Cylinder Head Developments
Cylinder Head Developments
56 Sherwood Road
Aston Fields Industrial Estate
Bromsgrove, Worcs. B60 3DR
Tel: 01527 870472

More Frequently Asked Questions

I've just started to strip and rebuild a post-1986 1400cc CVH lump. As I'm on a tight budget can I fit a 1600 head on the 1400 block? Will I gain any power from doing this, or will it lose power?

The 1.4 CVH is a lean burn engine so you'll have to do an enormous amount of work on it before you even start to see any power gains. The 1.6 head won't fit for a start - the bore on the 1.4 is 77.2 mm, while the 1.6 has a 79.9 mm bore. The most important thing is that the lean burn engine has a different chamber and piston design.

Only 15 per cent of the 1.6 CVH engines built were the lean burn type, so you might be better off looking for one of the non-lean burn 1.6 litres and transplant that in before you start tuning. It's really not worth bothering with the 1.4 whereas the 1.6 has an enormous amount of potential, whether it's using injection, carbs or turbo.

The RST head and the early carb or non-EFi heads are identical. RST pistons are flat, the others have a slight hump on them. On the CVH head, have the ports opened up and big valves fitted. Kent do a good range of cams for the CVH, but the choice will depend on what carburation you're running.

I have a problem with my 1979 Mk1 Ford Fiesta. The car has a standard and tired 117cc Valencia engine and the original four-speed gearbox. Recently, I restored this car as Supersport replica and now I want more power. The big problem is that in Italy it is illegal to change the engine and gearbox for a different one. Can I modify it?

The Valencia has been used in loads of the smaller-engined Fords, including most marques of the Fiesta, right up until the Ford Ka. The Valencia is a cross-flow engine, and it does respond well to tuning.

Kent do a good cam for the engine. We modified an 1100 Fiesta a couple of years ago, we gasflowed the head - noticeably different as it has square ports - and fitted the cam. It turned it into a nice tractable little motor. So yes, it's well worth doing.

I've had my Capri 2.8 Special for four years and have driven the wheels off it. It's time for a rebuild and apart from getting rid of the rot and stripping the interior, I want some more power. The V6 still sounds fairly good and I love the rumble of the engine, but I don't want to spend out on an expensive rebuild without exploring the options.

I've seen MkIIIs with Rover V8s and it would provide the right noises. I've also been thinking about going for turbo power and trying to track down a Cosworth lump. This would give loads of tuning potential. Any advice would be appreciated.

There are a few MkIIIs with the Rover V8 fitted around and they can be very impressive. It's a tight fit in the engine bay but the torque and the sound-track are addictive. But, and it's a big but, it's a very expensive option. Rebuild parts for the Rover are on the pricey side and getting it into the Capri with the right gearbox can mean some major surgery is needed on the shell, particularly to the transmission tunnel and bulkhead.

The Cossie engine will slot in comparatively easy and the potential for 400 bhp plus is there. But you have got to source the engine, and the ancillaries. Unless you get lucky, it's still going to be costly before you even start to tune the engine.

The best option may already be sitting under the bonnet. There's a lot of myths surrounding the V6 these days, a lot of people believe that they're really expensive to rebuild but that's not true. Sure, there's six cylinders to worry about rather than four but even things like pistons aren't that expensive. We still do a lot of 2.8s. The heads are horrendous as standard so they really do benefit from the gasflow and big valve treatment. The Kent V6T21 is an excellent cam, it's a sports road profile.

We can gasflow and do an unleaded conversion on a pair of Cologne heads plus cams which will transform the engine completely.

I've fitted a 2-litre Injection Sierra engine and box complete with injection system into my MkI Cortina. I have used a Pipercross cone filter on the air flow meter and a four-branch manifold with a modified ashley RS2000 two-box system.

Once the car is finished and the teething problems have been sorted, I intend to build a quicker engine. Would the injection system cope with a big valve head, a wilder cam and approximately 0.050 to 0.060 inch off the head? I may eventually fit a 2.1 bottom-end.

Yes, the injection system will cope but only to a degree. People tend to believe that no matter what you do to the engine, the standard ECU and fuel injection will be able to compensate for any increase in gasflow, but there is a point where it just can't cope anymore.

More than any other factor, it's the cams which tend to stress the injection systems on modern engines. The simple answer is don't got for too lairy a cam. With a race cam you're going to have massive duration and lift which, coupled with your planned big valve head, is just going to be too much for the standard ECU.

If you have it chipped you could afford to go a bit wilder with the cam but always consider what you're going to use the car for. If you're going to run it on a daily basis, good torque and tractability should be top of your priorities rather than massive power outputs. Let this guide your component choices and you shouldn't have too many problems.

I own a MkII Escort 1600 Ghia which is in really good nick. The bodywork has been well looked after and doesn't need all that much doing to it, and I know it's no RS, but I want to get more power from the engine.

I know the crossflow can be tuned and I'm planning to fit a K&N filter and sports exhaust system. What's the next stage? I'd really like to build a top engine. What parts should I be looking for, and can you recommend someone who can build the engine for me?

