M70B54 build

[petejk]

I haven’t been working on my car much lately, rather I’ve been reading a lot of threads on this board, and accumulating parts for an upgrade to the M73 block.

Today I had a M73 delivered, out of a 97 750iL with 105k miles, from AZ.

The plan is to get it on a stand this weekend, and start cleaning it up, and removing the heads

I’ll be using a Harbor freight 1000lb engine stand, which has a mounting point depth of 50mm. I checked that an M10 bolt can be threaded into the block by 25mm, so 4x hardened M10 75mm bolts should do the trick I hope!




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[petejk]

So after spending an evening removing the wiring harness, fuel rails, intakes, and valve covers, I have made some progress.



I do have a concern though - the engine, when shipped, flipped onto its side, as some slate of the pallet that it was transported on gave way.

It is upright, but leaning back towards the flywheel. In this next picture I can see a pool of oil in the chamber at cylinder 6.




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[cartoonz]

could have been shipped upside down, and even that shouldn't matter for what you are doing.

[petejk]

As I don’t own a pallet jack, I had to make creative use of a saws all to cut the pallet down to a narrower width to allow the legs of the hoist to fit around, to lift the engine.

Once that fun was over, I checked my crank removal tool - a Sir Tools BMW3034-1, which doesn’t have the correct bolt pattern for the M73 crank, despite being advertised as fitting M60, M62, M70 and M73.

I will have to wait until next week for the correct tool, # 83300490885

The other job I have to do before mounting the motor on a stand is flex plate bolt removal. When I got a wrench on these, the motor threatened to tip over, so it looks like an air ratchet is in my future.

Edit: 27mm socket over crank bolt, extension braced against the leg of the lift got the flex plate bolts loose!

I’m looking forward to these two jobs being out of the way so that I can pull the water pump, heads, sump etc.



Removal of the manifolds was easy - I was expecting a tougher job. I am going to have to figure out a temporary storage solution for this bounty of M73 parts.




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[CD05001CIA]

could have been shipped upside down, and even that shouldn't matter for what you are doing.

Second that.

[CD05001CIA]

When you get further down the road I suggest putting a REALLY good gasket in the valley pan.
(see pic) this gasket I cut is for my M60 motor, but M73 not that different. I am going to be re-tearing off the top of an M73 so we will be working in parallel. Me M73. You M70B54.
20190523_165007.jpg

[TedBobo]

I am going to have to figure out a temporary storage solution for this bounty of M73 parts.



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You're either single or your wife is stuck at her Mom's until the "Rona" restrictions are lifted because that's a mighty fine floor serving as a work area. Keep those updates coming.

[petejk]

When you get further down the road I suggest putting a REALLY good gasket in the valley pan.
(see pic) this gasket I cut is for my M60 motor, but M73 not that different. I am going to be re-tearing off the top of an M73 so we will be working in parallel. Me M73. You M70B54.
20190523_165007.jpg

Resealing everything with new gaskets is going to be critical to my satisfaction level with this when it’s done. Comparing how clean this engine is compared to the state that my M70was will motivate me to try to do the best job I can sealing it up

I have the Elring cylinder head set, 11129059239, and for the block, 11119059235, which is by AJUSA. Both came from eBay, one from the UK, for price/availability reasons. I recall reading that the oil pan gaskets are suspect, so I may need to grab those separately. Head gaskets will be Victor Reinz.

What are you doing for gasket residue removal - razor blade, or chemical stripping or some sort? And did the valley bolts give you any grief?


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[petejk]

You're either single or your wife is stuck at her Mom's until the "Rona" restrictions are lifted because that's a mighty fine floor serving as a work area. Keep those updates coming.

No one to complain about my use of floor space other than me - but I will have to get creative storing parts when I start to pull the M70 apart.


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[cartoonz]

Resealing everything with new gaskets is going to be critical to my satisfaction level with this when it’s done. Comparing how clean this engine is compared to the state that my M70was will motivate me to try to do the best job I can sealing it up

I have the Elring cylinder head set, 11129059239, and for the block, 11119059235, which is by AJUSA. Both came from eBay, one from the UK, for price/availability reasons. I recall reading that the oil pan gaskets are suspect, so I may need to grab those separately. Head gaskets will be Victor Reinz.

