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Esprit Turbo project car - part3 - the further continuation

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2 hours ago, Fridge said:

Personally, I think your assumption is flawed. Think about it. How many of these engines have similar factory followers and are still working perfectly? I think it has been a mistake to not forensically examine the sludge if that is the route you seem to want to take. It's engine basics really.

I believe that the damage to the cam follower is more likely due to a lack of oil from the oil way associated with it. Possibly restricted, or prevented from lubricating it. Whether that is bead, or by some other material.

I've said it before, and I'll state it again; Occam's razor and all that.

There are many opinions already posted by a wide number of folk with greater expert  knowledge in these engines than I, but I really do think you are barking up the wrong tree. New cam followers will not solve this problem alone.

 

I visually inspected the followers. I know of several builders, now I have started to investigate, who Ping them. If the sound is dull they are replaced. In my case the engine had a catestrophic faillure and was rebuilt in 1987, the entired bottom end was replaced. Maybe they reused the top end parts and this follower had been weakened by the previous Failure? The car did hardly any miles after the rebuild and was put of road. I have the reciepts for the work. I will check the sludge as I still have paper towels with it on.

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The failure mode of the cam follower seemed to be the skirt became detached so could this have been running silently for a while with half the side missing but being allowed to rock sideways in its bore causing damage and swarf build up in the top end around that cam before draining down?

The severely scored cam journals are they only adjacent to that cam follower fail?

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24 minutes ago, Andyww said:

The failure mode of the cam follower seemed to be the skirt became detached so could this have been running silently for a while with half the side missing but being allowed to rock sideways in its bore causing damage and swarf build up in the top end around that cam before draining down?

The severely scored cam journals are they only adjacent to that cam follower fail?

Sorry but no..   When these cam followers fail the crown cracks and they come apart from there ....   All the crack tests and experience shows that...  never seen a skirt detach, why should it , there is no impact or real stress on that surface , if there is then there is an underlying issue..    As far as the bits transferring in to the bearing face from there is not really possible , 1 the parts will be to big / heavy,  2 , the would have to migrate upward , 3 if any oil pressure was present it would be squirting out of the bearing clearance, which will be less than .001'' ,  4,  shattered pieces would be too big to back track into that bearing clearance gap.  .. 5. to get to all the other effected journals it would have to flow against the flow of oil without any mechanism to project them, and what about the bottom end ....    So no , highly improbable , there is no evidence to substantiate that claim .. .....         

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2 hours ago, CHANGES said:

I don't see the cam follower failing as the cause for all the damage to the bearing surfaces..    I base this on the fact the follower is external to all these parts.......   Once this has failed you would get the noise quickly and will have stopped running it..    Even if you carried on running it with broken cam follower it would not of damages the bearings or effected oil flow...  The followers are splash lubricated from the cam feed and bearings.. which is why you should be very liberal with the Graphogen in this area for start up, even when priming..   However this does not alter the fact any particles from the the failed follower would have in most remained in the crankcase or sump..  There is no way of them getting into the bearing surface without going through the filter first...... This is why our first port of call is to cut up the filter....  You may have signs of tiny pieces chunking up the oil pump , these will have been small enough to get through the pick up sieve.  After that they would be in the oil cooler lines and the filter no further..       I think it comes back once again to oil starvation, reasons yet to be determined ...  One should always remember flow is as just important as pressure , one without the other will lead to failure ..     From the pictures you have posted along with explanation given , oil starvation is the only conclusion i can come to....  The reason for this is still unclear and without seeing all the constituent parts personally one on one , I feel is as far as my advise can go..    If it is of any help , I have seen exactly this sort of damage on engines before , all were cause by some sort of oil starvation..  Reasons were blocked pick up sieves , filters , and failed oil oil line and pumps ...  None of which you seem to have experienced  ...  So as i say without doing my own autopsy , which would be awkward now you have already stripped it , that will be as far as it goes...    Good luck with what ever you decide to do..      

Thanks for the input. You might be correct I have to keep going with the analysis. The bearing shell pictures above show diffrent types of damage. The shell damage I have is consistent with both oil starvation and more importantly the scoring is consistent with iron particles( not glass bead) I only found about 1/10 of the cam follower skirt. The rest and some of the housing must have gone into the sump or be stucked into the filter eventually causing the grinding paste effect. I have a microscope on the way and will analyse the sludge thats still on my paper towels. 

The iron paricles (or bead) I have found are small and they could pass through the wire gauze. I'll post some microscope pics justbout of interest. Il get a magnet and ensure they are iron.

All of the oil cooler hoses are new as is the heat exchanger unless I can figer out how  to clean them they will have to be thrown away!  

 

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10 minutes ago, CHANGES said:

never seen a skirt detach, why should it

It did though in this case, I have seen the failed follower. But the points you raise make perfect sense.

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15 minutes ago, Lotusfab said:

The shell damage I have is consistent with both oil starvation and more importantly the scoring is consistent with iron particles.

This is natural when you have scored the surfaces from lack of oil , when the oil does flow it will transfer the particles  to other journals within the system before washing into the sump and then getting caught in the filter.  

 

15 minutes ago, Lotusfab said:

The iron paricles I have found are small and bead like they could pass through the wire gauze. I'll post some microscope pics justbout of interest. 

As i say these are all to be expected in this type of failure, they are not unique to this particular engine fail ..  The oil filter will gather them before they recirculate   However the damage is done the bearing surface conformity will have been compromised,  the clearances will have increased, the oil will not act as a floating cushion for the journals because it will be spewing out of the larger clearance, along with the now rough surface the inevitability of total failure as seen was just amatter of time ..     

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I still dont inderstand this, the oil pressure was well within limits for almost two months. 

Maybe microscopic pictures will add some clarity.

