Opinions please

joe_keefer · Post by **joe_keefer** » Thu Apr 21, 2011 6:51 pm

hi guys,

hey as some of you know a week or so back i blew a head gasket. well my question is....

should a lowish mile head approx 75-90k miles be put on a very high mile bottom end. 450k-500k miles all original rings etc. ?

i have a complete 3.3 i could put in. but i haven't been able to open it up and look at it yet. i was just going to use the head and get my car back on the road. but it was suggested that i just swap out the whole thing while i'm at it. other than the obvious fact i'm already more than 1/2 way there. just how much more compression is going to be made? enough to finish off my rings?

i'd do it but i don't have a hoist, while i might be able to get the 3.3 block on to my engine stand alone, theres no way i can lift the old 2.8 out by myself.

anyway opinions, suggestions etc. please!

thanks much, joe

Mike W. · Post by **Mike W.** » Thu Apr 21, 2011 9:09 pm

Not to worry, it's just an old wives tale that putting a good head or a fresh valve job will kill old rings. Now I'm not saying they're not worn out at that kind of mileage, but a good head won't hurt the lower end. The increase in compression on more than a cylinder or two is likely to be negligable anyway.

joe_keefer · Post by **joe_keefer** » Fri Apr 22, 2011 6:22 am

awesome, i was hoping that was the case. gonna go get the gasket set and put it together.

DEMIURGE · Post by **DEMIURGE** » Fri Apr 22, 2011 10:31 am

Hi Joe,

I agree with Mike - there is absolutely no problem to put a "fresh" head to a worn engine block. But...

Before you do this, maybe it is a good idea to check the compression on your spare 3.3 engine, if it is only 75-90k miles. Just for reference, measure the compression of the old 2.8 engine.
If the 3.3 engine parameters are still good - think about whole engine swap.

joe_keefer · Post by **joe_keefer** » Fri Apr 22, 2011 11:10 am

DEMIURGE wrote:Hi Joe,

I agree with Mike - there is absolutely no problem to put a "fresh" head to a worn engine block. But...

Before you do this, maybe it is a good idea to check the compression on your spare 3.3 engine, if it is only 75-90k miles. Just for reference, measure the compression of the old 2.8 engine.
If the 3.3 engine parameters are still good - think about whole engine swap.

i would, but i have already pulled both heads and have the lower mile one ready to install. the whole 3.3 engine has 150k. but it's an 80' and the head looks to have been replaced with one from 88' i just made a wild guess at the miles on it. 80k less than the motor. i would normaly just swap it out with out much thought. after all i want the extra 20-30hp. but i need to get the car on the road. plus i want to make sure the 3.3 is in good shape first.

thanks guys wish me luck. i will putting it all back together this weekend.

DEMIURGE · Post by **DEMIURGE** » Fri Apr 22, 2011 12:48 pm

The old head from the 3.3 was probably an '80 also - so for sure it was overheated, cracked and twisted. These era heads, till the end of the '81 are not so good, as the later ones. So, you have luck to own a much better and stronger head, regardless of the lower or higher miles. The only concern would be, if this head is from 3.5 engine e32/e34 era, then you'll get lower compression, because of the bigger combustion chamber volume.

Mike has a very useful writeup about M30 heads.

Mike W. · Post by **Mike W.** » Fri Apr 22, 2011 3:43 pm

joe_keefer wrote:after all i want the extra 20-30hp. but i need to get the car on the road. plus i want to make sure the 3.3 is in good shape first.

I don't always agree with BMWs HP ratings, but an '80, 3.3 is rated at a whopping 174HP, or a whole 5 more than the 2.8.

