Lotus Elan

Crankshaft identification

PostPost by: englishmaninwales » Tue Jun 02, 2015 10:06 am

What identifiers are there for a genuine twin cam 6 bolt crank? I've seen some with a cast 3020E number, plus are the main journals and crank pins for std/undersize as per the workshop manual specific Lotus or generic for Ford? Anything else?
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PostPost by: englishmaninwales » Thu Jun 04, 2015 8:03 am

Okay, 136 views and no answers, so I guess it's a bit tricky! I'm hoping to collect the bits to convert my 4 bolt rope seal crank to a 6 bolt lip seal. (And I've missed 2 later type sumps for sale now :cry: )
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PostPost by: types26/36 » Thu Jun 04, 2015 9:13 am

As far as I know Ford only made the 1500 six bolt crank for Lotus, previously Lotus had used the 1500 four bolt crank.
When the six bolt came out it was for the 11/13/1600 Xflow engine but because Lotus was still using the 1500 block Ford carried on making it as the Lotus 1558cc engine was still used in the MK2 Cortina Lotus (designation 3020E) so any six bolt 1500 crank with 3020E would be a Lotus crank.
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PostPost by: Craven » Thu Jun 04, 2015 9:52 am

Hi,
Ford did make a 1500 6 bolt crank for the Cortina, I understand it has smaller counter weights. I have no knowledge of identifying numbers but can confirm the Lotus 1500 crank has 3020E on it.
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PostPost by: types26/36 » Thu Jun 04, 2015 12:17 pm

Ron,
Have you any info which Cortina's had a 1500 six bolt crank? the Mk1's had the 1500 four bolt pre Xflow and the Mk2's had a Xflow engine a with six bolt crank although I do believe the first couple of Mk2's were fitted with the MK1 1500 PreXflow engine.
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PostPost by: Craven » Thu Jun 04, 2015 12:35 pm

Hi Brian,
I came across this type of crank in a factory exchange engine, it was fitted in an ?L? 701M block that had been linered back to 80.9mm by Ford. Just another one of the Ford ?L? block mysteries so no specific car sorry.
Ron.
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PostPost by: promotor » Thu Jun 04, 2015 2:02 pm

Hi Brian,

I've got a 6 bolt crank in my 1967 mk2 cortina 1500 (2731E block) which is definitely not a lotus crank as I've had it out not so long ago - I can't remember exactly but I believe the crank is also marked 2731E. It has much smaller counterweights on it to the genuine 3020E lotus crank.

EDIT : the 2731E block and crank was only in production for 8 months or so so are incredibly hard to find as singles never mind as a pair!
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PostPost by: types26/36 » Thu Jun 04, 2015 5:07 pm

Hi Al,
Thats interesting as I thought the 2731 was a Lotus four bolt engine, well at least this one is as it has the "L" cast in between the engine mount and as can be seen it has the Lotus front cover and four bolt flywheel :?
.......another day and another anomaly :shock:
PS. I still need to send you that bitsa diff if thats ok.
Attachments
2731E.jpg and
2731E L ON BLOCK.jpg and
2731E 4 BOLT.jpg and
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PostPost by: promotor » Thu Jun 04, 2015 6:01 pm

Brian et al,

I have had a look in my Ford parts books for mk1 and mk2 cortinas including Lotus cortinas -

the standard 1500 crank is 2731e 6303;
Lotus cranks are 125e 6303 for the 4 bolt crank/ropeseal and 3020e 6303 for the 6 bolt with lip seal;
The 125e 6303 crank is only mentioned in the mk1 lotus book;
The 2731e block is only mentioned in the mk2 book and doesn't mention Lotus;
120e Lotus blocks (aswell as standard 1500 120e blocks) are mentioned only in the mk1 book;
3020e blocks are mentioned in both the mk1 and mk2 books.

I expect the 2731e was the latest design of the Lotus blocks AT THAT TIME and those that we rarely see with 2731e and the "L" between the engine mounts is either a Lotus block that someone forgot to grind the number off (who knows if all the later blocks with the numbers ground off DIDN'T have 2731e on it prior to foundry workers getting there?) or from the "seconds/wrongly machined/cast line".
If the block has Lotus numbers on the engine mount then it must have come in a Lotus engined car from the factory, if not (engine numbers aren't in "Lotus" style but in a Ford style) then maybe it was used for something else such as a standard cortina. No reason that the other lotus parts couldn't be added by an owner at a later date.

HTH?

And yes - you can send me the bitsa diff whenever you're ready! Have you got tired of turning the other diff every week or so? :-)

P.S sorry to the O.P. for the thread hijack! Hopefully we'll be back on track!
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PostPost by: englishmaninwales » Thu Jun 04, 2015 9:16 pm

Excellent, that's very helpful.

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PostPost by: promotor » Thu Jun 04, 2015 10:53 pm

Forgot to mention that there is also the 4 bolt lip seal standard 1500 crank - that is 116e 6303.
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PostPost by: rgh0 » Fri Jun 05, 2015 9:18 am

I have been told that the Lotus 3020E 1500 6 bolt crank was also used on the Cortina 1500 GT when they converted to the 6 bolt crank sometime in 1967. i have never been able to confirm that.

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PostPost by: Alois » Mon Nov 07, 2016 10:14 am

please help tu identifi my crankshaft
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img_0119.jpg and
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PostPost by: promotor » Mon Nov 07, 2016 10:30 am

Alois wrote:please help tu identifi my crankshaft


That's a genuine Lotus Twincam 4 bolt ropeseal crank.
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PostPost by: englishmaninwales » Mon Nov 07, 2016 8:20 pm

I took a look at the 4 bolt crank that came out of my 66 Elan and it differs in 1 digit - 125E 6303, but with the same DO4. This number fits with previous posts above, so presumably there were 125E 6302 and 6303?
(It is purely academic now for me as I have up graded to a 6 bolt crank, absolute bliss with no rear crank oil leak).
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