e36 325i Coupe Project

[wrs 119]

B12 shocks rebuilt and kit installed. Lowered the front by 50mm+ and rear by 10mm (looked a bit like 'Back to the Future's' Delorean before). Now the car is level with front and back wheels about 10mm inside wheel arch. Handling is significantly improved. Previous suspension was stock 325 coupe with Sacks shocks all round. The shocks had probably done close to 100k's and still seemed ok until the Bilsteins went in. Either the billi's are a crap-load better or the old shocks were buggered. I suspect the matching of the Billi's to the Eibach spring has also helped. Corners that were previously 'on-edge' are now effortless.

Installed an e46 purple rack - took a bit of getting used to. Almost curbed some corners the first time due to turn memory on the steering wheel being wrong for the purple rack. Now I'm used to it I like it. Is a bit heavier.

Had a bad vibration in the rear. It didn't change while cornering at all so thought it might be the diff. Changed frequency with speed but didn't change in level if going from accel to decel at light loads. The local shop thought it was the diff. The diff was 3.07 and while great at 100km in 6th (2200 rpm) all the shift change points were wrong for most corners requiring either lots of revs two gears down or out of the power band in one gear down. It gave me the excuse to change from 3.07 to 3.46. The 3.46 is much better even after only driving on it for a short time. Didn't fix the vibration issue though. Went back to the shop today and put it on the hoist again. The left rear has some noise and if you hold the spring you can feel it give a kick about once per wheel turn. It's going back in on Monday for the rear left wheel bearing. Last time it was in I'd asked them to do the bearing but they were sure it was the diff...

Power steering pump is buggered. During the engine swap we put the M52 oil filter housing on the engine which caused some issues with the power steering pump (wasn't told about it - they just made it fit). I discovered the guys at the shop had the mounting of the power steering pump machined so it would fit. Now I have to get the replacement machined so it will fit. Most likely I'll go back to the M50 oil filter housing soon so everything fits up standard. I really want to fit the S50 oil filter housing but finding one is difficult. I'm changing oil about every 4000km because it goes dark brown at about this time and the lifters start getting noisy. It's really easy to tell when the oil is buggered - one day the car is good when started, the next it sounds like a tractor - change the oil and it's perfect again. It's always round 4000km it goes. I suspect an oil cooler will extend the oil life but I just can't find the S50 oil filter housing anywhere. Might have to buy a really expensive one from overseas...

The repaint is getting closer, probably another 6-8 weeks before it goes in. Photo's to follow the new paint job. Have discovered the front and rear window trims are fitted with the glass. Luckily I just got a big chip in my front windscreen so that will get done under insurance. The local glass guys recon they can remove the rear window without breaking it. So, when the repaint goes ahead it will be a full glass-out job so the edges will be perfect. The front window and trim will get replaced by my insurance the rear will just get refitted with a new trim I pay for. The current trim has shrunk and will probably get wrecked during window removal anyway. Not sure what to do about the sun-roof. I never use it and the mechanism has failed 3 time already (broken now). I actually eurothaned round the seal to stop water leaks years ago (so it can't open). Thinking about removing it for the repaint then sealing it up again.

 

 

Edited July 3, 2019 by wrs

[M3AN 4016]

Your vibration sounds (and feels) like the one that's recently developed on my 328... I'm also thinking wheel bearing so keen to hear your results.

[Eagle 1660]

Personally ive never seen a sealed hub bearing (or diff for that matter) cause any vibration on in car, you usually hear start things start bad long before they develop play. Did they isolate anything else back there? CV's on a hoist are at odd operating angles also esp with the wheels on. 

Sounds like your suspension is fairly sorted and most constant vibrations ive had in BMW's were traced mainly wheels\tyres or driveline

[zero 1162]

You are making good progress.

 

What condition are the bushes in, and how many did you replace?

[wrs 119]

It was the left rear wheel bearing - replaced and all is good again.

The bushes were nearly all replaced with stock ones about a year ago. The only ones I didn't replace were the diff bushes, glad I didn't now since I've changed diffs again (although this would have only affected the rear bushes). I've had tears forming in the rear diff bushes before but they're easy to check while the diff is out using a screwdriver through the screw hole and give them a twist.

