x-flow crank , steel or not ?

[stoppodriver]

I think there are 3 or 4 cars running in the Classics with standard cranks , and I believe they are "standard " not TC even . As far as I know no-one has broken one yet . Regards AL .

[giffo]

I have just been reading this with interest. Could I just add, back on the original question?

I was toying with the old idea of modified Datsun cranks as I have been offered a couple

As far as I'm aware Nissan made these cranks from forged steel as apposed to billet steel that the aftermarket steel cranks are made from. These almost fit straight into the Kent block & are fully, if not over counterweighted.
There is some good pictorial info available if you do a search on the web.
An L16 has a stroke of 73.7 & a L18 a stroke of 78. Both slightly longer than the Kent cranks. Big end width & dia are as good as the same. This throws out other options as the Nissan rods are L16 - 133lg, L18 -130.2 & L26/28 130.6 with a little end dia of 21 instead of the Ford 20.625. The right pistons & you have a match or you just use the Ford ones. For those not using metric divide the numbers by 25.4 for inch sizes to compare.
Another option (like my 1100) is running Toyota Camry rods (3S). These are forged steel from the factory & can be modified to suit the Kent. (they are 138lg)

As for revving, my current 1600 with stock C&R's regularly runs up to 7900rpm. Has done for 3 seasons now & so far all good. I did go to first gear once instead of third which was a little scary due to the obvious.
Another time tho I did try to put one at some figure over 8500 & had disastrous results. This at the time was due to an incorrect tacho & inexperience.
So based on my personal experience I'm happy to go up to 8k but wouldn't want to go over it. As for the Nissan cranks, I have the data above plus more but I don't run one. A colleague who has a machine shop has done around 15-20 of these mods with no issues but I cannot say to what revs they are pulling. I believe 9k would be acceptable but can’t confirm.

Cheers

[stoppodriver]

Giffo , thanks for that - interesting about the Camry rods . I'll probably use standard crank and rods for the first motor . What i said earlier in the post about the cams all being A6 - i don't think that's till next season now , so I can choose a cam /gearing etc and make the power at lower revs . If i get any unreliability with cast crank , i'll try the Datsun ones ( you're right about them being Forged - but they are supposed to be very tough ) Might contact your mate who's done a few before ( is he in the UK ? ) , wasn't too keen on trying to explain it all to an engineering firm who hadn't tried it . Many thanks , Regards Al.

[GORDON STREETER]

I have seen the Datsun crank mod, try this link
http://www.geocities.com/marty7_nz/d...ank-index.html

[giffo]

( is he in the UK ? )

Nope Sorry. Australia. You could come for a holiday tho.
The article linked above is another version of the same article repeated many times on the net. If you place the unmodified L18 crank on the block or next to a std crank is it quite suprising on how similar they both are.

The Camry rods that I have are on a 53.3 stroke crank with typ ford piston Comp Height of 44.75 & the rods being 138lg. This gives a c/l crank to deck of 209.4 (typ 1600 block) Now I never built this engine and since were are theorising if I were to do this I'd choose a 1300 block & therefore a lighter piston but still giving a high rod length/stroke ratio. Would it make a difference? No idea but the theory says it will.
Next question is why don't I run it. No class 1100 class here so I run a 1600 instead.
This is going o/t now tho.

[stoppodriver]

Gordon , I think that is the chap I had been talking to via a clubman forum . Giffo - I would think i could buy a steel crank for the cost of a holiday in Oz ! do you think they'd let me on the plane with a couple of Datsun cranks as hand luggage ? Regards Al.

[zefarelly]

I think the Datsun crank idea is great but I haven't seen a datsun in the UK for 20 years so its probably easier and cheaper to buy a steel one

the twin cam crank is good, as Gordon said, std is good, EN19 is good for 9krpm and under a grand, if you think you can build a screaming hot rod 10k RPM Gordonesque motor with a load of cheap std bits your going to very quickly end up with a bucket of oily iron chippings!

[Chris Y]

It'd be raining Datsun cogs.

[GORDON STREETER]

I know of one of the old ICS twincams that showed 11000 on the telltale after selecting 1st instead of 3rd, and lived to carry on !!!!!

[stoppodriver]

I have been offered two L18 cranks , but don't know what the cost of the engineering work would be and who would be the best to do it . So if there's any engineering firms who want some sponsorship on the car . . . . . . . .
Regards Al.

[giffo]

a steel crank for the cost of a holiday in Oz

A friend of mine brought a Hewland FT200 back from England as luggage so I don't see why not.
If you have been offered 2 L18 cranks, grab them, even if you don't do anything with them for some time. They are not likely to show up that often. Even here you need to go looking for a suitable one.
When I had a Datto 1600 20 years ago I was falling over bits, now like all things Kent they are getting harder to find the parts you want.
As for machining, I'd expect any competent machine shop could do it given the right instructions & details, which you have in the above link. I'm talking about an engineering firm (fitter/turners) not an engine rebuilder. Remember also that you will need a flywheel made & a couple of dowels added. The Datto is only a 5 bolt connection.
I'm not likely to back out to the wk shop for a couple weeks but assuming I remember I'll place the datto crank on a 711m block, take a photo & then post it here for your reference.
Of the L18, L16 cranks I've seen finish machined (Only a couple) they have been finished off very nicely & certainly don't look like a "make it fit" job. A good method of assisting in getting it right is to find a rubbish Cosworth or Steel one to use as a sample. This will help in getting the Counter weights to a more reasonable size. That is how it was done here.
Given what you have said about your regs at dia 83.25 bore & L18 crank will give you 1698.5cc & at dia 83.5 bore 1708.7cc. Will that put you out side of your allowed spec?

[giffo]

Image of a modified Toyata S3 rod in a 1100 kent engine


Image of an unmodified L18 crank sitting in a 2723E block

[stoppodriver]

Thanks for that giffo , the first oversize you mentioned ( 83.25 with the L18 crank ) would be within our limit of 1700cc . Do you have a part number for the rods ? or details of exactly which motor they were fitted to , so I could price them up over here . Many thanks , Regards Al.

[giffo]

The block above should rear 2737E
Sorry I don't have a part number for the rods but they are Toyota S3 @
138mm long. They won't do you any good unless you going to run a chambered head with flat tops. You'll need a piston comp height of about 32mm to do this. ((78/2) +138+32=209) 209 being the approx block height.