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The Oily Bits S1 Specific Topics
41

Simon,

I would suggest that you look carefully at the Caterham wet sump before advocating it’s use, even on static test rigs and at constant RPM the air content of the oil escalates rapidly due to drawing of air into the pump. The sump is very shallow and there is no proper well. Baffling is near impossible due to space constraints and the volume of oil constrained around the pickup is very small unlike with a proper welled sump. The nett affect is that any baffle keeps the oil away from the pickup rather than round it. There is a substantial thread about this subject on Blatchat.It is positively the worst sump I have seen and oil surge coupled with cavitation/aeration has been the direct cause of many bearing failures. In fact I have rarely seen a Caterham engine tha does not have damaged big-ends other than those fitted with an apollo tank or dry sump. There are mods that I make that help the oil drainage so that it is primarily concentrated around the pick up and these mods can help.

I always recommend the Pace system which is three stage with dual scavenge and am not a fan of the Caterham system however cleverly packaged it may be. In David’s case as in many it was already installed and I have spoken with him about possible problems with it’s use. I have seen three cases where the scavenge pump could not keep up with the pressure pump resulting in scant oil in the tank and too much in the sumo, one of these had an 80% blocked mesh on the pickup due to the use of innapropriate and excessive sealant on the sump pan (incidentally recommended by Caterham), the other two had a little wear on the pump which caused a problem in extremis.

I have a large stock of TF160/AS16 bearings and never use anything else unless I an asked to and have made it my business to promote their use since the day they became available. VP2 were being considered as the toughest type available, but the material is not without it’s own inherent drawbacks which I am fully aware of having used Lead-Indium bearings in one form or another for 30+ years.

I have explained in detail to those wishing to use VP2s them that the bearing clearances will not be as God intended, a recent R300 engine I stripped showed all the signs of inadequate bearing clearance, Minister just bolt in the VP2 bearings regardless of crank and rod grades and I am not a fan of this approach.

It wouldn’t surprise me at all if David’s engine parts were found to be out of spec. since he now has a different crank and rods. That’s why it is there.

I will measure David’s block before assembly and see what I find.

I am not at all sceptical about the ring problem having been through the loop of diagnosis, tear down and replacement of oil rings 6 times now and having seen said replacement of the rings completely eradicate the problem in every case.

The last one I examined had huge oil consumption on 2 cylinders which was evidenced by very high deposits in the affected combustion chambers, on removing the pistons the oil control rings on those cylinders were found to be bound up. Removal and replacement of the rings fixed the problem permanently. By all means speak with any of those affected, two who spring to mind are Mick Smith and Dave McCulloch, both blatchatters. In the meantime I will fish out a photo.

Dave

42

Dare I say that this is turning into a bit of useful dialogue?

Dave

Yes it absolutely is and to your credit you are ignoring any personal references, which as IDG points out only undermine the person posting them.

Please can everyone else continue in the same vein.

43

For all those interested in the now fixed ring problem on the Pistal pistons I hope the image below illustrates it well enough.

[image]AOL.co.uk | Breaking News, Sport, Features and Video - AOL.com

The new one piece ring prevents this bind up from happening.

Dave

45

Simon,

May I take it that you are no longer sceptical about the ring problem?

Without wishing to restart hositilities, could I suggest that you take your own advice and measure things before making statements.

You mention excessive skirt length on the Pistal pistons, I have just measured them and found them to be shorter than the skirts on both Omega and Accralite forged pistons by some margin. This was with each piston mounted alongside on the same pin. The measurements are not deadly accurate but with these differences they dont need to be.

Piston type …height crown/skirt…diff in crown height

Pistal … 44.20mm
Omega … 47.10mm … +.5mm
Accralite … 46.40mm … +.5mm

This means that the skirt on a Pistal piston is 2.4mm shorter than the skirt on an Omega piston and 1.7mm shorter than the skirt on an Accralite piston. I can easily photograph them alongside one another where the difference is easily spotted with the naked eye. Would you care to comment?