I've also had the exhaust redone. After lowering the car the exhaust was scraping on driveways, judder bars etc. The previous exhaust I put in to replace the mid section used a really fat 2 in 2 out resonator. Turns out this was totally wrong for the tuning back to the exhaust ports and caused a big flat spot between 2000-2500 rpm. I've dumped the big resonator and added 2 small resonators about where the cats used to be and put a H-pipe just behind the resonators. The result is excellent - it's much quieter and the flat spot is gone (I guess quiet = no fighting of the exhaust pulses in the pipes, previously there was a big drone between 2000-2500). It also sits about 50mm higher up into the arch so none of the exhaust now hangs below the body in the mid-section. The 2 resonators were custom built by AdrenalineR and do a really good job - no rasp at all despite only being 200mm long.

[wrs 119]

When the external engine parts were assembled from the long block we used parts from M50B30nv and M52B28 doner engine (the long block was a M50B25nv converted into a M50B30nv by one of the guys at HellBM). The oil filter housing used was from the M52 and worked fine on the M50B25NV iron block - just had to modify the power steering pump due to the mounts being longer on the oil filter housing).

Yesterday I finally changed the M52 oil filter housing to a S50 type and installed an oil cooler. So far with general daily driving it appears the oil cooler does nothing (hasn't got hot so far). So, either the oil thermostat is jammed or the oil just hasn't got hot enough yet for the cooler to be needed. I haven't given it any stick yet - still making sure there aren't any leaks before taking it out over some decent hills etc.

I installed new idler and tensioner pulleys at the same time + changed the power steering pump because the old one was whining majorly. One thing I found immediately was the belt was screeching on the alternator just after the engine was started. The tensoiner was at full extension but the belt wasn't tight. I've done a temporary fix by putting the old to idler pulley back on with most of the alignment spigot filled off so I could rotate it a bit further down (the one on the top alternator bolt). The belt is tighter now but still not as tight as it should be. Maybe I didn't put the tensioner hydraulic thingy back on correctly when cleaning the S50 housing or maybe it's not pushing out to full extension anymore - does anyone know if the hydraulic type loses it's extension range with time?

With the replacement power steering pump and new pulleys the engine bay is much quieter. Now the dominant noise is the Vanos (next job)...

So from above, hoping someone can help with 2 questions:

1. Does the oil cooler thermostat only open under sustained heavy load conditions (eg, big hill) or should it open during normal driving (eg cruising at 100km)?

2. Are the main serpentine belt hydraulic tensioners a know weakness on the M50 engine and fail so they don't fully extend?

Thanks in advance.

[M3AN 4016]

1. did you have excessive oil temps before? If not, adding an oil cooler will do nothing except increase the amount of oil you need to fill it up with.

2. No, the hydraulic tensioners can last for 100's of thousands of km's, the mechanical ones die quickly however.

[Eagle 1660]

2 hours ago, wrs said:

Are the main serpentine belt hydraulic tensioners a know weakness on the M50 engine and fail so they don't fully extend?

Not M50 engines but ive come across a few older BMW's with hydraulic tensioners that were clearly fatigued (maybe leaked out fluid) . Is the belt is good and the correct size?

What ive always done in a pinch is drop the belt size maybe 10-15 to compensate 

[wrs 119]

Hi All,

Been a while.

Have had my car repainted - just picked it up today. I took it back to an empty tin can to be painted + did sunroof delete. Novus removed the front and rear windows prior. Unfortunately when they reinstalled the rear window they did not fit the bottom rubber seal which appears to be important in getting the glass positioned at the correct height. So, the window now has too big a gap at the top and it's impossible to get the bottom seal in.

I suspect the window will have to come back out which risks breaking it again. The glue is only a couple of days old so may not be fully cured - likely the best time to remove it is now.

If it's removed again will I need a new top rubber seal of can these come out ok when removing the window?

 

The car isn't reassembled yet - pictures to come once it's all done. Looks like tiny-pic is dead, will have to re-up all the pictures and relink...

