Head and crank ?

[Anonymous]

Help ! Ive just discovered my head has nice little cracks in between the valves on 3 cylinders. A trip to a few local yards only turned up examples with the same problem.

What is the general consensus on the better head - ive heard about XD/E heads being better. If thats the case do these heads need any mods to run PULP?

I have also heard about some people using late model 4.0 cranks for smoother revs (or at least talking about it) and also getting a higher redline. Where would you get one of those and what would you expect to pay ?

Cheers
Tom.

 

[xctasy]

If the engine uses the stock management systems that XF and XG engines were equiped with, then thats the one to use. Ford spent a lot of time improving the burn characteristics of that head. The intake valves were bigger, but the intake flow was no better because the valve was shrouded. This creates more spin, better burning, better economy. The valve seats were of better material, and suit the pump ULP better than pre 1986 heads.

The point to note, though, is that if the kidney chamber is modified for performance, then it becomes detonation prone. Change the carb, shave the head, adavnce the ignition, or do something away from the spec Ford intended, then it's likely to detonate. The XF head would be much better with some grinding to remove the shrouding.

Care of Jacks Chross-flow Chronicles article.Both these heads show the types of chamber. The top one is the earlier XE EFI cahmber, common with XD's, the bottom is what I think is the carby XF head, with the high-swirl chamber BUT with shrouded intake valves.

The earlier XD1/2-XE head likes the XF-spec 1.8" intake valves, 50 thou up from the stock ones, and gains flow without shrouding. It is less detonation prone. The inserts aren't recommended as being ULP compatiable by Ford, but I've never heard of any problems with early failure. On the first awfull LP Gas system I used, a head gasket faliure resultied in the melting of the alloy chamber about the exhast of No.5, and we still used the stock insert after welding the head up again, and giving it a recut! Changes to the spark, compression ratio weren't an issue, but I'd personally not use ANYTHING LESS than PULP 96 on one of these heads.

The grade of pump petrol is fairly shocking. Even if its alloy, the head can't take lots of compression unless you have an octane booster, LP Gas, or water/methonol injection, stay clear of any more than 8.8:1 on an XF, or 9.35:1 on an XD/XE head.