x-flow crank , steel or not ?

[stoppodriver]

I'll be building a 1700 cross flow over the winter for use in a Classic Hot Rod , nearly all the other cars are running all steel bottom ends - is it really necessary ? I know Barry Lee ran a standard crank and conrods when they had the rule that someone could buy your engine for £350 . The races are only two heats and a final and are only about 25 laps max - revving about 8500 . I was toying with the old idea of modified Datsun cranks as I have been offered a couple . Any idea how long a standard Ford one would last ?

If you read this Gordon , I'd be interested to know what most people used in your Hot Rod days - if they used standard ones what treatment or engineering mods were used ?

Regards

AL.

[Al Weyman]

In my hotrod days we used the TC steel crank but never revved them to 8500 as I recollect. A few quid saved now may well come back and haunt you.

[phoenix]

As I recall, the standard x-flow crank gives a stroke of 77.62mm and, if everything is balanced is safe for ever at 6500 rpm continuous with occasional 7000+ rpm use.

The twincam had a stroke of 72.75 mm, so safe for higher rpm than the x-flow but not, I would have thought, 8500 rpm if you want reliability.

A steel crank seems to me a sensible choice - with the lightest possible pistons and probably some steel rods too - if you want the thing to last!

[AU N EGL]

Forged cranks, New and balanced.

[Gus534]

I was going to start a thread to ask if a crossflow flywheel would fit a twincam, but reading this thread the answer appears to be yes. Can anyone confirm this? Also does a 2000E box fit to the twincam block, and are there any issues about location of the starter motor?

[GORDON STREETER]

Don't forget that Fords (including Lotus) changed from 4 to 6 bolt cranks and flywheels and rope rear oil seals to normal oil seals. All the ford Kent engine stuff is interchangeable (sometimes with a bit of grinding) The gearbox is separate from the bell housing so you can mix n match with starter motor positions and hydraulic or cable clutch and all the older style 3 rail gearboxes will fit.
Fords also changed the size of the crankshaft spigot bearing in the early to mid sixties.

[Al Weyman]

I would say OK on all accounts from memory but as I have'nt messed with them since the 70's someone else should prehaps confirm.

Opps cross posted with Gordon and he knows all the answers on these.

[Copperbottom]

I rev my standard cranked 1700 xf to 8krpm regularily,I wouldn't expect it to last long revving to 8500 though,the best thing with using a standard crank in a classic hotrod is that you can use whichever cam that you want whereas with a steel crank you're limited to the old cosworth A6 profile,my engine makes maximum power (170bhp)at 7300rpm so there's no point in revving much higher than that.The fact that you can choose a cam profile means that you can build the engine with the power band lower down negating the need to use 8500rpm and gear the car accordingly.So no an all steel engine is not a necessity.

[GORDON STREETER]

Originally Posted by stoppodriver

If you read this Gordon , I'd be interested to know what most people used in your Hot Rod days - if they used standard ones what treatment or engineering mods were used ?

Regards

AL.

As most people were on a budget in the early days we used std Ford cranks and only in my last season did I use steel internals.
A well built and balanced 1700 crossflow will rev and hold 8000 without too much trouble and the cranks don't often break (except in FFs where the flywheel often hits the track) however std rods can be a problem and you should always use decent big end bolts. If you go for steel rods you might as well go the whole hog and get narrow journal ones complete with a steel crank as well, because if its put together properly you won't have any problems .
Don't forget that these engines are years old and are not as available as they were. Years ago you could go to most car breakers and find loads as the Kent engine (in different sizes) was fitted to most of the Ford range for 25 + years. Now they have dried up.

[bdwoody]

gordon i had a 1558 block and steel crank a few years ago and tossed it in the scrappy coz no one wanted it !!!!!doh.

[GORDON STREETER]

Originally Posted by Copperbottom

whereas with a steel crank you're limited to the old cosworth A6 profile.

Could you explain ?

[GORDON STREETER]

Originally Posted by bdwoody

gordon i had a 1558 block and steel crank a few years ago and tossed it in the scrappy coz no one wanted it !!!!!doh.

You think that's bad, I scrapped a complete Lotus cortina and used the engine in my old Anglia van

[bdwoody]

i did a similar thing scapped a lotus and put the motor in a mk1 escort....estate.:-]

yeh the camshaft thing is a new one on me ?

[Copperbottom]

Originally Posted by GORDON STREETER

Could you explain ?

Classic hotrod rules on engines:

3 – ENGINES

Ford Kent pushrod engines, limited to 1700 c.c

. Lightening and balancing allowed. Steel crankshafts and
con rods are allowed. Both cross-flow and pre-cross-flow motors permitted. Use of the 1500 block with a
cross flow head is allowed. Any other engine must be discussed prior to use. Engines must stay in original
position. Only the Cosworth A6 cam (or equivalent) is allowed in engines utilising steel components.
Engines built with cast components may use any cam. Vernier wheels are allowed. Offset dowels are
allowed. Duplex timing chains are allowed. Cylinder heads must be of cast iron with only two valves per
cylinder – otherwise free. Rocker gear may be modified, although roller rockers are not permitted. Steel
rocker posts are permitted. Any type of modified push rods are permitted. Manifolds are free. Carburettors
can be 40, 45, 48 or 50 DCOE Webers (or Dellorto equivalents) but in any case must only have a maximum

choke size of 36 mm. Only side draught carburettors may be used.

I use stress relieved, polished lightened and balanced rods with forged pistons and arp rod bolts btw.

[GORDON STREETER]

Explained ! Obviously I didn't know you were referring to those specs

[Copperbottom]

It's in the original question.... you know where it says "I'm building an engine for a classic hot rod"
Nice to meet you at HT racing last month Gordon

[terence]

Oh Gordon,you did'nt read the label.!!

[stoppodriver]

Thanks for all replies , Copperbottom - at the drivers meeting in September - it was agreed that all crossflows will have to use the A6 Cam , which is part of the reason I asked the question - as it was i would have done as you suggested and used a cam with a lower range . Regards Al.

[Copperbottom]

You could alter the cam timing to give max power lower down

[stoppodriver]

Very true , something i'll look into . Many thanks , regards Al.

[GORDON STREETER]

http://uk.youtube.com/watch?v=rZVgnCevtpI
Just something to remind some of us how good it used to be. With George on form !!

[zefarelly]

I ran an A6 in a 1500 for a few years and it was great, 7500 all day long, dead reliable

until I started fiddling with it!

[Copperbottom]

Good old crossflow power .George beat most of the regulars in his class in a borrowed/shared mk2 Escort at an open autocross meeting that my club ran near Heathfield in 1988,luckily for me I was in the class below

[Copperbottom]

Originally Posted by stoppodriver

Very true , something i'll look into . Many thanks , regards Al.

The A6 has a similar power band to the KC264 that I'm using in my rubber cranked engine so it should be possible

[JamesH]

S'Funny. George Polley lives in the next village running his tyre business. (deepest darkest Cambs) sometimes pop round if I need a new set for the Locost. Always very friendly bunch there, but you wouldn't think of him driving like that!!!!