[M3AN 4016]

You can reuse the top/side seal on the coupe and reuse it... if you're careful! Don't stretch or tear it. But I'd make Novus pay for a new one if it were me.

If you do reuse it you'll need to replace the tar-like sealant if the existing stuff has bonded. That would be a royal PITA. 

Edited March 23, 2020 by M3AN

[wrs 119]

Cheers, thanks for the info. I hope a new one won't be required - if it is I might not get it before we lock down... I'll check first thing if one is in stock in NZ and can be delivered overnight. If it is in stock and can be delivered we'll attempt fixing it (hopefully Novus will sort it out in the next 2 days...).

[wrs 119]

Update time:

Did a bit of a refresh of the Vanos + finally got round to fixing up all the errors made on the initial build. I got a donor Vanos and sent it to Dr Vanos to be rebuilt - they did a nice job. This was installed earlier in the week but the engine felt quite different and didn't seem right afterwards with flat spots where the cams switch and overall it felt sluggish. Looking at the photo's we took of the cam positions before taking the Vanos off and fitting the cam blocks it was clear the inlet cam was quite retarded compared to where it should have been. This was corrected when re-installed. I decided not to drive the car much until the tune was checked. With no MAF and oxy sensors the ECU couldn't do anything to correct what might have been wrong. The Link ECU tune I have is non-adaptive and uses just TPS, MAP, ECT and IAT so is fixed and can't adjust to any external changes.

Yesterday a slot became available on the dyno today so I fitted the bigger injectors that should have been fitted originally (pink top). I also fitted a modified throttle body with 22% bigger cross-section. The intake duct was increased from 76mm to 100mm and the airbox modified to a proper 100mm diameter outlet tube and trumpet. I then sent it of for a re-tune. It was well worth it. The bigger inlet tube did not add any extra noise.

Below is the dyno chart with the before and after curves. Before 263.5hp/313.5Nm, after 297.8hp/343Nm. So, I'm pretty happy with the result. The Vanos is also nice an quiet again which is another bonus.

Edited June 26, 2020 by wrs

[wrs 119]

After nearly 5 years and 85k+ my engine has developed a problem. Over the last few weeks I've been getting yellow gunk on the oil filler cap and the base of the CCV drain where the dipstick sits (yellow gunk on the dipstick too).

I've also been losing about 150ml a week from the cooling reservoir.

I drained the oil and waited for all drips to stop then pressurised the cooling system to 1 bar (usually runs at about 0.7 bar). After 10 minutes or so I started to get a drip every couple of minutes. It was just oil. After about an hour and having to add a bit more pressure to the cooling system from time to time as the pressure very slowly dropped, the oil drops started to contain water.

Probably the most likely problem is a leak in the head gasket between the cooling system and a low pressure oil return drain.

So, I've decided to either rebuild the engine or build another one so I have a spare. Either way I'd like to crack >300HP. Since I'm already at 298 it shouldn't be too difficult.

During the build a M54B30 rotating assembly was installed directly into a M50B25nv engine with US S50 cams and full M3 Evo exhaust (no cats) including the M3 Evo headers. This has likely resulted in relatively low compression, probably under 10:1 and more likely closer to 9:1. If I rebuild or build a new engine I'm considering after market pistons to 1: Raise Compression and 2: Increase capacity by boring from 84.0mm to 86.0mm to go from about 3L to 3.13L. I may also have to get some head-work done to improve flow a little. The compression increase alone should mean >300HP.

Is there anyone in NZ who can calculate the increase in piston height required to achieve 11:1 to 11.4:1 taking into account the increase in bore diameter?

Is there anyone in NZ who can check the bore thickness prior to boring to ensure there no asymmetry or irregularity in the casting?

VAC Motorsport have a range of oversize pistons with different deck heights for various compression ratios but they don't list the M50B25nv head in the options and it has a different volume to other heads so the stated CR likely won't be correct. They also don't list combo's for the M54B30 rotating assembly in my block + head combo. Someone has suggested Mahle as an option but it will depend if they're available in 86mm and if they can be machined to suit.

