Probably need new engine--now what

[usinjin]

Greetings fellow Mafia members--so recently I posted regarding a sudden degradation of engine performance. It began right after accelerating to get onto the highway. Firm yes, but not redlined by any means (car is an auto). Cylinder 1 showed no compression, wet or dry. The mechanic believes I bent a valve while accelerating. He's thinking replacing the engine may be a better route than pulling the head and doing a valve job (he cited issues with possibly stripping threads)

I thought this seemed strange. How would an acceleration randomly bend a valve? Engine has 101,xxx miles on it.

The mechanic did find traces of "dark dusk" that he said indicated a failing cooling system, and thought that it could have been overheated sometime in the past, weakening something.

I do have a local friend who has a totaled ZHP with a good engine--102,xxx miles on it and I think he's asking a good price for it.

My question is this--what would the next best step? I don't have any experience in this area. Is replacing an engine the norm in this situation? Would I get anything for the old engine? Should I sell/part out the car instead?

[az3579]

Get the used engine.

And him saying that accelerating caused this is bullshit. Acceleration by itself will not cause engine damage. There must have been a pre-existing condition that lead to this happening. Overheating seems like an unlikely thing to blame - that would be more of a warped head / blown headgasket sort of deal in my mind.

[slater]

i agree with BP.

get the used engine - the mileage similarity is destiny. ;)

[fredo]

Wow, that's bad news. Did you check with the Indy I recommended ? Buying the used engine is the way to go IMHO.

[usinjin]

Wow, that's bad news. Did you check with the Indy I recommended ? Buying the used engine is the way to go IMHO.
I did! That's actually where she's at right now. They quoted me $6000 for the valve work it required, if I went down that route. They are somewhat perplexed with the situation, saying that I either "burned or bent" the valve, and according to them this never happens.

If I went down the new engine route, they quoted me $4000 for the install (if I supplied the engine). Yikes. The engine is out of an '04
ZHP with 102,xxx miles, and they guy wanted $1500, which I thought sounded pretty sweet. But not the $4000 to install.

If I can't find a less expensive means of installing the engine, I'm really thinking about selling it as-is. Either way, very disappointing :(

[slater]

I did! That's actually where she's at right now. They quoted me $6000 for the valve work it required, if I went down that route. They are somewhat perplexed with the situation, saying that I either "burned or bent" the valve, and according to them this never happens.

If I went down the new engine route, they quoted me $4000 for the install (if I supplied the engine). Yikes. The engine is out of an '04
ZHP with 102,xxx miles, and they guy wanted $1500, which I thought sounded pretty sweet. But not the $4000 to install.

If I can't find a less expensive means of installing the engine, I'm really thinking about selling it as-is. Either way, very disappointing :(

$4000 for the install?! that's insane. if you were local i'd do it for $750. it's a day of labor, maybe 1.5 days. try to find someone local who can help out - it's not that hard of a job even though it sounds daunting.

[fredo]

I know another mechanic, not a BMW one, but I bet he can install the engine for less. I'll send you a PM later.

[az3579]

$4000 for the install?! that's insane. if you were local i'd do it for $750. it's a day of labor, maybe 1.5 days. try to find someone local who can help out - it's not that hard of a job even though it sounds daunting.

This. Holy crap that is an expensive quote.

Any shop is going to be in the 4 figures range, but 4k is excessive. I don't think you should be paying any more than $2k to get the engine installed...

[usinjin]

Thanks all--really appreciate the advice. I'll definitely ask around for some more reasonable quotes.

[usinjin]

Okay--dropped my car off--going for the replacement motor.

While most other mechanics were befuddled by how I could have hurt the exhaust valve, the last one was left in no doubt--"poor quality gas". According to him, a combination of "dirty" gas (also 87 octane..) most likely did it in. Under acceleration (kind of low on gas at the time, too--bad, bad, shame on me!), something got somewhat gummed up and hurt it. It's very possible I destroyed it and have no one else to blame.

Whatever the case--Shell 93 octane V-Power is all that's going in from now on. A friend tried to convince me that 87 octane gas is "just fine"--no more.

[az3579]

Whatever the case--Shell 93 octane V-Power is all that's going in from now on. A friend tried to convince me that 87 octane gas is "just fine"--no more.

Your friend most definitely gave you some very very bad... and very expensive... advice. Your car isn't designed to run on 87, and as a result was probably suffering from detonation, which could definitely destroy your engine. One must use whatever the manufacturer says to use for this reason.

Also, even if you were using 93, you shouldn't use crap quality gas. Use only Top Tier gas brands to reduce the likelihood of having gas-related problems.
http://www.toptiergas.com/

[BMWCurves]

Don't our cars have perfectly good knock sensors to help prevent early detonation? I feel like that's a pretty poor oversight if not and would assume you would have seen or heard of more BMWs having this issue given how many cars were sold.

[slater]

Don't our cars have perfectly good knock sensors to help prevent early detonation? I feel like that's a pretty poor oversight if not and would assume you would have seen or heard of more BMWs having this issue given how many cars were sold.

they do have knock sensors, however they are not designed to be run on less than 91 octane for prolonged periods of time. it says right in the manual, also i believe on the backside of the gas fill door, too?

whatever the reason, the manufacturer states to use 91 or bad things will happen. not worth the risk.

OP - are you having the replacement engine done at another shop? please tell me you're NOT paying $6000 to have this done!

