Puzzling combination of Type IV issues - it runs this advanced?

[Squeeze Cheese]

Hi all! I've been searching the related forums and can't get a sense of what I should do, maybe the type IV engine gurus can offer some insight:

I carefully rebuilt my 78' Westy's 2.0 over the course of the last 3 months using a combination of Tom Wilson's book, the Raby video, the Bentley, lots of patience, and the best parts and advice I could find.

Now the engine is in and running, but idles low, has low power, and runs hot. The only thing that seems to improve this is advancing the timing beyond normal.

Engine: It's a completely stock GE 2.0 using the original fuel injection, the only exception being a new Web Cam 107i and lifters, which is a mild "255 Duration, .430" Lift" cam, the only option for those that want to use hydraulic lifters and stock FI. Len Hoffman HAM heads with both coatings. New Mahle P&Cs. The 72-74 exhaust heater boxes and stock muffler. Blueprinted oil pump. And I took great care that there are no missing parts, new vacuum and fuel hoses. Timing set to 28 BTDC with the advance hose disconnected. Hydraulic lifters set to 3/4 turn past valve stem contact, recommended by Web Cam and are pumping up correctly. Currently has less than 100 miles, running 89 octane and Brad Penn 20-50W, outside temps are at least 90F.

Low idle issue: 500RPMs cold, barely running, maybe 700RPMs warm, with the throttle body bypass screw turned out as far as possible without falling off or sucking air through the threads.

Low power issue: Almost no oomph in the low end, hard to get going from an uphill stop, but picks up a bit around 2500RPMs and from that point just feels like an old tired engine.

Running hot: CHTs are higher than normal, even after the thermostat fully opens. Around 380F in stop and go and I saw it peak at 410F going up a nominal city hill. I don’t think it would cruise on the highway below 400.

Some other pertinent conditions: When I sent my deck height to Len Hoffman, which was .028" using the .009 case-to-cylinder gasket/shims but not including the 0.8mm step in the heads, he said removing the gasket would give me a total deck height of .047" and a compression ratio of 7.6:1. (Does that sound right?) That’s outside of the 7.75-8.25:1 recommended for the 107i cam, but Len said it would be okay. I’ve performed two compression tests and leak down tests, when the engine was slightly warm and one after driving for ten miles. Both compression tests are showing 85-90 PSI all around. The rings may not be fully seated but I was expecting to see much more, right? The leak down tests show around 20% with my possibly inaccurate HF tester, but further I can’t hear or feel any air escaping, even with my compressor set at 90 PSI.

What I've tried: I’ve checked twice and verified, no vacuum leaks. I even disconnected and plugged the brake booster connection to eliminate that. Interestingly, I did get a momentary increase in idle RPMs when I let some air escape past my finger, but I couldn’t sustain it.

I verified that all four spark plugs are firing and that all four injectors are squirting, although I did not check their spray pattern nor did I have them professionally cleaned during the rebuild.

I checked the AFM for indications of mixture issues, at the low idle giving a slight push to the wiper either way and the engine didn’t “want” a richer or leaner idle mixture; it seemed to be set at the best location. The idle mixture screw had no effect. The spark plugs when removed are a normal looking light brown.

I checked the AAR during cold and warm-up and the valve is closing correctly.
Dwell is 50, using the Pertronix Ignitor kit.

Len suggested two things, cam and crank gears being installed one tooth off or a badly retarded ignition setting. The first one would have been terrifying but it turns out you can go through the distributor shaft with an endoscope and eventually find the right spot to witness the meeting place of the two gears and mine are installed correctly.

His second suggestion got me thinking so today I tried more advanced timing just as a test, because except for the low compression test results, the engine basically ran like the timing was far too retarded. Like I said, I had my timing set at 28 BTDC full advance with the hose off. Advancing it to 30-32 BTDC gave some increase in RPMs but it wasn’t until 42 BTDC total advance (hose off remember) that the idle came up to 1000RPMs and actually sounded pretty good. I gave the bypass screw a turn in to get to 900RPMs and went for a drive. And it ran great! Good power, and CHTs were about 20 degrees cooler, and no pinging under load. For the first time it felt and sounded like a healthy engine, and it felt like I could have gone even more advanced, but I don’t dare till I figure this out. I drove to a buddies house and used his strobe light against mine and it showed the same, mine is accurate.

So now I’m wondering, why does it run great with the ignition timing set at 42 BTDC max advance, hose off, instead of the normal 28, where it runs bad? Is a more advanced ignition timing required in some cases? Is that sustainable? And if so, how do I find the correct setting for my engine?

