McArthur Boys BMW

[Tim_M]

Well one trip to the drags resulted in a whine and a bit of driveline vibration. So out came the diff again...back to the rebuilder for a look see. Amazing I had it out in less than an hour. Very easy to work on...



Still an M model:



Just in case, I sourced another 3.91 diff (open) for $90...I like it!:



Will also attempt to have the exhaust coated to preserve the system...some heat management as well:



Additionally, nearly complete on the cold air fence...my Dremel was smoking!

[Tim_M]

I should add this car is not to be a 'drag' car...just want to see the performance results compared to the auto / 6 cylinder. Next on the agenda is to fine tune the handling a bit more...until we run out of time.

[blacksheep-1]

Well done,
Former CEO Bob Lutz of GM once said. "the problem with the current car industry is that you don't have a 15 year old kid crying his eyes out, begging his dad to buy a Lumina". They are to busy on their phones and don't see have the compassion for cars like most of us did...also noting the fact that a Lumina was a pretty boring car.

[Tim_M]

Blacksheep: Thanks and agreed. It has been one of the most rewarding projects due to the interaction...a V8 powered E36 helps much!

Diff is nearly complete...the pinion was tight on the ring gear hence the noise. He swapped the gears nonetheless with fresh bearings. Hopefully back by Thursday.

Exhaust coating is not inexpensive - but it will preserve the finish and it looks clean! Back by Saturday morning.

In progress shots of the cold air fence:



Temp install:

[Tim_M]

Some updates...exhaust has been coated:





Installed...the easiest setup I've work with!:



Also completed the cold air fence deal:



Easy 50 degree drop in intake temps at idle and 30+ at speed (95 for a 85 degree day). Worth the effort and looks pretty good!

During our inspection...came across this on the right front!:



We are running -3 degree of camber...supposed to be zero toe...wonder if it actually isn't. Only the right side...and the car drives straight to boot! Nonetheless, purchased a pair of inexpensive shoes for the time being.

Should have mentioned the re-rebuilt diff has been reinstalled. New used gears with a bit more lash - hopefully a bit more durability. 3 bolts and its in...possibly a failure point too!

2400 miles and just shy of 20 mpg. 1 mpg less than the auto / 6 cylinder. Keep in mind WOT is much more entertaining and common with a bent 8 than the slush box 6.

[CaptainSquirts]

Wouldn't more lash(backlash) mean there might be wear on bearings/gears? Also how was the contact pattern?

[Tim_M]

Daniel: he commented this one is set up with a bit more lash...possibly a poor use of words. I'm not a gear expert nor did I get a chance to view the pattern (I picked it up ready to install). I would expect he set the contact pattern toward the inside of the ring gear so when the teeth deflected it centered under load. Bearings should be no issue...unsure of increased wear otherwise.

I'm guessing the crush sleeve that this diff uses wasn't up to full torque spec when we subjected it to some moderate launches...moving the spec slightly. Admittedly we bent the 'thrust' bolt so some force did exist...we are currently running rock hard, aged Firestones (245's) and an OEM Chevy LS7 clutch. I was surprised we had any issues as this should not be too harsh.

He was very accommodating to the situation...I knew fully that a visit to the drags generally means no warranty should be expected. I'd go back to him again certainly (Rutlusky Auto in Lutz).

We will look into 210 mm diff upgrade to the car. We've learned European M3's received 210 mm (ring gear size) compared to the US spec of 188 mm. That will be down the road...

[Tim_M]

Busy day today...mounted new front tires, 4 wheel alignment and then to The Heartbreakers:



Verdict is in! Little 5.3 with a cam pumped out 340 WHP/338 WTQ SAE corrected on a Dynojet! Operator's calcs 398 HP at the flywheel which is right in line with the Hot Rod build of this engine, making 410 crank horsepower. The single 3 inch likely gives up some power.



The Holley HP EFI ran spot on directing the fuel curve as desired. We tried 26, 28, and 30 on ignition timing...30 was the winner.



