Esprit Turbo project car - part3 - the further continuation

[Rolls 208]

Your post highlights how lucky we are to have this forum. The collective knowledge of all is invaluable.
 

Frankly, I could not restore my car without everyone’s assistance. This one issue alone will save many of us a lot of headaches. And money!

Wouldn’t it be great if we could get even more input from people like Mike?

[Lotusfab 3,210]

Head off, thanks sparky real easy if you jack the engine with the exhaust side mouting bolts loose. Head, pistons all appear good. Both cam carriers are damaged and are the cam shafts. 

[Lotusfab 3,210]

Rebuild starting again!

[Sparky 2,861]

Both cams and carriers damaged?  Did you find the shim?

[Lotusfab 3,210]

yep, it had fallen into the park plug well when I took the carrier off. The exhaust cams followers have almost no wear. Cam follower holes no wear.  Camshaft has slight scoring. The exhaust cam carrier has only slight wear on the bearings, compared with the inlet. I measured the first bearing clearance unfortunately  its on the limit of the spec, so it must be replaced. I spoke with an engineering company,  they can repair both but its £1000 each!  Its would involved camshaft bearing inserts. There might be other ways to repair, but its not cost effective.  So its a case of finding good used cam carriers. Still not confirmed as to the cause. The test kit hasn't come for the oil yet. My gut tells me the oil pump is the cause. Now I have a replacement and housing. When the engine is out I need to run extensive oil pump tests. 

[CHANGES 1,220]

2 hours ago, Lotusfab said:

Still not confirmed as to the cause. My gut tells me the oil pump is the cause. Now I have a replacement and housing. When the engine is out I need to run extensive oil pump tests. 

I am afraid to say if you have so much damage at the top end, which you believe is caused by oil stavation, Then your bottom end should also be toast.....   I say this based on the fact , the top end uses far less oil and has a fraction of the loading experienced by the main and especially big ends..     It would be prudent to fully strip these area's,  ascertain condition and make judgement call from there.  

Just a small observation from the head pic you posted  , which you could clarify quite quickly , the grub screw in the oil track on the head face is srewed well below the face height , I have only seen this on grub srcews that have been machine countersunk as to remain in position when skimming the head.    They are nornally still proud of the face when tight.   see pic  ,   Just wondering if you screwed it in to far and reduced the flow level to the point which may have given problems..    It is unlikly as we fit a reducer into that oil line at the block side to aid oil distribution and pressure as a tuning mod ,  As standard we normally get to much flow to the top end ,  which also adds to the question how  you have generated so much ware in so little miles.  Just thought it was worth a mention and something to check . 

 

[Sparky 2,861]

2 minutes ago, CHANGES said:

the grub screw in the oil track on the head face is srewed well below the face height

Oh, good spot!

[Lotusfab 3,210]

Thanks Dave, Ill check that. You could be correct the bottom end may have had it. Thats why its all coming apart and Im doing it all again from scratch.

[Lotusfab 3,210]

Still not sure whether its partly due to contaminant I have to wait for the oil analysis. Im going to test the pump and compare the results with the new housing, annulus and rotor which I know already work perfectly. Theres no guidance at all on here as to how quickly pressure should build. So ill post some figures.

[Lotusfab 3,210]

Just put a borescope down the opposite side grub screw. Fortunately its not protruding into the oil way and the oil way narrows just beyond it. I took some pics. Thats one thing ruled out. Onto the next.

My views are all speculative at the moment until the testing starts. It has to be a full rebuild or its a waste of time. The biggest problem I found is the manual is very scant on rebuild info. A lot of that comes from experience of this engine type , which it has to be said is different to otheres - due to the oil pump location. Many things I have come up against arnt really mentioned in any great detail on here. Epecially when it comes to the oil pump operation. We need numbers flow rate and pressure. Should it be achieved whilst cranking with the plugs out? How many seconds should it take to register pressure after start? 

i hope this blog slowly is covering most of these issues in much more detail than before. 

I now have several theories as to why this failed. I intend to systematically rule things out until I find the root cause of the failure. 

I also just tested the oil ways in the head, all are clear! The mystery deepens! The appears to be some blackness to the oil in the cam carrier edges, which I need to confirm is not blasting media residue. The oil analysis should show up what it is. 

[Lotusfab 3,210]

A millers Oil ianalysis kit just came. When the results come back Ill post them so if anyone else does a test they have a baseline.

[Lotusfab 3,210]

Engine ready for removal again!

[Barrykearley 6,967]

Looking very similar my end - except mines filthy dirty

[Lotusfab 3,210]

The inlet valve that was under the failed follower needs to be replaced and the guide. Hopefully it will be a straight foward job!

[CHANGES 1,220]

5 hours ago, Lotusfab said:

Just put a borescope down the opposite side grub screw. Fortunately its not protruding into the oil way and the oil way narrows just beyond it. I took some pics. Thats one thing ruled out. Onto the next.

Was worth a punt,  as you say has cleared that area now.   so the plot thickens !!!

Have we got any pictures of all these damaged parts... it may help us understand a bit more on what may have caused the failure.   Its still a bit confusing on what you have said so far..  some illustrations may help..  

[drdoom 415]

Fabian, I am not inclined to connect the frag'd tappet to lack of oil. For that situation to emerge the area would need to be distinctly starved of oil in which case one would expect plenty of comparable witness marks/damage nearby. Still fancy the tappet failure as your single source of the grief at this point though you must, as Dave advises, rigorously check the lot. You're not the sort to do anything in half measures as we all can see!