What are you doing for gasket residue removal - razor blade, or chemical stripping or some sort? And did the valley bolts give you any grief?


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The AJUSA kit is JUNK - please don't do that to yourself. This job is NOT something you want dictated by "lowest cost".
Especially use a REAL Elring or OEM upper pan gasket... do NOT use that cork crap from AJUSA
Scorebmwparts has the real set for $290... seriously, use that.

Plug the oil passages on the deck before doing anything else, you cannot risk debris getting down those. (Remember to take them ALL out before putting the heads on too)

As for cleaning, use a razor blade and CRC Gasket Removal solvent (also used to remove carbon from piston tops)
Also, get yourself some thread chaser taps... M6, M8, & M10 . Chase ALL the bolt holes in the block. Use a McDonald's straw taped inside a shop vac nozzle to clean out debris after cleaning.

Some valley pan bolts will break. Be careful, these are a bitch to extract. tighten/loosen rocking motion helps. (see below note for replacements)

Get a few of those "sandpaper sponges", rectangular abrasive blocks, very handy for prepping some surfaces.

*Note* After you have your block prepped, all covers spiffed up, etc., it is a good idea to use NEW higher grade bolts for as many as you can. Some bolts (like the longer water pump bolts) you'll need to re-use, but all those upper/lower pan bolts and most for the timing covers can all be sourced from BelMetric (and they are NOT expensive).
This was my last order, you may want to reduce the quantities a little... I have lots of engines to build.
-------------------------------------------
100 x BH6X30FYLW - Hex Bolt Yellow Zinc 10.9 Full (BH6X30FYLW) = $22.00
100 x WW6AYLW - Wave Washer Yellow Zinc (WW6AYLW) = $14.00
100 x BH6X20YLW - Hex Bolt Yellow Zinc 10.9 (BH6X20YLW) = $17.00
100 x NRH6YLW - Hex Nut Yellow Zinc Class 10 (NRH6YLW) = $12.00
30 x NA6 - Acorn Nut Zinc (NA6) = $9.30
100 x WF6YLW - Flat Washer Yellow Zinc (WF6YLW) = $6.00
50 x BH6X25YLW - Hex Bolt Yellow Zinc 10.9 (BH6X25YLW) = $9.00
------------------------------------------------------
Note these are all 10.9 bolts, NOT 8.8... these will NOT break at OEM torque levels. The original bolts can fatigue and break when reused, even at factory torque levels.

*** some bolts will have to be re-used, as BelMetric cannot supply a compatible length. For most of them from the order above, they are maybe 2mm longer than oem - which is fine. But on the 4 bolts along the back of the lower pan for instance, you need to re-use the OEM ones.

Use BLUE Loctite on ALL pan bolts.
Use Reinzosil at all seams.
Do NOT smear gasket cement / Reinzosil all over the lower pan cork gasket.

As for the lower pan.... if the bolt holes are "puckered" from some previous hack trying to fix leaking by overtightening (9 out of 10 pans), you may want to press those flat again. You can do this with an odd shaped body hammer and a dolly, or you can devise a long bolt, a stack of washers, a socket, and a nut on the back side to pull the dimple flat. You'll break a few of those bolts used in that tool, but it works well. Unless those surfaces are flat, the lower pan gasket will not seal as well as it should, if at all.

[petejk]

Cartoonz - Thanks for the great write-up! I hadn't made a concrete plan to address a number of basic steps, such as mating surface prep, thread chasing, and even the question of whether fasteners could or should be reused.

I have planned ahead in some respects, namely purchasing head bolts, rockers, lifters, and a pair of the tools required to set timing, but as far as the short block goes, I now have concrete advise to use. It would not have occurred to me to correct a deformed mating surface on the lower pan.

The list of fasteners is also very much appreciated - I'll make a (smaller) order based on that this week!

[petejk]

I tacked a job I had been putting off this afternoon - but after reading the ‘nose job’ thread a couple of times I felt confident enough to pull the front bumper and air boxes etc.




