Twin Cam Engine +2 S

[k44ent]

Hi, I have just joined this forum after lurking around for a while. I have a Lotus Elan +2S which I bought in 1999 and have not used much. I am in the process of a full rebuild and have just started stripping the engine. I would like to know more about the engine (and car) as I am suspicious that my car has a non-original engine. The casting number is 2731 6015E, also has T3 cast into it. The build date cast is 7B6. I have stripped the engine down and it has new QED pistons and the bores measure 83.9mm (+ 0.60") and still have the honing marks showing. The con rods are 125E and the crank is a 4 hole and has number 116E 6303 on it. The car was registered in September 1970 and has a chassis number 50/0110L, now has a non original Spyder chassis. The engine number according to lotus should be F21979 but I can only find 7 B 7 0 stamped on it above the engine mounting holes. The block is not stamped LA. LB etc.
I am really after some guidance as from what I can gather the engine block was cast in February 1967 , the chassis number would indicate a 1968 car but the car was registered in 1970 but was sold as built so what happened between??
Thanks in advance
Adam

[Elanintheforest]

Hi Adam and welcome.

Your chassis number is indeed for a Plus 2 S, which left the factory on 8th Sep 1970.It originally had engine number 21479, and the car was originally white.

The car has pretty obviously had an engine transplant at sometime, with a much earlier engine being fitted. Your original engine would have had a 6 bolt crank. That's no big deal.....it happened a lot with Elans!

Many cars have been fitted with a Spyder chassis. It's a matter of taste whether you prefer the Spyder one to the original, with the engineering types tending to prefer the Spyder, and the originality guys the Lotus.

Mark

[k44ent]

Mark, thanks for the info, it tallies with the data I received from Lotus but what I can't understand is that if the car was built in 1970 would the chassis number not start with 70..... From what I have read +2's started at 50/0001 in June 1967 so a car with number 50/0110L would be the 109th Elan +2S so I guess would have been built in 1967 / 68 as they reached number 2536 by December 1969 in which case is the engine not of the correct age with a casting date of Feb 1968? Have I got this completely wrong or is something not quite right. Maybe it was built in 1968 and not registered till 1970. How does the engine number quoted by lotus (21479) fit in with the chassis build date?

[Elanintheforest]

Sorry Adam, you are absolutely right....your chassis number should start with 70/09 for Sep 1970. What is actually stamped onto the chassis plate (rather than is in the logbook)? It could be stamped or scratched on by the way.

When cars had the 50/0110, they didn't have the 'L' on the end....that designated a domestic car in the new structure of the chassis number. So what you have seems to be a combination of the old and new, which seems odd. Transcription error somewhere?

A picture of the chassis plate may reveal all! If yours is an early car there will be plenty of evidence....different interior, door handles, dash, no spot lights, different boot opening mechanism and a lot of detail changes under the bonnet. Put some photos of your car up, and we'll soon see what it is.

The engine number is recorded against the 1970 September Plus 2 S with the last digits of 0110L, that's all. There is no numerical relationship. Engines were (roughly) numberd from no, 1 in 1962 through to no. 32000 (ish) in 1974.

Mark

[k44ent]

Thanks for your help Mark, appreciated. I am not with the car at the moment it's at my parents house. I'll nip up tomorrow and take some pictures. It's in bits at the moment and the chassis that came with the car is a replacement spyder standard chassis. The car does not have a chassis plate, would the number be marked on the body? it's red at the moment but I can see the white paint under it so maybe the original body!! Which bits do I need to photograph? I have a printout from Lotus and it reads as follows

Chassis Number. 50/0110L
Engine Number. F21979
Date of purchase. 16/09/1970
Assy. Built
Colour. White
Gear Box. semi
Engine. S.E
Tyres. Goodyear G800
Extras. Chrome wheels, tinted front screen.

Adam

[trw99]

Engine numbers starting 21### would be correct for 1970. In 1968 engine numbers were starting in the 17/18###'s.

