Mk1 Decisions... 1.5 or 1.6

[JamesT]

I need to decide what engine to put into my '78 Rabbit. A 1.5 n/a or a 1.6 n/a. This is going to be my low/slow car. I'm keeping the '93 1.9 TD as the reliable and comfortable car, so the AAZ swap has been ruled out by the wife.
I have a 1.5 n/a attached to a 4-speed. It leaks oil, but I drove the donor car and it runs like a top, started easily from cold in <10^o weather, and pulls alright for an old sewing machine.
I also have a 1.6 n/a attached to a 5-speed. The engine came from an '81 caddy, and I was told it ran well, but I never drove it. It cleaned up nicely, but it has been sitting for a couple years. I'm sure it would run with a bit of attention.

So the real questions:
Is a 1.6 noticeably more powerful than a 1.5? As in enough to make it worth putting a non-year-correct engine in the car.
The other question: Am I crazy for wanting to put a 4-speed into my car? I have a 5-speed in it right now with the gasser, but its not original to the car, and 5th gear is kind of useless in the thing anyways. With the FO gearing, I shift into 5th at 110km/h, and then the engine doesn't have enough power to pull it past 130 with that gear, so I have to use 4th to go any faster. The result is I only use 5th when coasting down a hill or on perfectly flat road at 110. Anyways, transmission ***ing aside, will I hate the 4-speed with the diesel on the highway? I believe it's a GC.

[Blocksmith]

I need to decide what engine to put into my '78 Rabbit. A 1.5 n/a or a 1.6 n/a. This is going to be my low/slow car. I'm keeping the '93 1.9 TD as the reliable and comfortable car, so the AAZ swap has been ruled out by the wife.
I have a 1.5 n/a attached to a 4-speed. It leaks oil, but I drove the donor car and it runs like a top, started easily from cold in <10^o weather, and pulls alright for an old sewing machine.
I also have a 1.6 n/a attached to a 5-speed. The engine came from an '81 caddy, and I was told it ran well, but I never drove it. It cleaned up nicely, but it has been sitting for a couple years. I'm sure it would run with a bit of attention.

So the real questions:
Is a 1.6 noticeably more powerful than a 1.5? As in enough to make it worth putting a non-year-correct engine in the car.
The other question: Am I crazy for wanting to put a 4-speed into my car? I have a 5-speed in it right now with the gasser, but its not original to the car, and 5th gear is kind of useless in the thing anyways. With the FO gearing, I shift into 5th at 110km/h, and then the engine doesn't have enough power to pull it past 130 with that gear, so I have to use 4th to go any faster. The result is I only use 5th when coasting down a hill or on perfectly flat road at 110. Anyways, transmission ***ing aside, will I hate the 4-speed with the diesel on the highway? I believe it's a GC.

A GC, you say? YES, you will hate it on the highway. Plugging the numbers in at scirocco.org, given a 165/65/R13, you'll be running the motor at over 3500rpm to cruise at a paltry 60mph (if it's got the .91 4th, then still over 3300rpm). Not so much fun, to my way of thinking.

You didn't mention what code the 5spd is, but I would pick it anyway. I can't imagine it'd be worse than the GC.
If you're worried about power in 5th gear, put a turbo on it 

[R.O.R-2.0]

I need to decide what engine to put into my '78 Rabbit. A 1.5 n/a or a 1.6 n/a. This is going to be my low/slow car. I'm keeping the '93 1.9 TD as the reliable and comfortable car, so the AAZ swap has been ruled out by the wife.
I have a 1.5 n/a attached to a 4-speed. It leaks oil, but I drove the donor car and it runs like a top, started easily from cold in <10^o weather, and pulls alright for an old sewing machine.
I also have a 1.6 n/a attached to a 5-speed. The engine came from an '81 caddy, and I was told it ran well, but I never drove it. It cleaned up nicely, but it has been sitting for a couple years. I'm sure it would run with a bit of attention.

So the real questions:
Is a 1.6 noticeably more powerful than a 1.5? As in enough to make it worth putting a non-year-correct engine in the car.
The other question: Am I crazy for wanting to put a 4-speed into my car? I have a 5-speed in it right now with the gasser, but its not original to the car, and 5th gear is kind of useless in the thing anyways. With the FO gearing, I shift into 5th at 110km/h, and then the engine doesn't have enough power to pull it past 130 with that gear, so I have to use 4th to go any faster. The result is I only use 5th when coasting down a hill or on perfectly flat road at 110. Anyways, transmission ***ing aside, will I hate the 4-speed with the diesel on the highway? I believe it's a GC.

the 1.5 and 1.6 will be about identical power wise.. if you can tell the difference in 4hp, then the 1.6 is more powerful..

AVOID THE 4spd GC at all costs!!!

the 4A (RARE!!!) is probably the best geared 4 spd available..

GP, and GY are also good 4 spd trannies, but the GC, avoid it like AIDS..

the caddy trans is probably an FF, FN, FH, or FJ.. either of witch are AWESOME!

the 5 spd and diesel should do better than the gasser did.. the diesel will have more torque..

