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May 14, 2012 20:28:41 GMT
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The Clan will be, yes. For now it'll get the rebuilt sport-ish lump, but in time I might build a blueprinted 875 screamer for it. I think it'd suit it nicely. ;D
The Imp, maybe not - it'll be a heavily used daily, and I'd quite like something cheap to replace. We'll see though.
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Alfa boxer lump would powerful, torquey everyday car...
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Koos
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jonw
Part of things
Can open a Mouse with a File
Posts: 768
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May 15, 2012 10:03:13 GMT
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Alfa boxer is a definate winner. Had one in a 145. Was reliable and howled like a banshee when on full power.... great engine.
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Suzuki SV650R The good Triumph T20 The Bad BMW G650GS The Ugly Matchless G12CSR The Smokey Toyota Hybrid One pint or Two?
Ingredients of this post Spam Drunken Rambling of author Bad spelling Drunken ramblings of inner voices Occasional pointless comments Vile beef trimming they won't even use in stock cubes
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May 15, 2012 12:27:56 GMT
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^ I know what's going in it, if anything is. There's even a mention of it on this thread. ;D
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tomc
Part of things
Posts: 29
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May 15, 2012 20:10:04 GMT
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Don't put a micra engine in it james! Keep with the imp engine. 875 with a nice cam (bp285 regrind)
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May 15, 2012 20:48:57 GMT
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Hi Tom - thanks again for the loan of engine. Nah, if this stays Imp engined (and it may do - but I'm fairly convinced on the swap) it'll definitely retain the Sport cam (with this L4 head) - to my mind it's ideal for a daily. Decent torque (important considering the comfort-related seats and sound deadening I have planned) and economy, with enough power to mix it with motorway traffic. The Clan, OTOH, will end up with a silly cam, a better head, fully "built" bottom end etc. Not sure whether to go for the BP285, the GE2, or the R20 though. Not sure about induction either - would like TB EFI and mapped ignition really. ;D
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tomc
Part of things
Posts: 29
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You've got to build a screemer up for the clan. Imp engines sound great at 7500+ rpm
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May 16, 2012 16:19:05 GMT
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998 with a R21 for the Clan!
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Koos
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May 19, 2012 18:06:36 GMT
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Last Edit: May 19, 2012 18:07:05 GMT by jrevillug
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May 19, 2012 19:12:24 GMT
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Nice combo.
I had a Carter 998 with R21 in my Mk5 Davrian and it was blindingly quick.
Nothing below 5200rpm, but it was light enough that you could drive it off cam in normal traffic, then hoof it on open roads. Boy did it scream, great fun!
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Koos
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tomc
Part of things
Posts: 29
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May 20, 2012 20:06:12 GMT
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Well when you build the lump up for the clan you should try a r17 in there (got one if you want to try it) with standard head (with a light skim) valve to piston distance is around 180 thou at tdc and the r17 is timed in at 105. So in theory you could only skim around 20-25 thou off a standard head and still have enough clearance between valves to the piston cutouts. Only downside to skimming only a small amount off of the head is you may not get the CR to 10.8-1 Which is prefered with the r17. have you got any of the old tuning books James?
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May 20, 2012 22:34:48 GMT
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mdh: yeah, it should be. I hope it'll be light enough to be reasonably drivable even with a hairy 875. Tomc: I've got Millington, and a couple of magazine articles (small bore power, dawson's dodges). The head has been skimmed quite heavily in the past - I'd need to do a dummy build with some lead wire to see what the piston-head and piston-valve clearances are. It's also been lightly relieved around the valves, so I need to measure the combustion chamber to see what the capacity is. Thanks for the offer of the R17, but I think I'll stick with the sport cam for a while - as much because I know that it's fairly economical and the Stroms and Sport dizzy are set up for it as anything else: it'll be my only car for quite a while. I'll look to build a hairy engine in something like a year's time, when I've got the Clan reliable and handling how I want it to (so I can properly exploit the engine ), and the Imp back on the road. ;D
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Last Edit: May 20, 2012 22:42:51 GMT by jrevillug
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May 21, 2012 16:51:51 GMT
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I've got a copy of the Tuning Imps book somewhere if it'll help get some Clan pics up sooner! :-)
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Koos
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May 27, 2012 23:11:35 GMT
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Managed to find a couple of hours to strip down the L4 engine from the Imp today, in order to assess the damage and free the crank for grinding.