Has anyone used ceramic coatings on pistons and combustion chambers before (lifetime expectation)?

Thanks in advance for any thoughts or suggestions.

[dirtydoogle 383]

Assuming new pistons are stock m54 comp height @ 28.32mm, and a standard thickness head gasket will net you 10.28cr 

M50nv head should be an average chamber of 33ish-cc 

I would go with a .050" compressed gasket, this would put you around 11.3cr 

It's a decreasing gain after that kind of comp though, and can create more issues 

 

Have used piston coatings, I'm not entirely convinced it's needed in a road going motor, especially one with low cylinder tenps and lower pressures, have yet to see a measurable or tangible benefit 

The key to your 300hp goal is, throw the cams in the bin and get something decent. All OEM BMW cams of that era are poo. The average valve lift is poo. Plenty of excellent options to suit your needs. You are already making very nice HP though 

Edit: block checking, I'd ring Marsh or Hartley for advice there

Edited September 25, 2021 by dirtydoogle

[wrs 119]

Thanks for the info. It would be a shame to throw out the cams as I purchased them new from Turners (Schrick S50 Intake: 252 degree, 10.2mm lift Exhaust: 244 degree, 9.5mm lift ). That said if there are much better options then why not. I went with the Shrick's because it meant no messing round with lifters and having to check spring binding, valve clearances etc and the duration and lift were better than standard M50 cams.

It also sounds like I don't need to do anything special in the way of pistons and can put those dollars towards something else (cams). If I do go with better cams I could likely on-sell the S50US cams to help offset the cost of replacements. There's another local guy with a real nice 328 M52 engine making around 316Hp, maybe I can talk to him about which cams he's using - it's a race car though and might not be that driveable round town...

As you say though, I don't need much more to crack 300Hp but why stop there, 320+ should be possible quite easily.

[thorburn 121]

I've got some s50 itbs and an adapter to fit it to an m50/2 head. If you wanted to go down that route pm me

Bummer about the current motor. 

[dirtydoogle 383]

23 hours ago, wrs said:

Thanks for the info. It would be a shame to throw out the cams as I purchased them new from Turners (Schrick S50 Intake: 252 degree, 10.2mm lift Exhaust: 244 degree, 9.5mm lift ). That said if there are much better options then why not. I went with the Shrick's because it meant no messing round with lifters and having to check spring binding, valve clearances etc and the duration and lift were better than standard M50 cams.

It also sounds like I don't need to do anything special in the way of pistons and can put those dollars towards something else (cams). If I do go with better cams I could likely on-sell the S50US cams to help offset the cost of replacements. There's another local guy with a real nice 328 M52 engine making around 316Hp, maybe I can talk to him about which cams he's using - it's a race car though and might not be that driveable round town...

As you say though, I don't need much more to crack 300Hp but why stop there, 320+ should be possible quite easily.

We are making 300 wheel with an m54 thats fairly basic. 

What work has been done to the head? 

I'm not a fan of the NV set up for a high rpm n/a motor, heavy springs and heavier valves. Modern spring, retainer and collet package is much better and lighter. 

Also have found mega seat pressure variations across stock motors, and usually not enough seat pressure anyway (typical beige OEM stuff)

 

We have a RS2000 Escort rally car here, it had the head done by a well reputed outfit. Seat pressure was almost double what it should be, set it up to be around 95Lbs and gained 16whp 

[wrs 119]

Current head, no work done that I know of, not even match-ported... The original M50B30 stroker came from Sam at HellBM - was built as a drift car engine but there was really no way it would have enough power as it was. I suspect it was just put together without any special work done to it.

I originally went with the nv head because of the double valve springs and an old-school Ford background where double valve springs when using high lift were the only option + it's what was on the engine when I purchased it from Sam. If there's a better option I'll certainly entertain looking at it. To date I've only been considering just over stock RPM for M50 based engines. The nv head means a 7k limit. On my current engine I've set the Link to limit at 6750RPM and I almost never hit it. With peak torque at 5500RPM there's little benefit going over 6.5k anyway.