The only thing different on this engine to all the other work I have done is I used aquablasting and bead blasting on the covers. going round in circles! 

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7 minutes ago, Andyww said:

It did though in this case, I have seen the failed follower. But the points you raise make perfect sense.

Sorry Andy ,I probably was not as clear as i could have been here..   The crown is where they all start to crack .. It will then fracture down the skirt as part of the failure . This is why it looks like the skirt has failed ....  You never see a fractured/ detached  skirt with the crown not showing evidence of prior failure ...      On the rare occasion when high lift cams or long skirt followers are fitted without measuring clearances ,   you can get the bottom of the cam follower skirts damaged or cracked if cast.   But that  wont of happened in Fabians case   

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I agree with your comments Dave.

I’ve had a play with different grades of media from my cabinet tonight and mixed it with thick gearbox oil.

D17D9015-D2B1-4DE3-BD19-6D74338A5B70.jpeg.27a7f1bee595514b9f890d42a574ae56.jpeg

Surely blast media is not enough to block a hot passage that’s under pressure?

Fascinating topic Fabian. I admire your calm approach. I would need therapy.

 

 

 

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Hi @Rolls I'm no chemist expert either, but have experience of media blasting of different sorts, and I'm sure the process, which adds energy in the way of force and heat, creates a structural and chemical change in the media and solution used (if any). So your test is too simplistic.

With this added energy, aggravation and breakdown of the media some of it will coalesce and then solidify. Which is why it seems like a protracted process for it's thorough removal. This is before an engine is eventually started. I'm sure that this gives this substance even more time to glue itself to the various surfaces that have been cleaned.

So yes, I'm very sure that any media will have the ability to block the small oilways and passages of an engine.

 

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Shirley the first place to look is in the sump. And why's no one mentioned f-ing silicon based sealants.

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3 hours ago, Sparky said:

Because nobody in their right mind would use them.  And stop calling me Shirley.

Any chance you could tell that to the bloke that did my gearbox?

Not the Shirley bit, obv.


Margate Exotics.

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The one good thing is all the sealants worked perfectly. I used wellseal, loctite and only silicon on the cam cover. No sealant residue in the sump.

The worst thing is I now  have to throw away the brand new oil cooler and all the new pipes! 

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23 hours ago, CHANGES said:

That boat has sailed Fabian...  You did a Stirling job cleaning all the media out.. So many other people use the Aqua blasting and other media blasting as a restoration tool without issue , including me ..   I don't think you should focus on that as a cause anymore ....  Yes there are scare stories on the social media sites from people who say it is wrong to use that process, but what you have to ask yourself is..   Who are they  . Is there any proof that what they say is true.   Or are they just making it up to look important and all knowing... Or did they use the process and not bother cleaning out after as you did and everyone else who uses the process does..   There is positive  proof that the process can be used without issue ...  Here on this forum , others and Me ..  Who do you believe the most ?    Best to concentrate on what you know and forget the Aqua blasting scare stories, this is a false trail.    

Dave please could you give me your opinion on the Burn in the head. Its tuned to optimum combustion at idle. Pump jets were way off, Looks rich my concern is Oily deposits. . No evidence of anything getting past the rings. Could it be from oil seepage on the exhaust valve guides ? They all measured in spec. I am considering a total replacement oIMG_0752.thumb.JPG.8ff1be5b92831807dbfcc40019d3b59b.JPGf all valves and guides. I would have hope it would burn better. Thanks.

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Pending opinion from Dave....

Do the HC/CO figures confirm that combusion was 'good' at idle?  (any uncalibrated tweaking of the mixture screws has a fairly significant impact on these)

Did you use new rings in old liners?   (they can take a some time to bed in)

Wont be exhaust guides, as they are  'post' combustion and operate in a pressurised environment. 

Was there any oil consumption?

If all valves/guides within spec, presumably the issue (if it is an issue) lies elsewhere.   If the engine had not failed, you would never have seen inside the combustion chamber and you have not done many miles.  It's entirely possible its all just still bedding in.  On the plus side, all chambers seem pretty consistent.  

 

Edited by 910Esprit
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The rings are all new. Liners and pistons pretty good. All valves in spec. No oil consumption that I noted. You might be correct more time to bed in. Just odd I didnt expect  to see this. Its quite interesting to take apart an engine you have just built you can evaluate all if it. 

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Sounds like a great plan Fabian and after you will have an epic engine which should last you out. You are very resilient and remained positive throughout.

The dent in the wallet will seem insignificant when your turbo is hitting three figures on roads permitting.

Dave :) 

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Do or do not, there is no try! 

 

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1 minute ago, LOTUSMAN33 said:

Sounds like a great plan Fabian and after you will have an epic engine which should last you out. You are very resilient and remained positive throughout.

The dent in the wallet will seem insignificant when your turbo is hitting three figures on roads permitting.

Dave :) 

I like your avatar picture! Just waiting for new pump jet springs to arrive then I will get the carbs done and get the test rig back to you. Thanks! 

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Absolutely no rush Fabian, anyone else who wants to borrow it to set their carbs just let me know.

The Evora is lovely but think another Esprit will be joining it in the near future.

Dave :) 

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Do or do not, there is no try! 

 

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Can we please have a collection for me so I can buy this!IMG_0829.thumb.PNG.33677650b106aab468aa4648132a4cb9.PNG

I need the full set!

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On 23/01/2020 at 12:56, 910Esprit said:

Just out of curiousity, what brand & type of oil were you using?   I'm not suggesting a connection, I'm just suprised that the viscosity has degraded so quickly due to shearing?   (I thought this happened over significant mileage due to the action of the cams breaking down the polymers in a multigrade oils).  

Did this get answered? Where you using non synthetic to run in?

buddsy


 

"Belief is the enemy of knowing" - Crrow777

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