Z4M S54: Rod Bearings Replaced

[G80indy]

I thought this may be interesting to some here....
link

In Depth Tutorials and Information
Crankshaft Lubrication

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1. Crankshaft Oil-hole Drillings

Oil from the main oil gallery reaches each individual main-journal and bearing. Oil is fed through a central circumferential groove in the bearing and it completely surrounds the central region of the journal surface. Diagonal oil hole drills are provided in the crankshaft which pass through the webs between the main and big-end journals (Figs. 3.62 and 3.65) for lubrication of the big-end journal. For effective lubrication of the big-end, these oil holes emerge from the crankpin at about 30 degrees on the leading side of the crank’s TDC position. The drilled oil passages should not be close to the side walls of the webs or near the fillet junction between the journal and the webs to avoid high stress concentration, which may cause fatigue failure. Also the oil holes on the journal surfaces must be chamfered to reduce stress concentration, but excessive chamfering can destroy the oil film.

Crankshaft with single diagonal oil drillings
Fig. 3.65.
Crankshaft with single diagonal oil drillings.

2. Lubrication Systems for Petrol Engines

In order to ensure adequate supplies of oil to the engine parts, a reservoir of oil is provided by the sump which is the lower part of the lubrication system and in automobile engines the sump is the oil pan. From the reservoir, oil is distributed throughout the engine either by the splash system or the full pressure system. In case of two-stroke engines, the crankcase cannot be used as an oil reservoir. The lubrication, in this case, is provided by mixing a small proportion of oil with petrol.

In the splash system the oil is maintained in little troughs (Fig. 11.9). There are dippers at the ends of the connecting rods to splash the oil on the various parts like cylinder walls, camshafts, gudgeon pins etc. as they travel through the oil troughs towards the bottom of the stroke of the piston. The oil is supplied to the main bearings under pressure due to an oil pump through drilled passages, in the crankcase, called galleries. The oil pump also replenishes the troughs. The system is now practically obsolete.

crankshaft Splash lubrication system
Fig. 11.9.
Splash lubrication system.
3. Full Pressure System

Automobile engines today use ‘forced-feed’ lubrication systems, generally of the wet-sump type in which the sump acts as both an oil-drain return and a storage container. A rotary-type oil-pump provides forced feed. The pump may be driven directly from the crankshaft or indirectly from the camshaft or any auxiliary shaft (Fig. 11.10). Oil from the sump reaches the pump through the submerged gauze strainer and pick-up pipe. The oil is then compressed, which passes through a drilling to the lubrication system.

A pressure-relief valve positioned on the output side of the pump controls the oil pressure. If the oil pressure becomes too high, the relief valve opens and bleeds surplus oil back to the sump. The relief valve may be installed on the filter unit, the crankcase, or the pump housing.

The oil-pump forces the oil through drillings in the crankcase to a cylindrical full-flow filter unit. The oil circulates around the filter bowl, passes through the filter towards its centre, and flows out to the main oil passage, called main oil gallery (Figs. 11.10 and 11.11) which lies parallel to the crankshaft. In most car and commercial vehicle engines, the oil gallery is formed by drilling a hole in the crankcase for full length of the engine and plugging the ends.
Main- and Big-end Bearing Lubrication.

The oil is fed to the crankshaft main journal bearings and in some cases to the camshaft bearings (Figs. 11.10 and 11.11) through various branch cross-drillings in the crankcase. A few heavy commercial engines use a separate pipe located underneath the main-bearing caps and by pedestal brackets. Drillings in these brackets connect the gallery-pipe oil to the main bearings. By diagonal drillings in the crankshaft a continuous oil is fed to the big-end bearings from the oil grooves around the main-bearings liners. These drillings pass from the main-bearing journal to the big-end crankpins (Fig. 11.10) through the crankshaft web.

crankshaft Forced-feed lubrication system,Front sectional view,Side sectional view
Fig. 11.10.
Forced-feed lubrication system.

