Longer conrods
Discussion
No I haven't, I've considered briefly it but like to keep within the risk boundaries I feel comfortable with and haven't been under a lot of pressure on that front, because most of the engines I work with have good deck height for the configuration. Some engines I run the pistons into a recess in the the head, because I re-machine the chambers so heavily to get more valve to valve clip clearance (a limiting factor in some of my engines and a rationale towards "optimum" rather than largest possible valve sizes 
) and there's plenty material to do that by CNC. Partly inspired by making certain available parts fit, but that's where many of my ideas have started development. This has also led towards taper squish, which I've been finding very productive in enabling higher ignition advance tolerance, with high CR and small chambers.
An engine builder I used to work with a lot, built many reliable tall block 2.4 XEs at 96mm stroke and 1.54:1 R/S, revving to 8500RPM and got brave enough to do a few 100mm stroke "2.5s" (not quite 2.5 in truth) at 1.45:1 R/S, which were reliable on 88mm bore, but I personally keep over 1.55:1.
Surprised DB didn't mention the MAE.
) and there's plenty material to do that by CNC. Partly inspired by making certain available parts fit, but that's where many of my ideas have started development. This has also led towards taper squish, which I've been finding very productive in enabling higher ignition advance tolerance, with high CR and small chambers. An engine builder I used to work with a lot, built many reliable tall block 2.4 XEs at 96mm stroke and 1.54:1 R/S, revving to 8500RPM and got brave enough to do a few 100mm stroke "2.5s" (not quite 2.5 in truth) at 1.45:1 R/S, which were reliable on 88mm bore, but I personally keep over 1.55:1.
Surprised DB didn't mention the MAE.
Sandy309 said:
I've built a variety of similarly spec'd engines with varied rod/stroke ratios and I've not seen any convincing trends on the dynamic properties relating to the "dwell around TDC" and it should be remembered that stress wise, the changes over the top are reflected inversely at the bottom. What I do know however is that the way the engine feels and performs at high RPM are certainly influenced by the changes in piston/rod mass and friction that you get from shorter pistons and longer rod designs.
KiaDiseasel, you write in a familiar manner. Looking back, I think it's over 7 years since I last got into a heated argument with you Dave Baker; I was about to see one of my engines (Fiesta Zetec-SE 1400, not a Peugeot as it happens) win the CCRC Saloon championsip outright with 9/9 class wins that year; the first of five consecutive overall titles for my engines in that series with three different cars/drivers. I've also proudly enjoyed overall wins in the ASWMC sprint and hillclimb championships, winning the MSA British Super1600 Rallycross championship at the first attempt in 2014, coming within 1 points of winning the fiercely contested and punishing BTRDA S1400 at the first attempt too and numerous 2nd and 3rd placed championship results. The ultimate of course has been winning the British Hillclimb Leaders championship 2015 and 2016 with Colin's 205, which holds saloon records at just about every significant hill in the UK now and he put in a stunning debut at the 2016 European Hillclimb Masters recently representing GB, at a venue he'd never seen before, finishing 2nd FWD overall.
I'd hoped the engine you were building Dave Adams, that was supposed to show me how it should be done, would come to fruition, but I gather it was not to be. Any other successes you'd like to share with me over that timeframe?
That's very helpful! KiaDiseasel, you write in a familiar manner. Looking back, I think it's over 7 years since I last got into a heated argument with you Dave Baker; I was about to see one of my engines (Fiesta Zetec-SE 1400, not a Peugeot as it happens) win the CCRC Saloon championsip outright with 9/9 class wins that year; the first of five consecutive overall titles for my engines in that series with three different cars/drivers. I've also proudly enjoyed overall wins in the ASWMC sprint and hillclimb championships, winning the MSA British Super1600 Rallycross championship at the first attempt in 2014, coming within 1 points of winning the fiercely contested and punishing BTRDA S1400 at the first attempt too and numerous 2nd and 3rd placed championship results. The ultimate of course has been winning the British Hillclimb Leaders championship 2015 and 2016 with Colin's 205, which holds saloon records at just about every significant hill in the UK now and he put in a stunning debut at the 2016 European Hillclimb Masters recently representing GB, at a venue he'd never seen before, finishing 2nd FWD overall.
I'd hoped the engine you were building Dave Adams, that was supposed to show me how it should be done, would come to fruition, but I gather it was not to be. Any other successes you'd like to share with me over that timeframe?
Sandy309 said:
KiaDiseasel, you write in a familiar manner.
I'm just a humble plumber from Scotland called Reg who tries to help out on here a bit when I have the time. Dunno what you're waffling on about mate. I don't actually think you're meant to advertise yourself though if you're some sort of engine builder as you seem to claim. Maybe tone down the "oh look how great I am" stuff a bit before the mods take an interest? Anyway, I must get back to my stopcocks and ballvalves. Always summat leaking in my game.Edited by KiaDiseasel on Tuesday 8th November 07:17
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