Mikey's Frankenmotor 1.8 build update - FAIL! ... sort of.

[MikeyM73]

Hey all,

Many of you have followed my 1.8 bastardized engine build with OEM 2L heads and offered great advice and council; for that, I give much thanks.

As an update, the engine has almost 3K miles on it and ran excellently... until today. Dropped the intake valve seat in #4. These were old VW 2L heads that checked out fine, no cracks, guides were good, etc. but we had no history on the heads... who knows how many times they were overheated, etc. We pulled them from a '78 2L parts bus. On the positive side, the seat dropped right after a warm start so nothing over 1k RPM when I heard that terrifying "tap tap tap".

I know the bottom end is good, solid, etc. My question is this - when I get new heads (Len, Brothers, or Headflow Masters) I will need to take into account the "step" that is machined into the new heads. When I installed the used 2L heads I lapped the barrels to the cylinder registers and didn't use a gasket. So to keep my .041/.042 deck height, I presume I just use a thinner cylinder base shim to compensate and measure out DH to .040ish, right? Which means the piston rings will ride slightly higher in the cylinder bores where they had not previously contacted. So a light hone on the cylinder, install the thinner base shim, confirm DH, re-lapp the barrels to cylinders, and put her all back together? Since there's so little wear on the rings and "lower" end I presume I can just reuse everything as long as I can't catch my finger on any ridge inside the cylinder,s correct?

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.

[timvw7476]

when an intake seat lets go, it's usually a cooling issue, failed flap, failed thermo, none of that with you? (mine was a misbehaving flap, stopped for
several minutes, fired again and there it was. I got repeated warnings pulling away from stops with a slight pinging (never happened before or since) .
That's all I have.

[busdaddy]

With the low miles a hone should do it, as for the new heads CC both them and the old ones and compare to decide on base shims.
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[Wildthings]

It is likely the seat was already working it way loose, you might have Adrian at Headflow Masters look over your heads and give his opinion on reusing them. If you go with a larger seat and accompanying valve you would want to do both heads the same.

Agreed that a short interval of honing would be all you need.

[Abscate]

You can count on parts Bus parts being worn out. You can’t tell the condition of stuff by looking at it, and if you have the equipment to evaluate it you are too busy building engines to waste time cobbling engines together.

The era of cobbling is waning, except for peach pie
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.ssS!

[Ryan P]

[MikeyM73]

Thanks for the replies. You all are pretty spot on.

WT, I agree - I think these heads were overheated but I decided to take a chance due to budget. But as it turns out, it didn't save me anything. Should have known. Lucky for me the engine was warm and the seat dropped right after sitting for 10 mins so it never saw high RPMs and then I shut it down. In one respect, I'm not too bummed this happened because I wanted to pull the engine anyway to retorque the heads, do some shift linkage bushing work, reseal the trans, etc. while the engine was out and at least I know my part of the build ("lower" half) is still solid (knock on wood) .

Ryan - the local shop measured the guide to valve stem clearance & cleaned & checked the heads for cracks and flatness, confirmed (as best they could, I guess) there were no signs of seat release, then the valve job and assembled. There were no signs of fatigue but as many of you have said - you really can't tell what the overheating cycles were. This new 1.8 normally saw temp ranges of around 270-290 in town for CHTs in town and maybe 320-330 sustained on the highway - Dakota Digital gauge, sender, etc. I think the gauge is accurate because I tested it by disconnecting the sender, running the wire down through the engine seal, and set up a camp stove right next to the bus, boiled a small pot of water and stuck it in - key on. It read 210-213 at that point. I realize there could be some variance in the temp reading at higher speeds but the engine was treated well and never saw over 350 (on the gauge) so I wouldn't think that a DD gauge & sender would be off by enough to shoot CHTs high enough multiple times to overheat. Although Clatter once said he had a VHT sender be off by about 60* so I suppose anything can happen.

At this point, we're just going to go new AA castings from Len, HFM or Brothers but most likely HAM. Probably do the 42/36 valves to get a little more flow and reuse them on a larger engine down the line.

My only concern is my deck height. I didn't use the head gasket rings, just lapped the barrels to the cylinders. The DH is pretty tight at .042/.043 so that should be about the minimum, right? I'd like to maybe get a tad more compression using the same pistons, cyls, etc. but not sure if I'll be able to based on the new heads. I'd be happy keeping the CR the same (around 7.6/7.7:1) but the old 2L heads CC'd out to around 51/52cc and I think the new AA castings are around 53cc?? If so, that should come close but any suggestions are welcome. Basically, my thinking is sense the new AA castings have the "head gasket" ridge machined into them that raises the combustion chamber so in order to keep everything the "same" I would need to lower the cylinders by the same amount using base shims, recheck DH, and proceed, is that right?? Maybe might even have to have some amount shaved of the tops of the cylinders. Is my thinking correct?

Thanks yall,
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.

