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BRAT Sandrail

Posted: Tue Sep 16, 2008 2:09 pm
by tundrawolf

I received a poor condition 1978 Subaru Brat recently..

It took me an entire day just to vacuum out all the packrat debris from the engine bay alone (You could not even see the engine!).

It has been sitting in the harsh High Desert of California for 20 years, unattended, no windows (Passenger window is there, but wasn't rolled up. All other windows smashed out!) or gas cap.

So.. Looking at this dented old hunk of metal, I was at a loss with what to do with it. I made a reasonable effort (Flushed gas tank and filler line, flushes gas line, replaced filter, oil change, dissassembled and cleaned carb) to get it started-and it started right up! WOW!!

As I examined it more, I found that it had an advanced independant suspesnion, both front and rear.. I like the small 4 banger for gas mileage..

So a still small voice inside me said one day-weld a tube frame for it and make it an AWD sandrail.

I am going to make it a plated sandrail, which means I can also drive it on the highway. I plan on using the Subaru driveline in it's entirety, but with my own "body".

I keep reading online that this powertrain is advanced, even compared to some vehicles today.

How is this so? Does it use limited slip differentials? I do like the 4wd on the fly transfer case, that is a plus.

Anything you guys can tell me about this vehicle is appreciated!

Re: BRAT Sandrail

Posted: Sun Sep 20, 2009 8:26 pm
by flat4x4onthefloor
Hey, that's a great idea ! Keep us posted with your progress, I'm interested to see what you can come up with, as I've been kicking the same idea around for quite some time...
The tiny EA engine in it (as stock) will possibly run forever if properly maintained, as they don't really make enough power to hurt themselves...helical gear-to-gear timing for the valvetrain, rotor type oil pump, low compression, got a crankshaft only 13" long (how you going to warp that with 80 HP?), it's water cooled, has an electronic ignition...just change the oil, don't run it hot, and check valve lash every 3 months ( whether it needs it or not ) and they will go and go and go....look on the engine block near the distributor to ID the engine, EA 71 or EA 81 (1600 or 1800). And weighs in at just over 100's that for the power/weight ratio ?
The dual-range tranny is awesome, just awesome! To change up you keep the steering straight, press the clutch, let the engine speed drop to near idle...gently (you'll feel it synchronizing up) pull the differential shift lever, release the clutch, and you're in 4WD-HI...repeat this again, and you're in 4WD-LO (hence "Bi-drive Recreational All-Terrain" acro-name!)! I don't hesitate to drop mine into 4WD-HI at 70mph if I enter bad weather on the interstate. Just remember to take it out of 4WD before making tight-radius turns or you'll experience driveline bind...try to push through that and you'll chronically replace front cv joints. But if you've got just 10% slip on the surface ( sand, mud, snow, ect..), then no worries !
Not sure how the mechanics inside the little gearbox work to change the Front Wheel Drive into a doesn't have the traditional transfer case associated with a 4WD, instead it uses a central differential like a FWD transaxle. The engineering behind it is a mystery to me, but I was told a pin is inserted into the center differential to lock it down, and a gear slides forward to engage the tailshaft, I just know mine is 26 years old and works perfectly in all ranges !