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Could be blowby, too!
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May 28, 2015 20:14
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Commodore_64 posted:Could be blowby, too! ... I need to do a compression test.
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May 28, 2015 20:57
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GoodbyeTurtles posted:... I need to do a compression test. If possible do a cylinder leakage test too. Often an engine will show good compression but will have excessing cylinder leakage where the rings or cylinders are worn, can cause excessive blowby and oil consumption.
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May 28, 2015 21:24
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Mooseykins posted:If possible do a cylinder leakage test too. Often an engine will show good compression but will have excessing cylinder leakage where the rings or cylinders are worn, can cause excessive blowby and oil consumption. I've been meaning to nag the boss into getting one of those for a while now, really good bits of kit if you know what you're doing with them. Though I still have access to the kit they have at college so I may be able to test it there for learning reasons.
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May 28, 2015 21:45
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GoodbyeTurtles posted:I've been meaning to nag the boss into getting one of those for a while now, really good bits of kit if you know what you're doing with them. Though I still have access to the kit they have at college so I may be able to test it there for learning reasons. Worth having. They show a lot more than compression tests do. I have a valve in my toolbox from a 3-cylinder Polo that had rough running. Everything checked fine, compression was ok, valve has holes burned through it. cylinder leakage showed what nothing else could.
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May 28, 2015 21:57
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How did it have any compression at all with a holed valve? 
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May 29, 2015 07:27
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Cakefool posted:How did it have any compression at all with a holed valve? No idea. And not just one hole and not just one valve!
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May 29, 2015 13:02
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I'd guess that if they were only very small holes there would still be some compression but it'd lose pressure faster? Possibly wouldn't be able to tell if you weren't cranking it for the same amount of turns or watching it drop afterwards. Again the holes would have to be very small but if it was the same on other cylinders you'd not realise how high the pressure should be.
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May 29, 2015 16:31
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I have had an engine start and run with a 1/2" wide gap burnt through the head gasket between two cylinders... two cylinders which are opposing, so one is on intake when the other is on power and one is on exhaust while the other is on compression. (3 and 4 in an I6.) It still had 30psi compression on those cylinders, and above 3000rpm it was compressing fast enough that it ran fairly smoothly since they would still build enough pressure to fire properly before it all leaked out the hole. You don't realize how much you can get away with till you do it. I don't think I would recommend this, especially with alloy parts that erode faster, but it was pretty eye opening. lovely compression does make starting harder, though.
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May 31, 2015 13:39
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Managed to do the compression test and leakage test. Sorry for the state of the video my new phone seems to like recording really narrow tall videos for whatever reason. https://www.youtube.com/watch?v=HMXFZB2a6nA  The wonderful sound of excessive blowby... Cylinders one, two and four all had compression at around 65psi. Cylinder 3 had 90psi compression. The compression should be 185-200psi at a 10:1 ratio (at least the manual says so, seems pretty high to me but it says it was unusually high for the time) so I don't know what the gently caress to think right now. It starts and runs well but how could the compression be that bad? Either way, that engine is coming apart soon. At least to see what kind of weird magic is going on in there to keep it alive. GoodbyeTurtles fucked around with this message at 22:53 on Jun 3, 2015 |
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Jun 3, 2015 22:38
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GoodbyeTurtles posted:Managed to do the compression test and leakage test. Rings/bores i would guess. Did you check leakage with the piston and the top and bottom of the cylinder? Usually you find there's more wear at the top of the bore and that shows on the leakage test. If you're down on compression but leakage is identical top to bottom it may be just the rings.
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Jun 3, 2015 23:02
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Mooseykins posted:Rings/bores i would guess. I couldn't stop it turning over when plugging the air-line in, even in gear with the handbrake on. I'd have to lock the crankshaft somehow and there isn't any access to the flywheel to lock it there.  I figured that the air pissing out of the dipstick tube said enough to bother doing any of the other cylinders after that, also the tester wouldn't fit in any of the other spark plug holes due to the limited space in the engine bay. Either way it's all gonna have to come apart, I'm expecting the worst.
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Jun 3, 2015 23:17
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GoodbyeTurtles posted:I couldn't stop it turning over when plugging the air-line in, even in gear with the handbrake on. I'd have to lock the crankshaft somehow and there isn't any access to the flywheel to lock it there. You'll just need to have it mic'd and see if you've got worn or ovalled bores. Often you can get away with just a hone and a set of rings, which isn't a huge deal. Also, your handbrake must be even more useless than mine if it can't even stop the engine turning over, under air pressure.