Torque, which is significant, is up 18, but a low compression 3.3 isn't as much of a bump as you might hope. Unless I just needed an engine and had one, I wouldn't bother with a pre 82, 3.3. 82+ 3.3s and 3.5s are worth the trouble, but not an early 3.3, IMHO.

joe_keefer · Post by **joe_keefer** » Fri Apr 22, 2011 5:12 pm

Mike W. wrote:
joe_keefer wrote:after all i want the extra 20-30hp. but i need to get the car on the road. plus i want to make sure the 3.3 is in good shape first.
I don't always agree with BMWs HP ratings, but an '80, 3.3 is rated at a whopping 174HP, or a whole 5 more than the 2.8. Torque, which is significant, is up 18, but a low compression 3.3 isn't as much of a bump as you might hope. Unless I just needed an engine and had one, I wouldn't bother with a pre 82, 3.3. 82+ 3.3s and 3.5s are worth the trouble, but not an early 3.3, IMHO.

huh,

well the main reason was the 500k mile motor in my car. but i thought that the 80 733 motor was 197hp. even better was the price, $300 got me the whole shootin match, like it was cut right out. tranny and all. dizzy water pump, a/c and power steering pumps, injectors, manifolds. well what ever it puts out is better than what i was making. maybe now i might even be able to break the wheels loose. lol.

its all good, i just want to get her running more reliable than she was. maybe i'll buy one of those real thin steel head gaskets when i rebuild the 3.3

labimmer · Post by **labimmer** » Fri Apr 22, 2011 7:39 pm

Are you guys talking about B32 engines? I am getting one swapped during this weekend.
I think mien is the good one Vin # 7355648 ?!

On 04/22/11, joe_keefer <joekeefer@yahoo.com> wrote:

Mike W. wrote: joe_keefer wrote: after all i want the extra 20-30hp. but i need to get the car on the road. plus i want to make sure the 3.3 is in good shape first. I don't always agree with BMWs HP ratings, but an '80, 3.3 is rated at a whopping 174HP, or a whole 5 more than the 2.8. Torque, which is significant, is up 18, but a low compression 3.3 isn't as much of a bump as you might hope. Unless I just needed an engine and had one, I wouldn't bother with a pre 82, 3.3. 82+ 3.3s and 3.5s are worth the trouble, but not an early 3.3, IMHO. huh, well the main reason was the 500k mile motor in my car. but i thought that the 80 733 motor was 197hp. even better was the price, $300 got me the whole shootin match, like it was cut right out. tranny and all. dizzy water pump, a/c and power steering pumps, injectors, manifolds. well what ever it puts out is better than what i was making. maybe now i might even be able to break the wheels loose. lol. its all good, i just want to get her running more reliable than she was. maybe i'll buy one of those real thin steel head gaskets when i rebuild the 3.3
Bones heal, pain goes away, and chicks dig scars! 1979 528i 500k+ miles "betsy" 2nd owner! 1994 Vw Golf 234k starts everytime!

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Mike W. · Post by **Mike W.** » Fri Apr 22, 2011 11:02 pm

joe_keefer wrote:
Mike W. wrote:
joe_keefer wrote:after all i want the extra 20-30hp. but i need to get the car on the road. plus i want to make sure the 3.3 is in good shape first.
I don't always agree with BMWs HP ratings, but an '80, 3.3 is rated at a whopping 174HP, or a whole 5 more than the 2.8. Torque, which is significant, is up 18, but a low compression 3.3 isn't as much of a bump as you might hope. Unless I just needed an engine and had one, I wouldn't bother with a pre 82, 3.3. 82+ 3.3s and 3.5s are worth the trouble, but not an early 3.3, IMHO.

huh,

well the main reason was the 500k mile motor in my car. but i thought that the 80 733 motor was 197hp. even better was the price, $300 got me the whole shootin match, like it was cut right out. tranny and all. dizzy water pump, a/c and power steering pumps, injectors, manifolds. well what ever it puts out is better than what i was making. maybe now i might even be able to break the wheels loose. lol.

its all good, i just want to get her running more reliable than she was. maybe i'll buy one of those real thin steel head gaskets when i rebuild the 3.3

I didn't mean to imply it was anything bad, just not to expect much more out of it. Do it because it's a good, low mileage engine, not because you expect a bunch more HP.