RS133 cylinder head work

Theres probably some improvemnts to be made from profiling the inlet valve guides or making them flush. Also, the siamese divider is rather blunt.


The step from casting to valve seat can be opened out and the seats cut to 30,45 and 60deg instead of the single angle cut thats there now.


The short radius between valve seat and the floor of the intake is way sharper than needs be, especialy where the valve seats have been machined into the casting


Not much room to go up a size with the valves


I'm sure the areas around the valves could be improved, which would give better flow at small valve lifts. Again, theres a sharp radius where the valve seat cut meets the floor of the exhaust port


Like the inlet side, the exhaust valve guides aren't that prety and the casting texture and joint marks could be easily improved.

As I'm going to be getting the valve seats re-cut, I'll leave the dremmel alone this time, even though it looks rather good when compared to old fords, vauxhalls and A seies heads that I've previously had a go at. The gains aren't going to be huge and could actualy go backwards if done badly, hence getting a recomendation from Paul at RS Tuning for having the work done by the place they use. Besides one of the exhaust valves being slightly bent, it's not looking too bad... Nothing that a good wash and hitting with a die grinder and sanding wheel can't fix

Interestingly, the two spark plugs nearest the waterpump looked to be in a simillar corroded state to the ones Karl took out of his motor :?

After speaking with Paul at RS Tunning, I have decided to get the work done localy as the place that does head work for them do BTCC, LeMans and proper race bred engines and charge accordingly

Dropped the head off at the local engine builders to have the valve seats recut to 3 angle seats and sort out the ports. His first words were "Hm, typical mass produced rubbish, the exhaust ports look shite" :lol: Should have it back again later next week.

Where you going to send off to get cams made?

That's good news tho , should see some good results by the look of the ports lol.

Where did you get hold of the head anyway? Scrapper?

Just off the phone with Catcams UK and is sounds highly unlikely that the cams could be reprofiled and last any significant time due to the negative radius cam profile. Turning down the base circle would mean excesive backlash and the valve train would shake itself appart fairly quickly.

They dropped the previously planned cams from their schedule because they were promissed a set of cams and head to play with but they were never supplied. Hmmm, I wonder where we could find a spare head and cams to send them :roll:

Hopefully I'll have the head back this week and get it posted off. Expected lead time is up to 12 weeks but may be sooner if their existing K4M profiles work and just need the VVC drillings :mrgreen:

did you plan to increase the R/V ratio?

put bigger or better valve ?

mazmaz":jn2e15fr said:

did you plan to increase the R/V ratio?

put bigger or better valve ?

Click to expand...

The amount of extra work and therefore huge increase in costs for going up a mm in size mean it's not realy worth it. If there was room to easily go up a couple of mm in valve head size and open the ports to suit, it may be worthwhile.

Theres certainly room for improvement where the exhaust valve seats and guides have been machined into the casting. The limitting part is the complexity of the water jacket and knowing how much metal is there.

New exhaust valves will be going in as one has a slight bend. Still deciding about a full set from ebay for £50 :lol: or new ones from Karl, or maybe some one piece replacements

The face will be machined to bring back the compression ratio and restore the sealing face after any combustion chamber work.
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Headwork is on hold for now, as the head has gone on holiday to West Sussex and Belgium, care of Catcams UK

Interesting stuff how did it all end up?

the head is still away on holiday with Catcams, being measured up for replacement sticks. Hoping to have it back sometime soon

I can understand that! Hope it gives some nice results, because to be honest I think the 1.6 RS engine is the weakest and most dissapointing point of an otherwise nice to drive car...

any news ?


I bouth a complete k4m engine (really sheap price so i jump on it)


I hope i can dismantle it this winter for improvment so I look forward your own !

mazmaz":2rsynkth said:

any news ?

Click to expand...

No :evil:

Is yours still out for measurement Neil?

I'm suspecting they have lost it. Getting rather pi55ed off now.

They arent even replying on there facebook page anymore...

Inlet ports machine bored, throats worked, valve seats recut and new guides




The exhaust side had the throats worked, the roof of the port opened out where there used to be a thick boss, valve seats recut and new guides.


Chambers had work around the valves, to unshroud the valve. Polished out the casting marks and then refaced the gasket face to restore the compression ratio.

So... the head work means the valves are going to get closer to the piston faces even before the cams are opening them earlier/longer/later? I envisage some serious clenching when the interference is checked!

Obviously this means your results will mean little or nothing to the rest of us that may be interested in the cams; I don't expect that bothers you much

neil that looks awesome, bet u cant wait to have it fitted, a new map on the cards now then?

BikNorton":3scyccjr said:

So... the head work means the valves are going to get closer to the piston faces even before the cams are opening them earlier/longer/later? I envisage some serious clenching when the interference is checked!

Click to expand...

I'd be lying if i said i wasn't aprehensive, even though I opted for a slight skim just to restore the C/R. I had thought about going for more but previous experience with negative clearance kept me sane

Obviously this means your results will mean little or nothing to the rest of us that may be interested in the cams; I don't expect that bothers you much

Click to expand...

your 100% correct on both points :lol:


15-16th jan for fitting and mapping. Not looking forwards to visiting the south coast if the weather turns carp

ill wait in anticipation how the end results will be ,lookin good