1.8 T4 replacement cam

[SGKent]

So would the plural of "gorph" be "gorphi, "gorphen," or gorphs?
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[MikeyM73]

I vote Gorphs .

Thanks guys. Clatter, kind words, much appreciated. I can see the advance weight stops in my old VW dizzy.. the little oval, metal, plate/plug is removed so I can spin the dizzy and see each of them. Now that I have an idea of what I'm looking for I'll pull the Pertronix as soon as I can.

So just for the sake of an "update", this engine shines where the other did not. On the freeway @ 67-68mph, my foot is barely into the throttle and CHTs are very cool... like almost scary, erroneously cool - 310-325ish @ tops on the highway @ about 85* air temp? Heck the old 1.7 ran @ 370* lower speeds; must have had something to do with the mouse bedding in between cyl 3&4 ). Highway power is far above satisfactory and under hard acceleration, the engine will pull surprisingly hard as long as I want it to... up to 4800 and beyond but I don't dare take it past that. Passing power on the highway is nice. Finally able to accelerate strongly from 65, up to 80+ and then back down into the slow lane. These characteristics are exactly what I was hoping for in this engine. Now, just to get the timing and fueling dialed in. Thanks again for all of the advice. You guys totally rock and are a large part of why this build was a success, thus far - still in the cautiously optimistic stage of post-break in. Once I have about 5k or so on it and switch to high zinc synthetic, I'll feel more comfortable .

And perhaps as a "phase II", my future plans for a mild stroker may be postponed, if not cancelled, if I can get a set of HAM 42/36 heads for this engine. If it performs better than currently, I may have no need for that 2L/mild 2109 stroker. But we shall see.

Mikey
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.

[SGKent]

glad it is running to your satisfaction. For the record the Web Cam 142 does the same on this bus but without the low idle issue although the head temps are hotter. That may be because of the need to run it a tad leaner due to smog, and also the catalytic converter. Everyone should be aware that the spark plug choice will affect what the head temp shows also.

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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Clatter]

[MikeyM73]

[orwell84]

On my 1800 with the web73, 70 mph would put me at 4200 rpm (with an automatic). It would pull until about 75, but not much more after that. I don’t think I’ve ever seen 5k rpm.

Sounds like you’ve got a nice combo. Pulling nicely through the rpm range and power to spare. Plus, you are still tweaking. What more could you ask for?

[MikeyM73]

Thank you, sir. And very good point... not much.

However, since you asked )... I DO have an 091 trans that I would LOVE to install to get my RPMs down on the freeway while still being in the proper cooling RPM range. At 70 RPM, my tach says right about 4000 with my 002 trans, today. According to my calcs and Spicers gear ratio to RPM calculator, an 091 trans would drop me from a 4.57 final drive ratio to about 4.02; that equates to a drop of only about 3-350 RPM which should be plenty for cooling but should also allow the engine to work not so darn hard at speed... load, wind, all other engine load factors, not withstanding. My only hesitation is I need to get the timing and fueling dialed in before I can guestimate how much low end power/torque/hill climbing ability I would sacrifice if the 091 goes in.

All that babble said, I'm perfectly happy with the way it is now. Maybe the 091 will necessitate an engine larger than 1.8 to retain the feel of the power it has now... makes sense since VW did it but they didn't have a bunch of mods, etiher. So we shall see )

Mikey
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.

[MikeyM73]

Hey all,

Got around to pulling the Pertronix dizzy. The internals are pretty much just like a 009; same type of weights - check out pics below. In my case, I got lucky and bent the tabs just a bit inward and ended up dead on 28* max centrifugal advance with 9* @ idle. I'll take that. For now. Much better. Low end response is better but still some tweaking to do.

This is for Ralph and anyone else who is interested in doing this. I've never done it before but no biggie. If you can take it apart, you can put it back together, right? This is what you see without ignitor module, vacuum pod, clips, etc.; basically stripped down to the advance plate. When you remove the dizzy cap clip retaining screws, that frees the mounting/advance plate assy and then it slides up and off the shaft, exposing all the centrifugal advance stuff.

This shows the internal centrifugal advance mechanism. Just like all dizzys with centrifugal stuff, the weights pivot on their pins and are thrown out against the stops. Bending those stops inward will limit total centrifugal advance. You can see the advance stop just to the upper right of the slot in the shaft that the rotor slides down into. They're L shaped and bolt to the spinning assembly and are static; they don't move. Bend the upper part of the "L" inward to dial back centrifugal advance. How much... how knows? Trial and error, I suppose. I got lucky.

