6 bolt crank in a 120E block.

[rjaxe]

Can anyone advise on this issue. I have seen an article which implies it is possible to fit the 3020E crank into a 120E block with suitable mods. I am not clear what these mods are, if anyone has experience of this arrangement their comments would be welcome.

[types26/36]

Yes you can fit the 1500 six bolt crank into the 120E four bolt crank engine, you would need a crank,flywheel and bolts, rear oil seal carrier and a sump.
The spigot bearing is a needle bearing and is a smaller diameter than the roller bearing or bush on the early models and you would have to fit a different spigot shaft or even turn it down to suit
You would also be advised to fit the 125E con rods if you don't have them, I think the old engines had a pressed steel front pully and the later engines have a cast pully which you could also fit.
I think you can use the original oil pick up but my memory is fading fast.

[rjaxe]

Thanks for your response Brian, found out a bit more myself, the crank webs hit into the block casting so some relieving required mainly at the rear of the block with just a bit at the front. I do not have a 6 bolt sump available but with a 4 bolt version positioning the original oil pickup and return there is no clash with the 3020E crank/bigend. So far so good. Just concerned about oilways etc is there anything needs to be considered here? Just to explain my interest in this issue, the current block on my Plus 2 is at +.040, so a sleeving exercise probably comes next, I have a 120E block which only needs honing to take it to standard size, a better bet on the face of it. I am sure some pundits would recommend the 701 block but finding one is about the same as my success at the lottery, I leave you to judge what this is.
Cheers

[rgh0]

The screw in centre oil pick up for a 120E block will require modification to the sump to remove the baffle that is in the way but otherwise fits in OK.

cheers
Rohan

[types26/36]

Hi Richard,
I'm surprised the the 120 block needs relieving as I fitted the 6 bolt crank to my S2 along time ago and don't remember having to relieve it, I subsequently fitted a 1600 711 crank and did have to relieve both the block and the crank (then balance the crank) plus some other mods.
If your 120E block was originally a preXflow OHV engine then there is a pivot pin in the front main bearing cap that needs removing (its for the timing chain slipper on the OHV engine)
I don't recall any issues with oilways except for the jackshaft, the Lotus one has more oil slots then the OHV camshaft so use Lotus jackshaft and spacer.

[rjaxe]

Interesting comment Brian, there was no doubt my block needed to be relieved, I have posted a picture below to show how much. Just guessing but maybe the answer lies in the block original use, the one I have was from a 1300cc pre-xflow Cortina so had a small throw crank. As I say just a guess I dont know enough about them to comment further. Thanks for the additional pointers on the front bearing cap spigot and the jackshaft and thanks also to Rohan for his very helpful comments.

[types26/36]

the one I have was from a 1300cc pre-xflow Cortina so had a small throw crank.

Richard, are you sure it is a 1300 as far as I am aware the preXflow was a 1200 & 1500 if your block is a 120E it would be a 1500.
If it is a 1300/1600 then it would have been a Xflow.
If you do have a 1300 block I don't think it can be done as the throw of the 1500 crank pushes the pistons well out of the top of the block.
http://www.lotus-cortina.com/library/block/blocks.htm

[rjaxe]

To be honest Brian I cannot be sure what the original engine use was, it was said to be a 1300 Cortina engine but I was only interested in the block so did not enquire further. But now having roughly measuring the parts, the crank stroke is 63mm and the bore is 82.5mm which makes a capacity of 1347cc which seems to make sense bearing in mind that the pistons are marked +.060". There was a Ford model called a Classic which I seem to remember had a capacity of 1340cc perhaps the engine came from one of these cars, who knows?
Nevertheless my main concern is suitability for twin cam use and so far the feedback has been positive provided I follow the advise given.

[types26/36]

Richard, if it has a stroke of 63mm then it is a 1300, I tried many combinations of con rods/cranks and blocks even using the short 1300 conrods and I just could not get the 1300 block to work.
It should have a casting number on the exh side which will tell you what it is.

[rjaxe]

Thanks again Brian, the block I have is definitely a 120E-6015 see picture below.

[types26/36]

Yep.....that will work.

[rgh0]

Interesting comment Brian, there was no doubt my block needed to be relieved, I have posted a picture below to show how much. Just guessing but maybe the answer lies in the block original use, the one I have was from a 1300cc pre-xflow Cortina so had a small throw crank. As I say just a guess I dont know enough about them to comment further. Thanks for the additional pointers on the front bearing cap spigot and the jackshaft and thanks also to Rohan for his very helpful comments.

Interesting that you had to relieve a 120 E block to fit a standard 6 bolt 1500 crank as my recollection was that it was not required - I know you have to do it to fit a datsun L16 crank or long stroke 1600 crank. The picture you posted shows similar relieving to what i do to fit the datsun L16 crank. I have a couple of standard 6 bolt 1500 cranks and lots of 120E blocks here and must check them more closely when I get a chance.

cheers
Rohan