I also separated the upper and lower bumper cover, and now have the upper stripped of kidneys and fastenings ready to be repainted along with some CSI bits.

The radiator’s out, which has freed up some space in front of the engine - next up will be the condenser, which will hopefully give me enough clearance to hoist the engine and transmission up, forward, and out.

Looking forward to next week, dropping the exhaust is likely to be a bear...


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[cartoonz]

be sure to replace the 2 rubber hoses & clamps to that Pentosin cooler while you have the nose all apart... or you'll later regret not doing it.

[rjjablo]

On some cars to get enough clearance to pull the motor and transmission together you jack up the back of the car.

Just a tidbit of info in case you need clearance.

Impact is your friend taking out bolts where you cannot stop something from rotating, like the flexplate

- - - Updated - - -

Every Rubber Hose on these cars is suspect. I just did my PS Hoses in the front and then I noticed the fuel hose over the tank were leaking.

be sure to replace the 2 rubber hoses & clamps to that Pentosin cooler while you have the nose all apart... or you'll later regret not doing it.

[CD05001CIA]

be sure to replace the 2 rubber hoses & clamps to that Pentosin cooler while you have the nose all apart... or you'll later regret not doing it.

He ^ Cartoonz gets the right answers.
WRT hardware I got a few pieces from the dealer. I see why he goes with those fasteners and supplier when buying quantity. The yellow zinc aka iridite, is used on some fasteners on the car. The orig nuts / bolts on the engine aren't yellow so a few nuts and bolts from the dealer won't break the bank.

20200419_185322.jpg

[CD05001CIA]

As I don’t own a pallet jack, I had to make creative use of a saws all to cut the pallet down to a narrower width to allow the legs of the hoist to fit around, to lift the engine.

Once that fun was over, I checked my crank removal tool - a Sir Tools BMW3034-1, which doesn’t have the correct bolt pattern for the M73 crank, despite being advertised as fitting M60, M62, M70 and M73.

I will have to wait until next week for the correct tool, # 83300490885

The other job I have to do before mounting the motor on a stand is flex plate bolt removal. When I got a wrench on these, the motor threatened to tip over, so it looks like an air ratchet is in my future.

Edit: 27mm socket over crank bolt, extension braced against the leg of the lift got the flex plate bolts loose!

I’m looking forward to these two jobs being out of the way so that I can pull the water pump, heads, sump etc.



Removal of the manifolds was easy - I was expecting a tougher job. I am going to have to figure out a temporary storage solution for this bounty of M73 parts.




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So have discovered that one of my DKs is sticking and has a rough feel to the action.
Was wondering if anyone has refurbished the more modern DK that are on the M73s?
Pete be sure to know that your DKs are operating smoothly. Sticky DKs can give you an EML light given the right(wrong) conditions.

[petejk]

be sure to replace the 2 rubber hoses & clamps to that Pentosin cooler while you have the nose all apart... or you'll later regret not doing it.

I agree - I replaced those two a few months ago the last time I had the radiator and condenser out of the car. I also replaced all hoses leading to the pentosin canister.

On some cars to get enough clearance to pull the motor and transmission together you jack up the back of the car.


Just a tidbit of info in case you need clearance.


Impact is your friend taking out bolts where you cannot stop something from rotating, like the flexplate


- - - Updated - - -


Every Rubber Hose on these cars is suspect. I just did my PS Hoses in the front and then I noticed the fuel hose over the tank were leaking.

It isn't until I replaced a couple of these hoses that I realized how degraded a lot of them are. Brittle and crusty!
The only hoses I haven't touched are the longer power steering and asc+t hoses - I'll have another look at them when I have the engine out.
As far as fuel hoses go, I will have changed out the lot once I get around to replacing the fuel pumps - not looking forward to draining a few gallons out of the tank first...

And thanks for the advice regarding lifting the rear of the car. I hope to get the engine and transmission out with a hoist this weekend, so I'll need all the clearance I can get.

So have discovered that one of my DKs is sticking and has a rough feel to the action.
Was wondering if anyone has refurbished the more modern DK that are on the M73s?
Pete be sure to know that your DKs are operating smoothly. Sticky DKs can give you an EML light given the right(wrong) conditions.

