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| Barney's secret https://www.ausmini.com/forums/viewtopic.php?f=2&t=3533 |
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| Author: | drmini in aust [ Sun Dec 19, 2004 10:15 am ] |
| Post subject: | Barney's secret |
Well I wondered how Barney the 998 leapt tall hills in a single bound.. Just stuck some welding wire down #1 & #2 bores, found there's a 1098 crank hiding in there! Combined with a late 998 smog head (small valves) torque is obviously `adequate' to quote Rolls Royce (at low revs anyhow). Painting the 1293 motor this week, so his heart transplant will be soon! Moral of story- never judge a motor by its (99H) engine number....!! <edit> typos |
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| Author: | 68matic [ Sun Dec 19, 2004 10:28 am ] |
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doc i dont really understand how you did the welding wire thing did you measure the distance from TDC to BDC or something like that? if 1098 crank, does it mean that its got a shallower/deeper stroke than a 998 crank |
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| Author: | drmini in aust [ Sun Dec 19, 2004 10:44 am ] |
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Duc, With any 4 cylinder inline engine the #1 & #4 pistons are up when the #2 & #3 ones are down. So, you turn the motor over until #1 is at TDC, #2 is at BDC. Stick a slightly curved bit of welding wire in thru the #1 & #2 plugholes (curved so it will touch the head of the piston, not the dish) and measure the difference in length. That is the stroke. Only real difference between 998 & 1098 motors is the stroke- 998 is 76.2mm stroke, 1098 is 83.7mm. 
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| Author: | 68matic [ Sun Dec 19, 2004 10:49 am ] |
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so thats how you know about the crank eh how does one measure the volume of a block? eg 998cc would you put one cylinder at BDC, measure how much water can fill it up (or even better, acid) and multiply by 4? |
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| Author: | drmini in aust [ Sun Dec 19, 2004 12:19 pm ] |
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Formula: Displacement= (Pi * D2) /4 x Stroke x 4 (no of cyls) Dimensions in Centimetres For a 1098, it's (3.141625 x 6.46 x 6.46)/4 x 8.37 x4 Filling the cylinder with water or whatever gives you capacity, which is different- it's the displacement + combustion chamber etc volume.
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| Author: | danidad [ Sun Dec 19, 2004 1:09 pm ] |
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so it has a higher compression ratio than you would have expected? |
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| Author: | gafmo [ Sun Dec 19, 2004 1:24 pm ] |
| Post subject: | |
What a Bonus...bad luck Anton 
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| Author: | drmini in aust [ Sun Dec 19, 2004 1:48 pm ] |
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danidad wrote: so it has a higher compression ratio than you would have expected?
No idea what the C/R is, maybe a little higher, but the valves & ports are small. The motor was rebuilt a 3 or 4 years back by Mini Kingdom, then it sat in Wayne's garage until he finished the body & fitted it last year. It would go even better with a proper 1098 (12G202) or 12G295 head. Dunno what I'll do with it yet, when it comes out at Xmas. Probably change the oil and park it, in case the 1293A+ is a lemon..
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| Author: | Lillee [ Mon Dec 20, 2004 10:35 am ] |
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Sounds sweet Kev! I remember you telling me how Barney had more torque than expected from large pipe and a standard 998 Bonus
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| Author: | J_A_M [ Mon Dec 20, 2004 10:55 am ] |
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hmmmm....... I am pulling the head off my 998 in the next few days Kev.....Might have a look-see in the bores and if it's no good....we might talk
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