Engine not pulling

[phaetn]

Finally, finally got the engine back together. Finally cured the burning coolant issue (likely at the intake gasket). I also put on a new head gasket (paper). Car is running after three weeks off the road.

I brought the head to a machinist where they put in new valves (stock size), Isky racing springs, new valve seals, and cut multi-angle valve seats. They also planed the surface.

I newly put on a 14mm spacer on the 32/36 carb, the originally was probably about 8 or 9mm or so. That should make for a longer plenum to draw more air.

So the car is running, but it's not pulling through the powerband. In fact, it just runs out of guts around 5k. It used to easily top out more than 1k more than that at over 6. It also feels sluggish earlier than this.

I had to take the Computronix distributor off to remove the intake while leaving the head on the second time I was changing a head gasket. After putting it back on, I took a timing light and checked btdc at 12° at idle, full advance at 34° (3200rpm) -- I have painted marks on the pulley to verify these, and check against the 0° long mark on the timing belt cover (which I know is good having verified TDC lines up with the mark). These are the right settings, but it runs rougher than if I put it much more advanced, but I know that's dangerous. I THINK I hear knocking when I left off the gas, but won't swear to it. I haven't changed jetting from what was there previously.

Given the history and symptoms what's the likely cause? Could it be lean and I need to up the jets? A multi angle grind is meant to breath much better and even add as much as 10hp to a 1.8L VW engine, from what I've read. Might it be an ignition timing issue?

I have confirmed valve timing multiple times -- it's spot on, even with the decked head. Crank is at TDC, aux shaft is 1 o'clock, intake pulley is 11 o'clock and exhaust at 1 o'clock, confirmed against the casting in the cam tower.

Thanks for any advice. The engine was great before, except it burned a tonne of oil on lift off (seals) and had a propensity to get coolant leaks in the head gasket. I'm hoping to get the engine back to at least as good as it was before.

Cheers,
phaetn

[phaetn]

I think I got the timing right -- but the header is leaking at the joint with the downtube. This might be affecting back pressure and that's why power is down.

I will see if I can get it welded by the weekend and go from there.

Cheers,
phaetn

[zachmac]

I know is is obvious but I assume you re-adjusted valve clearance after all of this? If you aren't getting the same lift you'll run out of juice.

[RRoller123]

A tiny amount of the exhaust cam being off will do this too. I was surprised how sensitive power was to this.

[phaetn]

I know is is obvious but I assume you re-adjusted valve clearance after all of this? If you aren't getting the same lift you'll run out of juice.

Thanks, actually it's not obvious. The machinist said it was adjusted to spec: .017-.019 on the intake and .019-.021 on the exhaust side. I had brought not just the head but also the cam towers with gaskets and gave them a bunch of shims across a range. He said he had had to use two of them.

That said, I haven't actually checked it. I suppose I should... It would be disappointing after spending the money if I had to re-do it myself, but maybe that's where I'm at...

Cheers,
phaetn

[ORFORD2004]

2 shims for 1 valve
Houston we have a problem

[phaetn]

He meant he had to use two out of the box that I gave him that had various sizes. Not two on one valve, but of the eight valves, he used the existing shims for six of them, and then swapped out two.

After the previous post I checked lash on intake valve #3 as it happened to be in the right position when I took the cover off. The engine was still slightly warm to the touch, but had been off for several hours. I know it's really meant to be measured stone cold. Anyhow, .017 was the result and is within spec of .017-.019. I imagine when it's cold that gap might widen ever so slightly. I can check all the valves tomorrow at the crack of dawn before work, but if one's right I'm pretty certain they all are as they said they did it.

Went out to the National Aviation Museum with a local airport (closed tonight) so I could have light in the parking lot and make loud car noises. Checked ignition timing. It's BANG on. 34° advance at 3200rpm; about 12-13° btdc at idle. Cam timing is also spot on, with the two holes in the pulleys lining up with the casting in the cam towers.

Only thing I can think off: Are the intake and exhaust pulleys different? I had three different ones from two different heads and they all seemed the same to me. Maybe I have an intake pulley in the exhaust, which would affect cam timing if they are different.

Only other thing might be carburation. I now have a 14mm spacer plus gaskets whereas before I had a smaller spacer (caliper indicated about 5.5mm in squished state). I also kept the previous jetting.

Oddly, the car sounds like it has preignitoon when I left off the throttle (I filled my 1/2 tank with 91 octane this am); it's also sluggish to pull through the powerband.

