A10 cylinder head reconditioning

[kiwipom]

hi guys,yeah Musky that was c.degs had me a bit worried as they took more than a light tap but they are in. They were standard guides so imagine they must be right, yes am getting the valves fitted with seats cut, I'll keep you informed,cheers

[compressorman]

Hi
 sorry i have been away from the forum for a while (work sucks)
i too have just re-conned my cylinder head but instead of replacing the guides i had them reamed out and bronze K liners fitted
this is recommended by ford for there zeteck engines i am led to believe the pros are better heat transfer,less friction,and more so for us it prevents the guides coming loose after many guide changes  and only ten quid each ! including the seats recut value !!!
il let you know how they get on
regards
ian

[kiwipom]

hi guys, got the valves sorted but just realised that I have the wrong springs and collars so more parts to get. The inlet valves are the 38mm/ 1.5'' big valve super rocket ones and exhaust 35mm/1.38'', cheers

[Nourish]

" and only ten quid each ! including the seats recut value !!!" - Who did that for you?

A pal of mine had this done on his Commando head by a racer/tuner up in scotland(he died not long after) but one of the liners came loose! I'd still consider having it done though - seems like good practice to me.

[KeithJ]

Interesting about the K valve guide liners.  It looks like K liners are made phosphor bronze but Colisbro guides are a copper-nickel-silicon bronze.  Think I'd prefer the Colisbro material.  I understand phosphor bronze works best when well lubricated, not the situation on an exhaust guide.  Surprised the K liners work so well.   
ATB

[chaterlea25]

HI All,
The big difference between Ford and BSA is that the BSA is aircooled !!!!!!!
I have seen a dropped valve caused by the liner dissapearing down the exhaust 
There are a couple of ways of removing the guides that do less harm to the heads

1) drill and machine away the guide above the head face and push down the guides into the port
this means that any carbon/crap does not get dragged iin between guide and head

2) drill out the guide as much as possible to weaken its grip on the head

3 ) tap a thread in the top part of the guide and then use a punch against a stud threaded into the top of the guide, this way the guide tends to stretch and shrink rather than compress /fatten

4 ) if the guide top is machined away then tap the bottom end and drive downwards or combinations of the above

Always heat the head to 200-220 deg C before removing or replacing guides

HTH
John

[sprint]

Some of you might be interested by this

I have just received my head back from the Cylinder Head Shop after having had it overhauled. It has been fitted with new valves, unleaded valve seats, and has been gas flowed. Here is a summary of the refitting instructions and what might be needed to get the best from the newly overhauled head.

?Having your seats cut or recut so accurately on the Serdi 100 will cause an enrichment of carburation on all engines. This is because your valve is now sealing more efficiently, and where we have fitted new guides or guide liners less air is being drawn down the side of the valves than before.. Your head will need to be re-carburated . For example fit next size down needle jet (106 down to 105). Machine or buy weaker slide (No 3 fit  3 1/2).

Main area of fuel change is the slide, then needle and jet. Generally all need weaker setting. Main jet may need richer jet - do the throttle checks first, but immediately. It may be that your ignition timing will need to be retarded by 2 degrees or more depending on how more efficient we have made your head. The head is claimed to be far more efficient than ever it was when new. Which is why these adjustments might be needed.

Always retorque  head and reset tappets after 10 miles or so and again after 500 and 1000 miles.

If possible use NGK iridium plugs.?

It will be interesting to see how all this turns out in practice.

Does anyone know if there is a suitable non resistive plug iridium available?

I had the same work done on my T120 Cly Hd by CHS. In my case I also had oil seals fitted to the inlet valves so even more likely to run richer as even less air is being drawn in during the induction phase. However, I found that I did not have to make any changes to the carb settings, so I would suggest running initially with your original settings and make changes if necessary.

With regards to having to re-torque the head we have always set my friends Super Rocket and Road Rocket to 23/24 ft/lbs during the rebuild and they have never leaked or required re-doing. May not be to everybody, but having the remove the rocker assys just to re-torque is a real pain.

I do the same on my T120 and again have never had any leaks.

[Jules]

Good read this, thanks...
In the text it refers to seating the pushrods, I have yet to finish assembling the rockers for this very reason , is there in fact an easy way to do this and is the comb a worthwhile investment?
I seem to remember doing this years ago without a comb and it it took an age, does the comb make a real difference or is there a better way? cheers

[terryg]

Jules - take a look at http://www.a7a10.net/forum/index.php?topic=6741.msg58441;topicseen#msg58441 for some further chat on fitting the rocker box.

[KeithJ]

I have never got on with the comb.  More hassle than its worth.  I find fingers best.  I have largish hands, not skinny ones and can manage to get my finger tips in to reach the rocker cups and "fiddle" to pushrod ends in to place.  Worth trying to see if you can do it, in my opinion.

[Jules]

thanks all, yep, just read the other thread too, looks like I'll carry on as before then and forget the comb! cheers

[trevinoz]

I always use the comb, have for over 40 years. Not that it is a regular occurence.

Trev.

[Peter in Aus]

Very interesting thread amazing what you learn on this forum
Peter

[sean]

I hope they have not reduced the BSA specified running clearance of the valves in the guides. They need to be quite sloppy or you can get seized valves.

I fitted colisbro guides to my super rocket head  SRM specs call for guide id 1 thou clearance on intake and one and a half on exh the hard part was finding hones for the colisbro material ....brush research sell flex hones ....I bought 3 different grades , but you have to keep measuring the bore of the guide they turned out perfect .....SRM sell the guides undersize and dont sell hones or know where to get them when I e mailed them they said take them to an engineering shop .I live in the boonies no one here knows what colisbro is , let alone carry hones for it .