During early 1970 after the introduction of the new VIN system, a number of cars were recorded still with the type number before the unit number, not by the factory but by dealers or licensing offices. It would appear that the previous system provided a convenient 'shorthand' number.

The suffix L would indicate that the full VIN would be something like 7008180110L indicating an August build date, batch number (18 or thereabouts) allied to an invoice/purchase by dealer date of 16 Sep 70 and you can put in your registration number here https://www.taxdisc.direct.gov.uk/EvlPo ... =directgov to find the date of first registration, presumably sometime after 20 Sep 70 or so.

Tim

[CBUEB1771]

When cars had the 50/0110, they didn't have the 'L' on the end....that designated a domestic car in the new structure of the chassis number.

The numbering scheme that included the alphabetical last character was introduced in January 1970. This is described in Lotus Service Parts Lists published from 1970 onwards. So if any documentation includes "L" as the last character the car would have been produced after January 1970. I suspect the information from Mark is correct. "L" does signify a +2S made for the Great Britain and Northern Ireland markets. I don't know how well locations of identification numbers for US market cars compare to those for other markets. My Federal +2S, 0170N, is an August 1971 build. The chassis plate in the engine compartment has an abbreviated number as does a plate on the driver's side door jamb. The door jamb plate has a slightly different syntax for the chassis number and also includes year and month of manufacture. The only place that the full number, beginning with "71", appears is the plate at the base of the windscreen. There can be many other places where hand inscriptions may be found but these are only shorthand that was probably used to sort parts on the assembly floor.

[trw99]

Russ

The location and style of VIN plates were different for the Domestic and Federal markets. Domestic cars only had the the full VIN on the plate located in the engine compartment.

Tim

[k44ent]

Thanks for all the info everyone. I am going to take a good look round the body tomorrow and look for a number starting with 70....
It looks like my car is a 1970 but the reg document etc just gives the last part of the chassis number.....0110L and the 50 is just carried over from the old system. It looks like the engine is from an earlier car but it does look in good condition so not all bad.

[promotor]

That engine block is a 1500 block for the early mk2 cortina. I have seen this with an "L" behind the engine mount but it's quite rare. The ones without the "L" were the last of the non-lotus pre-crossflow blocks to be produced and as such are believed to be a good block. I have one in my mk2 cortina.

The number stamped on it above the engine mount sounds like a Ford number.

The 116e crank could have come from either a mk1 cortina or a consul classic, or from a very early elan. It's not got the same bulk as a lotus 125e crank - 125e ones are bigger on the webs - but would have been ok for the earlier low power cars. I would say the crank may not be up to the requirements of 110+ bhp though.

Gives you a good opportunity to fit a 6 bolt lotus crank though - and you should already have the push-fit pick and return pipes in the block as that should be what came with the 2731 blocks. So you'd just need a 6 bolt sump.

Hope this helps.

[k44ent]

Thanks promotor, very helpful. It already has the 125E con rods but only the 116E crank. Any ideas where I would get a 125E crank and matching sump from?

[types26/36]

If you fitted the 6 bolt crank you will also need a 6 bolt flywheel, oil seal carrier, needle roller spigot bearing and the gearbox input shaft to suit.

[k44ent]

Ok, had a look at the doors and they have 70110 engraved, also a plate on the door bottom which reads H3-B.

[jono]

I think that there is usually a Dymo label under the paint within the trailing edge of the engine compartment on the drivers side which shows the unit number - sometimes it is obscured under layers of paint but it may be visible if present?

If I were you I would try and source a rebuilt short bottom end with all of the 6 bolt bits and sell of your short motor for parts - some of the vintage race boys and 'purists' may pay good money which might more than cover the cost of a new short engine.

Newark engines often have such short TC motors available.

Jon

[luckyboy]

hi any ideas about this "L" blocks story I have cam,pistons etc. and everything original
I want to sell it on ebay but can not find much info ,so I thought I would come to the profi's

2731E 6015 "L" block T1