Still scratching my head over this one...

Cheers,
phaetn

[RRoller123]

The Intake and Exhaust Pulleys ARE different. There is a thread somewhere here indicating the markings and how to identify them from each other.

[phaetn]

Okay, that's clearly one of my problems. I must have an intake pulley on the exhaust side. There was no casting on it, but I did use the one with an "A" on the intake.

I had a plastic one for the exhaust (marked with an "S") but it's hole lined up with the metal one I was using so I thought they were interchangeable, despite the flange being on the back rather than the front. I had read to change the plastic ones ASAP as they can get loose and separate in the middle, leading to possible bent valves.

Looked up an old pic of my engine from last year and I can see things don't quite line up with that plastic pulley:

There's a white mark that was used for timing. I don't know it that's because the plastic pulley had shifted or what.

I either will have to change the current position of the metal pulley that's on there or see if I can get another one.

Quick question: What position should a given lobe be in on the exhaust side with the engine at TDC on cylinder #4? I can set things visually that way even if the hole isn't lining up and make a new indicator mark.

Secondly, can the camshaft be off by a rotation on the engine? I know they rotate at 1/2 speed relative to the crank.

I would think TDC is TDC whether on cylinder 1 or 4 and it only matters for ignition. In my case, with the Computronix waste spark it doesn't really matter.

Thanks and cheers,
phaetn

[rebar1111]

Just a final summary of what I have determined is factual.

1. The exhaust camshaft on a 79 2L has the distributor gear.
2. The intake sprocket sometimes has an 'A' on it. The dowel pin holding the camshaft to the sprocket is correct as shown in both Hayne's and Chilton's manual drawings. Using the dowel pin location/center attachment bolt location/ timing hole location, will determine which sprocket goes to which cam.
3. The crankshaft pulley uses part of the key for the timing belt sprocket to locate the pulley placement. Only a small portion of the key projects out from the sprocket and therefore the pulley can be jam fit into the wrong angle.

The engine is back together following the above information. Thanks to all for the encouragement.

[phaetn]

Just a final summary of what I have determined is factual.

1. The exhaust camshaft on a 79 2L has the distributor gear.
2. The intake sprocket sometimes has an 'A' on it. The dowel pin holding the camshaft to the sprocket is correct as shown in both Hayne's and Chilton's manual drawings. Using the dowel pin location/center attachment bolt location/ timing hole location, will determine which sprocket goes to which cam.
3. The crankshaft pulley uses part of the key for the timing belt sprocket to locate the pulley placement. Only a small portion of the key projects out from the sprocket and therefore the pulley can be jam fit into the wrong angle.

The engine is back together following the above information. Thanks to all for the encouragement.

???
I think you might have meant to post in another thread/topic.

Glad we're learning together, though.

Cheers,
phaetn

[phaetn]

Finally got it! Thanks to CanadaDan for his help and expertise. Drove out to his place and we solved it pretty quickly.

Car had been way loud and didn't pull right, plus I could hear knocking at times.

Handily, he happened to have someone else's 1974 Spider on site so we could make a direct visual comparison.

Not only was the exhaust pulley off by a tooth (had to look and see the dowel hole barely peeking through) because I was using a metal intake pulley, but as it turns out I was off by a tooth on the crank, too, so intake was also affected. Egads! I can't remember once we discovered the crank was off it meant exhaust was now good, or if it was even worse and off by two teeth.

It had all looked good and like it lined up to the timing belt cover 0° notch, but it turns out it didn't. This was with my using a scope camera and confirming TDC. Only by comparing to the other car did we have a working point of reference and we could see the crank pulley and that it needed to line up differently to a point on the block. It's so easy to be off by just a tooth but it makes a huge difference!

Since the crank was off, that, in turn, meant my "bang-on" ignition timing was off (hence the pre-ignition). It was lining up with the mark, but too far advanced.

Now it's all good!! Great run on the highway on the way home under full song (boy I love going under bridges!) and odd not to have a trail of blue smoke as I lift off throttle, since it's had leaking valve seals for as long as I've owned the car.

Cheers,
phaetn

[AriK]

Great news! Sounded like quite the challenge ! Glad it's over. Will be glad to follow behind you next week without the toxic human repellent.

[spiderdan]

Great news.
What would we do without our Canadan?
AriK, if you miss or need to follow a bit of toxic human repellent... follow me!