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GeofP

RHOCaR Member
  • Content Count

    12
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About GeofP

  • Rank
    Builder
  • Birthday 02/11/1951

Previous Fields

  • Car type
    S7
  • Full name
    Geof Parr

Profile Information

  • Gender
    Male
  • Location
    Rake, Hampshire
  • Interests
    Robin Hood!
    Wife and family
    Electronics and Raspberry Pi.
    Playing in a brass band
    Walking
    remap.org.uk
  1. Paul, the cam is from my original engine in the 1980 Cortina 2.0 litre estate car with Weber 2V carburettor. The Haynes manual says the following: Inlet cam lift = 6.33mm, valve lift = 10.12mm, opens 24° BTDC, closes 64° ABDC Exhaust cam lift = 6.33mm, valve lift = 10.14mm, opens 70° BBDC, closes 18° ATDC
  2. Seem to have this extra post which I can't delete!
  3. Here is the playdoh on top of the piston
  4. So, I have done a trial build using a compressed gasket, playdoh in the combustion chamber and my existing cam. I turned the crank over 4 revolutions to go through 2 valve cycles and achieved some good impressions in the playdoh. Exhaust valve clearance to top of piston is 7.4mm and inlet valve 5.8mm, probably +- 0.5mm. I understand that a suitable minimum clearance is 2.5mm so this looks good. Now I have to estimate the clearances with a higher lift cam.
  5. Thanks, I looked at the Cometic and Athena gaskets but have decided to use a 0.5mm stainless steel shim from Gosnay's Engineering company with a standard head gasket (compressed thickness about 1.3mm). This will result in a CR of about 10.5. For the shim / block interface I will use spray Hylomar or liquid Wellseal. Now back to the original problem of estimating if the camshaft will cause the valves to hit the pistons.
  6. Thanks Paul I did the new calculation and the CR comes out at 11, as you say. A gasket thickness of 1.6mm would give me a CR of 10.6 I have read in a few places on the web that the crushed thickness of a standard pinto gasket is 1.6mm. If I could find one of those, that would solve the problem but the one I bought recently on line is only 1.5mm un-crushed. Geof
  7. Nigel I used the method described by you but with water and just measured one chamber. I have taken measurements of the compressed head gasket and space above the piston in an attempt to get a better idea of the CR. Can someone advise please if what I calculate below is correct, because if it is then perhaps the head is suitable for my standard pistons. My old compressed head gasket is 1.3mm thick and 9.3cm diameter Volume of gasket = pi x 9.3 / 2 x 9.3 / 2 x 0.13 = 8.8cc Distance of piston at TDC (measured with feeler gauge) is 0.53mm (correction from 0.2mm stated at start of thread) Bore diameter is 9.12cm Volume above piston = pi x 9.12 / 2 x 9.12 / 2 x 0.053 = 3.5cc Volume of combustion chamber measured above = 38cc Total volume = 8.8 + 3.5 + 38 = 50.3cc Piston stroke length is 7.68cm Bore diameter is 9.12cm Swept volume of piston = pi x 91.2 / 2 x 9.12 / 2 x 7.68 = 501.6cc So, is CR = 501.6cc / 50.3cc = 9.97 and therefore OK or is it not as simple as that?
  8. Paul I also prefer an engine with good torque and less high revs. Doing a search for a Pinto 2.0i cam led me to one sold by Burton which they describe as "Pinto 2.0/2.0i cam". Will this be an upgrade to my 1980 2.0 cam? Geof
  9. Paul With regard to a high energy ignition system, would the Powerspark High Energy Distributor plus Lucas DLB198 coil as sold by www.simonbbc.com be suitable? Geof
  10. Thanks to you both. I wish now I had got more info about CR before I bought the head. Still, at least I know a bit more about the subject and will start my search again for another head and try and sell this one. Geof
  11. Hi Paul. Thanks for your comments. I re-checked the inlet valve and it is 1.65" i.e. 41.9mm, so is standard. I have just measured the combustion chamber size with a 10ml syringe and it is about 38ml, i.e. 38cc. The head is definitively from a 2.0l but skimmed a lot. Does that make it suitable for my engine or would the CR be too high? Is the standard replacement 2.0 injection cam still a good choice and if so are you able to advise where I could source one and if you have a part number.? Regards... Geof
  12. I had a problem with my 2.0l Pinto cylinder head and bought another as a less-cost option to reconditioning mine. The head is unleaded with new valves and guides and has been skimmed “for maximum compression ratio”. I thought it a good opportunity to fit a cam that is better than the standard Cortina one. My Robin Hood S7 is only used for road and I’m considering the Kent FR31. However, I am concerned that there will be sufficient clearance between valves and top of piston. The engine is a 2.0l Pinto from a 1980 Ford Cortina. The block was skimmed when I built the car some 22 years ago. The engine uses a standard Weber downdraught twin venturi 2V carburettor, throttle barrel diameter 32/36 mm and an after-market 4 branch exhaust. Comparing the head with my old one, it looks like it has been skimmed by about 2.5mm. I note that the spark plug electrode will foul the piston unless it is inserted with the electrode at the top. Is it possible to tell from the following measurements if the valves will also foul the pistons? I asked Kent Cams but they weren’t really interested in helping. Cylinder head thickness, rocker cover to face: 91.95mm With valve closed and measuring from the edge of the valve closest to the face of the cylinder head: distance from exhaust valve to face: 6.68 mm distance from inlet valve to face: 5.84 mm With piston at TDC, and measuring from top of piston to face of block: 0.2mm Inlet valve diameter: 40.6 mm Exhaust valve diameter: 35.9mm I think the problem, if any, will be when the piston is rising and the exhaust valve closing but without knowing the cam profile I can’t predict this (not sure I could do the maths anyway). I could do a trial build and check for contact using Plastercine on the piston top, but that means buying the cam first which is a costly gamble. I would also appreciate opinions as to whether the Kent FR31 would be suitable or if there is a better option for my set-up.
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