Esprit Turbo project car - part3 - the further continuation

[Lotusfab]

Thanks Sparky!

[Lotusfab]

Already started to disasemble. Spoke to a few more people apparently this is a well known problem. I would advise replacement of all cam followers with any rebuild. I may have been advised to do this I cant remember. According to the experts there is a high probability of a bent valve underneath. I may be ok as it happened at idle. However it still needs to be checked. My plan is to remove the cam holder, check for damage and fit a repair sleeve if required. Then put in a new follower new belt and carry out a compression test. If all ok I will run the engine. If not the cylinder head is coming off. The valver clearances seem to be the same as before as I wrote them all down. It will be easy to strip down an: as always a lot longer to put back together. My last shiming effort took about three months. Now I will havevto start again with all new followers! 

[Lotusfab]

Jerrys pic of my car at Brooklands, it was all going so well! Funny how things can go pear shaped so quickly!

[Fridge]

You've obviously got a handle on this @Lotusfab and other's advice, especially @Sparky's all stack up.

Personally I'd be checking all valves just to be on the safe side. Highly probably that the damaged culprit is the only valve effected.

However, I'd suggest that whole cam tower assembly is fully checked for alignment and damage to cam cam lobes, etc etc., before proceeding further. Unlikely components will be further down, though oil ways are an obvious a path for loose metal. How far you decide to go with this is up to you.

The main problem you have is why did it happen?

Relying on the idea that it was just fatigue of the cam follower is limiting. Why now, and at idle and unstressed, after very few miles? I've done over 800 'shakedown' miles in my newly restored S1 since July. I doubt that you've done even half that. So the cause is far from over in my honest opinion.

If this engine has had a dubious history I'd be double checking as much as possible, setting aside the cam follower failure as potentially being the effect of an underlying problem.

Just my pen'arth worth.

[Lotusfab]

The engine failed in 1986  due to a wastegate problem. The entire block, pistons, crank all replaced and they have practically no wear as the car did about 600 miles after the rebuild then was laid up. . I have the original  receipts. I I checked and measured every conpinent and then got an expert to give a second opinion. The engine was already rebuilt before and not run, I have all the reciepts, but  I did it again - for piece of mind.  

Believe it or not fatigue on these is a well known failure to anyone who has done this for a long time, hence the repair sleeve that you can buy. I should have changed all of the followers and would have if I had seen Tim Engles artical. There were no cracks visible on any if the followers. The timing belt was set correctly. Just a piece of very bad luck. The head was in excellent condition. I will however go through this with a fine tooth comb. As soon as the cam tower is off I will know more. The standard repair is to hone the cam tower, clean it all up, chek for bent valve then reassemble. I may take the head off just for piece of mind. Shouldn't take long I have already started taking it apart. Should take a day max to get it all apart. 

[Smithy111]

Oh damn! Sorry to hear about this Fabian! After all the meticulous work you've put into that engine. Sounds like it could have been worst though. Hope you manage to get this sorted without too much bother.

[Lotusfab]

Thanks Chris, all part of the Lotus journey! I could do without the fiberglassing though! 

[v8vantage]

Even the best maintained engines can let go Fab. How many times has an engine let go on the Airbuses you fly and they are extremely well maintained. The older things get the more attention they need. At least it didn't bend the valve, hole a piston, brake a rod and destroy the block! Everything can be fixed and it always takes less time the second try. At least you got to drive the car and show it off first.

Roo

[Lotusfab]

Thats true, thanks Roo. I am very lucky the only problem I have is an engine! Im getting motivated  to fix it. I may take it out completely and start again. Its all nice and clean now and the bolts come off easily. I have Cranford engineering nearby to check stuff amd Paul there is an engineer second to none so Im well placed. Ill be back with a vengance hopefully before March! 

[Sparky]

OR... whip it out, send it to Pete at PNM who will do a full strip and analysis and repair what's needed, test, then report all details back to you.  That way you get it fixed, and receive expert feedback on the quality of your build.  Pete will find stuff that you, with respect, might miss.

Or, if you're a masochist, crack on!

[Lotusfab]

I agree Pete does great builds and knowledge is second to none.I got him to check over everything before I assembled it. If he was nearby I might be tempted! 

If I give it to Pete its acknoledging defeat. Its only an engine I think its time for rebuild no2! 😄😄😄This time carb pump jet calibration, new oil pump housing , rotor and annulus(thanks Andy) . I then would have replaced or rebuilt everything on this car! 

 

It took me three months to shim it last time but the clearances are perfect. i  now have all the kit and a lot of practice,  I hope to cut it down to about two months!  😄😄😄

[Lotusfab]

Having slept on it Im not happy with this engine. Im going to take it out and do it all again!  When im finished it must be as good as it possibly can be. No more fatigue failures. At least I have confidence in all of the sealants I used. No leaks at all even from the cam cover gaskets. Gearbox also it perfect, no leaks. Its a shame but necessary.

