Lord Flashart Posted November 20, 2013 Report Share Posted November 20, 2013 (edited) I had 40thou milled from the cylinder head on my TR4 on the advice of a well known UK supplier. The comp ratio was worked out at the time but I have mislaid the paperwork. Anyone know what the approx ratio would be for a totally stock head with 87mm pistons and a 1mm solid copper head gasket would be? I'm in the process of ordering a recurved distributer and they need the comp ratio and I don't fancy pulling the head off! Paul Edited November 21, 2013 by Lord Flashart Quote Link to post Share on other sites
Fireman049 Posted November 20, 2013 Report Share Posted November 20, 2013 (edited) Hi Paul ~ When I used to modify Mini Cooper cylinder heads I used to measure each combustion chamber volume (with valves fitted) using a pipette filled with paraffin and note how many cc's each chamber held. I forget the formula now, but I could calculate the compression ratio exactly. I remember I had to add the thickness of the head gasket and whether or not the pistons were dished or flat. I'm sure you can research this method from somewhere. Google up "Cars & Car Conversions ~ Clive Trickey" Hope this helps somewhat? Regards ~ Tom. Edited November 20, 2013 by Fireman049 Quote Link to post Share on other sites
Stanpartmanpartwolf Posted November 21, 2013 Report Share Posted November 21, 2013 I know the exact ratio from your data, but, being a rather rude fellow from Yorkshire, feel that guesswork will be the least controversial approach here, would you not agree? Best of luck old chap; free advice is always best. None intended or taken, by the way! Cheers etc Quote Link to post Share on other sites
Alec Pringle Posted November 21, 2013 Report Share Posted November 21, 2013 By 'eck Jon lad, was thee ale not good tonight then ? Give Paul a break and spill the beans for him, he's had more than enough grief with his blessed project, and I'm damn sure you can give him the correct answer off the top of your head and save him more grief - you're good like that. Cheers Alec Quote Link to post Share on other sites
Lord Flashart Posted November 21, 2013 Author Report Share Posted November 21, 2013 Cheers gents, Wife saved the day and found the paperwork! The new distributor should be here in a few weeks. I also found an excel spreadsheet that someone must have sent to me that calculated the ratio depending on the specs and that concurs with the paperwork from the machine shop. Paul Quote Link to post Share on other sites
ianc Posted November 21, 2013 Report Share Posted November 21, 2013 See Section P2 of the Technicalities CD. Ian Cornish Quote Link to post Share on other sites
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