To say we are satisfied with the performance is an understatement. With the previous discrepancies repaired - a 12 second run is likely, but unfortunately, won't happen for a spell.



And the exciting video:

https://youtu.be/IyeaHG-n6DQ

[twistedwankel]

That is so cool to be able to check those things. Here in Hernando all we have is a semi monthly tractor pull dragging a sled.

[Tim_M]

It is indeed. Many an engine has failed due to the 1500 pound roller strain.

Tractor pulls were a constant in the midwest when I was a kid...Betty's Headache was a crowd favorite. I didn't understand at the time that black smoke on the super stocks was a good thing. Admittedly, I was attending just to pick up the aluminum cans at a nickel a piece...buy some candy!

Fun project!

[Tim_M]

I despise wiring so put off hooking up a tach. My assistant digs welding (solder) and fire (heat shrink) so we spent a few hours pulling wires and connecting the 4 wires required for the Dakota Digital converter box.

The Holley HP provides the 8 cylinder signal...the converter box updates to 6 cylinder signal which the OEM tach reads.

Running the one wire to the back of the cluster took the majority of the time...also tended to the loose passenger side panels - actually using all the screws required. Amazing what that does for the elimination of rattles.

Even more fun to hear the V8 when you see the rev counter needle move in rhythm!

Might have to look at the temperature gauge next...

[twistedwankel]

I installed the new air dam on my vette backwards so at speed the wind dropped it into the pavement and ground 1/2" off it. It looked right to me and the old one was installed that way until it broke off. It was interesting sounding at the finish of the last event when I hit the brakes hard too. There will be no engine transplants in my future.

[Tim_M]

Doug - it happens to all of us.

I was so anxious to drive my newly installed drivetrain of my Nova...neglected to include a radiator support on my also brand new aluminum Dewitt radiator. All was well for 10 miles of easy cruising...a bit too much throttle pulling away from a light ended my drive with this:



Suffice to say, it took a year to finally pony up the cash for a replacement (stuck with the *original* brass model). It was rather impressive, felt like I was a WWI pilot getting shot down as the hood was off and when the radiator contacted the engine driven fan, coolant covered the windscreen something fierce!

Let us not share that with my assistant! Oh that's right - this radiator hangs on my wall of what not to do...along with a few other similar items...

Nonetheless, assistant and I spent last Saturday outfitting the M3 project with a working heater! Low priority on a FL car, but since we will be transporting this car to Iowa (enroute now!)...warm toes are a requirement in the incoming single digit weather.

BMW incorporates a heater control valve to cut off hot coolant from the interior mounted heater core. We decided to bypass this device to keep things simple - we figured the core was going to leak anyway and have to yank all this heater stuff back off once complete.

Well, 12 feet of 5/8 and 3/4 hose and a bunch of clamps...we were in business...and surprisingly no leaks! It works as advertised! Although the heater control valve is a requirement...enough warmth is produced by the heater core with the heater in the off position that the car stays warm even in currently 39 degree temps on the highway...

No images as our tomfoolery was not very 'clean'...alluding the expectant removal when the likely original core pops a leak. Note the original heater control valve never worked...no heat in this car prior. We wondered why after a flush, control panel replacement, etc. Once we pulled the hoses on the 6 cylinder install...it became evident:



Trip update...800 miles covered...average of 24 mpg. Adding some timing and leaning the AFR really helped!

[Tim_M]

See I didn't close this thread out...

Car made it to Iowa without issue last December. 24.3 mpg at 80 mph - no oil used. Yes the car wandered, the heater core fogged the inside of the windshield, and no cruise, but it was uneventful.

Cold storaged...until this weekend due to a visit. L33 engine fired right up (with a small fuel leak - screwdriver fix). Changed the oil, bypassed the heater core and cleaned the cob webs out. Told the assistant I would do a burn out for him, I did two and about a dozen run thru the gears at 6500 rpm.



A relaxed wash (instead of the previous 10 degree December cleanse) and back into storage...





LS swapped M3 is a sweet package.