zatsun Posted December 18, 2009 Share Posted December 18, 2009 77 non turbo, symptoms include: Smoke from tailpipe getting progressively worse over last few drives. White/blue tint, hangs in the air sort of like I read that coolant does when it's burned. Was losing water. After 15 min drive lost a couple gallons. Exhaust smelled really bad - think its running rich. Unplugged water temp sensor to see if it would make a difference but it was running too poorly to tell. When I turned on the car the last time it wouldn't run unless I kept foot on pedal. Once I got it around the block it cleared up a little bit, almost as if there was something that collected in the cylinders burned off. Exhaust tick, like a bad gasket seal. No loss of oil from what I can tell, but have driven less than 15 miles since these problems started. So, did a few tests.. Compression check cylinders #1-5: 150psi, #6 ZERO. Put some oil in spark plug hole to seal rings, still ZERO. Radiator pressure check. Pumped up to 11psi and it didn't change over 10 minutes. Noticed that the rubber on radiator cap was severely deteriorated on 2 seals. Spark plugs are bad. 4 of them are powdery black, 2 are shiny black with oil. Drained oil. No sign of water in coolant. Drained radiator. Brown fluid, not sure if it was because it was old or because exhaust gases leaked into it. Still smelled like antifreeze to me.. At this point I've taken off valve cover, fuel rail, intake & exhaust manifolds. My vacuum line goes in a T from the intake to the fuel pressure regulator and distributor. When I pulled the vac from distributor, fuel came out. I'll assume my FPR is toast. So this is my first question.. #1 I'll be upgrading to a turbo motor at some point in the next few years, can I get a Pallnet fuel rail and adj. FPR that will be compatable with both setups? I want to stick with stock injectors now and upgrade to the Supra or some other budget higher flowing injector and use the same Pallnet rail. OK so I can guess that if there was fuel going to distributor it was going into the intake as well, helping it run rich. Also, when I pulled the manifolds, the #6 exhaust was almost dripping with oil. #2 So at this point the head is about 30 minutes from being pulled, but its dark and cold now. I'm wondering if a bad headgasket can cause ZERO compression and oil in cylinder? Or valve seals, valve, rings? #3 The headgasket would explain the coolant loss, but there aren't oil passages running through it are there? #4 Should I pull the head and take it to NAPA and have them pressure check it? If the valves aren't adjusted right, would they know that or would it just come back as FAIL? Hopefully I can get the head off tomorrow and there will be an AHA! moment. I'm just hoping I don't have to tear the bottom end apart. Quote Link to comment Share on other sites More sharing options...
woldson Posted December 18, 2009 Share Posted December 18, 2009 Fingers crossed. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted December 18, 2009 Share Posted December 18, 2009 Have you tried rotating the engine and watching the valves for cylinder 6? Are they moving properly? Perhaps one of them is stuck open? Although I doubt this is the issue, if the valves appear to be moving properly for 6, check the valve clearances. Have you double checked that you have the compression tester properly screwed into the #6 spark plug hole? Did you hear any unusual sounds for #6 when cranking? I'd look at all the simple/easy stuff before I spent the money on a pressure test. I once had coolant mixing in with the oil and only the pressure test could find the pinhole casting defect near a valve spring base. For the symptoms you describe I expect you'll find something else more obvious. Quote Link to comment Share on other sites More sharing options...
CamH Posted December 18, 2009 Share Posted December 18, 2009 To me, that really sounds like a headgasket. It is probably blown between the piston and coolant passage. That would explain lack of compression, coolant out the exhaust, and losing coolant. It wouldn't hurt to pull the head and check things out, as it is a very easy job on our cars. Quote Link to comment Share on other sites More sharing options...
zatsun Posted December 19, 2009 Author Share Posted December 19, 2009 Zmanco, Yes I have the valve cover off. Everything in the valvetrain looks to be in order, but I don't have any feeler gauges to check clearances. As far as the compression test, I triple checked by going back to other cylinders to make sure tester still worked and made sure there wasn't anything on the mating surface of #6. Also made a little duct tape ball and turned the engine over. On #6 it didn't go anywhere, and on another cylinder it shot it across the garage. May be a few days before I get back out there, but will update once I get the head off. Quote Link to comment Share on other sites More sharing options...
Jehannum Posted December 19, 2009 Share Posted December 19, 2009 c'mon, a feeler guage is $6.00 at Sears. Pony up for the right tool for the job, 'cause Mk I eyeball isn't gonna cut it. Quote Link to comment Share on other sites More sharing options...
zatsun Posted December 19, 2009 Author Share Posted December 19, 2009 Just got back from Harbor Freight...feeler gauge was 2.99! Got oil pressure and compression testers as well, and the 10mm allen key socket for the head bolts. Don't go too hard on me guys I'm just getting back into the game here. Was still using the scissor jack that came with the car until Black Friday. Sears pretty much has all my money now. Quote Link to comment Share on other sites More sharing options...
zatsun Posted December 19, 2009 Author Share Posted December 19, 2009 Pulled the head today. The #6 exhaust valve hit the piston. Put a little ding in it on the rearmost part of the piston. The valve bent back to the back of the engine so far that I can barely get the .010 feeler gauge between it and the head when the valve is open. On the front exhaust valve (#1) there is way more clearance. Not sure how much exactly but biggest size on feeler gauge fits. So now what? I don't think I'd tear the bottom end apart to fix that piston. Can probably get a pic at some point, but its an arc about a 6 mm long and less than 1 mm deep. As for the head, I'm open to suggestions. How much do you think it'll cost to get the head fixed, as I'm guessing the bent valve tore up the seat. And the $ for a new valve. Or should I just find a new head? Quote Link to comment Share on other sites More sharing options...
zatsun Posted December 19, 2009 Author Share Posted December 19, 2009 Oh, and the headgasket was just fine. Not sure how I lost as much coolant as I did. Like I said before the radiator cap seal was bad and I didn't have a catch tank, but sure seems like a lot to boil over/slosh out. Quote Link to comment Share on other sites More sharing options...
