650

[Dave G]

Hey that's the ticket! I eased off the spring in the VAF quite a bit and I've got it idling OK (in neutral, anyway). Managed a spin around the block, but the idle needs to be speeded up more. I'm going to find a longer idle adjustment screw...

What I really need is a different spring for the VAF, with about half the strength of the original. As it is now, the engine still won't rev up very high on it's own, but if I manually rotate the air vane open while opening the throttle, it does. Sounds great, in fact.

Kinda wish I was working with a carburated engine instead...

[lilred]

what does it sound like. harley, briggs, festiva engine firing on two cyliders, ect

[Nerd Racing]

man I hope you can get her to rev and idle, I wanna see video!! :twisted:

[Dave G]

what does it sound like. harley, briggs, festiva engine firing on two cyliders, ect

Sounds perfectly normal. :roll:

I've done some more tweaking of this and that and have got it sort of drivable. I think the engine itself is just fine, and strong enough for driving like an old lady sort of stuff. I've been driving around on side streets near the house a few times and it's OK. The problems are with support systems, and due to reduced intake volume and reduced vacuum.

I need to read up on the automatic transmission - what does it do that reduces the idle speed so much? I know there is drag standing still in gear, but it also seems to effect the idle when rolling. This car had the same problem with the other engine - idle speed drops way, way down in gear. There has always been a plugged rubber hose sticking out the top of the transmission - looks like a vacuum hose maybe. I need to figure out what it is and what it's supposed to be connected to.

[pole120]

Have you considdered that the holes you drilled into the pistons may not have been big enough for them to operate as if they were'nt there? Could it be that the drag of them not moving the air efficiently enough is enough to slow idle and make the engine work too hard to sustain itself?

[Dave G]

Have you considdered that the holes you drilled into the pistons may not have been big enough for them to operate as if they were'nt there? Could it be that the drag of them not moving the air efficiently enough is enough to slow idle and make the engine work too hard to sustain itself?

No, it idles happily in neutral, and otherwise seems to be running fine. I just ventured out on a 45 mph road for a while - yee ha! It's just that in gear the idle drops way down. With the original engine, if I set the idle to say 900 rpm in park, it would drop down to 300 rpm or so in drive. I just got used to it. With the 2 cylinder it's probably down around 200 - 250 rpm, and shakes like crazy. I've got the idle speed set to (estimated) 1000 rpm in neutral now.

I've improved things a little bit by plugging up that big vacuum leak, the PCV valve outlet.

Here is the mystery hose on the transmission:



Anyone know what that is, and whether or not it's supposed to be connected to something?

[25Horseplay]

Looks like a vent.

[Nerd Racing]

That is a breather vent so that pressure doesn't build in the transmission. you might not want to put Vaccuume to that

Have you gotten it to rev higher since you adjusted it?

[Dave G]

OK thanks - that makes sense about the breather, as the "plug" in it is a tube with a loose cap on it.

As for making it rev up, yeah, I can get it going very fast if I'm standing there with my finger in the VAF opening the vane with the throttle. But on it's own it does not have the suction to overcome the spring. Need to do more experimenting... maybe another spring to act as a "counterweight".

As it is, it runs pretty well at speed (a whole 45 mph so far!). But it has no balls at all taking off. Of course, it's not going to be a powerhouse, but I think it could have quite a bit more if it was getting more gas at lower revs. I think tweaking the VAF is the answer.

[Nerd Racing]

why not try bigger injectors? might be a little pricy, maybe someone will donate some old B6 or B6t ones?

[Gforcefd]

His problem isnt the size of the injectors, his issue is trying to fool the computer into thinking its getting more air than it is, so his injectors will spray at close to the same capicity as in a normal 1.3

Logan

[skeeters_keeper]

While i think that the VAF is probably your problem, and that you should be able to fix that with a lighter weight spring, i was wondering about the idle.... with only half as many cylinders firing wouldn't you expect to need a heavier flywheel in order to keep it idling without increasing the idle speed a lot?
I understand you have it idling fine in neutral, but when its in gear with that extra drag the engine probably needs more rotating mass to keep it from bogging down. I know on my dads old 2cyl bikes they have a heavy flywheel so that they can still idle real low. of course it takes longer to rev up then, but your not going for fast acceleration

well, even with those small problems, the fact that you got it running pretty well is amazing.... good job! can't wait till you get the little quirks worked out!!!

[Dave G]

Well I've driven it around 20 miles this morning. Stopped and fiddled with the VAF a couple times while out. I think I've got it about as good as it's going to get without actually modifying the thing (the VAF). Although it *can* be driven around town on a Saturday morning, it's lack of acceleration makes it impractical; just too slow starting out to be safe in traffic. I did get it up to 55 for a little while though. (In a 45 zone - wouldn't that have been ironic to have gotten a speeding ticket?)

The automatic transmission is not helping one bit, of course. Need more gears & no vacuum shifting controls! The engine, however, does seem to be running well, and I know it's got a lot more power possible with some tuning work. (Again, if I work the VAF and throttle by hand, it really revs up.)

I think what I'm going to do over the next few weeks is fix up the car's original engine and put it back in for the winter. Then get another VAF unit from a junk yard and tinker with it so it takes half the effort to operate the vane. Then in the spring swap it into a 5 speed car and see how it does there.

[Kraig]

As mentioned earlier, I think the 5 spped is the way to go. Waiting to see your final results and mpg!! Neat project.

[25Horseplay]

Well atleast you can fix all the oil leaks in the old engine!