Dave McCulloch Posted May 27, 2008 Share Posted May 27, 2008 My 1900K scholar K series seems to have been adding its oil to the coolant for a while now - to begin with I thought it was oil left in the coolant passages in the engine following the machining work, but I flushed the whole system and refilled, and again there are globs of oil in the header tank, and the top of the header tank has a black gunky coating on it. The engine doesn't loose coolant at all, and holds temperature fine - it's never overheated. Am I right in thinking these symptons relate to the head gasket having failed between the oil way and the coolant ways? If so, why would this have happened and how can I avoid it happening again? Dave Edited by - Dave McCulloch on 27 May 2008 22:02:15 Edited by - Dave McCulloch on 14 Jun 2008 19:40:53 Link to comment Share on other sites More sharing options...
oilyhands Posted May 28, 2008 Share Posted May 28, 2008 This is not an uncommon problem in tuned K series engines especially those with inteference fit liners such as the Scholar conversion. The cause is the oilway down the front of the block where it meets the liner land inside the block wall. They have a tendency to crack here and weep a little oil into the coolant. The top of the block where the liner floats free moves a lot more that the bottom section where the liner clamps and that is why they crack. The solution is to sleeve the hole with some ductile aluminium tubing (6mm OD from B&Q as I remember), the bottom of the tube has to be carefully shaped to avoid masking the delivery hole at the bottom which is perpendicular to the drilling. The tube should be a relatively tight fit and need to be locked in palce with Loctite bearing fit or similar. Once this is done the problem should disappear. Or it could be HGF 😬 Oily Edited by - oilyhands on 28 May 2008 05:42:50 Link to comment Share on other sites More sharing options...
Dave McCulloch Posted May 28, 2008 Author Share Posted May 28, 2008 Oily Thanks for the reply - not sure whether that's better or worse than HGF.... Does this require drilling out the oilway or is the 6mm aluminium tube a tight fit in the existing oilway? I guess my question is how far do I need to strip down the engine to fix this? The engine has only done about 4,000 miles since I built it so I wasn't planning on a complete stripdown just yet. But there is quite a lot of oil floating in the header tank, so it does need fixing properly. Cheers Dave Link to comment Share on other sites More sharing options...
oilyhands Posted May 28, 2008 Share Posted May 28, 2008 It only requires the head to be removed as the drilling should be 6mm ex production. That said I have seen a couple that are undersized, these required pump removal to allow the oilway to be cleaned following drilling with a long series 6mm drill. The tube can then be lightly peened on the outside of the tube to key the loctite. Other than that , no further stripping should be required Link to comment Share on other sites More sharing options...
Area Representative Tin Man Posted May 28, 2008 Area Representative Share Posted May 28, 2008 Hi Dave I had the same problem with my scholar K series. Oily's fix solved the problem Link to comment Share on other sites More sharing options...
Dave McCulloch Posted June 1, 2008 Author Share Posted June 1, 2008 Right, got the head off today and the HG appears ok - the orangey seal material on the HG around the oil way looks intact. I haven't yet pulled out the dowel from the block, but will I be able to actually see the crack at the top of the oil drilling? Oily - you mentioned the need to carefully shape the aluminium tube at its bottom end for the perpendicular oil way - any pics / indication on how to shape this, or do you sell ready formed/shaped aluminium tubes ready to be fitted? To peen the outside of the tube, what's the best method - multipe hits with a centre punch around the tube? Many thanks Dave Link to comment Share on other sites More sharing options...
oilyhands Posted June 1, 2008 Share Posted June 1, 2008 You wont be able to see the crack... You may be able to insert the tube without taking the dowel out. I usually roughen the surface with a coarse file which I tap all around the outside. The end of the tubing needs to be cut in half and the front half removed for around 8-10mm from the bottom to allow oil to pass into the tube from the supply drilling through from the front of the block. If you give me an address I can prepare a suitable piece of tubing and send it to you, Just make sure it is a good fit, clean out the oilway by cranking the engine by hand *backwards* a little to displace oil from the pump and allow the oil in the oilway to drain down, then clean and dry it with a cotton bud *very firmly* attached to a piece of TIG wire or similar. Lock the tube in with Loctite 648 or similar stud lock. Oily Edited by - oilyhands on 1 Jun 2008 22:27:26 Link to comment Share on other sites More sharing options...
