Jentriken Posted December 13, 2023 Report Share Posted December 13, 2023 Hey guys so I recently grabbed this 4kc hicam for cheap. It’s to go in my kesev. I didn’t really look super closely at it as it was still in the car when I bought it. Figured it ran well and didn’t smoke so should be fine for my purposes (simple 4K daily) but after starting to strip down for a regasket I’ve noticed that the head is HELLA crusty and full of flakes of what I assume is old oil. So my question is, is this motor fucked? Like surely all the oil passages are blocked af and the oil pump is toast? Should I get rid of it and find another 4K or regasket it and chuck it in? Also can anyone identify tdc on the crank pulley? There’s like 3 marks and idk which one it would be. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted December 13, 2023 Report Share Posted December 13, 2023 Strip it completely and check the valves and bearings/pistons/bore. If it look OK, send it off to be cleaned and measured, then make a decision from there. It might just need a hone, rings & bearings and a gasket kit to give you another 200,000km, and a hot solvent wash would return it like new. If you don't want to spend that much and it looks half worn, I've put bearings back in a motor before and its ran fine, and the ultimate was building an Evo3 motor a few years back from 3 old motors and using pistons where the rings were seized solid with filth, going onto another set of conrods and being put in a third block... That motor did a year of rallies under a giant turbo without a problem. So strip it and clean it yourself, check it out and make a decision. The next motor you buy will probably be in similar shape, they're all getting old. The pulley is marked like this- I've forgotten what the other two marks mean, haven't had a 4K for a while now. Quote Link to comment Share on other sites More sharing options...
Banjo Posted December 13, 2023 Report Share Posted December 13, 2023 Hi Jesse, "Olde K series motors never die ! They just need cleaning up, & restarting !" This one certainly needs cleaning up, but if you've already heard it run; then there is nothing "broken" inside. 4KC was & is a great engine for many reasons. The engine was nearly perfectly "square", meaning it's stroke & cylinder bore were almost the same dimensions. That allowed them to be well balanced, & achieve higher revs, than say a 5K, which had more capacity, & was not as well "balanced". There was only one K series engine better than the 4KC, & that was the little seen 4KU, which produced also as much power as a 5K, as a result of better breathing. I've had a 4KU in my KE30 2 door sedan for years, & I swear by it, for reliability & general performance. Like Altezzaclub said, strip it down & give it a good clean, & then take a close look at bearing journals, cylinder bores & ring gaps. I would however suggest a new oil pump assembly, which you can still buy new; although they are probably "aftermarket" types. New oil seals at each end of the crank, & you'll have a very serviceable engine, & learnt a lot along the way. The main thing is to not mix things up. Make sure crankshaft bearing slippers are all keep in order etc, along with pistons & rings. Same goes for rocker arms. Come back & tell us, what you find, once you've stripped it down. Cheers Banjo Quote Link to comment Share on other sites More sharing options...
Jentriken Posted December 14, 2023 Author Report Share Posted December 14, 2023 20 hours ago, Banjo said: Hi Jesse, "Olde K series motors never die ! They just need cleaning up, & restarting !" This one certainly needs cleaning up, but if you've already heard it run; then there is nothing "broken" inside. 4KC was & is a great engine for many reasons. The engine was nearly perfectly "square", meaning it's stroke & cylinder bore were almost the same dimensions. That allowed them to be well balanced, & achieve higher revs, than say a 5K, which had more capacity, & was not as well "balanced". There was only one K series engine better than the 4KC, & that was the little seen 4KU, which produced also as much power as a 5K, as a result of better breathing. I've had a 4KU in my KE30 2 door sedan for years, & I swear by it, for reliability & general performance. Like Altezzaclub said, strip it down & give it a good clean, & then take a close look at bearing journals, cylinder bores & ring gaps. I would however suggest a new oil pump assembly, which you can still buy new; although they are probably "aftermarket" types. New oil seals at each end of the crank, & you'll have a very serviceable engine, & learnt a lot along the way. The main thing is to not mix things up. Make sure crankshaft bearing slippers are all keep in order etc, along with pistons & rings. Same goes for rocker arms. Come back & tell us, what you find, once you've stripped it down. Cheers Banjo I’m gonna wait to find until I get a workshop manual, cos I haven’t stripped a motor past the long block before. But once I pull the head off what would u recommend to clean the crud out? Quote Link to comment Share on other sites More sharing options...