Xnke Posted December 19, 2009 Share Posted December 19, 2009 10$ for the new valve; check with your local shops for valve job prices. Might only have to get that one seat done; but you might as well do them all. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted December 19, 2009 Share Posted December 19, 2009 I think what you do next has a lot to do with your plans for this engine. As Xnke says, you might just need to do one valve seat. But "while you're at it", you might as well do all. Plus, I wonder if the valve guide is ok for that bent valve. And then "while you're at it", what about the rest? Valve guides seem to be one of the first things to wear on our L engines. And you should change the valve seals too "while you're at it". If this is just a motor to keep running and you're going to do something else soon, perhaps you should just put a new valve in and call it done? "While you're at it" can quickly add up to a complete head rebuild for a few hundred dollars. But if you're going to keep this engine for a while, probably worth it as you've already got the head off. Quote Link to comment Share on other sites More sharing options...
zatsun Posted December 20, 2009 Author Share Posted December 20, 2009 Hey my buddy has a p79 head, same as mine i believe, with fresh rebuild, 3 angle valve job, and some "new parts" not sure what exactly but I think its a steal at $100 that he'll give it to me for. I'll eventually go Turbo swap including block and head, but I want to do suspension, wheels, and brakes first. So this motor doesn't need to be anything special nor spend more than necessary to make it reliable for a year or two. After head, gasket set, fluids, new used fpr and etc I may be able to get it back together for under $250 Quote Link to comment Share on other sites More sharing options...
zatsun Posted December 20, 2009 Author Share Posted December 20, 2009 Nevermind, I've got the N47 Head/N42 Block. I'll assume the pistons are stock but they have a dish to them. Will the P79 head my friend has work? I'm a bit confused on what I've read about interchangeability. Will the valves clear or will it mess up compression ratios? **edit** Arg. Found the L28 calculator. I see now it would drop my CR into the 7s and I'm not really up for changing pistons or milling the head down + shimming cam to bring it back proper. Will take my current head to NAPA on Monday to see what they have to say.. Will make sure they check out that valve guide too. Quote Link to comment Share on other sites More sharing options...
CamH Posted December 20, 2009 Share Posted December 20, 2009 Nevermind, I've got the N47 Head/N42 Block. I'll assume the pistons are stock but they have a dish to them. Will the P79 head my friend has work? I'm a bit confused on what I've read about interchangeability. Will the valves clear or will it mess up compression ratios? Yeah, but you will end up with a crappy compression ratio (like 7.3 to 1 or so) Quote Link to comment Share on other sites More sharing options...
Jehannum Posted December 20, 2009 Share Posted December 20, 2009 Pulled the head today. The #6 exhaust valve hit the piston. Put a little ding in it on the rearmost part of the piston. The valve bent back to the back of the engine so far that I can barely get the .010 feeler gauge between it and the head when the valve is open. On the front exhaust valve (#1) there is way more clearance. Not sure how much exactly but biggest size on feeler gauge fits. You realize you're supposed to check the valve clearance when the valve is closed, not open, right? Not sure what the clearance is on an L28, but it's .2mm intake/.25mm exhaust when cold and .25mm intake/.30mm exhaust when hot on an L24. Quote Link to comment Share on other sites More sharing options...
zatsun Posted December 20, 2009 Author Share Posted December 20, 2009 No no. The valve clearance between rocker and can isn't what I was referring to. I was measuring the distance between open valve and head face on the bowl side. the side of the valve, where it is supposed to seal on the seat, is practically touching the top of the bowl when valve is open. Quote Link to comment Share on other sites More sharing options...
Jehannum Posted December 20, 2009 Share Posted December 20, 2009 No no. The valve clearance between rocker and can isn't what I was referring to. I was measuring the distance between open valve and head face on the bowl side. the side of the valve, where it is supposed to seal on the seat, is practically touching the top of the bowl when valve is open. and you were doing this, why? Quote Link to comment Share on other sites More sharing options...
zatsun Posted December 20, 2009 Author Share Posted December 20, 2009 Just to explain how far it was bent.. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted December 20, 2009 Administrators Share Posted December 20, 2009 Just to explain how far it was bent.. Why was it bent? Bust the timing chain, valve stuck in the guide, valve float allowing the rocker to fall over and hold the valve open? If the valve is truly bent, it bent for a reason and hopefully you know why it bent and are aware of why, so hopefully it wont happen again. Quote Link to comment Share on other sites More sharing options...
zatsun Posted December 20, 2009 Author Share Posted December 20, 2009 I've only had the car for a few months, on the road around the neighborhood maybe 20 miles. The timing chain, water pump, distributor, clutch, and lots of other small stuff was redone about a year before I bought it and never ran right so it sat. Maybe the timing chain busted before and thats what caused it. Like I said, it has a new chain now and I know it will be adjusted right when it goes back together, so whatever is wrong with the head, in addition to valve, will be fixed at machine shop. Never heard of the last thing you mentioned BRAAP about the rocker falling over, but everything looked OK under the valve cover. BTW the clearance for the rocker-cam was .019 if I remember correctly. This is probably because now the valve isn't seating all the way, not because the adjusting screw is off. The other valves are all in spec. Quote Link to comment Share on other sites More sharing options...
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