As to blowby and leakage, have you performed a leakdown test on a hot engine fitted with the Scholar liners and Pistal pistons?

Even if the skirts were too long (which they patently are not) this might in-extremis cause a contact problem with the crank or even some NVH but I doubt it would heavily impact the oil consumption, when the piston is raised the bore is much more heavily coated with oil than the small extra protrusion of the piston at BDC.

Dave

47

Simon,

It might interest you to know that the picture was sent to me by Mick Smith directly after the piston was removed from his running engine. Are you calling him a liar? what would his motivation be?

Let’s lay this out, Mick Smith is lying about the ring problem, Dave McCulloch is too, Scholar are liars, Steve Butts is also lying about it as am I and at least a half dozen more who have had the problem corrected, well I’m glad that’s cleared up.

Mick (amongst others) has corrected the ring problem and is now happy with his engine, drop him a mail and ask. Why would he strip his engine if not to correct an oiling issue? I think you should be careful about making comments like that when you haven’t seen the pistons and you dont know the facts.

Removal of pistons from the block with the rings in that conditon has been witnessed first hand by a number of owners who , if you took the time to contact them would be happy to confirm exactly what they saw and some took photos at the time.

I still have the pistons as removed from David Ward’s engine and he has seen them first hand.

For those who are interested in knowing the facts, Mick can be contacted at [email protected] and Dave McCulloch at [email protected] they have seen the problem at first hand on their engines and are able to give an unbiased view. You can then leave me out of it since the oil control ring issue is not of my making, all I have done is to document it and correct it.

Scholar of course will be happy to explain to any interested parties the exact problem and will obviously have photos.

On the issue of ring damage, the overall circumference of the ring reduces when this happens since the expander ring moves up and over itself in the vetical plane only, directly into space made by the lower ring moving down. The authority of the expander ring is then lost and the ring contracts away from the bore and hence makes very little contact with it.

This is what leads to the high oil consumption and is the reason why the ring is not damaged.

You asked me to explain about an issue which is not of my making, where would my motivation be in presenting incorrect information? If that isn’t enough explanation for you then I am past caring, it is an old issue easily diagnosed, admitted by the supplier and it has now been solved.

Two minutes first hand inspection would confirm for even a layman exactly what has happened. I’m sure that those reading the thread have sufficient evidence to make their own minds up.

Are you telling me that the Omega pistons suppled ex-stock for the K series have shorter skirts then the Pistal racing ones or that the Accralite pistons as supplied ex-stock from Accralite have shorter skirts than the Pistal ones, if so please say so then I can publish photos of them on the same pin to make it clear that they are not.

If you have had pistons made with shorter skirts then bully for you, If you are saying that the Omega and Accralite pistons are also wrong since they both have even longer skirts than the Pistal ones then come out and say it. Bear in mind that you have by your own admission used these pistons in engines that you have built.

The Pistal pistons have shorter skirts than the other forged pistons available for the K series from both Omega and Accralite, that is undeniable.

I have also measured a stock pistons skirt and that is 1.8mm longer than the Pistal skirt, if you look carefully at your photo you will see that although the front skirts of the two pistons look the same level, the rear of the Rover OE piston skirt appears much longer because the pistons are tilted at different angles and they are not even mounted on the same pin to ensure that they are level with each other… the extra surface area protruding from the bottom of the bore with a Pistal piston compared to a stock one is barely measurable let alone significant in fact I reckon that is may be less than the stock piston, and it is way less than the extra area exposed with an Omega or Accralite which seems to make a nonsense of your theories about oil consumption increases.

In any event, if the skirts prove too long then it is a trivial matter to machine them a little.

My last conversation with Omega was about making pistons for the Scholar 82mm blocks and they indicated unequivocally that they would be happy to do so provided that the order quantity was right.It is my intention to have some made when I have sufficient interest.

I can see that shorter skirts could be useful when using a longer stroke, but that is not the issue here.