I have experience of this engine now so it should be much easier than the first time. Im going to take the head to a specialist engineering company and have it checked and redone as necessary. I am replacing all of the cam followers. I suspect damage to the hosuing. Whilst you can buy a repair insert I will now start the hunt for a replacement housing. I will have the camshafts checked as a matter of course.

If anyone has one to sell please contact me. 

Happy days, rebuild two on the way! 

I have completed half of the split mould. I have decided  to change the tooling resin I use to optimould. It has less strinkage and will speed up the job. I am busy waxing the first mould it needs 10 coats with 1 hr intervals! What a laborious process. Buy comparison an engine rebuild is much more fun and probably quicker. These racks have consumed many many man hours and are no where near finishing! 

I am more organised than before. I have large plastic cointainers for all the parts which are put into freezer bags and labelled as they are removed.

[Lotusfab]

Coming to pieces real easy!

split mould half done...

 

[Lotusfab]

Pump jet calibration

I need to devise a method for this. Pressumably pressurized fuel delivery will have no effect onnthe pump jet squirt over 20 presses. So as long as fuel is suppiled to the float chambers, I can actuate the accelerator 20 times and measurevthe fuel output? 

[Gis]

Good luck with the rebuild Fabian, if you have the carbs apart again, check the one -way valves in the accelerator pump covers. Make sure they move freely when you press down on the spring loaded ball with a needle. I had one of them blocked with fuel deposits and it caused a stumble. 

[Fridge]

9 minutes ago, Gis said:

Good luck with the rebuild Fabian, if you have the carbs apart again, check the one -way valves in the accelerator pump covers. Make sure they move freely when you press down on the spring loaded ball with a needle. I had one of them blocked with fuel deposits and it caused a stumble. 

Yes, folk often make the mistake of simply removing the carb tops and peering inside to see it looking generally clean. When in fact all the gunk and sludge drops to the bottom. Obviously. Fortunately @Final Edition did a great job of restoring mine, and Dave at Bogg Brothers near Malton has tuned it brilliantly. It has no stumble at all. He's a master of all classics, and knows his onions about remapping too!

[Andyww]

Another acceleator pump issue is the number of different diaphragms listed. Eurocarb list 6. 

When I ordered replacements from SJ the wrong ones were sent. The diameter of the piston was too big for the housing, if I had fitted them they would not have been able to move properly. I wonder how many people have been caught out by this withough noticing. Presumably SJ are sending DHLA45 ones instead of 40.

[Fridge]

1 minute ago, Andyww said:

Another acceleator pump issue is the number of different diaphragms listed. Eurocarb list 6. 

When I ordered replacements from SJ the wrong ones were sent. The diameter of the piston was too big for the housing, if I had fitted them they would not have been able to move properly. I wonder how many people have been caught out by this withough noticing. Presumably SJ are sending DHLA45 ones instead of 40.

It's simpler to go to Eurocarb direct in my experience. Always expert attention, as you would expect.

[Lotusfab]

Rob at Eurocarb is the chap to speak to. My carbs were stripped and cleaned by them. They replaced the spindle bearings with the sealed type for Turbo carbs. They then adjusted the butterfilies. All I did was srew the jets in and put the ancilleries back on. I fixed the stumble priorvtonthe engine problem it was the idle jet size. 40s were too small. 43s are now in and no stumble. 

Its quite good taking the car apart after you have rebuilt it. I have had a chance to inspect the gaskets. They were all good except the inlet manifold. The water channels were good butbsome of the nuts seem to have lost their torque settings. I think the valves are all fine but Im taking the head off anyway. Ive stripped it to the point of cam tower and head removal in about 3 hrs. Very easy when its all new. 

Thanks Gis I will check the valve. This time the pump jets will be calibrated to manual spec, even though I have fixed the stumble issue.

[Fridge]

Normally it's the emulsion tube that needs changing to eradicate the stumble. May be the same thing by a different name?

Fabian, don't kid yourself. Taking the car apart after you've just put it together is annoying work. You'd have loved life in Stalin's GULAG.

[Lotusfab]

I am Sisyphus from greek mythology! 

No I have stock emulsion tubes. I changed the idle jet at the bottom of the tube and it fixed the problem. It has a tiny hole that meters the fuel.  Car loves the size 43s. With 40s it feels like its being held beck. Although this is my car, others like Andys have 40 s and seem to run really well.

[Fridge]

Isn't that an STD?

[Lotusfab]

[LOTUSMAN33]

Keep going Fabian as like most of us once you get passed that cross and Why stage you just want to get stuck in sometimes making things even better!

You are still welcome to borrow my rig for accurate pump set up?

[Lotusfab]

Thanks Dave, that looks great! Presumably gravity feed fuel supply. Then just open the throttle fully and let close 20 times?