This one shows (poorly - sorry) the advance weight pushed up against the stop.

All in all, not a bad day. Took about 45 mins total. I figure I'll resync the carbs then play with timing a tad. I've been keeping records of CHTs at sustained highway speeds relative to ambient air temp (thank you Siri) so that should hopefully provide some type of data as to what timing runs cooler than another and the performance associated with it. It's no distributor machine but it's all I got so might as well 'git 'er done'as best I can, right?

And I have a question... can you run cooler @ highway speeds with more advance? My mind says no BUT then I think of the whole timing thing, efficiency @ a certain RPM with a certain fuel curve, etc. So.. just wondering. Please do educate.

Mikey
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.

[orwell84]

My neighbor timed my bus by ear once. It had a bit more oomph tryout could feel in the pedal but was quite a bit higher than the factory spec. I later learned that buses were de tuned to keep CHT’s down. When I reset it to the factory timing the performance loss really didn’t feel like much. The performance increase was not worth the risk of increasing heat for me.

The vac can is meant to give you a little advance from the vacuum created by the brief pressure change that happens when you tweak the throttle.

[RalphWiggam]

Thanks for the pictures. I am running a 9590 cam and from what Ive found, Raby originally spec'd a 12BTDC at idle and 28 max.

So basically ~16deg total mechanical. Im running a stock 72 distributor and it has much more mechanical advance than 16.

I will say though, Im kind of on the fence about messing with it. My bus idles really nice right now and I dont have any issues with power or hesitation.

[MikeyM73]

Orwell, Ii hear you. I had the same experience. I was setting the timing right after the build is when I really discovered I was over advancing. I would set timing to about 8* and then saw that the centrifugal was hitting 32-33* and I didn't want to chance it, either. I wouldn't have messed with it had I not learned that. That said, when I did run @ 32* my CHTs were still in check so does that mean that I'm NOT starting to burn through pistons? There was no pinging that I heard but I'm not sure but my lack of knowledge on that made me play it safe.

Ralph, I was kind of on the fence Also but figured I’d give it a shot. What is your idle timing at? And full centrifugal set at?
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.

[SGKent]

the mechanical factory timing on most buses total at 32 degrees. We retard them a couple degrees to get less heat. VW considered 32 BTDC at full in safe. 34 - 36 is not.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Clatter]

Perfect... Just Perfect.

First try.

Tune in the carbs and run it 9/28.

Get it broken in, rings seated, oil changed, couple of valve adjustments.
Re-torque rocker stands and exhaust manifold-to-head nuts..

Then drive it and monitor temps.
You already have a feel for how hot it runs pulling a certain hill on a certain temp day...

The motor might want a bit more advance - give it a bit more, re-adjust your idle air/mix screws if needed and drive it some more.
It will get more peppy both down low and on the highway with more advance,
And that’s good.
But be super aware of how hot it runs,
And never, never let it ping even once.
If you hear it ping, or god forbid rattle, back the timing off ASAP.

The timing scales on these things are notoriously inaccurate.
Jake of course had to recommend timing safe for customer/users that had a margin of safety.

Give it what it wants.
A smart/aware guy with a set of gauges, listening and feeling and paying attention will know when it’s timed right.

Tune it to run sweet, but play it safe.
Remember that on a super hot day, loaded, pulling a huge hill can get it hotter than it has ever been, and push it into detonation..

Get on with you bad self brother.
Rock that bad kid down the highway!
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Bus Motor Build

What’s That Noise?!?

[SGKent]

[MikeyM73]

Clatter, thanks. That’s what I’m tuning it for… The worst of scenarios so that I can drive it in all scenarios and not have to worry about pulling over and backing anything off. I think 28° is about right, it seems.. It has lots of top end, and still runs cool. The advance curve seems smooth so I think the only thing I have to figure out is a tiny bit of barely noticeable surging when I stop pressing the accelerator down at the top end of first, second, and third gears.There’s no missing, no flat spot it just seems like the engine wants more fuel at lower RPM. My air corrector jet is 200 and I was thinking of going down to a 190 or 180 because it really seems to come alive at 2000 RPM and up. But of course, that could just be the cam. Also, I learned that my ported vacuum signal is extremely weak so it looks like I’m just running centrifugal even though it’s connected. There was a slight bit of hesitation upon depressing the accelerator but I turned in the pump adjusting screws about 1 1/2 turns each and that seems to have made that better. I also picked up the Weber tuning manual and have been reading that so hopefully it will help.
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.

