Uuuhhhh I dont know if i blew my engine

[2shroom]

So it was an awsome sunday morning.........till this morning i was crusin in third about 80 till i miss shifted into 2 instead of 4th.

The tires didn't lock up in the miss happ. and when i got it to a sitting area all the coolant drained. Im not sure were it drained out of but it doesnt look like the engine block.It may have come out of the little coolant tub thing that sits next to the engine. But its drained out of the the fluid tub thing before and filled it up once and it was fine.

I try to push start it and it wants to go but i dont think i push it fast enough and haven't had the space to attempt anything more.

But if anyone has any idea, thought, twitch about what might have happened i would be greatly appericated.

[SiRed94]

possibly blown headgasket and doesn't have enough compression to start up... just a thought... id really have to be there to be able to diagnose it...

[killerdx]

what kind of noise did it make when it shut off

[Kaiser]

If you let the engine fully over-rev itself then it's possible that your valves floated and impacted the cylinders. This could have caused them to beat against the head and pushed against it, blowing the head gasket and possibly breaking some of the head bolts in the process :-\

Over-revving the engine woulda caused damage, but I dunno if it would have caused all the coolant to leak out...did you smell Antifreeze when you stopped, or see it dripping? It may have been dry before it happened, you should also check the lines at the bottom of the radiator and block to make sure they are still in good shape, but I have a feeling that your car won't start for a different reason.

[SiRed94]

If you let the engine fully over-rev itself then it's possible that your valves floated and impacted the cylinders. This could have caused them to beat against the head and pushed against it, blowing the head gasket and possibly breaking some of the head bolts in the process :-\

Over-revving the engine woulda caused damage, but I dunno if it would have caused all the coolant to leak out...did you smell Antifreeze when you stopped, or see it dripping? It may have been dry before it happened, you should also check the lines at the bottom of the radiator and block to make sure they are still in good shape, but I have a feeling that your car won't start for a different reason.

ok... WTF? what you just described has nothing to do with valve float... maybe you meant dropping a valve? and the process of lifting a head could indeed cause all of the coolant to leak out... however you could've just simply blown a radiator hose or the seal around the end tank of the radiator...

[SiRed94]

if you haven't got it fixed yet just report back with more info... pm me if needed....

[DaRussian]

you probably bent your valves. check the compression and youll be able to tell. i know a guy who misshifted to 2nd instead of 4th in his golf and it bent the valves.

[Kaiser]

ok... WTF? what you just described has nothing to do with valve float... maybe you meant dropping a valve? and the process of lifting a head could indeed cause all of the coolant to leak out... however you could've just simply blown a radiator hose or the seal around the end tank of the radiator...

I never said that it didn't cause a coolant leak, just that it's less likely that it would have fully emptied the radiator in the time span he mentioned in the posting.

Also, I would love to know what YOU think would be the primary cause of damage during over-rev, because most of the world's mechanics list impacted valves due to valve-float as high on the list, with sheared crank bearings and damaged piston rods just a bit below that. And yes, impacted valves in an engine can cause the head to become shoved up, shearing head bolts and causing gasket failure.

And yes, a dropped valve or seat could cause similar kinds of damage, but to that end it probably would have caused alot more catastrophic damage. The only other option then is overpressurization of the engine which might be the case in a non-interference engine, but since I have no idea what engine he apparently blew up, I really can't make any judgement calls on what the likelihood of that is.

PS: The reason why impacted valves caused by Valve Float would be my guess is because typically the valves that would get impacted first would be the Exhaust valves, essentially bending them to where they won't open, or at least not open properly, between the buildup of pressure inside the engine and the actual impact of the cylinder against the head via the valve, there's any number of things that can happen depending on what engine he has.

[2shroom]

Yea i should have mentioned that it is a BMW 325is 94. when i attempt to start it. The car sounds like it wants to start but just doesn't. it sounds like it fires through one cycle on the spark plugs then just kinda gives out.

so it may have lost compression some were. But thats just my assumption

[Echonova]

http://www.youtube.com/watch?v=VH-qT6g-oGI

[Kaiser]

http://www.youtube.com/watch?v=VH-qT6g-oGI

Lols. Not to laugh at the original poster of THIS thread, but that is a damn funny video. Rep'd.

Edit: You must spread some Reputation around before giving it to Echonova again.


To the original poster: You're probably going to have to tear-down the engine to find out what happened for sure, but check for some obvious signs of seal blow out and check where the head meets the block for obvious signs of damage and then do exactly as someone else suggested and get a compression tester and test it out.

[SiRed94]

I never said that it didn't cause a coolant leak, just that it's less likely that it would have fully emptied the radiator in the time span he mentioned in the posting.

Also, I would love to know what YOU think would be the primary cause of damage during over-rev, because most of the world's mechanics list impacted valves due to valve-float as high on the list, with sheared crank bearings and damaged piston rods just a bit below that. And yes, impacted valves in an engine can cause the head to become shoved up, shearing head bolts and causing gasket failure.

And yes, a dropped valve or seat could cause similar kinds of damage, but to that end it probably would have caused alot more catastrophic damage. The only other option then is overpressurization of the engine which might be the case in a non-interference engine, but since I have no idea what engine he apparently blew up, I really can't make any judgement calls on what the likelihood of that is.

