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M30 B34 Engine Rebuild

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jps635
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M30 B34 Engine Rebuild

Post by jps635 » Sun Dec 17, 2017 9:41 pm

Following are details of my recent engine rebuild which I briefly summarised in another post.

Engine is original M30B34. Mileage was 237K. Known problems were worn cam, and valve guides, otherwise was sound. All internals were original and the head hadn’t been off.
Upon removal, the head was naffed with some severe corrosion and head gasket on its last legs.

Aim was to build a strong durable street engine with torque being the priority over outright power. I did heaps of research on this and in the end relied heavily on advice from Korman Autoworks. I wanted to retain the M30B34 as a complete engine. While a lot of reading recommends using the B35 manifold, Korman advised the smaller dia B34 runners would provide better torque.

A big issue for me was pistons. I was hell bent on using lighter forged / hypereutectic pistons to raise compression, but after a number of discussions with Korman, finally agreed sticking with (new) cast pistons would be much more suitable for a street engine.
On top of this there was the issue of pistons being made on one side of the world and my block on the other other. I know a lot of people do this successfully, however my engine builder thought was a recipe for disaster, given the piston manufacturer wanted to supply to a finished bore size.

Work building up to this over the last few years saw replacement of:
- starter and alternator,
- all hoses
- installation of full fritz exhaust system
- Mustang 19lb injectors
- Link G4 Extreme ECU with custom mill-spec wiring loom
- Custom air intake and MAF delete
and an initial tune to get good base map.

Engine rebuild consisted of the following - all new:
- NOS head, ported and polished by Korman, port matched to inlet and exhaust gaskets, with 3 angle valve job
- Schrick 284/280 cam
- Korman race rockers
- Korman s/s/ swirl polished valves - retained the standard size 46/38mm
- Schrick single valve springs and titanium retainers
- New rocker shafts
- Korman rocker locks
- Timing chain, tensioner assembly and guide rail
- Adjustable cam gear
- Oil pump, and drive chain
- Pauter rods with ARB bolts. (These were a ‘selected set with max weight variance go 0.9 grams but further balanced and shot peened)
- Mahle 92.50 dia pistons (2nd overbore size)
- BMW head gasket
- BMW head bolts. Looked at using ARP’s but read that these resulted in too much end float on rocker shafts and were too high…….

Crank was checked, polished and journal feeds radiused.
Block was checked, bored, honed and decked, along with front cover. Looked into using a torque plate but couldn’t access or get one made for a reasonable price.

Head was fully checked, cc’d, valves checked for leakage etc.

Final compression was 10.6:1. Engine builder put some very small fly cuts in piston tops to ensure (from memory) 80 thou clearance. Initial cam timing set at 2 degrees advance and spray bar banjo bolts wired.

Engine was fully balanced, including with 60-2 tooth damper, 13lb flywheel (skimmed) and new M5 clutch. Before balancing pistons were +/- 4grams and crank was similarly 4 grams out.

Engine builder did a bloody good job, ensuring oil pressure ok and no leaks from rear main before handing over assembled short block. Provided full engine build spec.

Retained standard throttle body on the basis this was sufficient in the Group A cars for circa 300hp.

Engine and gearbox was removed and installed on sub-frame from under.

While engine was out, replaced:
- heater core and all heater controls (bugger of a job but managed to do this without disconnecting the bowden cables)
- ignition lock
- all central dash lights
- The factory silver reflective bulkhead foil was in tatters, so replaced with with Thermo-Tec Woven gold 24 K heat barrier, glued using Ados F38 high temp contact adhesive. I considered replacing all the bulkhead sound proofing, but in the end patched up the cracks with a high temp silicon adhesive.
- rebuilt steering box (that I got from Ron a few years ago)
- All but one of the high pressure power steer pipes/hoses which was NLA, and all the low pressure hoses
- oil cooler and oil cooler lines
- radiator, with wizard cooling all aluminium unit.
- under hood insulation for the second time. This time using 3M 90 deg adhesive
- washer jets and pump. I just using the intensive bottle, with wiring and plumbing re-arranged, the big bottle gone along with the headlight -
- washers/wipers. So now just a single washer hose with a single combined tee/check valve - very simple.
- head unit and speakers