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Jun 3, 2015 23:25
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Mooseykins posted:You'll just need to have it mic'd and see if you've got worn or ovalled bores. Often you can get away with just a hone and a set of rings, which isn't a huge deal. Maybe a higher gear would have been better... But yeah, either way it'll need a both the head and block skimmed (they have a habit of warping) so i'll be sending them to the engineer and it'd be daft not to get the bores honed at the same time. New rings should be pretty readily available through the Imp Club too. Not too big of a job but I'll want to do a full strip-down and rebuild of the engine once it's apart.
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Jun 3, 2015 23:36
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GoodbyeTurtles posted:Maybe a higher gear would have been better... Have the block deck checked with a straight edge for warpage before skimming it, as they tend not to warp quite as much as heads. And once torqued up they often pull straight with no issues. I have a great engine shop near me (North London) where if i call in advance they skim heads for me while i wait. Place looks like a bunch of big sheds, but they're awesome.
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Jun 3, 2015 23:39
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GoodbyeTurtles posted:It starts and runs well but how could the compression be that bad? There was someone here that posted about some old lady who owned an eighties 4 cylinder BMW that had such miserable compression that it would start rolling away parked in gear making a POOSH POOSH POOSH sound as it escaped. Car otherwise ran fine according to the owner.
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Jun 4, 2015 07:04
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Running the engine with the oil filler cap off you probably get about the same amount of air out of the filler as you do out of the exhaust. 
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Jun 6, 2015 22:27
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8ender posted:There was someone here that posted about some old lady who owned an eighties 4 cylinder BMW that had such miserable compression that it would start rolling away parked in gear making a POOSH POOSH POOSH sound as it escaped. Car otherwise ran fine according to the owner.
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Jun 6, 2015 22:48
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There's only one thing to do with an engine with that type of compression. BOOST 
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Jun 7, 2015 23:38
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You Am I posted:There's only one thing to do with an engine with that type of compression. I love this idea maybe too much.
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Jun 8, 2015 00:02
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So much sump goop
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Jun 22, 2015 18:37
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Apparently they are well known for lifting the head off the block. Sadly this would be the fate of this very fast imp that we got to see this weekend.
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Jun 23, 2015 03:35
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Oh no, something fell off! Oh dear, it's just getting worse!  Well drat.  Be free, little engine.  Took all of my lunch hour too! (More to follow, just wanted to keep the number of pictures per post down a little)
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Jul 1, 2015 22:38
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How was the paint where the section in the rear comes out? I've noticed things like that often end up being "painted in" a bit (or worse if it's been buggered about with, fillered over), and it can be hard to remove them cleanly.
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Jul 1, 2015 22:45
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Radiator looks good and according to the previous owner, it was meticulously flushed and cleaned a few years ago, so nothing to worry about there. Water pump, fan and alternator bracket.  Blurry manifolds and carb.  Carried over to the bench because it's stupidly lightweight. PLEASE NOTE: BOX LABELED 'TURBO' IS NOT RELATED TO THIS PROJECT  (Still more to come)
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Jul 1, 2015 22:50
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InitialDave posted:How was the paint where the section in the rear comes out? I've noticed things like that often end up being "painted in" a bit (or worse if it's been buggered about with, fillered over), and it can be hard to remove them cleanly. It wasn't painted in, but it did crack the paint a little around the edges as it was jammed in there quite tight, nothing a little touch up paint can't cover though! Going to be totally stripping and respraying it in the winter/ next year though so I'm not too worried about the paintwork at the moment.
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Jul 1, 2015 22:52
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Popping the lid off. Revealing the little camshaft.  Shaft out.  Thank gently caress the shims didn't drop out here or I'd be having a lot of 'fun' taking it all apart and rebuilding it over and over to get them in the right places.  Beheaded. The bores are hella glazed but you can't really see in this pic.  45 year old headgasket wasn't planning on letting go anytime soon.  Sump dropped.   Pistons looking a little worn on the sides, but it looks like it's just the very surface layer that has worn down.   And finally, the most worn big end bearing.  All in all the engine is actually in a pretty good condition. Looking at the wear on the pistons (very little wear, very little slap, if any) and the glazing of the bores I'm thinking a honing and a new set of standard sized rings will do the trick. I'm considering getting a new set of standard big end bearings too but I'm not entirely sure it needs them. The block is also straight and not at all warped (checked with a steel rule, of course), I've still gotta check the head for any warpage though, but in theory it should be the same as the block. Anyway, life has been pretty (really) lovely recently so I've been putting off this update (and actual work on the car) for a couple weeks, but with parts ordered things should start coming together soon.
