x-flow block - 681F

[DaveMorris]

Apart from their obvious age (IIRC then these blocks predate the 711M blocks),

are there any watchouts on this marque of x-flow blocks ?

 

I know that oil pressure tapping is different size but are there any other significant differences ?

 

 

 

X-flow(er) power now resting. Trying Vx for a change.

[Nigel Riches]

Hi Dave, I seem to recall there isn't so much "borabily" in the 681 block as the 711 type, you might call Burtons or some other Ford specialist if you were thinking of reworking the cylinders.

 

Just been out to the library in the garage in found my Wallage book on X flows, apparently the engine was strengthened in the mid 1970's, a stiffer crankcase, stronger main bearing caps, larger diameter cam followers, are some of the changes, hope this has been of assistance. Regards Nigel.

 

1982. 5 speed, clamshells. B.R.G / Ali. The True Colours.

[jingars]

From the introduction of`Rebuilding and Tuning Fords' Kent Crossflow Engine' by Peter Wallage;

 

"The Crossflow was considerably strengthened in mid-1970 with a stiffer crankcase, stronger main-bearing caps, larger diameter cam followers and various other modifications. The stronger engines are the ones to go for if you have higher power in mind. They are commonly known as `Seven-eleven M' engines because the casting number, which is cast in raised letters on the side of crankcase, starts with 711M. If you want to stay with the earlier engine for any reason - either because it's the one you've got or you need to keep the car in period as a classic - fine. The pre-711M engines can be tuned just the same as the later ones but, if you have the choice, go for the stronger 711M."

[ncm]

Hi Dave,as above for maincaps etc., BUT be aware that the width between the engine montings on the pre-711 blocks is narrower. If fitting into a Seven you will require a Twincam N/S engine mounting bracket if CC can/will still supply..

 

Brian.

It would also be worth checking to see if the block has the rear dipstick hole as early cortinas had the dipstick in the timing chain cover which would render it inacessible in a seven 😳

 

Edited by - ncm on 18 Oct 2007 14:48:53

[DaveMorris]

Thanks for the feedback.

I've heard enough (also talked to my usual engine builder who gave similar comments).

Dave

 

X-flow(er) power now resting. Trying Vx for a change.