I managed to take the timing cover off while leaving the head in place - it's sealed well and there's nothing wrong with the bores or valves, so it makes sense to leave it on: especially as it would need re-torquing after 500 miles.
It appears to be simply a well-worn crank. The new big end shells were adapted Mini items, which are wider than the stock shells. As such, the outer extremeties of the new shells were running on unworn sections of journal. This took up the clearance, and resulted in a quiet, smooth engine.
Unforutnately, the sections with appropriate clearance were too narrow to take much load, so the shells show significant wear around the edge - which is why it started rattling again. Otherwise the shells looked very good, with no signs of scoring etc. - although there were a couple of wear patches where the back of the shell was contaminated.
The mains looked pretty good really, but I'll get those ground and fit new main shells too.
The oil pump measured up within tolerance, but I'm tempted to change it anyway - I'll speak to a couple of engine builders and see what they think. If it stays then I'll be lapping the ends on a sheet of glass to close up the clearances there. I'll clean out all the oilways and the oil cooler, replace the cooler hoses, and generally make sure everything's spotless before it goes back together.
I checked the valve clearances too - a couple were out, so I'll measure up the shims next time I'm at A52 and source them ready to put it back together.
Note to self: buy new thermostat. The old one opened too soon, and is now in the bin. And new big-end, main and flywheel bolts: they've all well used and cheap to replace.
Once it's cleaned and I have the bits it'll be back together in a day. ;D
EDIT: Oh, and I can recommend Loctite 5910 gasket maker - I used it when putting the sump on last time, and it didn't leak a drop (from the sump :wink: ) despite not having a gasket. I will be using gaskets for this rebuild, but will use this to help them a little. I'll be using this grade for the rear main bearing cap, too. It might not leak quite as much this time...
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Last Edit: May 27, 2012 23:17:49 GMT by jrevillug
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May 28, 2012 12:34:06 GMT
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Mini bearings? Never heard that one before!
Who's gonna re-grind your crank?
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Koos
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May 28, 2012 12:38:35 GMT
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Mini bearings? Never heard that one before! Who's gonna re-grind your crank? A-series engines share the same crankpin diameter (other than the later, non-S 1275 versions, which have larger bearings), but the shells are wider. The tang needs cutting down a little to centralise them in the rods. As an added benefit, they are significantly cheaper. Not sure yet - thinking about finding a place locally.
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May 28, 2012 15:48:33 GMT
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You need to be very careful with centreing the bearing as I have found some cranks have a slightly larger fillet and the bearing can catch with serious problems. The alternative is to make a jig to hold the bearing with the tang in the normal position and then turn the bearing down to the same size as the Imp bearing. The latter is in my opinion the preferred route for standard and mildly modified engines. Filing the tang has the advantage of providing additional bearing area which is of assistance for highly modified race engines where the bearing surface area is marginal
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May 28, 2012 16:04:01 GMT
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Thanks for the info - hadn't heard that one before. This crank appears to have enough journal width between the fillets - just not enough diameter. I think I'll ask the people the re-grind to ensure that there's enough width for the Mini shells - filing the tangs is much easier than turning down the shells. ;D
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May 28, 2012 18:33:34 GMT
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Make sure they grind it with a fillet radius at the ends as without that it's a recipe for breaking the crankshaft.
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May 28, 2012 20:16:01 GMT
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Indeed so - diameter of 0.1" according to Dawson's Dodges.
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