Cylinder Head Removed
12-21-2009, 04:26 PM
#41
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Rings move under normal use. Don't expect them to be exactly where you think.
Given your pics of #4, I'd say that bottom end is probably in good shape. I would expect that all the valves are leaking some ( 2and 3 more?) and with a valve job the engine will probably be healthy again.
If you've got the money, I would say go for a full rebuild. If cost is a concern, you can probably safely gamble on a valve job (if the rest of the head checks out) and a new HG.
Given your pics of #4, I'd say that bottom end is probably in good shape. I would expect that all the valves are leaking some ( 2and 3 more?) and with a valve job the engine will probably be healthy again.
If you've got the money, I would say go for a full rebuild. If cost is a concern, you can probably safely gamble on a valve job (if the rest of the head checks out) and a new HG.
12-21-2009, 08:19 PM
#42
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Leak down showed 5% on 1 and 4, so leakage all around, but not a huge concern when compared to 25% on 2 and 3. I'm hoping new seats and a valve job will work. Hopefully I didn't bend anything.
12-22-2009, 03:09 PM
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Well got the call from the machine shop and they said that the head was fine. They vac tested it and the results were all 95 - 100%. It was a little warped, but all cleaned and milled now. So wtf next? Could the rings be bad with nothing wrong with top end or scoring of the walls? What, if any, is a way to check rings without taking the block apart?
12-22-2009, 04:05 PM
#44
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They milled it?!? Did you tell them to?
I'd want to know what a "little" warped was. If it's .002" or less, the stock HG can make up for that. Same for the block.
Get the block checked for flatness. Your cyl walls looked a little glazed (no hone marks left) but nothing out of the ordinary for your miles. It shouldn't account for more than 5% leak.
If the block was at .002", I suppose the HG could have failed, but I really doubt it. It would be worth, though, putting the head on w/a new HG and redoing the leakdown. Worst case, you pay for a HG and a leakdown. You don't need to put any other hardware on to do that (not even the cams or rockers).
If you have a friend with a portable compressor, or can rent one, Harbor Freight has decent leakdown gauges for <$50 (plus 20% off in-store coupons everywhere). The test is pretty easy to conduct. You can also get a machinists rule for cheap there, and feeler gauges, and check the deck for flatness. This should avoid having the car towed again if it's not at a shop right now.
Also, per your question, the cylinder bores glaze and the rings lose tension, but I've yet to see even a 200k mi motor that blew more than 10% leakage that didn't have badly pitted or bent valves or bad cylinder scoring.
I'd want to know what a "little" warped was. If it's .002" or less, the stock HG can make up for that. Same for the block.
Get the block checked for flatness. Your cyl walls looked a little glazed (no hone marks left) but nothing out of the ordinary for your miles. It shouldn't account for more than 5% leak.
If the block was at .002", I suppose the HG could have failed, but I really doubt it. It would be worth, though, putting the head on w/a new HG and redoing the leakdown. Worst case, you pay for a HG and a leakdown. You don't need to put any other hardware on to do that (not even the cams or rockers).
If you have a friend with a portable compressor, or can rent one, Harbor Freight has decent leakdown gauges for <$50 (plus 20% off in-store coupons everywhere). The test is pretty easy to conduct. You can also get a machinists rule for cheap there, and feeler gauges, and check the deck for flatness. This should avoid having the car towed again if it's not at a shop right now.
Also, per your question, the cylinder bores glaze and the rings lose tension, but I've yet to see even a 200k mi motor that blew more than 10% leakage that didn't have badly pitted or bent valves or bad cylinder scoring.
12-23-2009, 12:11 AM
#45
You have several options to test the piston-cylinder leakage:
- drop the oilpan (1/2 hour work) and loosen the nuts from connecting rod bearing #2 or #3, than pull that piston. Be carefull about the carbon area on top of the cylinders when pulling the piston. Better sand this area carefully a bit. Measure the cylinder diameter in several positions, have a look at the rings, the piston walls and look for wear. This is the precise method.
- drop the oilpan and put some gasoline on the top of the pistons. Watch how fast the fluid dissapears. Best would be to turn the crank so that all pistons are in the same position. This is only a indicator for differences between the cylinders.
- put a spy gauge in between the piston top and the cylinder wall to measure the gaps in all 4 cylinders at the same position. Turn the crank so that all pistons are in the same position.