[RabbitJockey]

i have what ever trans is below right below the 4a, my 4th is the same as 5th in an ff or fn.  good trans for normal driving, the only time i can really *** is on hills, its like you just can't find the right gear.  5 speeds are much nice to drive.

[ORCoaster]

If I were faced with the parts you have I would go the 1.6 and the five speeder.  That is what I drive all the time and it does great.  I think of it more as a 3 speed with two over drives.  Super Overdrive? 

When it comes to a sustained hill and I am fairly well loaded the down shift to 4th is really still over the 1.0 ratio.  And it generally pulls just fine.  If I want to pass in the dual lanes I drop to 3rd and wind it out.  It will do 65 in  third without any trouble and shift up from there.

My 2 cents.

[Wayland]

Is the 1.6 an 11 or 12mm engine? If it's got 12mm head bolts it might be worth it just to avoid possible head gasket/block cracking issues in the future. In my experience, there is a slight but noticeable difference in power between the 1.5 and the 1.6. The 1.5 revs a little higher and seems to be happier doing so. I believe it's possible to get slightly better fuel economy with a 1.5 too.

[fatmobile]

With the FO gearing, I shift into 5th at 110km/h, and then the engine doesn't have enough power to pull it past 130 with that gear, so I have to use 4th to go any faster. The result is I only use 5th when coasting down a hill or on perfectly flat road at 110.

 This sounds like a 1.5.
 The longer stroke of the 1.6 provides more torque.
 Handles highway speed much better.
 A hill and a headwind with a 1.5 will really slow you down.
 Around town it's pretty zippy though.

[JamesT]

Thanks. I guess every vote was against the 1.5 and 4 speed. That almost seems like a good reason to do it.
the 1.6 is 11mm. It has the taller FF trans, which is geared taller than what's in the car.
I'm pretty sure it's a 1.6 in the car, as it says 1.6 on the block. It does, however, have nearly 1/8" crank endplay, so the gas's ass is grass.

A 4A 4th is the same gearing overall as the taller FF/FN/FH/ect.

I probably won't make a decision until I have to clean one up.

[Wayland]

Go with the FF for sure. You'll like it. My Kubvan has an FN, and even w/ the 1.6 it was pretty good, so in a Rabbit it should be golden.

[fatmobile]

I wouldn't use a GC 4-speed but
 there are several other 4-speeds I'd use.
 
 Might be a little better to use a 5-speed but see how much play there is in the axle flanges, pick the tightest one.

[CRSMP5]

differance in 4hp... aka 1.5 vs 1.6...... you will find hills a 1.6 never knew existed...

[bajacalal]

Is the 1.6 an 11 or 12mm engine? If it's got 12mm head bolts it might be worth it just to avoid possible head gasket/block cracking issues in the future. In my experience, there is a slight but noticeable difference in power between the 1.5 and the 1.6. The 1.5 revs a little higher and seems to be happier doing so. I believe it's possible to get slightly better fuel economy with a 1.5 too.

The early 1.6 were 11 mm, the later ones were 12 mm. 1.5 were all 11 mm.

I would pick the later 1.6. Think of it this way... VW invented an engine back in the 1970s and steadily improved on the design, it took some time for them to figure out what worked and what didn't. You want an engine that had the most engineering revisions put into it.

The switch was around '82 when the turbos came out (though the non-turbos got the larger bolts then too). If you have an early '80s car it's probably best to verify for yourself.

[JamesT]

differance in 4hp... aka 1.5 vs 1.6...... you will find hills a 1.6 never knew existed...

Hahaha, I used to drive an early baywindow with a 1.6sp. I know where all the hills exist.
Every rational part of me has decided to dump in the 1.6 and the FF, but the sentimental part of me is fighting for that 4-speed.

[R.O.R-2.0]

differance in 4hp... aka 1.5 vs 1.6...... you will find hills a 1.6 never knew existed...

Hahaha, I used to drive an early baywindow with a 1.6sp. I know where all the hills exist.
Every rational part of me has decided to dump in the 1.6 and the FF, but the sentimental part of me is fighting for that 4-speed.

dont do it.. you will regret it.

[JamesT]

Well, the decision was made for me (more or less). I decided to go with the 1.5 just because I knew it had been driven recently, and I'd actually done a start from cold on it. I checked the axle flanges of my 5-speeds and they were both sloppy. The 4-speed had tight flanges, and appeared to leak the least, so I used that one. Guess what? You were all right. I hate it.
It's fine around town and up to about 90km/h, but after half an hour at 100 on the highway, the drone is nearly unbearable.  What I need to do now is find a half decent transmission, preferably an ACN with the later style flanges but with earlier type mounting points and do the swap. Right now I'm using a 5-speed shifter base and linkage, so nothing needs to be changed there, and I have my old driver's side mount to use with the 5-speed.
That being said, with the four speed, the 1.5 seems pretty ballsey and isn't crawling up hills as I suspected. I actually think it pulls better than the 1.6 gasser.