Non-Standard Engine Number

[Stevie-Heathie]

Hi there,

I have a Lotus-Ford Twincam engine with a 701M 6015 block. It runs really well and pulls like a train.

According to the unestimable Brian Buckland this 701M 6015 casting reference means it's one of the final run of the Mark 2 engines.

According to Lotus-cortina.com: "701M 6015: Found in the most odd places, rare and desirable . . . Something rather special, reputably of Ford Germany origin probably for the Escort T/C. Only made as an L block, a meatier casting altogether with big square main caps, the best basis for a competition engine, and much sought after".

So it's a good lump!

My curiosity concerns the engine block number. It's stamped in the normal place (between the mounts, on the carbs side), but it doesn't follow the normal Lotus convention i.e. LPxxxx. The number stamped there is "68M615".

The head does have a regular Lotus number "LPxx36" stamped in the usual place.

So - to the question:

Does anybody have an idea as to the origin of this engine block? Why doesn't it follow the "normal" Lotus numbering convention?

TIA
Steve

[Stevie-Heathie]

Well this IS a surprise. Silence reigns .

If this forum is stumped then this truly must be a mystery!

Steve

[rgh0]

Lotus heads stopped having the LP engine number on them around 67. So a 701M block does not go with your head. I presume the block was replaced at sometime. Where it was sourced from who knows, it may have had that number on it or maybe someone just made up a number and put it on. It is strangely similar to the casting number ?

cheers
Rohan

[elanfan1]

Steve,

I think you need to get in there with a fine wire brush and after a piece of chalk to show the numbers/markings up better maybe an inspection lamp might better aid a photo. The perceived markings can be very deceptive, once yo have it in your head it says one thing it is difficult to see what it might actually be. I've played with your photo a little and think I make out a G at the beginning. If your camera has a higher resolution mode use that as it as it will allow better zooming/editing.

image.jpeg (6.44 KiB) Viewed 1071 times

[Stevie-Heathie]

Thanks Rohan and ElanFan. Next time the carbs are off I'll get in there and have a good look at the block number.

[elanfan1]

Carbs?

[pharriso]

The number stamped there is "68M615".

That sounds/looks like an abbreviated 681M6015... an earlier block number, rather than an individual engine number.

[Craven]

I believe Twin Cam Escort engine numbers were prefix J . There are a number of 701 L blocks around that were used in a Ford engine replacement program and have no provenance with a LOTUS engine. The ones I?ve seen did not have any engine number stamped in the usual place.
Ron.

[512BB]

' The ones I?ve seen did not have any engine number stamped in the usual place'

Can also confirm a 701M engine I supplied and built for a customer recently did not have an engine number. I was annoyed with myself after some thought, as a block with no engine number could have gone into a car to make a numbers matching example, instead of a run of the mill Sprint. Hey ho..........

Leslie

[Stevie-Heathie]

Carbs?

I mean the carbs are in the way, preventing easy access to clean the stamping area.
Steve