- drop the oilpan (1/2 hour work) and loosen the nuts from connecting rod bearing #2 or #3, than pull that piston. Be carefull about the carbon area on top of the cylinders when pulling the piston. Better sand this area carefully a bit. Measure the cylinder diameter in several positions, have a look at the rings, the piston walls and look for wear. This is the precise method.
- drop the oilpan and put some gasoline on the top of the pistons. Watch how fast the fluid dissapears. Best would be to turn the crank so that all pistons are in the same position. This is only a indicator for differences between the cylinders.
- put a spy gauge in between the piston top and the cylinder wall to measure the gaps in all 4 cylinders at the same position. Turn the crank so that all pistons are in the same position.
12-23-2009, 01:54 AM
#46
As Marcucci suggested, I would install and torque down the head and perform a leakdown on each cylinder. Do this with the pistons at bdc and at tdc. If it comes up clean on the leakdown then you don't have to touch the bottom end.
While I agree that the spec sheets say the gasket should be able to handle a 2 thou warp, this is for a new gasket crushing down. If the head has warped over time, especially if its cupped so that its dropping pressure on the area between the cylinders, a used gasket that was initially crushed flat is not going to expand to fill up the space.
Before you assemble, have a really close look at the top ring for any cracks, your bores look clean so cracked rings would be unlikely.
While I agree that the spec sheets say the gasket should be able to handle a 2 thou warp, this is for a new gasket crushing down. If the head has warped over time, especially if its cupped so that its dropping pressure on the area between the cylinders, a used gasket that was initially crushed flat is not going to expand to fill up the space.
Before you assemble, have a really close look at the top ring for any cracks, your bores look clean so cracked rings would be unlikely.
12-23-2009, 06:12 AM
#47
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This is intake #3 from my old MY00, 145000 km engine.
Its a MY00 and had a healty appetite for oil.
Most of the time I just had the OEM plastic PCV valve, for about a year (IIRC) I had the KrankVents and they lowered oil consumption a bit.
The intake is spotless though, not even "wet" with oil.
How come your intake is black?
12-23-2009, 06:19 AM
#48
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Spitfire, I've never seen a head's intake side that clean except on an S with less than 30k mi or so.
Oil and carbon fouling on the intake side is fairly normal for high-RPM engines with a PCV system installed (vs just breathers). As mentioned by another poster there is some blowback up into the IM, especially the harder the car is driven, and obviously the more oil consumption you have the more oil will be in the head/manifold on the intake side, which will promote carbon to stick.
How you drive has a lot to do with it- keeping it in VTEC all the time, running uber-rich, will present a lot more carbon inside the motor, vs. running closed-loop and stoich or even lean most of the time.
Oil and carbon fouling on the intake side is fairly normal for high-RPM engines with a PCV system installed (vs just breathers). As mentioned by another poster there is some blowback up into the IM, especially the harder the car is driven, and obviously the more oil consumption you have the more oil will be in the head/manifold on the intake side, which will promote carbon to stick.
How you drive has a lot to do with it- keeping it in VTEC all the time, running uber-rich, will present a lot more carbon inside the motor, vs. running closed-loop and stoich or even lean most of the time.
12-23-2009, 06:29 AM
#49
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marcucci Posted on Dec 23 2009, 05:19 PM
This engine developed an oil warning light at idle at the Assen TT track on r-compounds in a long right hander.
The 3rd time it was there.
Fastest lap 2:18 or so.
Sure, I didn't drive "hard" (is like an idiot) to work.
How you drive has a lot to do with it
The 3rd time it was there.
Fastest lap 2:18 or so.
Sure, I didn't drive "hard" (is like an idiot) to work.
12-23-2009, 07:39 AM
#50
Compression loss and a lot of oil in the intake is a clear indication of massive blowby in the crankcase.
Some could argue that the oil is coming from somewhere else, maybe from bad valve stem sealings (is it the right name?). But then there would be no compression loss.
For me it's still a very clear indicator that there's a problem with the piston rings or heavy wear on the cylinder walls.
Some could argue that the oil is coming from somewhere else, maybe from bad valve stem sealings (is it the right name?). But then there would be no compression loss.
For me it's still a very clear indicator that there's a problem with the piston rings or heavy wear on the cylinder walls.