Non-BMW Stuff on a BMW Forum

[gilber33]

Boris3 said:

Reason I asked is that if these are shot it can also cause the clunk.

Differential bolts to the subframe are all tight? 

They should be. My hope is to pull the driveline out and do new guibo, CSB, diff mount bushing, and rear subframe bushings. 

SteelBlue said:

Or when the subframe is tearing the floor out of the car 

Ew

[gilber33]

Love comparing the size of older cars to newer ones. 

Also started cleaning up the head from the next engine. I should have taken some before pics because it was very gross. 

[gilber33]

I am probably going to take this block in to get honed, but in order to do so I need to remove these things. I believe one drives the oil pump and the other is the oil pressure sending unit. I know the gear for the oil pump can not just be remover and reinstalled, but can this little piece pop out? And how do I remove the oil pressure unit? 

[B C]

That aluminum bit is an oil pressure relief valve. You can remove it, no problem, with a 22 or 24 mm wrench or whatever it is. Theres just a loose spring on the other side.

the oil pump drive shaft can be removed via the recessed cap with the bmw logo on it. Make sure you do not forget to put that part in! Ive read a couple threads of people anxiously firing up the engine and quickly realizing they forgot a part. You should also use a drill and a 6/8mm socket on the other end of the shaft (the end under the bmw cap) to prime the oil pump and preoil the engine before startup

[jc43089]

Do NOT remove the intermediate shaft bearings unless there is something wrong with them.  Replacement is not an easy task.  They need to be honed to size after installation.

[gilber33]

jc43089 said:

Do NOT remove the intermediate shaft bearings unless there is something wrong with them.  Replacement is not an easy task.  They need to be honed to size after installation.

I'm not removing that. I just need to know if it's okay to remove this rod without doing anything crazy to reinstall it.

[jc43089]

gilber33 said:

I'm not removing that. I just need to know if it's okay to remove this rod without doing anything crazy to reinstall it. 

It should just pull out.  But it's been a while since I built an M20.  

You can take the intermediate shaft out for cleaning and stuff just the bearings should stay in place.

[gilber33]

Cars and Coffee in Cedarburg. Fit both car seats in the back seat! They fit much better than I thought they would.

[Jdesign]

Looks great!

[gilber33]

Jdesign said:

Looks great!

Thank you! 

Started assembling the head last night. Got a bunch of dremel buffing pads which made cleaning the valves and head pretty easy work. Dusty and dirty. But easy. 

[gilber33]

Looking for some insight here. Pulled the pistons out last night. My plan was have the block honed and then do new rings and bearings. There's some light scratches on the side skirts - you can't feel them. There's also no vertical scratches on the cylinder walls and the cross hatching is still very visible. 

I've read to take an emery clutch or scotch Brite pad or something to clean up the pistons. Think I'm okay to move forward with my plan? 

[B C]

The one side of the piston is a bit more scuffing that I have usually seen on an M20. When I asked the machinist/engine builder about it he said it is no concern/as long as the cylinder bores are clean.

[gilber33]

B C said:

The one side of the piston is a bit more scuffing that I have usually seen on an M20. When I asked the machinist/engine builder about it he said it is no concern/as long as the cylinder bores are clean. 

That's kind of what I've read too. The cylinders are all clean and there are no visible vertical scratches in them. The cylinder I took pictures of is the cylinder that 2nd piston came out of.

[jc43089]

Just polish them up and use new rings.  Check the ring gaps.  The cylinders look nice.  Any lip at the top where the rings don't touch?

[gilber33]

jc43089 said:

Just polish them up and use new rings.  Check the ring gaps.  The cylinders look nice.  Any lip at the top where the rings don't touch?

Zero lip on the cylinders. They're in really good shape, which is why I just wanted to hone, new rings and bearings and put it back together. 

I've never done a full rebuild on an engine before, so there's really no reason for this other than its something I've wanted to do. And the m20 is so affordable to rebuild.

[jc43089]

gilber33 said:

Zero lip on the cylinders. They're in really good shape, which is why I just wanted to hone, new rings and bearings and put it back together. 

I've never done a full rebuild on an engine before, so there's really no reason for this other than its something I've wanted to do. And the m20 is so affordable to rebuild. 

The cast iron used is very high quality.  The one I rebuilt that had unknown miles higher than 280k before the odometer quit working still had no lip at all and just needed a light honing and new rings.

[gilber33]

Crank out. Block mating surface cleaned up. And valves are all lapped. 

Next I’ll pull the block out into the driveway and pressure wash and then drop it off to get honed. Finish assembling the head. 

I think I’d like to get this back together before December so it can go into the car between the end of year and next June. Some big life events that will make car time limited.  

[gilber33]

Took a pressure washer to the block tonight. 

[gilber33]

My clunky drivetrain is getting a little clunkier. 

Gonna jack it up and check the mounts and make sure nothing’s loose. If there’s nothing obvious then looks like I’ll be tackling guibo, CSB, and diff bushing. 

Edit - checked the engine mounts, transmission mounts, guibo bolts... all tight. So, I’m not sure. It has gotten progressively worse. It used to be a single clunk where now it several. Happens when I’m rolling slow and push the clutch pedal in. Really sounds like it’s coming from the transmission/clutch.

[Jdesign]

Axles? CSB is backwards? Diff is loose? My diff was backing the bolts out all the time and then I realized the CSB was backwards.