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22 Apr 2010, 19:53 (Ref:2678035) | #1 | |
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Advice needed,rolling road problem
I'll try to cut a long story short: On wednesday 14th April I had my brand new engine run in and set up on a rolling road (I won't mention any names),it had about an hours' running at different revs before the 1st power run showed it to be running way too weak so larger main jets were fitted into the carbs,still too weak so larger still jets (180s) were fitted and the power came up along with the co level at high revs,the operator then fitted some 200 air correctors, ran it up to 7000rpm and said that'll do. He then tweaked the ignition timing and did a couple more power runs to find the best setting.
On Saturday I went out for qualifying,completed 3 slow laps to let everything warm up then as I came out of clearways went for a quick lap changed from 3rd to 4th at 7000rpm only to find that the car slowed down! I checked the temps and oil pressure but they were fine so pulled into the pits to have a check under the bonnet only to find a heavily breathing engine so I limped back to the paddock,left it to cool down and removed the head to find that no1 and no4 pistons had holes in them from detonation!! Who is responsible? The engine wasn't touched between the car being loaded onto the trailer and taking the head off after qualfying. The carbs,pump,distributor etc were used on my old engine which I actually refitted saturday night so that I could race on sunday and it ran like a dream after I swapped back to the old mains/airs. One thing that I have found is that the air correctors that were fitted to my new engine are all different sizes! 1 is 2mm (200) 1 is slightly larger and the other two much bigger. Engine is an 1800cc (85.9mm bore) ford crossflow with twin 45 Weber carbs on 38mm chokes. It looks like I'm going to have to buy 12 pistons just to get the 2 that I need as they are no longer made and the maker will only produce them in batches of 12! Your views please Gents. |
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22 Apr 2010, 19:57 (Ref:2678038) | #2 | ||
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i'd say the rr is responsible, BUT you've probably got more chance of me fixing your engine for free including buying 12 new pistons than getting any compensation etc from the rr.
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AKA Guru its not speed thats dangerous, just the sudden lack of it! |
22 Apr 2010, 20:38 (Ref:2678069) | #3 | |
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Is that an offer Graham? Pistons will take 14 weeks to make!
PS: I've double checked the volumes of the chamber and they all come out at 12:1 which is the same as my 1700 engine. |
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22 Apr 2010, 21:14 (Ref:2678091) | #4 | ||
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i might be able to help with air correctors!
accralite will make pistons in smaller batches, they will do as small as 4, but 8 by comparism are a much better deal, infact i had 9, they turned mine around in about 6 weeks. as i said thw weekend unless the skirts are mullered you dont have anything to loose by reuseing them, |
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AKA Guru its not speed thats dangerous, just the sudden lack of it! |
22 Apr 2010, 21:25 (Ref:2678097) | #5 | |
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I spoke to Sarah at Accralite today,it was her that quoted 12 units and 14 weeks.
I don't fancy re-using the existing pistons..............They would be more prone to detonation. |
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22 Apr 2010, 21:32 (Ref:2678105) | #6 | ||
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Were you using the same fuel on the rollers and the track? Do you use an octane booster? How long was the fuel in the car between rollers and track (i.e. the fuel going off)?
I know they're obvious questions, but still worth asking! |
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Dallara F307 Toyota, MSV F3 Cup - Class and Team Champion 2012 Monoposto Champion 2008, 2010 & 2011. |
22 Apr 2010, 21:35 (Ref:2678108) | #7 | ||
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just given them a polish!!!!!!!
re accralite, i didnt order them through sarah only debt with her later on, i actually found sarah hard work, iirc my 9 one off pistons were about £115 each, they too quoted me a longish wait but delivered much sooner |
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AKA Guru its not speed thats dangerous, just the sudden lack of it! |
22 Apr 2010, 21:37 (Ref:2678109) | #8 | |||
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Quote:
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AKA Guru its not speed thats dangerous, just the sudden lack of it! |
22 Apr 2010, 21:49 (Ref:2678116) | #9 | |
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Same fuel,left in tank from wed to sat, no octane booster, twas a mix of V-power and tesco 99 (mainly V power) The "old" engine ran fine on the same fuel the following day.
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22 Apr 2010, 21:51 (Ref:2678117) | #10 | |
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The rr operator denies the fact that different size airs would make it go lean enough to detonate! Shame of it is that I used to put a lot of work his way.
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23 Apr 2010, 07:06 (Ref:2678239) | #11 | ||
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Go on,tell us which rolling road it was!!
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23 Apr 2010, 10:01 (Ref:2678320) | #12 | ||
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You say they 'tweaked' your ignition, I hope they never done that while engine was running to get best power because although it may be making best power it may also be too far advanced. I had first hand knowledge of this when we built a 400 SBC and the dyno operator against the advise of the company owner (so I had no redress although he helped me rebuild it) said lets advance it up a bit, within seconds of running it up it detonated the pistons! Big mistake.
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You can't polish a turd but you sure can sprinkle it with glitter! |
23 Apr 2010, 12:55 (Ref:2678410) | #13 | ||
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From bitter experience and not listening to people who know, I have destroyed about 3 engines through detonation. I doubt the jets or air correctors, 180 are massive, would have made it run lean. What jets and air correctors did you start with and what changes were made to the timing?
