BMW 325e engine rebuild

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New Orleans
#1
What am I getting myself into if I want to rebuild my engine?
I really havn't done a whole lot of work on engines in general, how hard is it?
How expensive is it?
My car has over 150000 miles.
 
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Reading,PA
#2
How much work have you done on cars in general? Exhaust, brakes, etc? Or other mechanical work such as motorcycles, lawn equipment, or industrial machinery?

If you have no experience on any of the above, an engine rebuild is a stretch for a first project. Otherwise, the the biggest issues are:

1. Proper documentation - Bentley Manual, no exceptions or substitutions! Plus the web, there is a ton of great rebuild info out there if you look hard enough.
2. Range of good hand tools - shallow and deep sockets, a few different length extensions, torque wrench, box and open end wrenches, breaker bar. There's nothing worse than being in the middle of work and needing to go buy a tool!
3. Good organization skills - As you tear down, your want to organize parts so you don't need to remembe where they go. I use plastic bags and write on them with black marker - i.e. Water Pump bolts, head bolts, left exhaust bolts, right exhaust bolts, etc.
4. Take pictures at various steps of disassembly. Can be a big help during reassembly!!
4. Time and patience - Rushing and frustration leads to errors. You don't want to reassembly the whole thing, and realize you forgot to torque the head bolts!!! If it is your daily driver, you will want to rush to get it done, but that is counterproductive.
5. Understanding how to evaluate parts - You'll need to make a lot of decisions about what parts to replace. Some are easy (broken parts), others not so easy, i.e. bearings, pistons, rings? On a total rebuild, you replace all. Obviously affects cost.

You can save a ton of money doing it yourself, and wind up with a well equipped toolbox at the end! I have done 4 car engine rebuilds over the years, just finished one several months ago on a GM V6.
 
Messages
111
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Location
New Orleans
#3
How much work have you done on cars in general? Exhaust, brakes, etc? Or other mechanical work such as motorcycles, lawn equipment, or industrial machinery?

If you have no experience on any of the above, an engine rebuild is a stretch for a first project. Otherwise, the the biggest issues are:

1. Proper documentation - Bentley Manual, no exceptions or substitutions! Plus the web, there is a ton of great rebuild info out there if you look hard enough.
2. Range of good hand tools - shallow and deep sockets, a few different length extensions, torque wrench, box and open end wrenches, breaker bar. There's nothing worse than being in the middle of work and needing to go buy a tool!
3. Good organization skills - As you tear down, your want to organize parts so you don't need to remembe where they go. I use plastic bags and write on them with black marker - i.e. Water Pump bolts, head bolts, left exhaust bolts, right exhaust bolts, etc.
4. Take pictures at various steps of disassembly. Can be a big help during reassembly!!
4. Time and patience - Rushing and frustration leads to errors. You don't want to reassembly the whole thing, and realize you forgot to torque the head bolts!!! If it is your daily driver, you will want to rush to get it done, but that is counterproductive.
5. Understanding how to evaluate parts - You'll need to make a lot of decisions about what parts to replace. Some are easy (broken parts), others not so easy, i.e. bearings, pistons, rings? On a total rebuild, you replace all. Obviously affects cost.

You can save a ton of money doing it yourself, and wind up with a well equipped toolbox at the end! I have done 4 car engine rebuilds over the years, just finished one several months ago on a GM V6.

I have done some exhaust work and some brake work on cars. And I have worked on some lawnmowers but overall not a whole lot of work.
I have always wanted to make my car fast, but the engine is old and has a lot of miles on it, and I don't want to break it. I was thinking of doing a total rebuild with the top of the line replacement parts so that I won't have to worry about breaking my engine any time soon. I am in college right now as a freshman studying Mechanical Engineering, so stuff like this is what I really want to do.
 
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#5
I have done some exhaust work and some brake work on cars. And I have worked on some lawnmowers but overall not a whole lot of work.
...
I am in college right now as a freshman studying Mechanical Engineering, so stuff like this is what I really want to do.
I'd go for it!!
 
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Winston Salem, NC
#6
I have done some exhaust work and some brake work on cars. And I have worked on some lawnmowers but overall not a whole lot of work.
I have always wanted to make my car fast, but the engine is old and has a lot of miles on it, and I don't want to break it. I was thinking of doing a total rebuild with the top of the line replacement parts so that I won't have to worry about breaking my engine any time soon. I am in college right now as a freshman studying Mechanical Engineering, so stuff like this is what I really want to do.
I'd say go for it, but don't count on the engine rebuild making the car fast. It's pretty difficult to make a 325e fast without forced induction. The other question I have is why are you needing to rebuild it? Is it burning a lot of oil or something? 150000 miles is nothing on a 325e engine - mine had 260000+ on it when I totaled it and the engine was still running like a top and didn't burn a drop of oil.
 
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Location
Toronto, Canada
#7
I hear you justin. Unless the thing has no rings or valve seals left, get a valve job, some new plugs, wires and distrubutor cap and be done with it. Chances are getting a rebuild will cost (possible) more than the value of the car. The "eta" engine has lots of grunt, but no get-up-and-go, but it is a good engine. If you're going to need a donor car for learning at school, go for it (with the proper supervision and a manual), but price out all the new parts first and see what you think.
 