Also
- removed in car A/C blower unit
- rebuilt and balanced drive shaft
- rebuilt gearbox. This required replacing the layshaft and 2nd gear assembly. Parts for these are NLA and have to take your chance with used. (I went from a 22 tooth second gear to 19 tooth, overall ratios the same).
- clutch and slave cylinder

A heap of ancillary bits and pieces replaced, engine and gearbox mounts etc

All engine components either painted or HPC coated. Headers and collectors coated inside and out. Paint used was Eastwood Brake Grey which was very close match to HPC gunmetal. Pulleys and brackets HPC black satin. Engine block POR-15.

Head had final torquing after cam run in and valves adjusted again when cold. Cam was run-in using Lucas 20W-50 high zinc, run in oil, which was changed out after a couple hundred km’s test runs. Now running on Lucas 20W-50 high zinc mineral “Hot Rod” oil. Oil clean as clean can be after 1200km.

I had left the centre console out and lower dash off to fully check everything once running. So drove the car home in this state. The A/C unit was gone and i hadn’t plugged the condensate drain hole above the gearbox. What bloody racket with this one hole open to road. Surprising how noisy the gearbox is. After plugging I covered the mounting plate with 10mm thick HD foam.

I also cut out a square of 50mm low density foam around gear shift to pack out the space under the gear shift boot, up against the console. 

Is now very quiet with no gear whine heard inside.

Initial running was a bit hairy and lumpy with a reluctance to idle when cold. This improved with km’s, en-route to tuner.

I had left the centre console out and lower dash off to fully check everything once running. So drove the car home in this state. The A/C unit was gone and i hadn’t plugged the condensate drain hole above the gearbox. What bloody racket with this one hole open to road. Surprising how noisy the gearbox is. After plugging I covered the mounting plate with 10mm thick HD foam.

I also cut out a square of 50mm low density foam around gear shift to pack out the space under the gear shift boot, up against the console. 

Is now very quiet with no gear whine heard inside.

Has now undergone further dyno and road tuning including attention to cold starts. No doubt this will be revisited again though, as will likely require a 3 way idle control valve come winter to assist with cold start idle, but this can wait for now. 

Even though engine has good hardware and will rev higher, have retained stock rpm limit of 6150 (link has soft cutout) given where peak power is generated. iHave programmed sequential shift lights coming on from 5550.

Results:
- RWHP @ 209, and peak torque @ 375 NM with a long flattish torque curve. (see dyno chart) Noticeably torquier and more rapid. (3.45 LSD). Can be a lot more selective with gear in gear use.
- Oil pressure now sits at circa 4 bar at 100-110k/hr in 5th. Used to sit at about 3.5.
- Water temp now sitting at circa 87 (previously 90) at steady cruise. Oil temp 88-94, depending on speed, but no more than 89/90 at cruise. Is quite warm here at the mo - mid to high 20’s, so good test weather for cooling system. Wizard radiator provides better cooling and compensates for increase in power/ temp.
- Davies Craig pusher fan operation via ECU now properly synced. Comes on at a tad over 90 deg c and cuts off at 88. Was 29 deg coming home after tuning and got delayed in stop start traffic due to an accident. Was no need for manual intervention. The HPC coating of the headers also helps with lower under hood temps.

Attachments
Valve cover - HPC.jpeg
Valve cover - HPC.jpeg (83.7 KiB) Viewed 4264 times
Old head 3.JPG
Old head 3.JPG (143.58 KiB) Viewed 4264 times
Old Head 2.JPG
Old Head 2.JPG (154.9 KiB) Viewed 4264 times
Old head 1.JPG
Old head 1.JPG (149.5 KiB) Viewed 4264 times
'85 635csi JPS (RA2-66)

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jps635
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Re: M30 B34 Engine Rebuild

