Esprit Turbo project car - part3 - the further continuation

[CHANGES]

1 hour ago, Lotusfab said:

It occurs to me it should be possible with the  pistons out to bolt the camshafts onto the head without permabond, rest the cylinder head over the block with no timing belt or pistons and rotate the cam shaft by the end bolt to adjust the shims. This can then be checked after the head is bolted on and the permabond is in. Has anyone done this? It seems to me it may speed the job up???

Good luck with that...    It all depend if going round the circumference is quicker  when the diameter gets you there. 

1 hour ago, Lotusfab said:

Note in the guidance notes with Loctite 504 you should allow 0.0015 inch for the 504 thickness when calculating shim sizes. I plan on using permabond 136. In the absence of any other suggestions I will use the same 0.0015 inch allowance for permabond thickness when calculating the shim sizes.

Note the word Guidance  ,  this is something only experience will give you...  

1 hour ago, Lotusfab said:

Apparently the inlet clearance increases with wear and the exhaust reduces. So I plan to take this into account with the shim selection.

So i take it from this you are going to make some tight and some loose... Uhmmm  considering it takes thousands of miles for any wear to be noticed , this seems a bit of over kill...  also experience has shown me those wear statements are not always as stated.  

1 hour ago, Lotusfab said:

Also has anyone used Wellseal with a modern gasket just around the rubber O ring where the oil flow ocurrs? This is recommended in the manual, but may not be relevant with the modern gasket?

This again is down to the experience and expertise of the engine builder .  Some do some don't , circumstances and face quality can dictate how to proceed. 

6 minutes ago, 910Esprit said:

I always initially set shims with the head off the car and on a bench. 

With respect to Steve,  I never do it on the bench, because for some reason when all bolted down things changed very slightly..  Don't know why but they did..  Saying that it was only slight and if you set middle of tolerance you could get away with it.. but as I don't  it seems pointless doing the job twice..  

hope that helps..   

[eeyoreish]

I read somewhere on here that for Permabond A136 there's no need to make any allowance for thickness. Certainly within the accuracy of my feeler gauges (and 'feel') there was no measureable difference on the final fit with sealant vs the dry runs...

[fjmuurling]

Same here for the Permabond A136, it does not add "thickness".

[Lotusfab]

Thanks Chaps. Found this.https://www.permabond.com/wp-content/uploads/2016/04/A136_TDS.pdf

Nothing specified for Cylinder head thickness in the above but it does have gap fill up to 1/2 mm . Might be sensible to add the Lotus allowance in the shim calculation then select shims that compensate for wear and Bond  thickness. By this I mean the inlet and exhaust settings have an allowable range, so select the shims to place the clearance at the edge of a range ( compensation for future wear and bond thickness) which will improve as wear occurs. Once the shims have been selected and it has been set up bolt the head on put it all together and check the result. If it isn't correct take it apart and do it all again. 

I will try this and postvthe results.

[fjmuurling]

Gap fill is the abibility of the sealant to fill gaps when the two mating surfaces are not perfect. For instance if there is a scratch on one of them.

When bolting down the camcarriers with the head on the workbench  the head will distort (differently than when the head is on the engineblock) causing the clearances to alter when putting everything back on the engineblock.

 

 

[Lotusfab]

19 minutes ago, fjmuurling said:

Gap fill is the abibility of the sealant to fill gaps when the two mating surfaces are not perfect. For instance if there is a scratch on one of them.

When bolting down the camcarriers with the head on the workbench  the head will distort (differently than when the head is on the engineblock) causing the clearances to alter when putting everything back on the engineblock.

 

 

Thanks. It’s interesting I wouldn’t have thought the original sealant would have any thickness when the carrier is torqued affect either,  but Lotus made an allowance. All I can do is try it and report back with calcs. You may have gathered I don’t consider doing a job more than once a problem, especially this which relatively is quite quick. On my S1 I did some things over and over some taking up to six months to perfect. I see this as no different. I won’t be finished unless the clearance are exactly spot of to the figure I am trying to achieve. 

[Lotusfab]

Just noticed I've been building this car for two years and five months!😬😬😬😬😬😬😬

[Lotusfab]

👍

Nearly there!

[Lotusfab]

How to

[eeyoreish]

I found the manual was pretty good at showing which side of bolt holes to go. Inside for the sump, outside for the cam tower.

[Lotusfab]

Piston ring spacing. 

Do any of you experienced engine builder Chaps disagree with the piston ring gap spacing! In the picture?

For Lotus rails 25 mm either side of oil control ring gap, which faces to the rear of the engine and compression rings 120 degrees from the oil control ring gap??

[Lotusfab]

I decided to get some expert advice from a very well known Lotus expert who I trust 110 percent.  The concensus is the crankshaft has to come out. Even though the main bearings are new the end float had to be reduced to spec with a new thrust washer and the bearing mod checked. The pistons are good and the rings are new. The big end lines were most probably caused by dirt and start up after the rebuild, this is not unusual. Be cause there is no unevenness they are fine for refitting. 