[Clatter]

Like i said,
Many have to fight to get a decent vacuum signal from a set of Webers.

Some of those afromarket vacuum cans are setup for more vacuum than we get from our little watchwinders..
Might be worth it to try and maximize the signal,
Or find a can than needs less vacuum to give you that advance.

Or not..
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Bus Motor Build

What’s That Noise?!?

[orwell84]

I will be glad when I’m in your shoes driving and tuning. I’ll get there. I have never been much of a tuner...just slap stuff on and hope for the best. My last engine ran quite well and I was very happy with it, but I knew it had a lot more potential and at this point I feel I am in a much better place to get my current build dialed in.

I bet there are a lot of people driving around with ok engine setups that could run so much better. A good engine can be a total dog or a a nice runner depending how it’s tuned. Most people get it domewherbin between and call it good. I look forward to your updates.

[MikeyM73]

Clatter, any idea on how to increase the signal? When I put a vacuum gauge on the T going to both carbs' ported vacuum port and come off-idle, I barely get signal. I have a check valve inline just in case but the needle moves just off the peg. It takes about 1.5" vacuum to start to move the vacuum pod diaphragm.

Thanks,
Mikey
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.

[MikeyM73]

Hey all,

Update on the Jetting and timing. 566 miles on the engine so far, decent mileage. Getting about 22/23ish on the highway somewhere in that range.

The timing is at 10* idle, 29* (not over 30) at 3k, still no vacuum advance but the engine still drives nicely, responds well, and doesn't really seem to care.

Idle jets are 60s, changed the mains to 135s - they were an improvement over 130s in that the acceleration now felt more smooth as it was transitioning through the carb circuits - less jitter and just very smooth. Throttle response was crisp, highway performance better than 130s, CHTs were slightly lower but that was most likely because of the air temp - about 7-8* cooler today. Although, CHTs were never close to 300 in town and barely over 300 on the highway. I think yesterday with the 135 mains @ 67 mph I was right around 320-325* sustained for about 7 miles. Changed to 140s for testing - they felt ok but a but mushy - took a hair longer to get to 80, floored. Smooth but mushy so I drove it for a while and concluded that 135s were where I would stay for a while and do some mileage and spark plug testing.

So far so good, just need to iron out one tiny little flat spot only while at the end of depressing the accelerator quickly so I think I'm going to try increasing from 50s to 55s on the pump jets and see where that lands me.

Mikey.
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.

[MikeyM73]

UPDATE:

1850 miles and running well. Mid to top end is... wonderful. Settled on 60 idles, 55 acc pump jets, and 130 mains so far. Timing is good and the bus is very responsive. Oil is clean and it's on it's 3rd oil change so far since break in... just to be safe.

I must say... I was really on the fence about the HPMX carbs but hearing of how folks really didn't seem to like the Weber USA kits, I opted for the HPMXs based on the reviews.... I really didn't find any bad ones. Bottom line is I'm very impressed. Sure, they could use better air filter elements and I'll probably change out the hiem joints for better ones but the carbs, themselves, are good. Smooth, responsive transition from idle to main circuit and top end is awesome. So far, this engine is doing exactly what I was hoping it would.. cruise between 65/70 mph with ease and be able to blast up to 80-85 quickly to get out of the way or pass and back down to 65-70 back in the slow lane. Plugs look normal so at some point, I'll head down South to Clatter's pad (if I'm still allowed )and get them really dialed in.

'till then... this concludes the update of Mikey's Franken 1.8 build.

Peace.
Mikey
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'73 Pop-top Westy, found sitting in a field for 10+ years, cleaned up, rebuilt furniture, reloved. Original 1.7 block/fully polished crank, 93mm 1.8L balanced AA pistons & cylinders, new 1.8L balanced rods, HAM 42/36 heads, Scat C25 cam & lubalobe lifters, Dual HPMX40s, R2C filters w/ Outerwears pre-filters, functioning thermostat & flaps, Pertronix Flamethrower III, 4-1 exhaust w/ Cherry Bomb 2" turbo muffler & OEM heater boxes, averages about 19-22ish on the highway.