I would go with the timing being too far advanced, on my hemi headed Jaguar I've now gone down from a max of 36-39 deg advance to 29degrees. On the old setup the engine would be fine until I pushed it over 5K then it would overheat and I suffered various bearing and crankshaft failures and luckily last time only the head gasket melted, since I retarded it the temp never goes above 75-80 degrees and I can safely rev it to 6.5K. Also don't forget that doing a few short runs on a rolling road is nothing like driving on the track for stress on the engine. |
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23 Apr 2010, 17:26 (Ref:2678587) | #14 | ||
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I agree I also agree with the other poster who basically said you don't stand a cats chance in Hades of getting any money out the company. You have got to prove for a start that you never tampered with the timing or anything else when it left the shop. I remember a sad story about a chap that took a very well known company to court because basically his Fiesta CVH race car couldnt catch similar cars with another companies race engine and he argued it was down on power. Prooving it is totally differnent, one mans race engine is another mans fast road engine. I warned him to drop it when it got slung out the first time in court but no he went to appeal and ended up loosing a massive £30k in costs and fees and culminated in him loosing his house!
BTW you may want to think twice about naming and shaming them here on an open forum however justified you are. |
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23 Apr 2010, 19:28 (Ref:2678657) | #15 | |
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Much of the damage may have been done on the original lean runs, and presumably the rr operator didn't do the first set up? Who knows.
I would point out the obvious that a decent support network for racing is absolutely key, once you've found someone you trust stick to them like glue through good and bad. I trailer my car across the south of England come what may to go to the same place I've been going since '98. Even then it won't always go your way. By way of example I had a new engine dyno'd last year, all seemed OK so I trailered her up and trundled to Brands GP, unloaded and polished her before cracking open a beer and chuckling at those less ready than myself. Only to discover in qualifying the next day that I had naff all power whatsoever. And I do mean naff all. Turned out a side seal spring had failed on the last run. First time that had happened in 10 years of rotaries. Stuff happens as they say. The only other solution is for you to find someone who builds engines and dynos them as well. Then they are accountable for the whole deal and give it back when it has the power and all is well.. I've done that before and it works well. Not an option if you want to mix and match builders, or have a go yourself of course. My thruppence worth is to put it down to experience and move on. Life is too short. Oh yes, and don't mention them in here.. There will be 20 popping up saying how crap they are, and 20 saying how they've never had a problem, and hours of your life soaked up in needless hassle. And we're all getting a bit old for all that now, even me. Atb. S. |
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23 Apr 2010, 22:01 (Ref:2678726) | #16 | ||
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On the subject of pistons JE will make you a set of custom made pistons through one of their Agents for about £500 in four weeks and In about 10days with a 50% premimum if you really need them now(as I did at the start of the 2007 season.)
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24 Apr 2010, 17:23 (Ref:2679036) | #17 | |
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It all sounds so familiar . . . .
too much advance will have killed first is my bet |
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25 Apr 2010, 19:08 (Ref:2679533) | #18 | ||
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£500 for only four pistons? Crikey! I'm so glad I'm running American metal. I bought a set of EIGHT custom made pistons from CP Pistons in California, they are the mutts nutts - used by a number of leading NASCAR teams - and with UPS expedited shipping, import tax, etc.. they ran in at about the same kind of cash as your four (which will no doubt be £500 + shipping + VAT)
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There is no substitute for cubic inches. Harry Belamonte - 403ci Vauxhall Belmont!! A 700hp wayward shopping trolley on steroids!! |
25 Apr 2010, 19:40 (Ref:2679552) | #19 | |||
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AKA Guru its not speed thats dangerous, just the sudden lack of it! |
26 Apr 2010, 18:54 (Ref:2680090) | #20 | |
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Right,instead of answering posts individually I'll try and do it in one go;
I'm NOT going to name and shame as I don't think it will serve a purpose.(pm me IF you really must know) The dizzy was advanced without the engine running then it was run up to 7000rpm and then turned off several times until it was found that where I'd already set it was best,the max advance that I use on my engines is usually 28 degrees as that's what I've found to work best,it was only tweaked because the engine is 100cc bigger so we thought it was worth trying. Jetting that we started with (38mm chokes) was 180 airs and 155 mains which is what I use (along with 36mm chokes) on my 1700,we ended up with 200(ish) airs and 180 (ish) mains. Oh and I build my own engines. I also wonder if it was the 1st few runs that did the damage as no setting up had been done (other than the timing). Hope this makes sense. |
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27 Apr 2010, 10:16 (Ref:2680403) | #21 | ||
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All I could add to that was when my engine on the dyno detonated it was within mere seconds of a pull after the ignition had been advanced, it dont take much to do the damage on a high compression motor.
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You can't polish a turd but you sure can sprinkle it with glitter! |
27 Apr 2010, 10:30 (Ref:2680409) | #22 | ||
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Quote:
Were you monitoring the exhaust with a lambda sensor during the power runs and if so what A/F ratios were you seeing, particularly during the early 'lean' runs? Last edited by phoenix; 27 Apr 2010 at 10:39. |
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27 Apr 2010, 11:14 (Ref:2680429) | #23 | |||
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Quote:
if you ask me and i saw the engine in the paddock with the head off, its failure was a combination of a top end weakness worse on some cylinders due to the variations in air corrector jet size, and lets not forget the gas analyiser only shows an average mixture so it could of beeb running dangerously lean on one or two cylinders and okish on the others and therefore wouldnt of showed up as being dangerously lean, that coupled with slightly too advanced, lets remember rich mixtures burn slower so if the timing was set with the jetting rich, if it finished up too lean it would effectivly be over advanced even if the timing haddnt be touched again. if it were mine i would just back the timing off a couple of degrees and install a set of 190-195airs, having checked the sizes with a jet gauge first!!!!!! |
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AKA Guru its not speed thats dangerous, just the sudden lack of it! |
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