And… what’s up with the low compression test results? Is 85-90 (and no detectable leak down) acceptable for my engine set up?

Any ideas on what I should try next?
_________________
63' Ragtop Beetle

78' Dakota Beige Westy. “Skills” EJ25 engine conversion w/ zero mile factory short block, Delta 1000 cams, heater core and modified Gilmore AC. Matt Steedle 091 transaxle upgrade w/ 4.14 ring and pinion, Folts aluminum gear carrier. General Grabber AT2s on stock wheels. Solar powered aux battery w/ inverter.

[busdaddy]

I'm thinking your fan keyway is missing, you are looking at the wrong mark, someone's had the fan apart and put it back together wrong or the pickup is on the wrong lead.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[Squeeze Cheese]

[SGKent]

Typical when someone changes things from or near stock. The stock hydraulic cam has an advertised duration of about 195. You chose a cam with an advertised duration of 225. That drops vacuum at the low end that is needed to open the AFM. The advertised duration on that cam is 255/255 degrees. I use the 142 solid lifter on my bus which is advertised at 247/242. Even that lowers the vacuum signal at the door enough to require tuning the AFM. Your AFM might have been lean to begin with and your cam duration could have made it leaner.

You used Pertronix instead of points. That CAN alter the waveform that the ECU uses to shape the injector pulse. How that would affect the ECU I can't say. Pertronix can't either - they just put a disclaimer on their site doesn't work with all fuel injected engines.

The way I see it until you put an air to fuel meter on the engine to see where you are, you won't know if this is a cam and ignition driven performance issue. I am not saying that it is but I am saying that it could be and you need to measure the air to fuel to know.

Did you verify where TDC is on the pulley while you were assembling the engine? Using .020 drop on either side of TDC and making a mark on the flywheel when building - a sharpie will do, you can spilt the difference and get TDC. Then when it is full assembled you can compare that to where the pointer is on the shroud. That is how I do my engines to verify TDC.
_________________
"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[CessnaJon]

I had to advance the timing on my 2.0 liter equipped 73 to 42 degrees as well, otherwise it had no power. At first this concerned me, but it stayed cool and ran great.
I’ve been running this arrangement for the past 14 years all over the southeast.
_________________
1973 Westy (shared birthday)
1990 Westy Multivan
2015 Passat TDI 6sp
2015 Sportwagon TDI 6sp
LR-JET, Gulfstream 159

[Squeeze Cheese]

[CessnaJon]

🤔😊
_________________
1973 Westy (shared birthday)
1990 Westy Multivan
2015 Passat TDI 6sp
2015 Sportwagon TDI 6sp
LR-JET, Gulfstream 159

[SGKent]

[Squeeze Cheese]

SGKent, good advice. I’m going to verify my TDC mark is right. And try a swap out of the Pertronix for points and see if there’s a difference.

I’ll have to see if anyone around has a LM2 so I can get into the air/fuel numbers, which will require some research on my part because I don’t know what I should be looking for.
_________________
63' Ragtop Beetle

78' Dakota Beige Westy. “Skills” EJ25 engine conversion w/ zero mile factory short block, Delta 1000 cams, heater core and modified Gilmore AC. Matt Steedle 091 transaxle upgrade w/ 4.14 ring and pinion, Folts aluminum gear carrier. General Grabber AT2s on stock wheels. Solar powered aux battery w/ inverter.

[gintaras]

[Squeeze Cheese]

[airschooled]

Can we see a picture of this timing notch?

Last year I worked on a T4 with a notch about 30 degrees off. Turns out it was from a 914 or Type 4 car and had notches invisible from the bus access hatch, so someone made a notch that looked descriptively factory, but it lined up with the case parting line like a Type 1 when at TDC..

Aftermarket silver timing scales have been up to 4* off, you’re runnig a factory plastic scale, correct?

Give the engine a thousand miles or so before you expect compression readings to be accurate.

I agree sniffing the exhaust is the best course of action here.
Robbie
_________________
One-on-one tech help for your vintage Volkswagen:

www.airschooled.com

https://www.patreon.com/airschooled

[tommu]

[SGKent]

[timvw7476]

Have you confirmed the throttle moves from idle to wide open?
The linkage in the splash pan area can get ovalled-out & cock the
push-pull rod attached to the crank that tugs the throttle cable.
This would explain your miserable 85-90lb compression numbers and
horrible performance.

[Squeeze Cheese]

[Squeeze Cheese]

[Xevin]

When it runs crappy at 28BTC does it ever start performing better, say in 5-10min of mixed driving?
_________________
Keep on Busin'

[Squeeze Cheese]

[Squeeze Cheese]