Engine identification

[types26/36]

Here is a little more to add to the "L" debate, a couple of pics of a 2737 E block and its an "L" block.
Both the Lotus Cortina registry and the Dave Bean book list the 2731 E as a 1500 used by Lotus and they list the 2737 E as 1600 XFlow yet this has the "L" casting.
Quote: "2737E 6015 Early 1600 Xflow, 1600E, etc. "
Idea's anyone? I've heard the theory that the "L" has nothing to do with Lotus.....will we ever know?

[Dag-Henning]

I find it strange that something that "everyone" have judged as "never existed" , all of a sudden appears out of the sky.
This item has been discussed pages up and down over the last twenty years, and still something quite new pops up....
Proven wrong Rohan ? - not quite sure..! They fly people to the moon, and it may have been "usefull", - cos it's not difficult -, to put an "L" onto anything to achieve a better price. These days people pay ?1500 for a MkII Cortina airfilter-box, so why not....
Still, - yes, I may be wrong...!

[rgh0]

Well we keep learning new things - so what do I believe I know about the topic now

1. Ford made at least some 120E 6015 style castings with an L but not all Lotus Mk1 twin cam engines made with 120E blocks had the L
2. Ford made at least one 2737E 6015 style tall block casting with a L
3. Lotus Mk2 Twin Cam engine block castings from Ford all had the L ( 2731,681F 701M) -- but as I have not seen all Mk2 engines maybe some did not have the L - does any one have an porginal Mk2 engine block without an L?
4. Ford made at least one 681F style casting but with a ground off engine casting number xxxE 6015 and this was used by Lotus in a Mk2 engine
5. We dont know what the L stands for but it may not have anything to do with Lotus specific castings
6. The L castings appear not to have significant differences in dimensions or tolerances than the standard non L castings of the same casting style.
7. Across the years while the casting syles changed in details of external ribbing the key dimension of Bore Casting OD did not change and no block style or casting number including L castings are thus preferred for boring out or appears to have any preference for use in a bored out Lotus Twin Cam
8. I have never seen a 116E or 122E style casting with a L but that does not mean they dont exist

Can anyone dissprove any of those statements or can add any more true stratements to the list ? Are people adding the L to castings to get more money ? I guess its possible but its not that easy to do so it cant be seen.

cheers
Rohan

[types26/36]

I find it strange that something that "everyone" have judged as "never existed" , all of a sudden appears out of the sky.
This item has been discussed pages up and down over the last twenty years, and still something quite new pops up....
Proven wrong Rohan ? - not quite sure..! They fly people to the moon, and it may have been "usefull", - cos it's not difficult -, to put an "L" onto anything to achieve a better price.

I am not quite sure if I am being accused of something underhand here but if that is the case I take exception to the insinuations
I cannot vouch for the authenticity of the 2737 pics as they were sent to me by another forum member who was considering buying it and wanted my opinion, in the event he did not buy it but as far as I remember it was being sold as an XFlow (see the pin in the front main bearing cap for the timing chain slipper) and not a Lotus engine (so not commanding inflated Lotus prices)
As regards the moon landings ....well that's a whole new subject and there will always be the "Flat Earth Society" and the conspiracy theory's of the crackpots
BTW its not about proving anyone wrong, its about all of us learning about the origins of Lotus and I am surprised that there is no one around who worked in the foundry and can give some definitive answers as this and the "T" number which has been tossed about on many forums for years.....but I digress.....
Just to throw a little more into the melting pot, I found some more pics of my friends "L" engine LP 3719 LBA from his Lotus Cortina (and it was a 1965 C registered) he has had it more than twenty five years, long before ebay created a thriving market for anything Lotus.
Although I assumed it was a 120E I am now having doubts as this pic shows an "L" at the end where Lotus ground off the casting number! I cannot think of any casting that had the L as the last digit unless I am missing something.......this is interesting stuff (IMHO)

[paddy]

Some photos here from Leslie of another block (are these markings doctored?).

Paddy

[types26/36]

I don't think so as it clearly still shows its a 681F.
Here is couple more 681F blocks that have been on ebay.

[512BB]

The pics that Paddy posted for me, thanks Pad, show a 681F L block, with SQUARE main caps, as it came from the factory. Quite unusual no? I would think that this block was one that was cast in around 1970, as Ford were going over to the 701M L block for Lotus, but the case casting number has not been changed yet.

Leslie

[types26/36]

show a 681F L block, with SQUARE main caps, as it came from the factory. Quite unusual no?