[Clatter]

[MikeyM73]

Thanks all,

Clatter, that was my thought as well. Cry once, right? Hell 2k for the best set of heads available is not terrible at all. I figure if a well built, healthy, SB Chevy / Mopar can be built from start to finish with good parts for 3500-5k, that's not terrible and the same holds true, here. I spent about 1500-1700 total with cleaning, checking, etc. and the valve job so spending around 2k or so on heads would only finish the job properly and I wouldn't have to worry about it again. Still, I don't feel that's a bad overall spend for a new T4 engine that should last a long time.

Thanks,
Mikey
_________________
'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]

In my own experience, valve issues have been the biggest issue for me driving a bus for 30 years. I have never really had issues with the bottom end. It makes sense to me that heads would cost more proportionally compared to the rest of the engine. I think it’s a good place to spend money.

If you are cool with tinkering, I don’t think there’s anything wrong with getting a valve job and running used heads. It depends on what your expectations are and how hard/fast/far do you drive your bus. An engine that will putter around New England for ages can last a long time or a few days climbing to the continental divide in July. At least that is how it has worked out for me.

[MikeyM73]

Thanks Orwell. I should have listened to my gut when I tore down that old 2L. The heads looked like they had hot oil stains baked on... I guess that's a pretty sure sign of running hot, don't know, but the cam bearings on it were wasted. Oh well.. just saving my pennies, now. We're neck deep in home projects at the moment so the Popibus must wait.

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.

[raygreenwood]

[MikeyM73]

Hey all,

Just an update.. the deal is in the works. I spoke with Len and will be getting a set of his 42/36 T4 heads soon. I'm going to run all this past him but my question revolves around my current DH.

Right now I'm at .042ish DH with OEM 2L heads and no head gasket - just lapped the barrels to the cylinders. To keep that as close as possible I would need to replace my .040 cylinder base shims with nothing which would move the cylinder and head closer to the case... which means the piston ring will contact an area it had not previously which means removing the cylinders, honing, etc. No problem with that.

But - instead, should I ask Len to remove that step? If that's done and I don't remove the cylinders then just the head comes down a bit and it should literally be remove, reseal, and replace, correct?

Then recheck VT geometry and go from there? Actually, now that I'm typing it out, I'll probably have to remove the cylinders anyway to relapp the cylinders to the heads again. Damn. Oh well.

Thanks all,
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]

Hi all,

Here's an update to the saga... After installing Len's beautiful new heads AND THEN bending an intake valve on #2 due to overlooking a pushrod not being seated in it's rocker cup, I removed the passenger side head for repair. Only the valve was slightly bent, the seat and guide were fine. Len was kind enough to ship me a new intake valve so I lapped it in, checked, the pattern, checked for leaks, and reassembled. Engine fired right up, carbs adjusted, etc. and so far have about 400 miles on the heads and they are awesome. Freeway power is more than the OEM 2L heads. Also, seems to want to rev a lot higher (although I don't) and it pulls harder from mid to top end due to the larger valves and minor port work Len does. The weather these last 2 weeks has been in the low 90s and CHTs on the freeway at 65mph sustained for about 8 miles are about 340-350, about 20* or so less in town. So far, haven't gone past 370 and that was on a pretty long hill pull up hwy 101 @ 60 mph with 5 people, myself included. So.. super good stuff, I think.

All in all, I dodged a bullet and the bus is back on the road. For those that would like to know, pulling a cylinder head with the engine in the bus is not bad at all. just takes time. Everything came apart easily and went back together easily. Lemme know if anyone needs pointers / details on the head removal.

Take it easy,
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.

[Clatter]

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Bus Motor Build

What’s That Noise?!?

[orwell84]

Glad it worked out. Good call on the heads. They take a lot of abuse and are fairly complex and maybe the hardest part to get right.

[MikeyM73]

Totally. Taking advice from many here, Len was the guy.. Adrian and Brothers were a close second but when you hear so many people vouching for his work, craftsmanship and attention to detail, plus the price was in line with the rest - done. He was very patient with me and ALLLL my questions, etc. and that goes a long way. Anyway, we did a short camping trip from Napa to Guerneville this past weekend and the Popibus ran great. No power issues at all, just cruised right along. We liked the place so much, we're going back this weekend.

Take it easy,
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]

[MikeyM73]

Hey all,

Just a quick update for anyone interested. So far about 8k miles on the engine, 4k on the heads, a few valve adjustments and all is well. A couple minor oil leaks from a couple of the PR tubes that I haven't gotten around to yet but all in all, a good, strong, solid running engine. I think I've dialed in the dual 40s about as much as I can with the resources available so far - plug coloring seems decent enough. CHTs are generally sub 300 in town, sub 340 on the highway at 65 mph. All around power is excellent (for a 1.8 ) and far above the old engine.

We've done a bunch of coastal trips and a few considerably longer trips up hwy 1, through the windies, etc. and power has remained good. Our most recent trip was from Napa, over to the coast via 116/101 River Road to 1 then up to the Manchester Beach KOA. Came back by heading North on 1 to 128 and coming back 128 the whole way to 29. On that trip from start to finish we averaged just over 18 mpg with the usual camping gear and firewood for a couple days.

Wanted to, again, extend a sincere shout out to all of you who provided guidance, input, and your knowledge along the way on this build. Couldn't have done it without ya'll so thanks!

So far, so good!

Cheers,
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]