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10 Aug 2009, 15:34 (Ref:2518899) | #26 | ||
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Caused by too much load on the bearings, did you check that link page I posted.
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10 Aug 2009, 16:13 (Ref:2518921) | #27 | ||
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Yup, thanks for that, I've also been depressing myself reading the various causes of detonation. I just hope it hasn't fractured the crank.
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10 Aug 2009, 16:51 (Ref:2518942) | #28 | ||
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10 Aug 2009, 18:32 (Ref:2519023) | #29 | |||
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Its perfectly feasable to do but yes you would have to make up a little jig, where there is a will there is a way ;-). A far easier way of couse is if the spec of the piston is known. Here is a nice little online easy to use C/R calculator I use which allows a negative value for for the piston dome to be factored in. http://cochise.uia.net/pkelley2/crc.htm For a rough calc allow about -10cc for the dome and see what it comes up with.
I would doubt its fractured the crank, I got away with a good polish (should I rephrase that?) and mine was seriously bad! Here is a way of measuring the dome using a flat piece of simple plastic. This is for a Supra so measurements may vary but the theory is there. Quote:
Last edited by Al Weyman; 10 Aug 2009 at 18:57. |
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10 Aug 2009, 20:22 (Ref:2519100) | #30 | |
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sorry I'm late
I've been financing Messrs Payen (I've tried all the posh variants, no difference other than cost, some expensive ones are worse) well over the last year as I've been trying to gain something, and have done, albeit briefly, so now I'm reverting to 2006 spec, competitive (then) and utterly reliable my conclusions are Anything over 12:1 is failure, 11.5-11.8 seems fine, 11:1 or less will run on pi55, 12.2 blew with sunoco 105 at Lydenn (11:1 with 2 gaskets) and 12.5 blew at SPa last year, holing a piston at the top of the Kemmel straight. my engine doesn't like really high CR. I am running flat everything . . . . wire ringing works as someone else will testify and that is the way to go for really hot motors but it won't cure advance related det or sh!t fuel. I've used 'posh' petrol and the difference there seems negligible over super/CVL, at least in my limited experience. power wise I've gained very little extra at high CR and wasted lots of time and money so I'm going 11.5:1 32 max advance . . . aa a minor aside, I'm restricted to 40's and have found the limit If |I don't cure my problems maybe I'll buy an Anglia and take that to Spa |
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10 Aug 2009, 20:32 (Ref:2519107) | #31 | ||
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And get some Jap bike carbs on it and you will be away :-)
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10 Aug 2009, 20:37 (Ref:2519110) | #32 | |
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I think I already proved otherwise on the 40's, points too
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10 Aug 2009, 20:44 (Ref:2519123) | #33 | ||
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You certainly did!
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10 Aug 2009, 21:38 (Ref:2519174) | #34 | ||
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Balls of steel (knob of butter) They're Asking For Larkins. ( Proper beer) not you're Eurofizz crap. Hace más calor en España. Me han conocido a hablar un montón cojones! Send any cheques and cash to PO box 1 Lagos Nigeria Africa ! |
12 Aug 2009, 16:25 (Ref:2520320) | #35 | |
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rules is rules Gordon
I have a pair of Italian weber 48's under the bench |
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12 Aug 2009, 17:52 (Ref:2520357) | #36 | ||
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12 Aug 2009, 18:48 (Ref:2520376) | #37 | ||
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All very interesting chaps but what caused the head gasket failure!!!
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12 Aug 2009, 19:07 (Ref:2520386) | #38 | ||
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I thought most were going along the lines of detonation. I don't think the gasket was seated properly and one side of the sealing rings may have been slightly offset and judging by the burns on 1 and 2 it could have caused a hot spot. Not sure about No.6 though.
I will try sitting another gasket on there to see how it fits. Question, and it may be silly; When an engine is rebored, how is the boring machine lined up with the block, would it be possible for it to run out of line from one end to the other? |
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12 Aug 2009, 19:21 (Ref:2520395) | #39 | ||
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That would depend on the actual Boring machine/operator Tim.Run a straight edge on the outside of the bores,that should give you a rough idea.
BTW Tim,Webbers were always made in Italy,the crap one's come from Spain,you can easily tell the difference,if they are Spanish,they'll have a lot of "Flashing" on the bodies. |
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12 Aug 2009, 19:22 (Ref:2520398) | #40 | ||
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The boring machine bolts to the block as far as I am aware unless there is modern ways of doing this.
I noticed the other day that Edelbrock 4 barrel carbs for yanks are made by Webber at least they have the name engraved on the body. |
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12 Aug 2009, 19:51 (Ref:2520423) | #41 | |||
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Quote:
BTW, I am pretty sure I have a CR of 9.6:1 |
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12 Aug 2009, 20:37 (Ref:2520443) | #42 | ||
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12 Aug 2009, 21:55 (Ref:2520473) | #43 | ||
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It may even be a diesel! :-)
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12 Aug 2009, 23:07 (Ref:2520506) | #44 | ||
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Normally the boring machine is centralized up with the bore that it's cutting at the time. So unless the block was machined wrong from new this shouldn't be a problem.
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12 Aug 2009, 23:09 (Ref:2520507) | #45 | ||
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Balls of steel (knob of butter) They're Asking For Larkins. ( Proper beer) not you're Eurofizz crap. Hace más calor en España. Me han conocido a hablar un montón cojones! Send any cheques and cash to PO box 1 Lagos Nigeria Africa ! |
13 Aug 2009, 08:19 (Ref:2520659) | #46 | ||
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Sorry to quote small block GM V8's but the theory is the same. I have read that a phenomena known as 'core shift' can happen on these blocks during the casting process that can cause bores to be ever so slightly out. Thats probably why the small block has a generous 35 thou or so between the bore and the gasket. Yours is probably a bit marginal in any case but at 60 thou over bore and high compression may be all getting on the ragged edge side of reliable.
Yes but we all know you have a genuine FIA 1200cc Anglebox with the correct homologated single choke down draught carb Gordon that can race anywhere! :-) |
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13 Aug 2009, 08:33 (Ref:2520669) | #47 | ||
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Balls of steel (knob of butter) They're Asking For Larkins. ( Proper beer) not you're Eurofizz crap. Hace más calor en España. Me han conocido a hablar un montón cojones! Send any cheques and cash to PO box 1 Lagos Nigeria Africa ! |
17 Aug 2009, 20:35 (Ref:2523229) | #48 | |
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18 Aug 2009, 19:15 (Ref:2523884) | #49 | |
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ok . .. 12.2 CR failed at Lydden . . .I've sliced 1.5cc from the chambers today so hopefully 11.7 will prove a bit more reliable . . .
now . . .which head gasket? . . . . . |
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18 Aug 2009, 19:21 (Ref:2523892) | #50 | ||
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A thick un!
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