Dave

48

What I think is really interesting is the text on the newspaper behind Simon’s piston photograph.

“…the contradictions and confusions. The gap between the appealing rhetoric and the reality…”

Bernard

49

What I think is really interesting is the text on the newspaper behind Simon’s piston photograph.

“…the contradictions and confusions. The gap between the appealing rhetoric and the reality…”

Bernard

PMSL

50

A very piquant observation Bernard.

BTW are you sceptical about the Pistal ring problem?

Dave

51

and i thought I had too much spare time reading all these posts!!!

52

A very piquant observation Bernard.

BTW are you sceptical about the Pistal ring problem?

Dave

No, I’m in full agreement with you Dave. You only have to look picture to see it’s going to be a problem when the engine runs.

Bernard

53

I have never suggested that balancing is a minor issue, simply that you are too hung up on it.

I’m a novice; can you ever have an engine that it too balanced?

T

54

Perfect balance is impossible to acheive, however the idea is to get as close as possible, it is an activity that gives results which have diminishing returns. It is not possible to be ‘too balanced’ but it is easy to be too upset about it. There are normally target tolerances for balancing that indicate the magnitude of the out of balance forces that are acceptable and the balancer will aim to acheive or better those tolerances. Some do it better than others, either through dint of technique or diligennce, some use balancing machines which introduce their own margins of error and produce poor results which may seem OK from the machines point of view.

In Simon’s view there is only one person in the world who can balance the ‘K’ (and presumably any engine) to acceptable tolerances. Anyone who submits engine sets to any other balancer is on a fools errand. Any engine that has not been balanced by this person is essentially, in Simon’s view a pile of vibrating scrap. Hence my comment.

Dave

56

I’ll keep this simple for interested parties. The statement that the last three engine sets are the “first for years” is a lie. I use that word advisadly since I have already pointed out that it is in error and yet it has been repeated. Prior to the the last 3 sets I took at least one set to Steve either earlier this year or late last year, when I find the receipt I will have a date, it was picked up and paid for by Steve Butts since he was picking up/dropping off some other bits at the time. I note that the statement has already been revised from ‘the first for 4 years’ since I pointed out that it was demonstrably crap.

I was having engines balanced while Simon was still sucking his thumb. At that time his knowledge of balancing was no doubt confined to his ability to either stay on the potty or fall off. Until he picked up s book about balancing 3 or 4 years ago, that was no doubt the extent of his knowledge, now of course he invented blancing and everyone else is an idiot.

I will repeat, Steve is not the only balancer in town. One thing is for sure, I will be speaking with Steve about the misinformation supplied by him and asking him exactly what he has said and why and asking for an explanation and an apology. Be sure that it will be published here Not that the frequency of my visits to him has anything remotely to do with you Simon.

All the rest is the same old rhetoric that we’ve all heard time after time. As stated before (and no doubt I will have to state it again and again since Simon rather tiresomeley brings up the same old garbage again and again as if it were startling new information and not that it has anything remotely to do with you Simon but…), David’s engine was balanced during it’s previous build and the only moving components changed were the pistons which were scale weighed so please spare me/us the sermon. If you bring it up again it will be ignored by anyine sensible.

I note that Simon has yet to respond on the so-called ‘excessive skirt length’ on the Pistal piston, yet another classic red-herring and shot in the foot.

His comments on the Scholar blocks will be fed back to Scholar to see what they have to say, but an 8 thou bore discrepancy would surely lead to an instantaneous seizure since the bore clearance is less than half that measurement. I would be surprised if the piston could actually be fitted to the bore with that large a discrepancy. They have supplied hundreds of blocks and these have been the basis of some of the most powerful K series engine yet built.

I routinely measure the bore taper and out of round and skirt clearnances before assembling an engine and have as yet found no cause for concern on the Scholar blocks that I have used. So again STFU it’s all rather boring.

I have sent a Pistal piston to Fred at Omega for him to examine the ring problem first hand, I will wait for his comments to see exactly who is piling the bllsht. I suspect that if the results run counter to Simon’s stance they will simply be ignored rather than him admit that it was all a torrent of sh*te.

