Past Lotus Business Practice Question

[type26owner]

Was it common practice for Lotus to install cylinder sleeves in new engines back when our cars were new? I had a sleeve in number three cylinder which appears to me to be a factory installed one but I'm only guessing since I'm not the original buyer. I'm the third owner but it had only 69k miles on the odometer because the waterpump had failed and it sat for 25 years waiting for me to bring it back to life. Whoever did the sleeve installation did it poorly since there was left an 1/8" gap at the bottom to the shoulder in the block. The new sleeve I installed yesterday has no gap and therefore cannot slide down away from the headgasket compression crush rings like the old sleeve did. The really odd part was the OD of the sleeve was 3-7/16". I never go bigger than 3-3/8" and have never ever seen a bigger one then that used before. Does this info jog anyone's memory on this subject? Just curious. Never had a problem with the sleeve coming loose for another 100k miles of everyday motoring until flogging it on the racetrack recently. It was totally worth it though.

Did the rod and main bearings always come from the factory at the standard diameters too?
-Keith

[rgh0]

Hi Keith

The OD of the sleeves I use in my blocks is 87.25mm for a 83.5 mm bore finished ID. That OD is 3 7/16 inch for those still using imperial measurements and the same as the sleeve in your engine.

I have never heard of sleeved blocks or undersize crank journals in new cars but knowing Lotus anything is possible especially if it saved a dollar ( or pound sterling ).

Rohan

[lotuselanman]

Gidday,
Yes I have heard of sleeved blocks but only on the very early cars. Cast your minds back and you will find there were many inconsistincies with the the early cars. Lotus Cortina's I believe had the same problem but once again only in the very early cars.
As for Cranks being undersize, no that's a new one but they were run through with OVERSIZE specs on the OD of the shell as the blocks were line bored during production.
In reality I don't believe anyone knows what mischief Chapman / Lotus got up to.Not much help ay !!
See ya, Les

[type26owner]

There remained the evidence of two voids (porosity) in the cylinder wall about 10mm across which did not clean up entirely from them machining the pocket to accept the sleeve originally. Suspect that those voids penetrated the finished surface of the cylinder wall and that's why it was sleeved to begin with to save that block. When I machined away the old sleeve it was apparent by the corrosion pattern there has been for sometime a vertical crack about 75mm long midway up the cylinder wall between the thin web section between #3 and #2 cylinders. The block is stamped LA-B as the cylinder wall thickness grading. Is there a web resource somewhere that explains that grading system? I'm having it pressure checked first before the honing gets done.

Bet with a thinner walled sleeve the cylinder wall would possibly not have cracked. Thanks for the responses!
-Keith

[types26/36]

Keith,
Never seen a web explanation of the block grading but on page 28 of the Wilkins book he gives some explanation of the system although he does not mention LBB.
LB for 1558 engines only
LA can be bored to 85mm and used for 1558 to 1650
LAA unsuitable for 1558 but can be be bored from 83.5 to 85mm
Brian

[types26/36]

That should have read "does not mention LA-B"
Brian

[rgh0]

Keith

I have had the sleeve crack when the cylinder wall behind them developed a crack. The lack of support from the cylinder wall in the area of the crack leads to an overstressing of the sleeve.

Mine was in the side of the bore adjacent to the thrust face of the piston. Your crack is in a better location from a loading view point but you still may face a problem. I assume you are running standard bore pistons and the thicker sleeve will certainly help resist a crack developing in the sleee itself.

Good luck
Rohan

[type26owner]

Rohan,
Should be okay with this repair but only time will tell. The sleeve to bore interference was about .0007" total which is ideal. With this thickness of a sleeve it should be ok but I have no experience here. Would definitely prefer a thinner sleeve with an intact crack free cylinder wall in the block though. Was sweating that the perfect sleeve OD could be found but I've patronized the same parts guy now for 35 years for good reason. He came through for me again.

Got 83mm (+.020") pistons installed now. It had 82.88mm (+.015") ones when I got the car. We run 83.5mm pistons in 85.73mm OD sleeves on our BRM race engine. Permits sleeving all four cylinders without distorting the block at all.
-Keith

[type26owner]

Picked up the block tonight after having it pressured checked at 60psi and the sleeved cylinder honed to size. I'm good to reassemble it this weekend. I'm only installing viton lipseals on either end of the crank (ropeseal) this time around. It's the only elastomer to not suffer from being exposed to hot synthetic oil.

Chicago Rawhide's new website kicks butt!
-Keith