[BMWM3186]

I highly doubt the low octane would have done it in, but then again maybe it could. Also the gas travels through a fuel filter to filter dirty gas. Anyways my f150 has some sort of timing issue and has always had very audible pre-detonation, and it has not blown up yet. In addition, I know many people who run 87 in their cars that require 91. None have suffered consequences from it. I believe cars should retard the timing, giving you worse gas mileage and less power to avoid pre-detonation. I myself run 93 just because it does not bother me that much to spend the extra few dollars at the pump.

[usinjin]

I had never heard it pinging on 87 octane--of course, just because I didn't hear it doesn't mean it wasn't happening. I feel like it probably was a mix of poor engine care/maintainace/gas. I only hope the engine I'm putting in was treated better.

And hah, no, definitely not paying $6k..a place is doing parts + labor for ~$2700.

[az3579]

And hah, no, definitely not paying $6k..a place is doing parts + labor for ~$2700.

Win! That's a good price.

[slater]

And hah, no, definitely not paying $6k..a place is doing parts + labor for ~$2700.

excellent - that is a good price. i hope it turns out well for you! :cheers

[Dave1027]

Even if it was detonating or pre-igniting, neither of those will bend or burn valves. Prolonged pre-ignition can if left too long burn a hole right through the piston top. But for that to happen you would have been hearing a constant knocking for a long time.

Under normal circumstances the knock sensor will sense the knocking and tell the ecu to retard the timing which will stop the knocking. The problem you'd then have is reduced performance. Still, not a engine killer.

I still think the head needs to come off to learn the real cause of this mystery.

[az3579]

Even if it was detonating or pre-igniting, neither of those will bend or burn valves. Prolonged pre-ignition can if left too long burn a hole right through the piston top. But for that to happen you would have been hearing a constant knocking for a long time.

Under normal circumstances the knock sensor will sense the knocking and tell the ecu to retard the timing which will stop the knocking. The problem you'd then have is reduced performance. Still, not a engine killer.

I still think the head needs to come off to learn the real cause of this mystery.


I am curious as to what really did the engine in.

[usinjin]

I am curious as to what really did the engine in.

Me too, very much so--I hope to still have access to the old engine, if so I'll definitely see if I can't get the head pulled and report back with some pictures.

[usinjin]

Update.

Got my car back. New (used) engine, new CCV valve and hoses, new DISA valve, new VCG, Oil pan gasket, OFHG, oil filter, secondary air pump hose, lower radiator hose, and freon recharge. Car idles silently and pulls amazingly hard and smoothly.

Interestingly enough, the mechanic wasn't very happy about my catch can setup--according to him, it was installed incorrectly (needed to pass through the CCV and not into the intake manifold). He also stated that heater hoses were detrimental to the oil passing though.

Next step is to go back and pick up the old engine--planning to pull the head myself. I'm as curious to know what caused the valve to fail. I'll report back when I have it off!

[fredo]

Sounds like you are a happy camper. Congrats ! :thumbsup

[slater]

Update.

Got my car back. New (used) engine, new CCV valve and hoses, new DISA valve, new VCG, Oil pan gasket, OFHG, oil filter, secondary air pump hose, lower radiator hose, and freon recharge. Car idles silently and pulls amazingly hard and smoothly.

Interestingly enough, the mechanic wasn't very happy about my catch can setup--according to him, it was installed incorrectly (needed to pass through the CCV and not into the intake manifold). He also stated that heater hoses were detrimental to the oil passing though.

Next step is to go back and pick up the old engine--planning to pull the head myself. I'm as curious to know what caused the valve to fail. I'll report back when I have it off!

glad you got it taken care of!

re: the CCV - it definitely does not need to be routed through the CCV, that is why the PCV valve is used. re: the heater hose - it should stand up to the oil, but it's too weak for vacuum - it will collapse. you need high pressure oil-resistant hose.

[johnrando]

congrats on getting it back

[san]

+1 congrats! Keep us updated...


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[Sockethead]

re: the CCV - it definitely does not need to be routed through the CCV, that is why the PCV valve is used. re: the heater hose - it should stand up to the oil, but it's too weak for vacuum - it will collapse. you need high pressure oil-resistant hose.

Yep! It took me a trip to 7 different places to find the right stuff for my catch can

[Asiah119]

From personal experience, unless you really want to save money, rebuild. Youre going to risk finding other problems but when you're done you're going to know the motor is solid.

Several years ago I learned I had bad compression on 3 cylinders. I went with a swap and despite not having any issues with the motor I still wish I'd gone w a rebuild just for the peace of mind.

[usinjin]

From personal experience, unless you really want to save money, rebuild. Youre going to risk finding other problems but when you're done you're going to know the motor is solid.

Several years ago I learned I had bad compression on 3 cylinders. I went with a swap and despite not having any issues with the motor I still wish I'd gone w a rebuild just for the peace of mind.

A bit late for that, considering it's all buttoned up :-)

Luckily, the motor came out of a car of a friend of mine (he lives about 10 mins from me)--he's owned a least a dozen-odd BMWs over the years and he takes care of them well. Regular maintainence and all that.

If I went the rebuild route, I'd end up spending thousands more on a motor that I don't know the history of. I've had this car for 5 months--who knows what it's been through. It could have additional issues, perhaps this is even related to the death of the valve. Who knows, the Floridian who owned this could very well have driven it to death, with low oil, overheated it, subjected it to aggressive use without ever providing proper maintanence--the new motor actually gives me a better piece of mind in this case :-)