A. Front sectional view. B. Side sectional view.
Crankshaft Oil Passages.

Crankshaft oil passages feed oil from the main-journal bearing to the big-end journal. In its simplest form, the oil passage is a diagonal drilling (Fig. 11.27A) running from the main journal to the big-end journal. Normally the diagonal hole is drilled at an angle to the crank-web centre-line so that, when the crank-pin is in the TDC position and combustion force pushes the connecting rods downwards, some oil still enters between the journal and the bearing. It is because if the exit of the diagonal hole is exactly at the top of the big-end journal, oil can not enter between the bearing and the journal in the TDC position. Additionally the effective projected bearing area is also reduced by chamfered oil hole.

To have an improvement in oil delivery, a cross-drilling (Fig. 11.27B) runs straight through the big-end journal and a diagonal drilling from the main-bearing journal intersects the big-end cross-drilling. Another hole is also drilled diametrically opposite the diagonal-hole’s entry in the main journal, so that when the bearing is loaded at the top or the bottom of the stroke, the other side of the bearing permits oil to enter.

Crankshaft oil passages,Crankshaft with single oil passage,Crankshaft with diagonal web passage and right-angled cross-drilling in the big-end journal
Fig. 11.27.
Crankshaft oil passages.

A. Crankshaft with single oil passage

B. Crankshaft with diagonal web passage and right-angled cross-drilling in the big-end journal.

[LangRacingDevelopment]

We did rod bearings today on an engine before putting it in a race car. Donor vehicle had 40k miles on it and was a Z4M. We had always assumed these engines would be better buys than the M3 engines. Engine looked clean inside, one of the cleaner ones we'd seen. Rod bearing wear was more significant than I would have expected.

[onebluemcm]

The above post is good information to have and thank you very much for posting it but...it is NOT something I want to hear at just a tic over 30k miles now....

[StickMon]

Yes very good info, and not something I want to hear at over 98k.

Blackstone Labs

[thekurgan]

The "2005" must be a misprint or it's not a Z4M.

[David70]

Originally Posted by thekurgan

The "2005" must be a misprint or it's not a Z4M.

Couldn't this be the manufacture date of the engine and not the model year of the car? You could get 2014 model year cars in 2013 and I am assuming they built many 2006 Z4M's in 2005 (especially the engines).

[sipman]

Anyone come to Z4s from VW/Audi? Reason I ask is I seem to remember GIAC flashing the ECU on those cars to allow for User Selected modes.
One mode would be for performance where they raised the Rev limit, increased turbo boost, and eliminated the 155mph top speed.
Another would allow even higher boost, but required racing gas of 104 octane or higher.
Another would be Valet mode, where it limited throttle application, boost, etc so the valets couldn't hoon you car.
I'm wondering if there is, or if we could get a reprogrammed control that would set the RPM limit to 7000rpm, until we select track mode and then it goes back to normal?

[jdoublehcubed]

I had a TT before. Got rid of it before chipping it, but I looked into it a few times. The multi-mode thing you're describing is offered by APR. The chip/programming holds up to 4 different programs, so you can have 91 octane, 93 octant, 104 octane, plus valet mode all in the same car. Maybe its offered by GIAC as well.

ECS Tuning offers the APR chip above for like $550, about 3 months out of the year. Otherwise its like $850. Pretty cheap either way.

[bibbly]

looking at buying an '06 z4mc that been through 3 owners...don't think it has seen track time, but it's pushing 50k miles. one owner added some go fast and handling parts, so there is some concern over driving style. never had oil analysis done, but that is the first part of a ppi. don't think i saw a post regarding the cost of bearing replacement as described....anyone have a ballpark idea?

[SCHMOUPE]

Originally Posted by bibbly

looking at buying an '06 z4mc that been through 3 owners...don't think it has seen track time, but it's pushing 50k miles. one owner added some go fast and handling parts, so there is some concern over driving style. never had oil analysis done, but that is the first part of a ppi. don't think i saw a post regarding the cost of bearing replacement as described....anyone have a ballpark idea?

I think you are looking at somewhere between 1-2K

[bibbly]

thanks. appreciate the quick reply

[jdoublehcubed]

Originally Posted by SCHMOUPE

I think you are looking at somewhere between 1-2K

I think you're closer to $2500 unless you're in a location with unusually low labor costs. Bavarian Specialties in Philly quoted me about that, and their labor costs are lowish at $100/hour. Parts alone are over $1000.