First question I always ask is what are you planning to use the car for? The filter and exhaust will help the breathing and give a little bit more power if it's set up correctly but won't radically alter the characteristics of the way the car drives. But to go further will mean altering the engine's internals and you need to choose the parts carefully, not only because of cost but the wrong part could make the car difficult to use.

For instance, the choice of cam. If it's a road car, you don't want a race cam. If you fit a race cam and you haven't changed other components, you could end up damaging the engine - the cam will give higher valve lift so the valve springs would probably need to be changed, and it may even need different pistons to avoid them clashing with the valves. Bear in mind that some parts need other work done on the engine to complement them, so don't buy the parts in isolation, plan the ultimate spec of the engine before you buy anything and make sure that it's all going to work well together.

I make sure that anything that a customer buys from me is right for them and I need to ask them as many questions as they should be asking me. As a supplier it's critical that I get the right information - and from your point of view, it's important that you buy specialist parts from people who are going to give you the right information.

My baby is a 1983 Granny MkII 2.8 Ghia. My problem is unleaded - I am getting conflicting advice. Some say I need to adjust the timing, but I think not because I had to use an emergency tank of unleaded with additive and the car ran fine. Very smooth with just a little drop in power.

I'm worried about my valve seats, though one engineer and one mate told me she'll be fine, but for how long? Can you give me a balanced and objective view of my options and the consequences. This car is a fine original example and I see her in my long term future, I just want to do the best for her.

There was a big scare a few years ago about leaded fuel disappearing and we had a real rush on converting heads. They've settled down a bit now as people have learnt more about the impact of using unleaded fuel in engines designed for leaded petrol.

If you run on unleaded with the standard valve seats, you'll get valve seat recession on the exhaust valves so you'll need to adjust the tappets on the exhausts quite a lot. This doesn't happen overnight but the amount of wear will be down to how often you use the car - it's impossible to say exactly how long you'll get before you'll need to have work done on the heads.

You say that you plan to hang on to the Granny, so there are a few options. First, continue to run it on leaded fuel. Thanks to companies like Bayford there is still a reasonable supply of four star, and you can find out if there's a garage near you by visiting

Second option is to run on unleaded with an additive. If you do this, use an additive recommended by the FBHVC, and get the ignition timing ajdusted to compensate for the lower octane rating of the unleaded fuel and to prevent pinking.

The third option is to have the heads converted to run on straight unleaded fuel which means having hardened exhaust valve seats let into the head. I'd wait until the head needs to come off anyway but if you're desperate to have it done now, you might as well have the heads gasflowed and checked at the same time. The gasflowing will more than compensate for any loss of power you suffer from using the lower octane fuel.

I've seen big valve crossflow heads advertised and I wouldn't mind buying one for my MkI Escort. I've done all the work on the car myself and fitting the new head is no problem. But I don't really know what I should be looking for in a modified head. Are there any problems I should be looking for if it's second-hand?

There's no black and white when it comes to second-hand heads, particularly modified ones. If someone had a go in the garden shed, you aren't really going to be able to tell - you've got to know what you're looking for. I've seen people who have been sold a modified head and when I look at it, it's standard. The only solution is to take someone with you who knows what they're looking at.

If you do go ahead, there are a few things you should be aware of. Heads can crack - some cracks you can see, others are internal so you'll need to get the head pressure tested. The crossflow head can crack between the waterways on the head face - in fact, it's the most common place for them to go, but if it does, it's not the end of the world.

The crossflow heads don't tend to warp as they're cast iron but you can skim them until the cows come home anyway. The valve guides are part of the head, so if they get damaged it's not just a case of pressing new ones in. The head needs to be machined and then valve guides are pressed in.

The crossflow head is repairable in many ways which is good. It used to be that if a crossflow head was damaged it was cheaper and easier to get hold of another casting, but they're getting harder to find, so they're worth repairing.

My 2-litre Capri Laser needs more power. It's my everyday car and I don't want an engine that needs to be revved to the redline every time I pull away, so torque figures are more important than big bhp. What bits should I buy?

I would recommend a nice ported and gasflowed head with standard valves. You should also budget for a cam as whether you're afer torque or horsepower, it comes down to cam choice more than anything else in the engine.

Kent do a sports tour cam which suits this kind of engine perfectly. It's relatively mild but if you're only putting in a mild cam, then there's no need to put big valves in it. There's a simple equation used by the trade to work out the optimum valve lift which in the case of an 18 mm valve is 0.095 inch.

It's good that you're focussing on the torque characteristics of the engine as one of the most common questions I'm asked is "What bhp can I get out of this?". You want the most useable horsepower. I did a Cossie engine for a guy last year - it was for a competition car - he originally wanted to go rallying but ended up sprinting when the money ran out.

In the different disciplines, it's all about when the power comes in and this guy was being thrashed by Fiestas with a quarter of the power but because their engines had been built with sprinting in mind, the torque was right there when they wanted it.

A Fast Road engine is more about torque than power, and if you go for the gasflowed head and sensible cam, it will give you a nice tractable, perky 2-litre.

Need help? Contact Andy Weston:

Tel: 01527 870472 (National)
Tel: +44 1527 870472 (International)
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