[imagoonmx6]

http://autozine.kyul.net/technical_school/engine/smooth2.htm

Read this info on 4 cylinder engineering.

~Chris

 

[anarchyx34]

Fascinating... Ok, who wants to take on the twin balancer shaft mod?


On a side note. My volvo's 2.3l SOHC engine (B230FT) dosent have any balancer shafts, however the DOHC version (B234) does, both located to left of the crank (at least according to where the sprockets are). I've driven one and it's definitely smoother than mine.

 

[Guest]

The F2t has a pretty balanced crankshaft, Problems from engine balance would not appear in the 0-6500rpm range.

Exhuast restriction due to a miniscule turbo, and a long stroke is why the F2t won't make power at high revs.

The long stroke is why the F2t doesn't rev up quick like a honda, or my B series Protege.

Besides, the additional drag from adding balance shafts would probably slow the engines rev down even more.

 

[SleepCounter]

Exhuast restriction due to a miniscule turbo, and a long stroke is why the F2t won't make power at high revs.

Mostly long stroke (piston travel). Even with whammier turbo, that piston travel will consume too much of the additional power created at higher Rs.

The long stroke is why the F2t doesn't rev up quick like a honda, or my B series Protege.

And counterweights (longer stroke means larger counterweights). And heavy flywheel/harmonic balancer.

Besides, the additional drag from adding balance shafts would probably slow the engines rev down even more.

And add rotational inertia (where's our wannabe engineer?) to make it rev up even more slowly. And make for a heavier car which will therefore accelerate a little more slowly.

I think the first thing I would do were I racing a Mitsu with balance shafts is throw them away. They're there mostly for a little more "refined" feel to the car (less buzzing at highway speeds), not for performance.

What the referenced article says, I endorse in the main. Raced and built flat 4s (VW) for a couple of years. All you need to do when you switch pistons in a balanced engine is equalize piston weights.

 

[Guest]

I touched on the counterweight issue on the top of my first post.

I have a subaru that doing a headgasket job on in the next week or two. Fasinating motor, Maybe you can elaborate on the advantage of running a flat 4 instead of a v4? Is it just for the mentioned engine balance, or does the angle of the cylinders do more than that?

Back to balance shafts...I agree with getting rid of them, its really to bad A12192341231832712 (or whatever) isn't around anymore to argue

 

[SleepCounter]

I have a subaru that doing a headgasket job on in the next week or two. Fasinating motor, Maybe you can elaborate on the advantage of running a flat 4 instead of a v4? Is it just for the mentioned engine balance, or does the angle of the cylinders do more than that?

My experience is limited to that air-cooled flat 4 designed by Ferdinand Porche. That guy was a genius.

Best I can tell, the only other advantage is low c/g.

Disadvantages are mainly the width of the engine (even the VW -- pushrod engine -- is wide enough that you cannot reach some head "bolts" when engine is installed in order to retorque, and you need to retorque aircooled engines often.)

The article cited mentioned manufacturing/cost disdvantages -- that would be twice as many cams needed for ohc, twice as many heads as I4, twice as many exhaust manifolds and, of course, twice as many head gaskets.

Ride a Gold Wing (or 2-wheeled Beemer) to know how smooth a boxer can be.

 

[SleepCounter]

Miss Spell, etc

****ens of a sig, there, 'Swat.

Sorry, I meant "Dïckens of a sig". Furshluginner censor software.

 

[anarchyx34]

advantage is low c/g.

Disadvantages are mainly the width of the engine (even the VW -- pushrod engine -- is wide enough that you cannot reach some head "bolts" when engine is installed in order to retorque, and you need to retorque aircooled engines often.)

On Subaru's, the motor has to come out in order to change head gaskets. Quite a PITA.

 

[Guest]

I know i have to pull the motor to get the heads off, but its a simple motor to pull from the looks of it, and plenty of room to work.

If only Subaru had used head bolts instead of head studs, I probably would be able to get it off without pulling the engine....maybe.

