Motorsport Mickey Posted May 22, 2015 Report Share Posted May 22, 2015 (edited) Bent rod, if the rod is straightened with a newly honed little end it will come out as +3 even across the gudgeon pin plane, then comparable to the others within a thou. Mick Richards Edited May 22, 2015 by Motorsport Mickey Quote Link to post Share on other sites
PeteT Posted May 23, 2015 Author Report Share Posted May 23, 2015 Thanks Mick, I will seek out somewhere to straighten it, do the little ends and balance all four to match the rest of the bottom end. Many thanks Pete Quote Link to post Share on other sites
PeteT Posted May 23, 2015 Author Report Share Posted May 23, 2015 Hi Mick, Good news! I've found another rod and it gives a better reading than number two above. This one is zero in all planes except the front which is +3 thou. So I will drop the rods off on Tuesday and have the bushes done and balance them all. The Pistons will need between 4-7 thou off to give me the 40 thou I need. Next question: I've measured the CR at just over 9.75:1. Will this be ok on regular unleaded? Is there any benefit in rounding off the step in the combustion chamber like the 4a head? This would also reduce the CR of course. Many thanks, Pete Quote Link to post Share on other sites
Motorsport Mickey Posted May 23, 2015 Report Share Posted May 23, 2015 (edited) Hi Pete, I presume your head is a TR2 ? if so it wouldn't faze me to shave the combustion chamber a touch and help the flame front across it. The compression ratio for you depends upon how finicky your engine is likely to be regarding pinking. I'd be happy at 9.75 and maybe use as good a quality petrol as you can find, or even use a booster with it. Just a tedious point, when you get the rods back I'd remeasure the piston heights again fitting them into the engine before sending them for machining on the crowns, never trust a machine shop to do it right. The more finicky you are about checking the more the shop will realise it may as well do it right first time and protect their profits, and if it can't do it right you don't need to be going there anyway. Mick Richards Edited May 23, 2015 by Motorsport Mickey Quote Link to post Share on other sites
PeteT Posted May 23, 2015 Author Report Share Posted May 23, 2015 Thanks Mick, Yes it's a low port TR2. I think I will blend the step like the 4a head. I will remeasure the CR when it's done. Thanks for all your good advice I really appreciate it. Regards, Pete Quote Link to post Share on other sites
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