Hi Leslie, yes thats quite unusual, I noticed the square caps but assumed they had been changed...... as we know with Lotus very little is written in stone or even cast in the same mold
Leslie, what size welsh plug (cor plug) does that engine have in the rear face (flywheel end) I could be wrong but I seem to remember the 701M has a 2" .....the same as a 711 where as the 681F is 1 5/8" same as the side ones.

[Dag-Henning]

Brian, I am not suggesting you have done anything suspecious, I have no reason for even thinking that you have ! What I am saying is that this is the first time in my 30 years with these blocks, that I see a 2737 "L".... ! On the other hand, I have never ever seen a 681 with square caps either, - unless later added -, so I may have a lot to learn still !
The "common truth" is that square caps came with the 701-block, but again, that may also be wrong. And when did the hole in the gallery for the oil pressure pipe go from 1/4 to 3/8 ??? ( - hope I remember the sizes now...... )
Dag

[bcmc33]

And when did the hole in the gallery for the oil pressure pipe go from 1/4 to 3/8 ??? ( - hope I remember the sizes now...... )

I guess the sizes were 1/8" BSP & 1/4" BSP - as my current 681M block has 1/8" BSP and the previous 681M block had 1/4" BSP.

[512BB]

Good afternoon Brian,

The picture of my 681F with the square caps has the smaller core plug on the rear face. I am sure that these caps came with the block from the factory, as I have examined the block very carefully, and any markings for position of the caps, ie 1 2 3 4 & 5 have only been done once. Also any original machining marks between the block and the caps correspond.

Whilst we're on blocks, does anyone know the definitive answer as to why on some blocks, the identifying casting number has been ground off, leaving just the 6015 BA, or no number at all. I have heard it is to get past scrutineering, if you are trying to use a later block than is permisable in a given class, for racing.

Answers on a postcard............

Leslie

[Dag-Henning]

- there are no definate answers , that's for sure...... However, according to some litterature, you will find 120E, or 122E, on some Mk.1 Lotus Cortinas, and I guess S1 Elans as well. When the Mk.II Cortina Lotus came out late -66, the model was designated 3020E. I have blocks with the "120E" ground off, and the 3020E stamped on the flattened face..... My very unqualified ( ) guess is that this was done in between the 120-blocks and the 681, just in order to be able to mark them. What is being done nowdays is another story, and a lot (!) of pre-65 racecars run 701 blocks with no casting numbers on. Cheating ? No, I don't think so, but that is another discussion..... ( - with no definate answers either...)
Dag

[rgh0]

The engines were orginally assembled by JAP and then by Villiers and finally by Lotus when they moved assembly to Hethel in 1967. I have always assumed that griinding off of the Ford casting number was done either by Ford or by Lotus or the other assemblers due to some sales agreement restriction that stopped Lotus using the Ford casing number. it only appears to have been done in the 65 to 69 period from what I have seen in cars but with so many engine changes its hard to tell exact start and end dates

regards
Rohan

PS the original twin cams came on a 116E block which was the first 5 bearing ford 1500 block and strangely not mentioned on the Lotus Cortina web page. I have never seen a 122E block so not sure what they look like or where they where used versus the 120E and 116E blocks in ther mk 1 twin cams

[elansprint71]

I'm struggling with engine identification on my "new" Elan; the PO, who's father owned the car from 1970, said that his Dad took it to Mike Spence to have the engine upgraded to BRM spec; it carries a Mike Spence plate on the orange crackle BRM cam cover with the engine number 125670/1 (which, of course, means very little, at least to me, the most cynical of cynics).
Stamped in the usual place (what kind of idiot hits an iron casting with a hammer and stamps?) appears to be: P12916L A-A although this is a little feint.
In the DVLA document the engine number is shown 036/1 (the chassis VIN number is also wrong, but that's due to a shaky hand with the electro-engraver and can be fixed by me sending them a photo.

Any views on the engine number(s)?

edit: btw engine block is dark green.

[trw99]

Pete

I suspect that the engine no should read LP12916, which were fitted to Elans from July 1968 through November 1968. However that is a full year earlier than the date of first registration of your car. Was your car retro fitted with an earlier Spence engine? The LA-A refers to wall thickness of the block.

Someone posted a description of the Spence BRM engine numbering system on here a while ago. I can not find it via a quick search. I believe the 036/1 number may have something to do with that. They were stamped onto the Spence cam cover plate.

I think Mark will be able to help you more on this question.

Tim