On lack of oil pressure I offer, not for the first time, a little saga of engine operation after proven loss of oil feed. A mate and I were packing it up after an evening out at the bar and, after an incident most peculiar by which the oil pump drive chain on his BMW 530i was thrown into the sump, the car was driven gingerly home to his residence, a distance of some 6km's. Up a moderate 1/2 km hill to start, over an expansive, arched bridge, the remainder of the journey level and no damage of consequence was found in either valvetrain or bearings in that very recently blueprint built lump. This known because the thing was torn down after as a precaution, of course. So correct oil splashing about under no pressure in a well built engine may stave off disaster for a limited time under light load, apparently. Something to ponder.

Dave, is that an unqualified endorsement for the oil feed restrictor mod?

Cheers

[Lotusfab 3,210]

On the inlet all the cam follwer skirts are worn. I belive they were then wobbling whilst moving up and down and the weakest one cracked. 

The exahust side hardly any wear on the followers, but this side is much lower on the engine. Points to an oil pump issue.  If it was blast media the wear would be equal. When my oil sample comes back I will be able to rule out contamination.

My gut is the oil pump caused all the issues. I believe the PRV is not operating correctly. 

 

[CHANGES 1,220]

4 hours ago, drdoom said:

Dave, is that an unqualified endorsement for the oil feed restrictor mod?

No,  Its quite qualified,  we have been doing it for years ,  The standard oil feed gallery is 7mm in which we insert a grub screw drilled through to suit individual engine spec , most common is 3.2 - 3.5 mm  ..  my own high spec engine is fitted with 2.5 mm restrictor.  see pic

It was covered in the 412 BHP...THAT WILL DO NICELY......   posted half way down page 11  from April 16 2015 onwards 

[drdoom 415]

🙃 My term "unqualified" was perhaps not the best choice - my intent was to ask whether there were further details  by which you would "qualify" the advice!! That has arrived with your comments just posted, thank you!

Cheers

[Lotusfab 3,210]

Well I have been thinking rather than messing around measuring valves and guides etc I am going to renew the whole lot. New valves inlet and exhaust and new guides. I am going to get the head completely redone. I am also going to replace all of the bottom end bearings. Its a very small cost in the scheme of this build, which has gone way beyond what you might expect. Its actually frightening considering I have done all the work. Its essentially a new car and the engine has to be just as good. 

The next time this engine is run it will be better than before! I am tempted to get new cam shafts rather than use used ones. I will fully investigate the oil pump and system. I have a spare auxillery housing Andy gave me which i can use to determine how it works.

I will have the engine out today or tomorrow. 

By end of March latest it will be running again and fully rebuilt.

 

Not sure if I want to fit an oil restrictor, especially when my problem seems to be lack of oil. Ill think about it.

[Sparky 2,861]

39 minutes ago, Lotusfab said:

By end of March latest it will be running again and fully rebuilt.

Anyone fancy a flutter?

[Lotusfab 3,210]

Maybe the odds just changed?  I had a spare 5 minutes so I  took it out by myself, I would suggest two people is much easier. If you take it out yourself you really need to split it and take the gearbox out first to avoid damage. The discs need to be off because its tight. Now lets get building again!

There really isnt much to this engine. But crucial info you need for rebuild is not all in the manual! I now will start oil pump tests. 

[CHANGES 1,220]

Still no pic's of damage cam's, cam carriers, followers , etc...    did you forget to post because we are all keen to see them .. 

6 hours ago, Lotusfab said:

Not sure if I want to fit an oil restrictor, especially when my problem seems to be lack of oil. Ill think about it.

You may be correct here ,  especially when your problem seems to be a lack of understanding..  !!!     However if you ask i am sure someone will explain.. 

[LOTUSMAN33 1,470]

I thought the idea of the restrictor was to slow the draining of oil back to the sump keeping the cams maintaining better top end lubrication?

Well done getting the engine back out and onto the engine stand, always stressful on your own in case something moves the wrong way or slips causing damage. 

Keep going Fabian, I think March is realistic allowing for any machining.

Dave  

[Lotusfab 3,210]

Hi Dave(changes) , sone people might get upset by some of your comments - not sure if you intend for them to come across as they do? I'm too old a bunny to be concerned. I havnt  got around to doing the cam pics because Im busy taking the engine out and its low priority. My garagevis small and they are on the other side of all my parts. 

 I read about the restrictor mod on the Lotusbits website aboutv7 years ago! As you said to me about the cam followers, why change the spec?  Incidently,  Gary Kemp sells those followers and told me they  will work with a standard 107 camshaft. They have advantages over the shorter skirt in my opinion.

The oil pump is pretty simple. The problem on here is no one has bothered to post any significant detail about it. All I found was its difficult to build pressure, but no explanation of how it works. Hopefully that will change as I go into it in much greater detail then ever before, with figures! 

Im very pleased all the the sealing is perfect on the engine. Now I just need to rip it apart and see whats happened. Should not take too long. I have already done  the difficult parts the first time around, second time piece of cake.  Everything is so much easier with practice. Im learning a lot and will have this up and running towards the end of March. Guess what if it isnt perfect I'll rebuild it again, if only to make a point and set an example for other enthusiasts.