AMMO Posted September 4, 2005 Author Share Posted September 4, 2005 Rob I've decided to try to resist the temptation to go all the way. Maybe just the big valve head, cams, rods and pistons and keep the standard crank. Dunno, I change my mind every day. The big valves are on their way so work on the head should start soon. AMMO Link to comment Share on other sites More sharing options...
Graham Perry Posted September 4, 2005 Share Posted September 4, 2005 Ammo, you could use it as a demo car for customers that you could take them for rides in (I assume most of your customers are seveners) and you could then frighten them silly. They are bound to want one after that Link to comment Share on other sites More sharing options...
AMMO Posted September 4, 2005 Author Share Posted September 4, 2005 Graham You've convinced me. 😬 I gave a passenger ride to Nifty at the fish and chip run. He thought the engine was awesome but failed to get his chequebook out. AMMO Link to comment Share on other sites More sharing options...
Dobuy Posted September 4, 2005 Share Posted September 4, 2005 Nifty was probably more interested in the quality of the potatoes at the chippy 😬 Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
AMMO Posted September 8, 2005 Author Share Posted September 8, 2005 Got my big valves. Will be having a serious look at a head today. Also taking final measurements from a 2.3 crank to have a steel version made for 8.500 rpm. What would you like Santa to bring you this Christmas? Could I have a 300 bhp Duratec please? 😬 AMMO Link to comment Share on other sites More sharing options...
Mike Bees Posted September 8, 2005 Share Posted September 8, 2005 Why only 8.5k if you're going to the bother of having a steel crank made? MIke Link to comment Share on other sites More sharing options...
dannylt Posted September 8, 2005 Share Posted September 8, 2005 Rather long stroke on the 2.3? Link to comment Share on other sites More sharing options...
AMMO Posted September 8, 2005 Author Share Posted September 8, 2005 Mike I think the stroke is rather long at 94 mm. The mean piston speed is way up at over 26.5* metres per second at 8,500 rpm. Limiting the rpm is a way of ensuring engine longevity. An extra 500 rpm may turn the expensive bits in your engine into just an expensive pile of bits. Personally I don't have the budget to find out what happens if we go to 9,000 rpm. Cosworth rev their 300 bhp Formula Atlantic Duratec to 8,600 and get away with it. Touring car engines with 82 mm strokes revved to 8,500 (due to rules) were only 23 metres per second. 2.3 Duratecs with stock cranks are also only 23 metres per second. WSBK Suzuki engines that revved to 15000 rpm only had a mean piston speed of 24 metres per second. Better safe than sorry. Edited to say: * In old money this is 5200 ft per minute. When I first started getting involved in engine tuning the figure was around 4,000 ft per minute for mean piston speed. AMMO Edited by - AMMO on 8 Sep 2005 15:05:35 Link to comment Share on other sites More sharing options...
Mike Bees Posted September 8, 2005 Share Posted September 8, 2005 OK, just curious. This is going to be a limiting factor for ultimate specific output (compared to BDs & things which will rev to 10k). I use 9.2k in the lower gears when I'm against the clock 😬 Mike Link to comment Share on other sites More sharing options...
AMMO Posted September 9, 2005 Author Share Posted September 9, 2005 Mike I guess your crank stroke is around 84 mm for your 1700 K. At 9200 rpm that is 25.8 metres per second piston speed. So quite similar. I had a visit from a crank manufacturer yesterday who told me that some F1 engines have strokes of 35 mm. Even at 20,000 rpm this is only 23.3 mps. AMMO Link to comment Share on other sites More sharing options...
Mike Bees Posted September 9, 2005 Share Posted September 9, 2005 Aren't the laws of physics great Mike Link to comment Share on other sites More sharing options...
Pooh_R Posted September 9, 2005 Share Posted September 9, 2005 Why is piston speed the limiting factor? and why the average speed not the max speed? I would have guessed the acceleration would have been more important. (F=ma etc). Pooh A Bear of little Brain! Link to comment Share on other sites More sharing options...
DohNut Posted September 9, 2005 Share Posted September 9, 2005 Acceleration is the killer but as all engines have the same basic crank rods piston setup a piston speed number gives a pretty good indication of the stresses caused by the acceleration of the pistons at each end of the stroke Average piston speed tells you nothing (as such) but is easy to calculate and infers quite a lot. conrod length does have an impact on the shape of the acceleration curve but is a relatively small variation in this context Nick Link to comment Share on other sites More sharing options...
