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Esprit Turbo project car - part3 - the further continuation - Page 150 - Esprit 'Project & Restoration' Room - The Lotus Forums Jump to content
Lotusfab

Esprit Turbo project car - part3 - the further continuation

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On 17/01/2019 at 09:07, Lotusfab said:

Bauke, I like your work! Now have you got some cheap early wing mirrors to sell me? 

sorry i dont have them in stock for sale, hopefully you will find some,

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Hope so else my project will be ruined! Found two Essex front lips, but owners won't sell as they are keeping them for spares. The only option will be to CNC them including the rolled edge with a complete scan of the original. Fortunately I have one original. I don want to go down this costly route, but may have no option. If I have them coded I will be able to get more CNCd if anyone wants one, but it won't be cheap! 

Valve Clearances

IMG_5998.thumb.PNG.56b14bb89632ca8cf5f11875ff4147f5.PNG

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

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

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The preferred (by me!) Loctite 518 no longer materially alters the clearance.  Not sure about Permabond. although I'm sure it will also do a good job.   I always initially set shims with the head off the car and on a bench.  (if being rebuilt)   Genuine Goetze head gaskets have a rubber seal for oil feed.   Some pattern gaskets have a copper washer.  I'd probably wellseal use for metal to metal but not for the rubber seal

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Thanks Steve, excellent info. I'll check the literature for permabond, it might be the same.

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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..   

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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...

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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.

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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.

 

 

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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. 

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

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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.

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Piston ring spacing. 

Do any of you experienced engine builder Chaps disagree with the IMG_6005.thumb.PNG.5083d451df811df1710c8ce0f031cc4d.PNGpiston 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??

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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.

IMG_0103.PNG.d4ff2f7ac1cd20de9204d6b26ecbd714.PNG

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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!IMG_6008.thumb.JPG.5199c0f4f70b751beb06b635d2a93005.JPGIMG_6009.thumb.JPG.c57f4d96ee86be9fe596fb3b75553c3c.JPGIMG_6010.thumb.JPG.31f7966a7e09591165567a9bf7aa9a8c.JPGNow lets have some measuring fun!

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IMG_6012.thumb.JPG.a2f5d81f453aa1d3604e35f16640bbd9.JPGIMG_6011.thumb.JPG.bceaf959f947466c13d5f41f21608085.JPGHere are the thrust washers, one on each side. 

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

😬😬😬😬😬😬😬😬😬

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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!IMG_6013.thumb.JPG.33c109b23851f7583f273bb484e44dee.JPGdIMG_6014.thumb.JPG.d0741d7ed017886937b2ffee837dbd10.JPG

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

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Thanks slowly getting there! 

 

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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!IMG_6008.thumb.JPG.5199c0f4f70b751beb06b635d2a93005.JPG

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

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