panza4
Part of things
married
Posts: 474
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Hi all, bit of a cvh escort question , when I took the head of my xr3 carb engine, it had a hcs head on it, the bottom end is a standard one. Now I know that fitting a cvh head on a hcs bottom increases capacity but lowers compression. so does it work the other way round, does fitting a hcs head ( hcs I think stands for heart shapes chamber) on a cvh bottom end increase compression? The engines really poky and quick to accelerate and with it being a 4 speed box as well , it's quiet a potent little beast. Next question is, what other tuning is there to do on the set up I've got? I've put a better exhaust on it, and I want to keep the original twin webber 2v carb. Any thoughts on the first question would be great.
Thanks joe
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If it aint broke, take it apart and find out why!!
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I'm sorry to say I can't answer any of your questions, but have you been to Passionford? It's a forum with a huge amount of knowledge (and opinions) - I'm sure they'd know every trick under the sun for tuning NA CVH's.
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I've got Rovers.
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HCS stands for high compression swirl and CVH is compound valve hemispherical if my memory is correct although I could be wrong...and I also didn't think the CVH engine had anything interchangeable with the HCS engine, especially not cylinder heads. One engine has a cambelt the other has pushrods or am I getting mixed up?
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Have you made a mistake with the 'HCS' designation? The HCS is the 1.1 and 1.3 pushrod lump with a chain-driven cam from the early-90s Fiesta and Escort - a tarted up crossflow. The CVH is a completely different engine: much bigger and overhead cam with a cambelt. I'm quite sure they can't be swapped.
Changing the head cannot alter the cylinder capacity - that is defined by the diameter of the pistons (the bore) and how far they move up and down (the stroke). The head can alter the compression ratio, with different size combustion chambers. If you have an engine with cylinders of 1L each and a head with a 100ml combustion chamber, the CR will be 10:1. 200ml chamber would be 5:1, while 50ml chamber would be 20:1.
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panza4
Part of things
married
Posts: 474
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Yes, a smaller head chamber will up the compression ratio, we used to do it with pinto engines, a 1300 head on a 2 ltr bottom end. The head is definitely a hcs head, the chambers are heart shaped, and the bottom end number matches the engine on the log book. ............I've just read an interesting article on google regarding the hcs heads, and it looks like it was a popular thing to do as its an unleaded head awell, not like the old head. No wonder it's quiet quicker than normal.
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If it aint broke, take it apart and find out why!!
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Just out of interest - how are the valves operated? I've just been reading (Wikipedia, admittedly) that the HCS is based on the Kent (Crossflow) as jrevillug suggested. edit - just found this - a CVH 'lean burn' head -  Is this what you have? |
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Last Edit: Aug 7, 2012 23:40:09 GMT by SamR380
I've got Rovers.
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bortaf
Posted a lot
Posts: 4,549
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Yep heart shaped chambers are the post 86ish leanburn head the HCS is indeed the later Xflow vairiant, totaly differant engines  |
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R.I.P photobucket
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Last Edit: Aug 8, 2012 0:00:11 GMT by jrevillug
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panza4
Part of things
married
Posts: 474
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Yes, that's the head I've got on mine, wield set up that heart shape chamber tho, I suppose ford invested millions in development so it must work. I've got a head from a series 1 rs turbo I was tempted to put on, what kind of results would I gain or even loose by fitting that?
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If it aint broke, take it apart and find out why!!
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