mr_ed Posted October 16, 2002 Share Posted October 16, 2002 How many times can you have a crank reground before it becomes useless (ie bearings not available) ? or is that a bit like 'how long is a piece of string' ? I dont know too much about engine rebuilds me. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 16, 2002 Share Posted October 16, 2002 Just linishing the bearings is repeatable and it removes the potential for hotspots when bedding in new bearings. If damage to the journal necessitates a regrind, then you are limited to the availability of bearings for undersize journals. For the k-series, IIRC, there is only one size of under sized bearings available. Link to comment Share on other sites More sharing options...
Rob Walker Posted October 16, 2002 Share Posted October 16, 2002 The other consideration is the depth of the nitriding. Link to comment Share on other sites More sharing options...
greg Posted October 16, 2002 Share Posted October 16, 2002 Just linishing linishing ???? Whats that? Greg, Q 86 NTM (Green 185BHP XF) Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 16, 2002 Share Posted October 16, 2002 Linish: to give a smooth, clean surface to metal [from linen and finish]. ... In practice it means very lightly and evenly going over the surface with a fine grade of wet and dry, using plenty of WD40 as lubrication and not letting it clog. I looked into the nitriding thing and believed that a Doug Kiddie crank would still have a respectably hard surface from the nitriding if reground. Link to comment Share on other sites More sharing options...
greg Posted October 16, 2002 Share Posted October 16, 2002 Thanks Peter. Greg, Q 86 NTM (Green 185BHP XF) Link to comment Share on other sites More sharing options...
EFA Posted October 16, 2002 Share Posted October 16, 2002 Peter, My engine has a reground Doug Kiddie crank and the nitriding appears to still be doing its job. Fat Arn Visit the K2 RUM website See the Lotus Seven Club 4 Counties Area Website here Link to comment Share on other sites More sharing options...
V7 SLR Posted October 17, 2002 Share Posted October 17, 2002 Peter, I'm curious how you tighten your head bolts. Being of twice the cross sectional area, I guess you don't torque them to 15Nm and then give them 2 further half turns or they'd crush the head gasket. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 17, 2002 Share Posted October 17, 2002 Three stages of tightening. 20lbft, 35lbft, 55lbft. Before you damaged the head gasket, the pillars in the head would collapse. The K is quite close to the limit in this area. Link to comment Share on other sites More sharing options...
V7 SLR Posted October 17, 2002 Share Posted October 17, 2002 Interesting. Now that my head's off (again) I've been looking for potential places to improve oil drainage. There aren't any are there? I've read (and taken part in) the discussions regarding scavenging the head, but it always comes down to the problem of locating the pickup(s). As the oil always pools on the right hand side of the head, I wondered if the side of the head could be tapped and external oilways built into it which collected together and led down to the sump. Seems a bit extreme. Is oil drainage in the head actually a problem or just an nuisance when you take the head off and get oil all over your trousers? Perhaps the problem is more extreme with the VVC head? Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
oilyhands Posted October 17, 2002 Share Posted October 17, 2002 There are places where drainage of the oil that pools around the exhaust valve bases can be improved, its very tricky to do, but it can be done.. Oily Link to comment Share on other sites More sharing options...
V7 SLR Posted October 17, 2002 Share Posted October 17, 2002 "Tricky to do", as in " might lead to you scrapping the head" or simply "difficult to achieve, but at no risk"? But again, is it really a problem? Does the oil find it's way past the oil seals, or degrade them more quickly or could you simply ignore it and it'll never become troublesome? Blimey, I'm dead excited about getting my engine back together again. Feels like it's been months since I drove it last. 😬 Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
oilyhands Posted October 17, 2002 Share Posted October 17, 2002 Tricky to do as in wallpapering your house via the letterbox, there is no real danger of terminal damage unless you are extremely clumsy or your name is Marston (tee-hee), I have just bought a very long (6 inch) carbide burr for just that purpose. Oil pooling around the base of the seals allows oil to leech past the seals when the conditions or seals aren't perfect. Oily Edited by - oilyhands on 17 Oct 2002 11:28:18 Link to comment Share on other sites More sharing options...
oilyhands Posted October 17, 2002 Share Posted October 17, 2002 Oops.. double post.. Edited by - oilyhands on 17 Oct 2002 11:29:58 Link to comment Share on other sites More sharing options...