PS: The reason why impacted valves caused by Valve Float would be my guess is because typically the valves that would get impacted first would be the Exhaust valves, essentially bending them to where they won't open, or at least not open properly, between the buildup of pressure inside the engine and the actual impact of the cylinder against the head via the valve, there's any number of things that can happen depending on what engine he has.

haha bro you're like not even paying attention to what im saying... i never stated that i thought he dropped a valve... i just said that thats about the only he would have lifted the head with a valve related issue on a pressumeabley stock car as you suggested... most cars have a rev limiter that will prevent them from being revved so high that the valves float enough to actually stay open long to come into contact with a piston, so that would've been most unlikely if the valve springs still have a reasonable amount of tension... he couldve blown a headgasket due to just having increased the cylinder pressures so much during so suddenly if the car has a significant amount of miles on it.... and please don't ever question my mechanical knowledge... do you even know what valve float is.... without using wikipedia???

[Kaiser]

haha bro you're like not even paying attention to what im saying... i never stated that i thought he dropped a valve... i just said that thats about the only he would have lifted the head with a valve related issue on a pressumeabley stock car as you suggested... most cars have a rev limiter that will prevent them from being revved so high that the valves float enough to actually stay open long to come into contact with a piston, so that would've been most unlikely if the valve springs still have a reasonable amount of tension... he couldve blown a headgasket due to just having increased the cylinder pressures so much during so suddenly if the car has a significant amount of miles on it.... and please don't ever question my mechanical knowledge... do you even know what valve float is.... without using wikipedia???

I never stated you thought he dropped a valve. I'm apparently paying just as good attention as you are, you just seem to like annoying people. And you're wrong about a valve/valve seat being dropped being the only valve related problem that would displace a head, I already corrected you about that. Impacted valves can easily cause a displaced head. He COULD have blown a headgasket due to just having increased the cylinder pressure so much. He's also driving a BMW with a 10:1 compression ratio and an extremely tight fit between the valves and the cylinders, especially on an engine that is known to have commonly experienced cracked or displaced heads. Maybe on a Honda valve impact wouldn't cause head displacement, but that's not always the case. I'll question your knowledge of mechanics for as long as I feel like, unless you prove it's extensiveness. You should respect that and feel free to return the favor. I certainly don't claim to know everything and I love being proven wrong with facts. The bad part here is we won't know what happened until he gets it taken apart to see what all occured. Also, Valve float's when the rocker arm or the valve itself doesn't remain in contact with the camshaft. The camshaft essentially leaves the valve or follower hanging because the valve-train parts can't move fast enough to follow the cam. Considering the piston continues to rotate at a speed that coincides with the location of the camshaft, tightly manufactured engines that are over-revved mechanically (Which can bypass the rev limiter, since the actual wheels themselves are forcing the engine to move past it) can experience valve contact with the pistons, causing bent pistons, damaged heads, and even in some bad cases it can unseat valves. Does that prove I know what valve float is? Does that prove I know a little about how BMW engines in the early to mid 90's were manufactured? Does it prove I can read? Not really. Doesn't prove crap. He might have just blown his head gasket. He might have impacted his valves. He'll have to tell us what happened.

Also: The reason I guessed valve impact due to float was because of the fact that he has "e36 noob" as his title. I figured he was probably driving the e36 BMW. I also figured he had one of the M50 Straight-6s. I was not surprised when he told us what car he was driving. I've rebuilt that engine before, and there's not a whole lot of clearance for the valves to be at all out of place. If the springs are worn even a bit, over-revving can put 'em into harm's way easy.

[mocha latte cupcake]

you know there is a gate in that shift area for a reason?

*note: do not release clutch until you are SURE of your gear.... i'd rather lose a race etc etc than lose an engine...

also, no holes means bad head imo

[SiRed94]

No, I’ve been just seeing your post in all these tech threads and they aren’t even making sense… and I don’t like ppl being fed B.S. by ppl who think that they know how to work on cars just because they dig up some info on the net… and you haven’t corrected me on **** homie… but I have to study for finals now… I will pick apart your post later if you’d like Mr. “overheating piston rod” guy rite here…. Haha later

[SiRed94]

In my case the piston rings went bad in number 2 and caused blow-past which overheated the piston rod and burnt the crank bearings, melting the rod and causing it to warp and causing the bearings to seize and shear.

and this is what i mean...

[turbosx©]

gotta ?, how can you melt the rod and then have it warped?

[Kalifornia087]

Yea i should have mentioned that it is a BMW 325is 94.

Now that you said what it is, im going to go ahead and tell you that you most likely bent your valves. 99% positive. Sorry man. Its just what happens when you overrev those motors.

Austin

[Kaiser]

gotta ?, how can you melt the rod and then have it warped?

I removed a pretty cynical remark here, and just have to tell you: I don't understand your question bud. Metal bends after it gets hot. If pistons bent under normal conditions in the way this one did then none of our engines would run.

[turbosx©]

yeah I know that but melted is not the word to use.thats a word used when a substance has changed form.So you as you put it you warped the liquid rod?