Banjo Posted December 14, 2023 Report Share Posted December 14, 2023 Hi Jesse, Take the head off, which only involves 10 bolts off memory. Undo the head bolts in the same order, as they suggest doing them up. The head is small & relatively light; & is best worked on on a bench of some kind. You will need a valve spring compressor, although you could make a hinged one with a long arm. Once you have the valves laid out in order, you can inspect valves & their seats in the head, along with valve guide wear. clean out the combustion chambers & look for cracks or damage. Then clean out the ports. You can also spent a lot of time cleaning all the rocker gear, including posts & shaft. It's very rewarding, especially if you take a before & after pictures. Cheers Banjo Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted December 15, 2023 Report Share Posted December 15, 2023 Once you have the head off drain the bock as much as you can, all the oil & water. Tip the block over on its side and scrape the dry rust out of the water jackets, mainly around cyls 3 & 4. This is where it builds up & stops water flow, causing overheating on the back cylinders. With the manifolds off put a straightedge along the manifold faces. They must be straight and aligned with each other, and mis-alignment is the cause of many an exhaust gasket failure. There's stuff to look at in here- https://www.rollaclub.com/board/topic/42407-the-girls-ke70/ Cheers Quote Link to comment Share on other sites More sharing options...
Jentriken Posted December 16, 2023 Author Report Share Posted December 16, 2023 On 12/14/2023 at 10:26 PM, Banjo said: Hi Jesse, Take the head off, which only involves 10 bolts off memory. Undo the head bolts in the same order, as they suggest doing them up. The head is small & relatively light; & is best worked on on a bench of some kind. You will need a valve spring compressor, although you could make a hinged one with a long arm. Once you have the valves laid out in order, you can inspect valves & their seats in the head, along with valve guide wear. clean out the combustion chambers & look for cracks or damage. Then clean out the ports. You can also spent a lot of time cleaning all the rocker gear, including posts & shaft. It's very rewarding, especially if you take a before & after pictures. Cheers Banjo So I’ve pulled the head off very crusty but hopefully will clean up ok. I’m thinking after looking at the coolant passages in the block, that I’ll probably use the bottom end that’s already in the car (as long as the valve that stuck didn’t smack the piston) as the condition can’t be any better than my original motor. Thoughts on what to use to get all the crud out of the head once i get the valves out? How aggressive can I clean it without risking damage to the head? Also what would u recommend to remove the gasket material without scoring up the mating surface ? Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted December 16, 2023 Report Share Posted December 16, 2023 That looks pretty terrible! OK, the front water holes are not used, we figure Toyota made a cock-up in their circulation design and tried to make the water circulate around the rear cylinders more by closing off the front holes with the head gasket. However the rear holes on your head/block also look crap! So, someone used no coolant for a decade or two, and never changed the oil in the same period! If you're going to use that head, get it professionally cleaned, it needs to come back spotless. If the valves aren't too thin around the edge and the seal on the seat looks OK & not burnt at all, just get the head cleaned and grind the valves in yourself. I use a wide snap-off craft blade (no knife, just the blade) to carefully scrape the old gasket off the head, it doesn't want to be too new of you can dig into the head surface & ruin it. Take it easy & slow. Finish it with a sheet of 320grit wet & dry sandpaper with some WD40 on a flat steel surface. If you don't have a flat steel, get on, you'll need it sooner or later. Even a piece of 150mm wide steel by 10mm thick by about 200 long will do, just make sure there are no edges sticking up. Any steel supplier can sell you something. It does the manifold surfaces and everything. If not, have the workshop that cleans the head skim it lightly. With both heads off put a pair of pistons on TDC in each block and rock then left & right across the block with your thumbs. Pick the block with the least movement, the piston slap. Look for the smaller lip at the top of the bore too, although really the pistons and bore should be measured accurately. Tip both blocks over and take off a main and a big-end bearing, and compare those between motors. Decide which motor has the least wear & damage and use that, probably the one you were using but you never know. If the bearings in the original block don't show signs of wear, just put the two you took out back and hope... If not, pull them all off and lift out the crank. Keep all the bearing shells in order, take lots of photos. Either they are all good enough to use, or some are more worn or damaged by dirt. At that time you need to decide on new bearings, mains and big-ends... which may mean paying for the crank to be ground if they are down to the copper backing, or just get the crank polished and fit new bearings of the same size. Make sure you scrape the water jackets out on the block you are using. If the pistons feel OK, leave them in the block, just sort out the bearings. You could check the cam chain & tensioner for wear and slack, another job worth doing while its apart. Why did the valve hit the piston in the original motor, and how well did it run for the month or three before it died? Just too many revs?? Tappet clearance problem? Where abouts are you in Aussie, someone might be close enough to give you a hand. Quote Link to comment Share on other sites More sharing options...
