket failures. Of course, it could still be a dimensional issue caused by Phil's crankcase stretching/distorting as a result of all the welding, but that doesn't explain the previous example on Richard's engine where the gasket blew and 0.002" of liner protrusion had disappeared on just one cylinder for no reason (that crankcase had not been welded).

Gravity at work. Is it possible that a liner sitting in the crankcase with the engine the right way up could catch on the sealing flange edge when the head is installed, while the adjacent liner ends up perfectly square - why not? Is it likely - I'm not sure about that! I know that Mike has an engine assembly stand which always holds the engine the right way up. Many many people have installed Jav/Jup heads with the engine in this upright orientation over the years, so the question is why would it be an issue in just these three instances?

I actually have an engine stand very similar to the AC-Delco unit that you included in your document. I had already decided to assemble my Series III engine with the liner axis vertical, exactly as you suggested - great minds think alike!

Cheers, Andrew

[Mike Allfrey]

Nothing to add, just spent afternoon putting a response together and I was automatically logged out!

[Andrew Henshall]

Below is the text that Mike had created before he was automatically logged out.

Good Afternoon All of You,

First, Keith, that micrometer looks exactly like the one that was stolen from my Jupiter when it was shipped from UK in 1968. Hang onto it!

Getting back to cylinder liners, it is my normal practice to set the liner protrusion in the bare crankcase halves on my free-standing bench, with the liner bores vertical. I measure each liner from its seating ledge to its outer lip, then I sort the liners into pairs - based on as close as possible to measurement matches. I place a white marker number on each liner's water jacket area. I then lightly oil the crankcase bores so that the liner spigots slide down freely. The liners are then shimmed appropriately to provide maximum lip protrusion tolerance, in the case of the Auckland head gaskets, this is as close as possible to 0.008-in., measured with a feeler gauge blade using a straight edge (Moore & Wright steel ruler), which then in this case, was followed by sliding a cylinder head downwards onto the liner lips. After doing that, the head is tightened down (literally) to 20 lbs. ft. and the gap measured all the way round with feeler gauge blades. The result, in this instance (on new copper spacer washers and shims) was 0.006-in. at both halves of the crankcase set. I was happy with the result at bottom end of specification tolerance, mostly because of the abused condition of the crankcase. At the time I do record the shim and spacer pack values on paper, but once the job has been completed, the paper gets recycled.

Once this action had been completed, the liners and their shim packs were kept together while crankcase assembly continued. I must confess that I have never given much thought to cylinder liners leaning in their crankcase bores, I have accepted that JCL did get most of that right. I have also noted that the shims had flattened nicely after they had been clamped. I am fairly certain that I would have noticed any odd markings on the shims.

During assembly, I have been applying a very thin smear at the liner edge, of Loctite Master Gasket 515, only at that edge - not between shims or the spacer washer. While pistons and connecting rods are installed, crankcase with sump surface uppermost, the liners were lightly clamped, each with four tubes, washers and nuts to firmly clamp the liners while pistons are installed and crankshaft rotated during assembly.

Question - does the tightening of the six crankcase tie bolts/studs (75 lbs. ft.) affect the cylinder liner seat position?

To date, I have not found a Javelin/Jupiter cylinder head that has warped at the head gasket surface. Our engine machine shop has lightly skimmed head surfaces to clean up rust and present a clean surface for the head gasket. This is the first engine where the head gasket surfaces at the crankcase set had been skimmed due to the uneven surface due to, most likely, abuse and weld distortion. With all head studs, except stud No.1, being located in Recoil (Helicoil) inserts, it can only be imagined what went on before!

I believe very strongly that my procedure described above is as correct as possible. I do have doubts, however, about using Loctite 515 as a sealant. The prime reason in this case was because the balance pipe nip flares had been skimmed off, although nature's sealant would have been good enough. My only major doubt at present is that No.1 cylinder liner may be lower in protrusion than that for No. 3, however, I think that the clamping of the cylinder head would have exhibited a considerable variance in the gap if that had occurred. In addition, a 0.0015-in. feeler gauge blade was tried all round No. 1 cylinder's liner lip, it came to a stop on encountering the lip's edges. That sort of satisfies me, but I will double check check that forthwith.