[XMetal]

Bringing this back...

PAL,
Did you ever found what was the cause of the rising sodium on your car? Mine is also spiking on the last 3 oil analysis and curious to hear what that may be. Interestingly, of all the Blackstone results that I had seen, most of the higher sodium readings than normal are from Z4M! I don't believed I had seen this on the E46 M3.

[Randy Forbes]

Originally Posted by XMetal

Bringing this back...

PAL,
Did you ever found what was the cause of the rising sodium on your car? Mine is also spiking on the last 3 oil analysis and curious to hear what that may be. Interestingly, of all the Blackstone results that I had seen, most of the higher sodium readings than normal are from Z4M! I don't believed I had seen this on the E46 M3.

When Blackstone started detecting trace amounts of sodium in the oil from my (Dinan/Vortech) supercharged S-52 enigne'd M Rdstr, it proved to be the headgasket breached between coolant and oil passages under boost conditions.

The only other obvious symptom that eventually developed was the cooling system getting over pressurized.

Blackstone caught it before any other markers were noted.

[XMetal]

Originally Posted by Randy Forbes

When Blackstone started detecting trace amounts of sodium in the oil from my (Dinan/Vortech) supercharged S-52 enigne'd M Rdstr, it proved to be the headgasket breached between coolant and oil passages under boost conditions.

The only other obvious symptom that eventually developed was the cooling system getting over pressurized.

Blackstone caught it before any other markers were noted.

Thanks for the feedback. Did you lost any coolant or observed any oil in your coolant?

[ctdriver86]

Hello, I just started taking the car apart to do the rod bearings. I wanted to find out, did you use the engine support on top of the radiator support? I noticed the z4 chassis doesn't have the fender support like the e46 m3 to run the engine support top of the bracket.

[Randy Forbes]

Originally Posted by ctdriver86

Hello, I just started taking the car apart to do the rod bearings. I wanted to find out, did you use the engine support on top of the radiator support? I noticed the z4 chassis doesn't have the fender support like the e46 m3 to run the engine support top of the bracket.

[ctdriver86]

^ That holds? There's no support I noticed under the fender itself.

[Randy Forbes]

Originally Posted by ctdriver86

^ That holds? There's no support I noticed under the fender itself.

Looks like I did one this way, but there were no issues on the 1st way I showed.

[ctdriver86]

Thank you! I'm assuming the 1st picture is a roadster? My fenders look like the 2nd picture that doesn't have the railing parallel to the engine bracket holder. It's cut out. I will see if I can make my engine support work with that angle. May have to grind down my square triangle support. Thanks!

[Randy Forbes]

Originally Posted by ctdriver86

Thank you! I'm assuming the 1st picture is a roadster? My fenders look like the 2nd picture that doesn't have the railing parallel to the engine bracket holder. It's cut out. I will see if I can make my engine support work with that angle. May have to grind down my square triangle support. Thanks!

I did the rod bearings on three (3) Z4Ms, all coupes (2 were white & 1 black).

Mileages of the first two were near identical at 60,000 (one had about 60 'track days" and zero history of the other one) and one at less than half that (27k, IIRC) and the bearings looked bad in all three.

This was from the 60k-no history engine (for the 60k/60 track day bearings, refer to post #1 in this thread)









The 27k (26,921) car



I've seen enough S54 bearings to convince me that the post 04/04 bearings were not such an improvement over the pre 04/04 ones (all they needed to do was correct the clearance issue, NOT switch from lead/copper/tin to an aluminum/tin composition.

What are you replacing them with B&E Bearings? https://store.langracing.com/product...bmw-e46-m3-s54

[XMetal]

Originally Posted by Randy Forbes

I've seen enough S54 bearings to convince me that the post 04/04 bearings were not such an improvement over the pre 04/04 ones (all they needed to do was correct the clearance issue, NOT switch from lead/copper/tin to an aluminum/tin composition.

I thought all S54 bearings materials are lead/copper/tin? Didn't the 2011 and newer E90/E92/E93 with the S65 got the aluminum/tin composition? Even the pre 2011 S65 got the lead/copper/tin composition?