Banjo Posted December 17, 2023 Report Share Posted December 17, 2023 (edited) Hi Jesse ! I've got to say: I'm an "old timer" K Series fan, but I don't think I've ever seen as bad a build up of dry oil & crud, in one of these engines, as your pics have displayed. Water coolant passages, will get corroded, but the amount of crud in the oil lubrication return paths to the sump, has me baffled, as to how it could get that bad: & secondly how did the engine function at all. I am hoping not; but I think the most enlightening picture, is going to be the one you take, once the engine is upside down, & you have removed the sump. I think that might be your next best step, as if you spend a lot of time cleaning the block & head faces, it may well all be a waste of time, once you remove the sump. I hope not; but I am trying to warn you, that it's condition, may be a bit of a shock; for all of us. On the water coolant passages, the dished Welsh Plugs situated around the block, always look pretty good on the outside, but can be badly pitted & corroded on the inside. I've come across them so thin, that centre punching the middle of the plug, whilst trying to remove them, has had the punch penetrate straight through. I would remove the sump before going any further, & lets have a look at the "full picture", before you spend any more time on this engine. You are at the stage, with the head removed, that you can turn it over, & have the sump off in about 10 minutes. You might get some inspiration from this video, if You haven't already come across it. https://www.youtube.com/watch?app=desktop&v=1RX_AJRbYzc Cheers Banjo Edited December 17, 2023 by Banjo Quote Link to comment Share on other sites More sharing options...
ke70dave Posted December 17, 2023 Report Share Posted December 17, 2023 (edited) Drop that bad boy off at an engine reconditioner and get them to clean it and inspect it for cracks and face the surface. then you'll get a shiny flat head with hopefully no known cracks. But put a straight edge (metal ruler will do) across it from corner to corner and see if its flat first. but a machine shop will quickly tell you if its saveable. Edited December 17, 2023 by ke70dave Quote Link to comment Share on other sites More sharing options...
Jentriken Posted January 10 Author Report Share Posted January 10 (edited) Ok so update if anyone is interested, I ended up cleaning the head myself which came up ok eventually, except I had to use the rocker assembly from my old head as the ones from this head had blocked oil passages. I got the head skimmed and checked the valves sealed. Pulling my old head off was positively surprising, the cylinder walls looked great, there was no noticeable piston slap and once I cleaned off the old gasket material, the block surface seemed straight enough. Torquing the head down went smoothly, and after cleaning everything and putting it all back together it started right up. 👍cheers to all who helped along the way Edited January 10 by Jentriken Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted January 10 Report Share Posted January 10 Excellent! Well, there ya go, now you're educated and experienced and it didn't cost too much! Quote Link to comment Share on other sites More sharing options...
ke70dave Posted January 10 Report Share Posted January 10 nice outcome. I do miss working on the old K engines. So simple. I love how much ground you can see when looking down into the engine bay. hah. Quote Link to comment Share on other sites More sharing options...
Banjo Posted January 12 Report Share Posted January 12 Hi Jesse ! Yes well done, & a good outcome ! Once you removed the head, did you get around to turning the block upside down, & removing the sump, & inspecting therein. Seeing your pics of the head, I was concerned that the bottom "sump" end; could be in a similar, or maybe even worse condition, that the top/head end. Cheers Banjo Quote Link to comment Share on other sites More sharing options...
Jentriken Posted January 12 Author Report Share Posted January 12 3 hours ago, Banjo said: Hi Jesse ! Yes well done, & a good outcome ! Once you removed the head, did you get around to turning the block upside down, & removing the sump, & inspecting therein. Seeing your pics of the head, I was concerned that the bottom "sump" end; could be in a similar, or maybe even worse condition, that the top/head end. Cheers Banjo Yea the block on that motor was also fucked, turned out there was a rag in the sump that seemed to be blocking the oil from circulating properly which may have caused all the crust?. That’s why I ended up using my og bottom end Quote Link to comment Share on other sites More sharing options...
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