As far as the piston ring orientation I will fit as above. I have also checked the literature for NPR, a well know piston ring manufacturer. Basically as above. The only difference between the Lotus manual and their recommendations is they put the scraper ring gaps 25 mm from the oil control gap, whereas NPR use 45 degrees. A negligible effect I would think. Basically no gaps on thrust faces and the oil ring gap to the rear.

Right now I need to get on with it,as all the measuring kit has arrived! I'm a trained physicist, but was having trouble remembering how to read a micrometer. Fortunately in the thirty years since I last used the skill we have invented the Internet, where there are some very good videos. Because the readings are so critical a little practice might be required! 

As always anything copied on this blog is entirely at your own risk. The blog is just for interest only and is not intended to be used as an assembly manual. I accept no liability if you copy anything I have stated or done. I suggest you Seek professional advice if you deviate from the Lotus Manual.

[Lotusfab]

Nice!

[Lotusfab]

Well what do we have here? An unmodified No 5 main bearing. This is why the endfloat was 12 Thou! Very pleased I took this apart. The good news the main bearings are new! So I will carry out the mod and change the selective thrust washer, job done! It took my first engine apart at 9 years old. It was a Honda c90 moped engine. This one is a lot better!Now lets have some measuring fun!

[Lotusfab]

Here are the thrust washers, one on each side. 

Ohhh sh...t. What have I done?

😬😬😬😬😬😬😬😬😬

[Lotusfab]

Finally gear lever is done. The best of both worlds the thicker base where it snaps and the elegant upper part. Expertly done by Paul at Cranford Engineering!d

[Lotusfab]

I can't  take credit for this, it's all down to Fulcher Coachtrimmers. I did fiberglass the header rail though - which was a click one before it went full James Bond!

[stephenwhyte]

That all looks perfect Fabian and the chromed thinner gear lever will make such a difference when you see it all finished👏👏

[Lotusfab]

Thanks slowly getting there! 

 

[Lotusfab]

[CHANGES]

 

22 hours ago, Lotusfab said:

Well what do we have here? An unmodified No 5 main bearing. This is why the endfloat was 12 Thou! Very pleased I took this apart. The good news the main bearings are new! So I will carry out the mod and change the selective thrust washer, job done! It took my first engine apart at 9 years old. It was a Honda c90 moped engine. This one is a lot better!

Try looking on the other half of the crank housing..  The mod is usually done on there not the block half.. !!!!

[Lotusfab]

2 hours ago, CHANGES said:

 

Try looking on the other half of the crank housing..  The mod is usually done on there not the block half.. !!!!

Thanks!  Good job I havn't adjusted it! Hopefully I would have checked the manual again before doing anything! Dave, do you notice anything usual about the second compression ring in this picture? I.e. Is it up the correct way? There are no markings  any of the rings and they have all been installed lip to top??.

have measured the end float on the camshafts inlet 10 thou, outlet 8 thou.

main crank 12 thou.

crankshaft journals all inspec.

Pison/liner measurents

liner 1 95.30mm

liner 2 95.28mm

liner 3 95.28mm

liner 4 95.29mm

piston diameters

piston 1      95.17mm

piston 2      95.17 mm

piston 3       95.16 mm

piston  4       95.16 mm

of course there is an error margin on the measurements which I have repeated several times.h

I have grade B liners and pistons.

Dave is the second ring on correctly? Groove at the top????a

There are no markings on any of the rings. The upper ring is rectangular so appears it can be fitted either way. The second to me appears as though it should be the other way and the rails and scraper look ok.

If you expand the pic you can see the groovevin the second ring faces upwards.

[Lotusfab]

Note some of the measurements are close to the edge of spec. Because of the reading error I'm inclined to refit the pistons and use the existing liners. I think though because of the importance of getting this correct I'm going to have it all checked by an expert before reassembly. Nows the  time to replace parts if necessary. Was quite surprised by the mount of end float on the camshafts. One is out of spec. Once again very please I took this apart! Right off to check the other bearing housing for the mod! 😀😀😀😀Glad I hadn't done it or it might not be so Funny! Thanks, Dave! 👍🏻

[Lotusfab]

No bearing mod. No groove in the No 5 bearing shell.

[Lotusfab]

Well have stripped the cam shafts and head. stranegly the inlet valves all seem very clean and perfect in their seats. The exhaust valves have too much play. At least a couple need replacing and possible guide work. Looks like someone has done the head, but not a very comprehensive job, in fact only the inlet side! 

I have also decided because of my unfamiliarity with the engine I will take all of it up to PNM for an expert opinion and detailed examination. I think they will have to hold onto the head for a recon. We will see.