They use OHC in the subaru's, two tiny cam's. Reminds me of working on a 2 cylinder OHC propane buffer once.

Anyways...funny we got onto the subject of boxer motors.

P.S. Thats only Chapter 1 sleepcounter, I might put chapter 2 on in a week or so

 

[SleepCounter]

a simple motor to pull

Well, this thread is well and truly hijacked.

Beetle engine held in with 3 bolts and a nut. No motor mounts (just hangs there on the end of the transaxle -- ain't magnesium wonderful?)

Throttle cable, gas line, alternator wiring, coil wire. That's it. Exhaust stays on the engine, starter stays on transaxle, no water lines to disconnect.

I've pulled one in 3½ minutes and I've seen a complete switch between races in less than a minute and a half (5 guys thrashing)

This IS the "other cars" area, ain't it?

 

[Guest]

Heh, I'm sure the lack of mounts causes some stress problems in hi-milage bugs?

This motor isn't that simple to pull, I'll have to unbolt the two exhaust manifolds and undo the water lines.

Other than that, it looks like undoing the usuals (throtte, gas, wiring harness) and unbolting the mounts/tranny.

 

[SleepCounter]

Heh, I'm sure the lack of mounts causes some stress problems in hi-milage bugs?

Naw, the engine only weighs something like 177 lb complete. Magnesium cases, aluminum heads. Transaxle case also diecast magnesium. Bellhousing magnesium. The engine bolts on to the bellhousing. Raced 'em off-road and despite some incredibly hard landings after some spectacular aerial manoeuvres, never managed to break a case.

The older transaxle cases sometimes succumbed to too much torque and tried to push the diff out the side of the case, but mostly everyone who raced used the Type II (transporter) transaxles.

When I hung a 12A rotary (~195 lb +coolant) on the bus transaxle in my single seater, I put mounts on the engine, just in case.

 

[anarchyx34]

I know i have to pull the motor to get the heads off, but its a simple motor to pull from the looks of it, and plenty of room to work.

If only Subaru had used head bolts instead of head studs, I probably would be able to get it off without pulling the engine....maybe.

They use OHC in the subaru's, two tiny cam's. Reminds me of working on a 2 cylinder OHC propane buffer once.

Anyways...funny we got onto the subject of boxer motors.

P.S. Thats only Chapter 1 sleepcounter, I might put chapter 2 on in a week or so

What kind of subaru is it? I may be able to give you some advice. Most of them use bolts, not studs, but if it's a loyale based car I dont actually know as I've never done one.

 

[Guest]

Its a legacy, the EJ22 motor. On second thought, I believe it is bolts.

Still won't have enough clearance unless I cut my wheel wells

Pulling the motor is no biggie, just have to make time to do it.

 

[SleepCounter]

On Subaru's, the motor has to come out in order to change head gaskets. Quite a PITA.

On the other hand, how much would you have paid for it if R&R heads was 1.6 hrs in the flat rate book?

 

[gtdreamdxbudget]

beetle engines are great...unless one catches fire, ive seen a couple that have and it isnt pretty, large portions of the rear oddly missing. as for a performance bug, the way ive found best is scrap the teardrop body, make a singleseater tube chassis and rotate the engine/transmission assembly 180 degrees,(( as well as change a few gears in the differential to accomadate<-spell check.. for the change of direction, and produce a mid engine open wheel car that weighs in at 1000 lbs. not too expencive..and not street legal, though they're a lot of fun.

 

[Jbrun64]

Exhuast restriction due to a miniscule turbo, and a long stroke is why the F2t won't make power at high revs.

yup. Balance shafts are for smoothness, not power. If you want power, get rid of them.

My dad has a 1973 superbeetle. That thing is sweet. You have to manually adjust valve clearance, and it has like 45-55 hp i think. They last forever too his is restored somewhat though. No big things to worry about, just make sure the fan is always spinning otherwise its gonna fry.