Dave McCulloch Posted June 3, 2008 Author Share Posted June 3, 2008 Can't find Loctite 648 locally - but I already have Loctite 271 which says its a stud and bearing lock - is this essentially the same stuff and ok to use? Thanks Dave Link to comment Share on other sites More sharing options...
Julian Thompson Posted June 3, 2008 Share Posted June 3, 2008 The 648 maintains 75% of its strength at 150 degrees but the 271 is down to 50% strength at that temperature.... Link to comment Share on other sites More sharing options...
Dave McCulloch Posted June 3, 2008 Author Share Posted June 3, 2008 Julian Thanks - couldn't find that info before - I guess that answers my question! Need to find a source for the 648 asap so I can start putting the engine back together again.... Dave Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted June 3, 2008 Leadership Team Share Posted June 3, 2008 here Stu. Joint Area Representative MAD Sevens (Merseyside And District) www.superse7ens.co.uk..........the rebuild 😬 Link to comment Share on other sites More sharing options...
Jason Plato Posted June 3, 2008 Share Posted June 3, 2008 I used epoxy when mine needed inserting. here is C7 TOP Taffia rear gunner Link to comment Share on other sites More sharing options...
Dave McCulloch Posted June 4, 2008 Author Share Posted June 4, 2008 Sourced the Loctite 648 today from a local bearing supplier. Now turns out I've got one of the blocks with a drilling that's smaller than 6mm - oil pump's off but I now need to buy a long 6mm drill bit to get the whole way down the oilway. Ho hum... Dave Link to comment Share on other sites More sharing options...
oilyhands Posted June 4, 2008 Share Posted June 4, 2008 Dave, That is b*st*rd luck... I have a long 6mm bit here for just that purpose, from J&L industrial supply. hope it all works out OK.. Oily Link to comment Share on other sites More sharing options...
Dave McCulloch Posted June 5, 2008 Author Share Posted June 5, 2008 Cheers Dave - ordered one from J&L this morning - should be here tomorrow, so should hopefully be able to sort out this weekend now. Dave Link to comment Share on other sites More sharing options...
Dave McCulloch Posted June 14, 2008 Author Share Posted June 14, 2008 Finally got the engine all back together and fired it up this morning - complete with new mechanical oil pressure gauge. Fired straight away with good oil pressure - but a problem soon materialised. Steam started coming out of the top of the dry sump catch tank - pulling the breather hose out of the tank showed a constant stream of steam. Initially thought it might just be evaporating off some coolant which had got into the oilways / sump from when I pulled the head off, so drain catch tank and took car for 30 minute run. Temperature and oil pressure behaved perfectly, but when I got home again there was still steam coming from the vent pipe and the catch tank again had a small amount of slightly oily water in the bottom of it. Now, the question I have is whether this is indicative of my repair to the oil drilling being unsuccessful - previously I was getting oil in the coolant, not coolant in the oil - or have I created another problem? Really not overly happy at the prospect of having to take the head off again - it wasn't exactly a five minute exercise... Thanks Dave Link to comment Share on other sites More sharing options...
Dave McCulloch Posted June 15, 2008 Author Share Posted June 15, 2008 Having thought about this some more, I'm guessing it can't be the repair to the oil drilling being unsuccessful - the oil is always at a higher pressure than the coolant (OP at idle is min 30psi compared to coolant where header tank cap vents at 1 bar - 15psi) so presumably you can never get coolant entering the oil system via the oil drilling. So, I can only surmise I've fouled something else up in reassembling. Any thoughts or pointers gratefully received! Dave Link to comment Share on other sites More sharing options...
Dave McCulloch Posted June 16, 2008 Author Share Posted June 16, 2008 *arrowup*Anyone 🤔 In particular can someone confirm my logic re the oil drilling repair - ie that as the oil is higher pressure than the coolant, it's impossible for the coolant to enter the oil at that point? Thanks Link to comment Share on other sites More sharing options...
CageyH Posted June 16, 2008 Share Posted June 16, 2008 The oil pressure is 30 psi near the pump. I would expect it to be lower elsewhere in the system. Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
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