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Location
New Orleans
#9
I'd say go for it, but don't count on the engine rebuild making the car fast. It's pretty difficult to make a 325e fast without forced induction. The other question I have is why are you needing to rebuild it? Is it burning a lot of oil or something? 150000 miles is nothing on a 325e engine - mine had 260000+ on it when I totaled it and the engine was still running like a top and didn't burn a drop of oil.
What is forced induction?
Nope, it doesn't burn any oil. Its just that when I drive it over a long period of time, or if I drive it more aggressively I can hear a knocking sound coming from the engine, but this happens only when the car is idling, otherwise it runs smoothly through the RPMs. My odometer broke at 130000 and that was 3 years ago, so it probably has 150000+ I won't go for the rebuild if I can find out what the problem is...
 
Messages
111
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Location
New Orleans
#10
I hear you justin. Unless the thing has no rings or valve seals left, get a valve job, some new plugs, wires and distrubutor cap and be done with it. Chances are getting a rebuild will cost (possible) more than the value of the car. The "eta" engine has lots of grunt, but no get-up-and-go, but it is a good engine. If you're going to need a donor car for learning at school, go for it (with the proper supervision and a manual), but price out all the new parts first and see what you think.
I don't know about the valve seals, but it has a new spark plugs and a brand new distributor cap. How much does it cost to get a valve job? I don't know enough about engines to know what parts I need to buy and what they are called. The car is pretty quick, I chipped it and gave it an air intake and am now doing a cat back. I think it has almost 160hp and a little over 200tq.
 

Big Daddy

Senior Member
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PNW (Left) Coast
#11
Sounds like a timing belt/tensioner issue, when was the belt last changed? When you lift the throttle after acceleration do you get puffs of white smoke, if not your valve seals are most likely ok.
 
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Location
New Orleans
#12
Sounds like a timing belt/tensioner issue, when was the belt last changed? When you lift the throttle after acceleration do you get puffs of white smoke, if not your valve seals are most likely ok.
so you think I need to get a new timing belt? Or tension it?
I don't know when it was last changed, I have had the car for almost 3 years.
Nope there is absolutely no smoke.
 
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Location
Bay Of Islands, NZ
#15
If i were you I'd pay to have someone do the cambelt for me.

You are obviously a little new at this (no offence - we all start somewhere).

If you have a friend who can do the belt and tensioner for you, get them to show you what to do and do it with them. Great way to learn.

Do not attempt a rebuild yourself. If you "don't know enough about engines to know what parts I need to buy and what they are called" and need to ask What is forced induction?" then chances are a rebuild is alittle outside your skill level at the moment - start on something a little easier.

Forced Induction = Turbo or Supercharger.
 
Messages
111
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Location
New Orleans
#16
If i were you I'd pay to have someone do the cambelt for me.

You are obviously a little new at this (no offence - we all start somewhere).

If you have a friend who can do the belt and tensioner for you, get them to show you what to do and do it with them. Great way to learn.

Do not attempt a rebuild yourself. If you "don't know enough about engines to know what parts I need to buy and what they are called" and need to ask What is forced induction?" then chances are a rebuild is alittle outside your skill level at the moment - start on something a little easier.

Forced Induction = Turbo or Supercharger.
No offense taken, I know I am new to this stuff, I am fresh out of High school, thats why I am asking you guys.
Ok, so I'll ask my mechanic to do the timing belt for me and the tensioner, but do you think I can do the water pump?
My car seems to overheat pretty quickly and every time I open the coolant reservoir it boils over.
Plus I get a little grinding sound (when the car is hot) at the very start of first gear but then It quickly goes away as I go through the gears.
Hopefully a new timing belt, tensioner and water pump will fix this problem.
Thanks for your help guys.
 
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Location
Bay Of Islands, NZ
#17
You need to remove the cambelt to do the water pump, so your mechanic should do this while he is there.

If you are having serious overheating issues, you may have a blown head gasket or a warp or crak in your head. Get your mechanic to perform a compression test while he is doing the other stuff which will help rule out or pinpoint the liklihood of some of the above problems.

There are planty of things you can do on the car yourself to build up experience, and then tackle the harder things as you grow more confident.
 
Messages
111
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Location
New Orleans
#18
You need to remove the cambelt to do the water pump, so your mechanic should do this while he is there.

If you are having serious overheating issues, you may have a blown head gasket or a warp or crak in your head. Get your mechanic to perform a compression test while he is doing the other stuff which will help rule out or pinpoint the liklihood of some of the above problems.

There are planty of things you can do on the car yourself to build up experience, and then tackle the harder things as you grow more confident.
Yea, that is what my mechanic told me.
What is a compression test?
Thank you.
 
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Location
Australia
#19
Yea, that is what my mechanic told me.
What is a compression test?
Thank you.
Although you should search many of the questions you are asking (simple questions just google em')
A compression test is checking the "compression" of each cylinder by removing a spark plug and replacing with a pipe connecting to a gauge one by one.
All compression numbers SHOULD be the same or very close or around what is writen in the workshop manual.

You do this to determine if:
1. Cylinder rings are worn (according to workshop manual)
2. valve seals are worn (performed by a leak down test - squirting oil in the spark plug holes etc... google.com)
 


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