I will also ask him to comment on the ‘excessive’ skirt length given that the Omega pistons currently on sale have significantly longer skirts.

Then perhaps we can put that to bed and the completely and utterly ludicrous assumptions about the increased oil consumption being down to oil splash on the skirts, kindergarten stuff.

Dave

57

Here is a receipt for an engine set balanced in March this year.

[image]AOL.co.uk | Breaking News, Sport, Features and Video - AOL.com

Nuff said

58

The man defends himself well!

Ian

59

For those genuinely interested I have just spent a happy half hour measuring the ovality and taper on David Wards 82mm Scholar block. This is without the torque plate.

I don�t have access to the required micrometer to give an absolute measurement, but be sure then when I get it back I will post the absolute measurements. The device I have enables comparative readings to be made on the bore to an accuracy of .005mm or 0.2 thou give or take a small rounding when converting from mm to inches.

The readings were taken at the 3 positions in each bore , 1cm from the top, in the middle and 1cm from the bottom. Each measurement was taken down the line of the engine and across at a 90 degree axis across the thrust faces to measure ovality.

The results show how each measurement deviates from the top-inline measurement and gives an indication of out of round/ovality and taper, and there is also a comparison with the previous bore reading in absolute terms

Cylinder 1

Top in line 0
Top at 90 axis -0.0013 (1.3 thou) ovality 1.3 thou

Middle in line -0.0004 (-0.4 thou) taper .4 thou
Middle 90 axis -0.001 (-1.0 thou) ovality 0.6 thou - taper 0.3 thou

Bottom in line -0.0002 (-0.2 thou) taper 0.2 thou
Bottom at 90 axis �0.0013 (-1.3 thou) ovality 1.1 thou � taper 0.0 thou

Cylinder 2

Top in line 0 (1.0 thou smaller than bore 1 at this reading)
Top at 90 axis -0.0002 (-0.2 thou) ovality 0.2 thou

Middle in line 0 taper 0
Middle at 90 axis +0.0004 (+0.4 thou) ovality 0.4 thou - taper 0.2 thou

Bottom in line +0.0007 (+0.7 thou) taper 0.7 thou
Bottom at 90 axis �0.0002 (-0.2 thou) ovality 0.9 thou � taper 0

Cylinder 3

Top in line 0 (also 1 thou smaller than bore 1 at this reading)
Top at 90 axis -0.0002 (-0.2 thou) ovality 0.2 thou

Middle in line -0.0004 (-0.4 thou) taper 0.4 thou
Middle at 90 axis +0.0004 (+0.4 thou) ovality 0.8 thou � taper 0.6 thou

Bottom in line 0 taper 0
Bottom at 90 axis 0 out of round 0.0 - taper 0.0

Cylinder 4

Top in line 0 (1 thou smaller than bore 1)
Top at 90 axis +0.0007 (+0.7 thou) ovality 0.7 thou

Middle in line 0 taper 0.0
Middle at 90 axis + 0.0012 (+1.2 thou) ovality 1.2 thou � taper 0.5 thou

Bottom in-line +0.0004 (+0.4 thou) taper 0.4 thou
Bottom at 90 axis 0 ovality 0.4 thou- taper 0.7 thou


Could be better but that doesn’t seem horrendously bad to me given the tales of woe posted earlier. Definitely not scrap.

Dave

60

Ah… I now have the necessary equipment to measure the bore diameters on David Wards engine.

Bore 1 82.025 by 81.985
Bore 2 81.99 by 81.985
Bore 3 81.99 by 81.985
Bore 4 81.99 by 82.01

The consistency of the bores looks quite good to me and they appear to be from 0.5 thou undersize to 1 thou oversize (taking into account ovality), bore one appears to be around .7 thou larger on average.

The measurements may be the odd .2 of a thou out but the consistency should be good. And of course… they were double checked.

Dave