Dobuy Posted September 9, 2005 Share Posted September 9, 2005 AMMO, did Cosworth mod their timing chain tensioner assembly at all for 9000rpm? Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
MikeE Posted September 9, 2005 Share Posted September 9, 2005 Neil - I think I know where the questions coming from and if so the person who suggested you need to modify the timing chain tensioner assembly doesn't even believe you can get 300bhp from a Duratec (yet) BTW Did you pick up your dry sump bits yesterday? Did you see the complete assembly on my car?(haven't been over yet to get a progress update) R400 Duratec Build and Modification Pictures here Link to comment Share on other sites More sharing options...
MikeE Posted September 9, 2005 Share Posted September 9, 2005 Ammo I'm sure you know this but.....Cosworth list a2.3l crank on there site here can you not use this? I see they also have a dry sump pan with internal scavenge pumps which looks good as well here R400 Duratec Build and Modification Pictures here Link to comment Share on other sites More sharing options...
Dobuy Posted September 9, 2005 Share Posted September 9, 2005 Mike, You car had the DS pan fitted, tank in place but no hoses or pump fitted. Your pump was sitting on the bench in the engine build room, so was in really close proximity to the car Peter was not there for the day, just Chris. Still waiting on my pump to come from Titan............................ As to the Cossie, steel crank, no price as yet, which infers that it is not in production yet. Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
AMMO Posted September 10, 2005 Author Share Posted September 10, 2005 MikeE, Dobuy Cosworth have only made cranks for their own use so far. They are made in-house in their impressive crankshaft / camshaft department. They will be released at some point. I couldn't wait and wanted to do my own thing anyway. Should have the crank for the end of October. Hopefully have an engine on the dyno before Christmas. The Cosworth dry sump with internal scavenge pump did look like a nice piece of kit actually. Be interesting to see how it compares to the Raceline / Titan one. Have ordered bigger valve seats so big valve head should be on the flowbench in the next three to four weeks time. 😬 AMMO Link to comment Share on other sites More sharing options...
MikeE Posted September 10, 2005 Share Posted September 10, 2005 Ammo, I don't know if you have any dealings with Mountune but I understand they are looking at a big valve head as well. R400 Duratec Build and Modification Pictures here Link to comment Share on other sites More sharing options...
AMMO Posted September 11, 2005 Author Share Posted September 11, 2005 MikeE I don't deal much with Mountune. I indirectly supply engines to them via another engine builder and have spoken to them a couple of times on the phone regarding any problems they may have had revving the Duratec. I did meet Dave Mountain and Dave Vizard in the late '80's whilst dyno testing. Dave Mountain looked very young and made lots of phone calls on his Motorola mobile which was the size of a brick 😬 Most Duratec engine tuners will be playing around with bigger valves. I am using 36 / 31 mm as opposed to 35 / 30 mm which is fitted as standard to Duratec. 36 /31 is an old Ducati Superbike size which I also used on my Guzzi race bike. I have done a lot of work with these valve sizes. Ducati then increased to 37 mm inlets. There are 37 mm inlets for the Duratec but I am worried that fitting even bigger seats may lead to cracking of the head. Better safe than sorry. Edited to say to Dobuy that Cosworth have not modified their chain tesioners. AMMO Edited by - AMMO on 11 Sep 2005 10:44:37 Link to comment Share on other sites More sharing options...
Dobuy Posted September 14, 2005 Share Posted September 14, 2005 Pictures of the Titan / Raceline dry sump pan on my Duratec page below, still waiting for the pump Duratec SV, built in Dubai Link to comment Share on other sites More sharing options...
MikeE Posted September 14, 2005 Share Posted September 14, 2005 Neil Spoke to Peter today and my installs been put on hold for a couple of days, still hopeful it'll be finished by Saturday and we can get it on the rolling road early next week. I'll let you know the results. cheers R400 Duratec Build and Modification Pictures here Link to comment Share on other sites More sharing options...
mic Posted September 16, 2005 Share Posted September 16, 2005 There are a couple of pictures of the Titan 3 stage pump on my web site. here Link to comment Share on other sites More sharing options...
MikeE Posted September 16, 2005 Share Posted September 16, 2005 Hi Mic, I thought the Titan pump was two stage scavenge - the pressure pump being the standard Duratec pump? R400 Duratec Build and Modification Pictures here Link to comment Share on other sites More sharing options...
Dobuy Posted September 16, 2005 Share Posted September 16, 2005 Mike, You can have either a 2 or 3 stage pump. Some regard the 2.3's internal pump as not being up to the job. Mine is going to be a 3 stage like Mick's Mick, looks good, how does it run? Looks like you got the modified casting to clear the engine mount. Any other problems with the install? Duratec SV, built in Dubai Edited by - Dobuy on 16 Sep 2005 19:05:59 Link to comment Share on other sites More sharing options...
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