V7 SLR Posted October 17, 2002 Share Posted October 17, 2002 I'll have you know that I've successfully wallpapered the whole of my upstairs from the letter box. I'm attempting the same of my neighbours house from my letter box tonight too. 😬 With regards to the seals, will I have to replace my current ones after next weekend's head-work? Obviously I'll have to strip the head before machining, but does this means replacing them too? Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 17, 2002 Share Posted October 17, 2002 Opening up a breather in the head improves the drainage considerably for dry sumped applications. Edited by - Peter Carmichael on 17 Oct 2002 12:00:58 Link to comment Share on other sites More sharing options...
V7 SLR Posted October 17, 2002 Share Posted October 17, 2002 As you may have read, Julian is having a set of cam covers made up similar to yours. I'll probably take that opportunity to install a breather sometime after. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Julian Thompson Posted October 21, 2002 Share Posted October 21, 2002 Guys - do we mean a breather from the top of the cam cover then? Back to the catch tank? As well as the one in the swirl tower? Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 21, 2002 Share Posted October 21, 2002 Any breather in the head will mostly inhale. This is good news. You can either put a filter on the breather or you can tee it from the catch tank. The difference is this: Filter: Catch tank exhales copiously, with significant oil mist coating the underside of the car etc. Full evacuation of acidic condensate from combustion products, so oil stays in better condition. More frequent oil checks are required because quite a lot disappears as mist. Tee: Catch tank vent exhales the volume of blowby fumes only. Acidic fumes are recirculated through the head and crankcase, contaminating the oil particularly when run from cold. Engine loses less oil. I run with a filtered breather. Link to comment Share on other sites More sharing options...
Julian Thompson Posted October 21, 2002 Share Posted October 21, 2002 How does the breathing improve matters inside the engine? Why do you think *the factory* choose to blank off the breathers in the cam cover as *standard*? Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 21, 2002 Share Posted October 21, 2002 Factory decision comes down to: 1. Industry myth that a crankcase vacuum gives more power 2. Industry myth that a vacuum helps scavenging (in fact exactly the opposite) 3. Ease of implementation. 4. Some race teams with properly designed dry sump systems do it. Even Neil at Pace gave me a story about alternative laws of physics that apparently apply. The symptoms of a vacuum in the crankcase can be as a result of good scavenging. A vacuum in the crankcase does not of itself mean that good scavenging is going on. The only thing that gets the oil out of the engine and into the scavenge pump inlet side is a pressure gradient. If the pressure in the crank case is reduced then the pressure gradient to the entry of the scavenge pump is also reduced. If the cam cover is sealed, the only net matter being introduced into the engine cavities is piston blow-by gas. Blow-by gas introduced in the crankcase prevents the oil draining from the head at a faster rate than the oil is being pumped into the head. Opening up a breather causes a draught to blow from the top of the engine down to the pickup. This assists oil drainage from the head. Link to comment Share on other sites More sharing options...
murph7355 Posted October 22, 2002 Share Posted October 22, 2002 The open breather pipe I had on my cam cover exhaled black ****e all over the side of my car. Of no particular relevance. Just thought I'd let you know. It's fixed now. Link to comment Share on other sites More sharing options...
Julian Thompson Posted October 22, 2002 Share Posted October 22, 2002 Thanks Peter, Andy. I *might* add a union to the cam cover and whack one of those boy racer "Pipercross" breather filters on to it like the scallywags have on their XR2's. The Pipercross logo alone will ensure an extra 40bhp............... Link to comment Share on other sites More sharing options...
Peter Carmichael Posted October 23, 2002 Share Posted October 23, 2002 Worked on my engine... and the R300 ankle-biter seems to go better than it should... Link to comment Share on other sites More sharing options...
murph7355 Posted October 23, 2002 Share Posted October 23, 2002 Just make sure the filter has anodised purple edges. The Pipercross name is only worth 20bhp in any other colour. Link to comment Share on other sites More sharing options...
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