I think i fucked up my motor PLease help
10-19-2007, 08:09 PM
#41
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just curious. could i get away with just replacing the rings for all my cylinders? i know i know im down there and have it all apart i might as well upgrade **** but i realy have no money do to no job so yeah.
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10-19-2007, 08:51 PM
#43
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ok well ive priced it and i think im just gunna rebuild my whole motor as sooon as i get a job and if i can hold out long enough ill keep the miata and just use my wifes car for a daily and build up the motor to handle the 9lbs of boost.
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10-20-2007, 12:25 AM
#44
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Well, I see two avenues here...
One- at this point the head has gotta come off anyway. Why not just pull it now (a couple hours' work) and survey the situation. Maybe a piston has melted, but then again maybe not.
Two- if the motor is in fact blown, perhaps simply replacing it with a junkyard engine rather than rebuilding it would be a more viable option? Taking the engine down to the block and rebuilding it with "built" parts is sexy and attractive, but unnecessary. A completely stock engine is more than adequate for 9psi. Hell, most of us are running a lot more than that without ever having pulled the oil pan.
One- at this point the head has gotta come off anyway. Why not just pull it now (a couple hours' work) and survey the situation. Maybe a piston has melted, but then again maybe not.
Two- if the motor is in fact blown, perhaps simply replacing it with a junkyard engine rather than rebuilding it would be a more viable option? Taking the engine down to the block and rebuilding it with "built" parts is sexy and attractive, but unnecessary. A completely stock engine is more than adequate for 9psi. Hell, most of us are running a lot more than that without ever having pulled the oil pan.
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10-20-2007, 02:25 AM
#46
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ok well im curious guys. ive looked around online and found some products that are suppossed to restore the rings and there seal. do you guys knoow if something like that might work as a temp fix?
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10-20-2007, 11:05 AM
#49
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Sounds like a strong case for option two, then. Start shopping. Find an engine that runs, and drop it in. Maybe replace the seals and timing belt first, but otherwise just pop that baby in.
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10-22-2007, 12:25 AM
#50
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well i think im just gunna replace the bottom end with a junk yard bottom end because itll only cost me 57 bucks now how can i do a compression test on it with out the starter? will the numbers be still norm by me cranking it by hand? also i was wundering which would you suggest using the flyinmiata head gasket for boost? or buying a stock one from like checkers?
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10-22-2007, 02:03 AM
#54
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ok i just noticed its for bored over pistons. well so what all would you suggest i replace while its open? im gunna put on my new water pump from my botton end. i also have a new timing belt. im gunna put on my oil pan so its gunna get a new oil pan gasket. what else would be really easy to do and cheap also again i ask will the compression numbers for it be able to be reached with it being turned over by hand?
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10-22-2007, 02:18 AM
#55
Just replace maintenance items, otherwise it will get expensive very quickly. Also, there is not oil pan gasket on the miata, you just need to get some of the grey permatex that is made for oil pans, etc...
Compression number likely will not be reached by hand. I've never tried it though.
Compression number likely will not be reached by hand. I've never tried it though.
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10-22-2007, 11:27 AM
#56
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All engines have some leakdown. Rings have gaps, valves aren't 100% perfect. The engine needs to be turning fast enough to overcome these losses.
If you look closely, you'll see that the FSM actually specifies that the engine must be turning at 300 RPM during the test.
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10-22-2007, 01:03 PM
#58
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once you pull the head look at the cylinder walls. you'll most liekly see veritcal scoring and oil on the piston. examine the head gasket.
this sounds like a typical case of too much boost. I've seen it happen before and the same thing happens, you lose #4.
swapping the block with a known good one as you suggested is the easiest solution (or a full on engine swap). in the meantime get a new water pump, timing belt, head gasket, and mill the head. that's the bare minimum you'd want to do.
this sounds like a typical case of too much boost. I've seen it happen before and the same thing happens, you lose #4.
swapping the block with a known good one as you suggested is the easiest solution (or a full on engine swap). in the meantime get a new water pump, timing belt, head gasket, and mill the head. that's the bare minimum you'd want to do.
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10-22-2007, 01:05 PM
#59
Well you could just jerry rig the starter or your very best bet would be to find a running motor. All and all taking of the head and looking at the cylinders and walls for scoring is easy and effective. Most motors might only need a rering unless the where exploded with detonation. The head would not need to be milled if it is true though so give it a once over and confer with the machine shop on wether it is nice and flat.
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