My DKs were rebuilt by dragon850, so I'm confident that they will be good to go when the time comes. I'm not sure if he can do the same with the Siemens model that you have.
Failing that, I have a couple from this 105k motor, of unknown quality if you needed a spare.

[CD05001CIA]

As I don’t own a pallet jack, I had to make creative use of a saws all to cut the pallet down to a narrower width to allow the legs of the hoist to fit around, to lift the engine.

Once that fun was over, I checked my crank removal tool - a Sir Tools BMW3034-1, which doesn’t have the correct bolt pattern for the M73 crank, despite being advertised as fitting M60, M62, M70 and M73.

I will have to wait until next week for the correct tool, # 83300490885

The other job I have to do before mounting the motor on a stand is flex plate bolt removal. When I got a wrench on these, the motor threatened to tip over, so it looks like an air ratchet is in my future.

Edit: 27mm socket over crank bolt, extension braced against the leg of the lift got the flex plate bolts loose!

I’m looking forward to these two jobs being out of the way so that I can pull the water pump, heads, sump etc.



Removal of the manifolds was easy - I was expecting a tougher job. I am going to have to figure out a temporary storage solution for this bounty of M73 parts.




Sent from my iPhone using Tapatalk

So have discovered that one of my DKs is sticking and has a rough feel to the action.
Was wondering if anyone has refurbished the more modern DK that are on the M73s?
Pete be sure to know that your DKs are operating smoothly. Sticky DKs can give you an EML light given the right(wrong) conditions.

[CD05001CIA]

I agree - I replaced those two a few months ago the last time I had the radiator and condenser out of the car. I also replaced all hoses leading to the pentosin canister.




It isn't until I replaced a couple of these hoses that I realized how degraded a lot of them are. Brittle and crusty!
The only hoses I haven't touched are the longer power steering and asc+t hoses - I'll have another look at them when I have the engine out.
As far as fuel hoses go, I will have changed out the lot once I get around to replacing the fuel pumps - not looking forward to draining a few gallons out of the tank first...

And thanks for the advice regarding lifting the rear of the car. I hope to get the engine and transmission out with a hoist this weekend, so I'll need all the clearance I can get.





My DKs were rebuilt by dragon850, so I'm confident that they will be good to go when the time comes. I'm not sure if he can do the same with the Siemens model that you have.
Failing that, I have a couple from this 105k motor, of unknown quality if you needed a spare.

Thank you. I'll try to refurbish this Seimens DK first. As can be seen it's a little different. (see pic)
20200422_112438.jpg 20200422_113039.jpg

[petejk]

Thank you. I'll try to refurbish this Seimens DK first. As can be seen it's a little different. (see pic)
20200422_112438.jpg 20200422_113039.jpg

Your intake manifold and DK seem to have a cutout that the parts that I pulled off this engine don’t have.
I’m not sure if that’s an M73 E31 thing or not. This engine came out of an E38.





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[CD05001CIA]

UH OH....

I think I'm gonna need more than a DK.
(see pic)
20200422_122819.jpg

[CD05001CIA]

Your intake manifold and DK seem to have a cutout that the parts that I pulled off this engine don’t have.
I’m not sure if that’s an M73 E31 thing or not. This engine came out of an E38.





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Yep these are cutout after the throttle. This is unique to this car only. There are DKs that have had their diameter enlarged by a machine shop and a larger brass disc throttle placed also.

[CD05001CIA]

Pete, you certainly have an eye for detail.
Here are a few more pics as I look into this engine failure.
20200422_151329.jpg
20200422_151324.jpg

20200422_151312.jpg

[CD05001CIA]

Found reason for failure. Forgot to properly tighten hydraulic timing chain tensioner. FK !

20200422_173910.jpg
20200422_174532.jpg

[petejk]

Found reason for failure. Forgot to properly tighten hydraulic timing chain tensioner. FK !

20200422_173910.jpg
20200422_174532.jpg

Ouch - that is a major failure. Are you going to be replacing the valve, or using a different head?


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