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Jul 1, 2015 23:12
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New title: The Hillman Imp: ... I need to do a compression test.
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Jul 1, 2015 23:18
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Remembered that I was going to drain the coolant that was still left in the engine out and noticed something. 45 years of sediment built up around cylinder 4, which is the main cause of the warping that these engines are notorious for. Before I started hacking away at it the sediment was most of the way up the bore, which isn't good news but it could have been worse! I've since managed to scrape 95% of it out but I'll likely be doing more tomorrow. Also a package arrived today.  Lots of goodies!
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Jul 2, 2015 17:54
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I'd get a giant HDPE bin and soak the block in Evapo-Rust diluted with deionized water for a bit. Then again I never actually get anything done, just incrementally cleaner than I found it.
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Jul 2, 2015 18:35
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Commodore_64 posted:I'd get a giant HDPE bin and soak the block in Evapo-Rust diluted with deionized water for a bit. Then again I never actually get anything done, just incrementally cleaner than I found it. Well, I was gonna jetwash it out but apparently I'd have to take the crank and everything else off to do that and  The current plan is to scrape it all down and rinse it through a few times, which should do the trick once I've chiseled the last of the solid sediment out, but the amount of crud in there has be wondering about the state of the rest of the cooling system...
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Jul 2, 2015 18:56
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GoodbyeTurtles posted:Carried over to the bench because it's stupidly lightweight. PLEASE NOTE: BOX LABELED 'TURBO' IS NOT RELATED TO THIS PROJECT Well that's a cute little sewing machine. Valve pics as promised:  
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Jul 2, 2015 22:23
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Mooseykins posted:Well that's a cute little sewing machine. Haha wow. That's probably the most impressive thing ever to come from a 3 cyl polo! How does that even happen? I'm guessing hot-spots from carbon build up or just overheating and cracking?
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Jul 2, 2015 22:59
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That still made compression?
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Jul 2, 2015 23:02
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Seat Safety Switch posted:That still made compression? So did one of my engines with a half inch wide gap burned through the head gasket between two bores, so I'm not too surprised. I mean, you had to get it above 3000rpm before those cylinders would do anything resembling firing, but it did work. It made 30psi compression still on those cylinders at cranking speed  Why do the Imp engines sludge up the water jacket at that point, just poor flow?
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Jul 2, 2015 23:22
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kastein posted:So did one of my engines with a half inch wide gap burned through the head gasket between two bores, so I'm not too surprised. You're pretty spot on, it's poor flow due to being the furthest corner from the water pump and the angle that the engine sits just causes everything to settle there. These engines (the earlier MK1 moreso) are well known for the water jacket clogging up around cylinder 4 and loving everything up. Though considering it's been sat around for so long and has never been opened before I should have expected it really, I'm just glad I didn't toast it when hammering it around town.
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Jul 2, 2015 23:38
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You assume it's silt/sludge. Why do you think the engine's called a Coventry Climax? 
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Jul 2, 2015 23:41
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InitialDave posted:You assume it's silt/sludge. Why do you think the engine's called a Coventry Climax? I suddenly feel like I need to shower...
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Jul 2, 2015 23:47
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Mooseykins posted:Valve pics as promised: I did that to a valve on my Saab 99. It went when I was struggling up a 1 in 5 hill in the peak district on a hot summer day with 4 people + kit in the car, all while running it on badly set up (lean) LPG. Was still drivable for the next 1000 miles till I had time to pull the head. I saved the valve but can't find it anywhere now 
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Jul 2, 2015 23:49
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No pictures but I managed to get the piston rings I needed. Got a slower drill to hone the bores out with too. After taking the engine apart, life decided it was about time to gently caress me over, twice. So much painful bullshit but that's all done now. So after having everything on hold for a month I decided that I needed a deadline or some kind of goal to take my mind off of things; I'd get the imp ready for a local classic car show. On the second of August. I have 6 days to reassemble the engine (flush rusty poo poo out of the water jacket, hone, clean, rings, pistons back in, everything else), renew the coolant hoses (all of them), repair clutch slave cylinder, reattach all ancillaries, get it running and tuned up (if it needs it). Probably will find more that needs doing before it can be run anywhere too. Not impossible, but holy poo poo there is a fair amount of work to do in not a lot of time. But gently caress it, I'll have that goddamn engine running and the car looking better than ever by Saturday if it kills me. If not, I'll be dragging it to the car show with my loving teeth and finishing it there. GoodbyeTurtles fucked around with this message at 17:33 on Aug 1, 2015 |
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Jul 27, 2015 22:06
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