Surprised no-one else has clocked this.
At first I was somewhat cynical. But then …
ebay.co.uk/itm/Lotus-Twin-C … R9Vu5U4z64
Tim
Surprised no-one else has clocked this.
At first I was somewhat cynical. But then …
ebay.co.uk/itm/Lotus-Twin-C … R9Vu5U4z64
Tim
Thanks for posting. Looks like Lotus brush painted the early heads grey prior to assembly with the block. Looks like they painted the interior with Glyptal too, I think they stopped painting the later heads grey (around 1970-71) based on what i can gather. Would have cut a lot of cost by doing so. What a find!
Certainly an interesting piece of history. But there’s a bit of work to turn it into a working engine and add the required parts so not much change out of 10k pounds and you can build a new race engine for that. If looking for an original engine of the time its invaluable but you still will not have a true “matching numbers” engine if originality is what you value.
It also shows how poor the casting and surface machining of the heads was back then, its needs work before assembly IMHO !
Its also had some “playing” with over the years. If you look at the head face photo you can see some of the valve head faces have cylinder numbers etched on them and some don’t and those with numbers are not all in the right cylinders. Normally you only etch valve numbers when dismantling a head or building a blue printed engine.
I have always believed Lotus painted the engines after assembly from original engines I have seen. Maybe because this was sold as a set of spares they painted the head without assembly, with it rather roughly with paint on the gasket face. They did not bother to paint the block
I would love to be able to afford to buy just for the history and to have the opportunity to measure up in detail an original set of major engine components. I hope whoever buys it posts some more photos and details
cheers
Rohan
Based on detective work on two Twin Cam Escorts of remaining original paint chips I think the completed short block assembly with front pulley and timing cover less oil pump (less sump also in the case of the Escort) was painted as a unit separately from the head. On 70-72 Escorts at least the head was not painted and fitted as cast.
The only way I think it would be possible to determine whether the head and block were originally painted together in the assembled condition is to find an original engine where the original rubber head to block breather is still intact. If it has grey paint on it we can then deduce that they were painted together - now there’s a challenge for the anoraks!!
I’m a fan of NOS parts as generally speaking the quality and tolerances are much better.
I would have been tempted to buy this if it has been marketed a few years ago. Someone will make an interesting purchase.
In the case of engines, the excellent availability of accurate engine parts makes the find less “essential”.
That engine would be better left as is as a museum piece and measurement reference standard.
No bidders, now re-listed:
Looking at the cam caps - does anybody know when nyloc nuts were introduced? From memory, I think contemporary Jaguar XK engines used plain nuts and serrated shake proof washers.
I observed that as well and wondered the same?
I have found only ‘aerotight’ type nuts when stripping down my '68 car which has never been apart, no nylocs.
A search reveals the following…
The Locknut using fibre instead of nylon was apparently first invented in 1931:-
en.wikipedia.org/wiki/Locknut
This company claim the first US patent on the Nyloc in 1964:-
aicfast.com/nylon-insert-locknuts/
So it seems they were around in 1964 when it is claimed the engine was new.
Alan
Thanks for that Alan.
I asked a chum whom runs an E-type Jaguar restoration business, he reckoned it’s bad engineering to use a nyloc in an engine, I didn’t tell him that I’ve been doing it for forty years
Did he explain why he thought this?
The heat from the engine softening the nylon inserts and the possibility of bits of nylon coming off.
I can’t say that the nylocs have ever caused me a problem.
Yeah he’s probably over-thinking it. Most types of nylon are good up to somewhere above 200C.
Probably nylon burns, I bet there is some residual.
Ever burnt your shoe lace ends, thats over 200
Betcha residual locks the nut
To my knowledge, no manufacture uses this. Nor has ever, the engineers use mechanical forces. Not suspect glue/composites.
I believe wire strand washers, are modern practice in this application.
This doesnt mean composite plastics dont work, merely not practiced. If you look at heat ratings of some poly/nylon that is pliable and resistant up to 350. But 500-700 is a bit of a stretch.
The reason you don’t see locknuts of any type in most engines is because the fasteners are tightened to a level where the stretch in the bolts/studs is sufficient to keep things so they won’t come loose. For those cam cap studs the industry standard for that size fastener is 21Nm but Lotus only specifies a figure of 12Nm (probably to save the threads in the head stripping). At 12Nm the stretch in the studs is insufficient to prevent things coming loose and so locknuts rather than regular nuts are specified in this location
On the subject of cam caps, they have been numbered - typical of a machine shop prior to disassembly. I guess Lotus could have done this, but neither of my heads has numbered caps. This would lend more weight to Rohan’s observation about the numbered valves - which are possibly in the wrong cylinder.
It is still an interesting find, but it does look like the head is a bitsa.
The cam caps should be numbered 1 to 10 and should match the numbers stamped on the head top surface adjacent to each cap. Some cam cap sets have other identical numbers on them also on early heads which appears to have been to keep the cam caps sets together. I have always presumed this was done during manufacture and not after during servicing due to the quality and consistency of the extra number stamping
cheers
Rohan