M52 engine removal by knock sensor bolts

[cjames10]

Has anyone removed a M52B28 engine by the knock sensor bolts? I did it last week, but it was an aluminum block and the head was off. The transmission was attached.

Now I am putting a cast iron M52B28 back in the car complete with transmission. The 2 knock sensor bolts are in the perfect spot for the hoist leveler and engine angle. The question is, 'are the bolts strong enough to support over 600 pounds of engine and transmission?

The bolts are M8s and go 18mm into the block. The block is cast iron so I would assume the threads in the block would pull before the bolts would break.

Anyone care to comment?

[bmwdirtracer]

Why not use the front bracket, and rear eye which BMW provided for this?

I do not think you'd do any damage by using those knock sensor bolt holes, but these two holes would be subjected to a direct "rip the thread out" kind of load, rather than the perpendicular load provided by using the stock locations for pulling an engine.

Personally, I wouldn't try it, especially with the weight of the full engine and trans.

[pbonsalb]

There are plenty of other bolt holes to use.

[ross1]

If you can get at the knock sensors then the intake is out of the way which for me is always the PITA item when hooking the back.
No bracket by the VANOS solenoid?
IF I were to use the knock sensor bolts I'd be damn sure to have some sort of bracket bolted firmly in place there and not just have a long bolt hanging out for attachment.
Old seatbelts have lots of uses too.

[cjames10]

One reason for not using the VANOS strap is because the head was off the block. The other reason for using the knock sensor bolts was to get the leveler as close as possible to the block. I was able to remove the block and transmission without removing the hood or the front of the car. I just had to put the hood in service position and tilt the engine at a steep angle.

Putting the engine back in is going to be tougher. Now the cylinder head is on the engine. I could use the VANOS strap but that will put the leveler up higher and I may not get enough clearance too put the engine back in. I really don't want to remove the front of the car or remove the hood.

I did some research about bolt strength. If the thread depth is 2 times greater than the bolt diameter then the threads will be stronger than the bolt. The bolt becomes the weak point of failure. Even the lowest grade M8 bolt can hold 1800 pounds proof load. I believe the engine and transmission together are under 700 pounds.

If I decide to do this I will definitely have some back up chains.

[cjames10]

Why not use the front bracket, and rear eye which BMW provided for this?

I have a Z3 with a 2.8, 5 speed. Do you know if I could use the front bracket and rear eye without removing the hood or the front end?

[bmwdirtracer]

I've never removed a Z3 engine, cjames, but I've removed a bunch of BMW engines.

First, be aware that the hood is held on by four little bolts. Mark the relationship between hood and brackets, get a friend to help, and that obstacle is out of the way in 10 minutes. Most BMW hoods will prop up almost straight, in "service position", if you remove the hood struts at one end. With some BMW's , you stick a bolt in each hinge to hold it there; with some, you just use a big prop-rod. If you can remove and reinstall an engine, the hood is a very minor inconvenience,

[cjames10]

Thanks for the advice 'bmwdirtracer'. I do have the hood in service position. The Z3 has an unusually hood because it forms part of the fenders. It is a heavy piece, but my son is home from college and he could help remove it. You are right it would be easier to remove it than the alternatives.

Plus if the bolts would fail and the engine would drop, the resultant damage would be catastrophic. Why take the risk?

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I have removed at least 6 engines from different makes of cars. This will be my first BMW. I keep seeing(You Tube) rem

ove the front ends of BMWs to remove the engine. It seems like a lot of work. Am I missing something. Is there a good reason to do this?

[325bob]

Thanks for the advice 'bmwdirtracer'. I do have the hood in service position. The Z3 has an unusually hood because it forms part of the fenders. It is a heavy piece, but my son is home from college and he could help remove it. You are right it would be easier to remove it than the alternatives.

Plus if the bolts would fail and the engine would drop, the resultant damage would be catastrophic. Why take the risk?

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I have removed at least 6 engines from different makes of cars. This will be my first BMW. I keep seeing(You Tube) rem

ove the front ends of BMWs to remove the engine. It seems like a lot of work. Am I missing something. Is there a good reason to do this?

I haven't pulled front ends for engine swaps, but think its because of the extreme angle needed to drop eng/tranny in, the car has to be raised to allow tranny to clear various stuff.

[cjames10]

Ok, so for anyone who is interested. The engine is now in the car. It is possible to put the engine and transmission into a Z3 2.8 MTF, without removing the front end or hood. Here is what I did.
- Used a leveler with the engine hoist
- Used the traditional lift points at the VANOS and at the loop in the rear of the block.
- passenger side motor mount must be removed. (found this out the hard way)
- air conditioner mount must be removed. (found this out the hard way)
- remove exhaust manifolds
- be prepared to support the tail of the transmission with a jack or wood blocks.

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- put hood in service position

[bmwdirtracer]

From my experience, I'd do almost anything to install the engine WITH the exhaust manifolds attached. Some bodyshells are harder than others, but I've spent as long bolting on the manifolds as the rest of engine installation. Out of the car, it takes 10 minutes...in the car, it can take HOURS. Don't put that engine mount on until the manifolds are bolted up. by the way.

[cjames10]

With the Z3 I was able to remove the exhaust manifolds with everything in tact. They slipped down between the crossmember bracing.

When I put the engine back in the cylinder head had to go right against the passenger side shock tower just to get the oil pan around the steering rack/column. Using the traditional engine hoist points put a rotation of the engine to the passenger side. So the passenger side was low and the drivers side was high.