If there's options to reliably increase peak RPM a little and move peak torque up accordingly then why not. I've always liked big RPM but now prefer reliability over RPM. Maybe new cams to move peak torque up 500RPM + some head work to get the flow required + maybe ITB's. Maybe better to buy a S50/S52 and rebuild that...

What head would you recommend - M52B28?

[dirtydoogle 383]

M50tu and b28 are exactly the same casting 

Depends how much you want to spend. I would do a tu/m52b28 head with a spring and retainer package, plus a better cam design (you should pick up torque too) 

But if you're not keen to drop that kind of money on a relatively small increase, measure the seat pressures on the existing head, replace the cams if you can, and at least new retainers and collets. Have seen quite a fair few pull through from fatigue. Check for coil bind at max lift too 

 

I'm hoping you have oil pump lock mods, a tensioner and new gear and shaft? If not, you will have to keep the revs down 

[polley 916]

Revved my m50nv to 7200 for years, no problems. But it was the model that had oil pump chain tensioner standard.

[dirtydoogle 383]

3 minutes ago, polley said:

Revved my m50nv to 7200 for years, no problems. But it was the model that had oil pump chain tensioner standard.

The 3.0 has a nice little harmonic issue, I would say rod/stroke ratio is a big factor in it, the 3.0 is a bit pants in that respect. Even a non tensioner 2.5 or 2.8 will do it for a long time. But not a b30 

[polley 916]

5 minutes ago, dirtydoogle said:

The 3.0 has a nice little harmonic issue, I would say rod/stroke ratio is a big factor in it, the 3.0 is a bit pants in that respect. Even a non tensioner 2.5 or 2.8 will do it for a long time. But not a b30 

Yeah have seen a couple 3 liters sh*t the bed from it. You can kinda feel it when you rev them high it doesn't feel right, they don't like it.

[wrs 119]

2 hours ago, dirtydoogle said:

M50tu and b28 are exactly the same casting 

Depends how much you want to spend. I would do a tu/m52b28 head with a spring and retainer package, plus a better cam design (you should pick up torque too) 

But if you're not keen to drop that kind of money on a relatively small increase, measure the seat pressures on the existing head, replace the cams if you can, and at least new retainers and collets. Have seen quite a fair few pull through from fatigue. Check for coil bind at max lift too 

 

I'm hoping you have oil pump lock mods, a tensioner and new gear and shaft? If not, you will have to keep the revs down 

Thanks, all good points and likely increase reliability somewhat.

I have the oil pump mods already done.

[wrs 119]

I've collected a few items with the intention of building a second engine and will fix the current engine to keep as a spare.

M50B25tu engine (blown head gasket)

M54B30 (crank & rods donor)

S50 ITB's & Plenum

S50 to M50 Adapter https://www.driftshop.com/itb-adapter-spacer-bmw-m50-m52.html

I'm looking to bore the M50 block to 86mm, use aftermarket 86mm pistons (increase to 3.15L) and use a thinner than standard head gasket (Cometic) to raise CR to around 11.3:1. On Doug's recommendation I'll get better than S50US cams (probably CAT cams with more lift) and do a spring/retainer change. Will also do some minor porting and match porting to the ITB adapter and S50 Euro headers.

I'm currently running pink top injectors but they are running at 100% duty from peak torque at 5.5k rpm up. If I'm intending to get more power I'm going to need bigger injectors. The pink top are supposed to be 21.5lb/225cc. I suspect 20-30% bigger will allow the headroom without compromising idle and low throttle stability too much. There's a set of S50 injectors that came with the ITB's (Bosch 0-280-150-701) but I think these are only marginally bigger than the pink tops at around 23lb/240cc and likely won't be big enough and I have no idea what condition they're in. Even 24lb/252cc blue tops could be too low flow.

Can anyone suggest a good injector and supplier for replacements? Should I stick with EV1 or look at EV6 or EV14 type with EV1 connectors?

I suspect I'm going to need 270cc to 300cc to allow some headroom so I'm not hitting 100% duty at full power.

[thorburn 121]

Would've assumed you wouldn't be making too much more power than an s50. I'd get the s50 injectors cleaned up. Failing that msel in Auckland have a good selection of injectors