Seeing the Hall Gasket packaging has brought back memories, but not related to our engines. The mention of aluminium plates as gaskets is intriguing, maybe what I saw years ago - or, was someone planning on decompression plates for running on TVO during the Suez Crisis?

More thoughts to come,

Mike A.

[Andrew Henshall]

Dear Mike,
I'm surprised that you set the liner protrusion on each crankcase half prior to assembling the crankcase and tightening the tie bolts.

Am I correct in my understanding that after assembling the crankcase and tightening the tie bolts, you have never re-checked the gap between the head & the crankcase when assembled without a gasket (tightened to 20 ft/lb)?

Clearly the crankcase would see a very different stress distribution once the tie bolts are tightened, when compared to sitting as a half crankcase on the bench in the free state. Tightening the tie bolts could move the liner seat position in the crankcase relative to the cylinder gasket face of the crankcase, particularly on a crankcase that has had extensively weld repairs after breaking a con-rod at speed on a freeway.

Perhaps when you rebuild Phil's engine with Bill Lock's Czech gasket you could set the liner protrusion after assembling the crankcase and tightening the tie bolts? Even better, why not follow your usual procedure, but then re-check the liner protrusion after assembling the crankcase and tightening the tie bolts because this will tell you if the crankcase has changed geometry as a result of the stresses created by the tie bolts.

Kind regards,
Andrew

[Keith Clements]

Mike, What was the explanation given by Bill?

[Mike Allfrey]

Basically, it is the specification provided by professional engine re-builders that do Jowett engines.

Not too sure about that, but will try it anyway.

[PJGD]

Going off on a bit of a tangent, I am sure that someone can remind me where I read that some engines (presumably competition engines at the factory?) were built with modified liners where the outside diameter of the upper half was machined down to the same diameter as the lower spigot up to the top flange and an aluminium sleeve shrunk on. Thus the load path ran from the crankcase shelf through the sleeve, then the liner flange to the gasket and the head - my attached sketch gives the idea [split on C/L between standard and modified]. I have not bothered to illustrate the sealing means which would likely be an o-ring.

There are a couple of advantages to this arrangement, both of them very small but at least they are directionally correct. One is that the differential linear expansion issue between crankcase and liner that reduces the gasket clamp load in an operating engine is essentially eliminated since the sleeve expands as much as the crankcase. The other advantage is that the liner probably runs hotter than the over-cooled standard set-up which therefore reduces viscous friction between piston and liner, a source of parasitic power loss. Note that many modern engines have gone to a higher controlled temperature of the liner for this very reason. One can also potentially machine the sleeve to individually match the liner protrusion to the crankcase.

[David Morris]

Hi All,

These posts show the best of the club...informative and highly professional, well done by all! My contribution is to recommend using earlier crankcases for your next rebuild. They are simply heavier than the Series 3 ones ( does that mean they are thicker where it counts? ) and really do seem to suffer less from corrosion. OK... they didn't have the internal strengthening webs of the Series 3 and suffer from smaller oil ways. But do what Jowett's did on rebuilds. Remove the oil way plugs and open up the oil ways with a really long drill, plus opening up the feeds to the main bearings. Jowett's fitted large brass plugs to cap the open ends of the enlarged oil galleries. Also, fit a later oil pump after opening-up the feed oil way in the block to the oil filter. John Airey has done all this to several blocks and I am sure he could advise?

Some time ago I heard a rumour that Jowett's used a different method of casting for the later crankcases? Perhaps someone else can fill in the details?

Often you will find owners have set aside an earlier crankcase in preference for a Series 3. Dig it out from the back of the shed, brush off the cobwebs and look for the corrosion at the bottom lip of the crankcase, where it forms the water seal with the head gasket. We have often found really early crankcases with almost no corrosion here and a good solid 12mm of metal. Series 3 one's often have almost nothing left here. Goodness knows how badly their internal water channels have corroded and hence their strength may have diminished, as previously noted in earlier posts?

If you do reclaim an earlier crankcase and continue the rebuild with later components, do check the crankshaft rotates freely once the tie bolts have been tightened and everything is back inside. We have discovered 'fouling' of crankshaft webs with one or two of the inner ends of the liners, sufficient to stop rotation or at least cause a bad 'knock' when running. You may need to 'ease' the offending bits with a little bit of judicious grinding?

Hope this helps such an interesting debate?

Stay safe,

David