Post by jps635 » Sun Dec 17, 2017 9:43 pm

New Head
Attachments
New head 4.jpeg
New head 4.jpeg (61.74 KiB) Viewed 4262 times
New head 3.jpeg
New head 3.jpeg (62.35 KiB) Viewed 4262 times
New head 2.jpeg
New head 2.jpeg (64.29 KiB) Viewed 4262 times
New Head 1.jpeg
New Head 1.jpeg (87.18 KiB) Viewed 4262 times
'85 635csi JPS (RA2-66)

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Re: M30 B34 Engine Rebuild

Post by jps635 » Sun Dec 17, 2017 9:45 pm

Porting, Oil, Headers
Attachments
Oil.JPG
Oil.JPG (124.03 KiB) Viewed 4262 times
Inlet ports.jpeg
Inlet ports.jpeg (39.79 KiB) Viewed 4262 times
Headers - HPC.JPG
Headers - HPC.JPG (120 KiB) Viewed 4262 times
Exhaust ports.jpeg
Exhaust ports.jpeg (50.38 KiB) Viewed 4262 times
'85 635csi JPS (RA2-66)

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Re: M30 B34 Engine Rebuild

Post by jps635 » Sun Dec 17, 2017 9:46 pm

Bulkhead + Engine
Attachments
Engine 2.JPG
Engine 2.JPG (127.39 KiB) Viewed 4262 times
Engine 1.JPG
Engine 1.JPG (134.78 KiB) Viewed 4262 times
Engine & gearbox.JPG
Engine & gearbox.JPG (132.39 KiB) Viewed 4262 times
Bulkhead.JPG
Bulkhead.JPG (104.96 KiB) Viewed 4262 times
'85 635csi JPS (RA2-66)

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Re: M30 B34 Engine Rebuild

Post by jps635 » Sun Dec 17, 2017 9:48 pm

Engine bay
Attachments
Engine bay 4.JPG
Engine bay 4.JPG (135.64 KiB) Viewed 4262 times
Engine bay 3.JPG
Engine bay 3.JPG (137.86 KiB) Viewed 4262 times
Engine bay 2.JPG
Engine bay 2.JPG (147.33 KiB) Viewed 4262 times
Engine bay 1.JPG
Engine bay 1.JPG (142.81 KiB) Viewed 4262 times
'85 635csi JPS (RA2-66)

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jps635
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Re: M30 B34 Engine Rebuild

Post by jps635 » Sun Dec 17, 2017 9:49 pm

More engine bay
Attachments
Engine bay 8.JPG
Engine bay 8.JPG (132.11 KiB) Viewed 4262 times
Engine bay 7.JPG
Engine bay 7.JPG (147.02 KiB) Viewed 4262 times
Engine bay 6.JPG
Engine bay 6.JPG (139.06 KiB) Viewed 4262 times
Engine bay 5.JPG
Engine bay 5.JPG (123.27 KiB) Viewed 4262 times
'85 635csi JPS (RA2-66)

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Re: M30 B34 Engine Rebuild

Post by jps635 » Sun Dec 17, 2017 9:59 pm

Dyno
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Dyno 2.JPG
Dyno 2.JPG (141 KiB) Viewed 4260 times
Dyno 1.JPG
Dyno 1.JPG (139.04 KiB) Viewed 4260 times
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GazM3
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Re: M30 B34 Engine Rebuild

Post by GazM3 » Mon Dec 18, 2017 2:01 am

Nice job there. Pretty handy power but the single TB and plenum will be a restriction once to about 5300 although u can rev it harder power will plateau.

If u stumble on a set of itb and a Paul Burke adapters it would make power to 6500-7000

As a street engine it’s plenty as it is. Very tasty.
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Re: M30 B34 Engine Rebuild

Post by Mamod17 » Sat Feb 23, 2019 1:27 pm

That engine bay is immaculate :D :D
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Re: M30 B34 Engine Rebuild

Post by Shipper 01 » Tue Feb 26, 2019 7:35 am

Just noticed this thread after following the link from Dennis's Group C build thread. Love the car. That engine bay is the best I have laid eyes on. Incredible job!

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