71 hightop engine build

[DrKamikazi]

Figured I'd post here as well as my bus's thread to get some advice on this engine build. So a quick backstory, got a 71 hightop bus we bought last summer. Engine was a 1776 with a CW crank, cromoly pushrods, 043 heads. Came with aftermarket chrome tin and dual 34 icts and a dual quiet pack exhaust (I think that's what it was, pretty rusted out.) Full flowed with an external oil cooler.
So we pulled the engine to install OG German tin and thermostat, dual weber 40 offs, and an A-1 sidewinder exhaust. Long story short after a leak down and deciding we needed to repull the engine and we found the oil full of bearing material. So now it's time for a rebuild!

Plan initially was to try stock 1600 with some small performance upgrades potentially. But I've been doing lots of reading and am keeping open to other potential displacements. Probably going to start from scratch and build a new longblock, at least a short block for sure. I have no idea what's inside the case as the PO I bought it from didn't build it. He claimed the guy that built it said it was a stroker, but isn't that wrong with a 1776? So I have no idea, but there are tons of signs of shoddy workmanship all over the engine.
Main reason for looking into potential higher displacement is I would like to keep the weber 40s and the A-1 sidewinder.

Goal is to build an engine that will run cool and reliably. Doesn't have to rip in the left lane ever, but want to be able to ride on the highway and make it up mountain passes. Plan on putting the OG german tin back on so don't want to make the engine much wider than stock. Would love to keep the stock size pushrods for quick repair sake in roadside emergencies, but could go with custom length if it works with the engine.
So some initial thoughts:
Probably going with the DPR counterweight crank, either 69 or small stroker
Are all 043 heads the same? Should I just reuse mine? I got the upgraded heater boxes from A-1 with the exhaust. But I don't remember the size of them so don't know if I can use larger valves. Going to try and find that out today.
Thinking either 85.5 or 90.5 for cylinders, but maybe 92s are good as well? Want something with stock thickness since it's a bus (and a heavy one).
Want a mild cam, but which one? This is where I am the most ignorant and need the most guidance. What cam could work with an upgraded displacement and carburetors?
I didn't mind the 1776, but I think if I'm going to go up from stock I might as well put a stroker crank in it. Been playing with an engine calculator just trying to see what looks like what together. 74mm or 76mm x 85.5 or 90.5 seems like popular combos that can be made reliable. 92 with a stroker just seems so big to me for what I am looking for.
Currently I am in Oklahoma working for about a month and the bus is in SC waiting for us to get back to it. Plan is to figure out a build and get all the parts ordered so we can get a mockup when I get back and get the parts sent to balance. Open to any and all opinions and advice!
See ya out there (soon we hope)!
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SOLD-Layla - 1978 Riviera, 2.0L, FI
1971 hightop, 1776 dp, dual Weber 34 ict

[nsracing]

First, you need an honest goal what you want...and a budget in mind. If you intend to build a stroker, then build so. If you have no done one before, then I suggest you just rebuild the engine you got there..if it is already a 1776cc.

For complete reliability, I would suggest running stock cam and rockers. Refresh the heads. Get rid of those pesky carbs and use dual Kadrons instead. Run the same exhaust.

I may travel to Abbevile, SC in a couple of months to pick up something. Maybe I can bring you a motor? In case you rather not build and just install a motor instead.

Im in northern VA. YOu can PM me.

[jeffrey8164]

All engines can be reliable, so don’t be afraid of displacement. In fact a larger engine won’t have to work as hard to push your bus around.
Since it is a bus and top speed isn’t a goal, keep the cam duration short so the power band is from 1500-3500. That way you’ll have the low end torque you want for the mountains. Maybe even keep the stock cam and use some 1.25 ratio rockers. You’re not racing so keep the stock flywheel as well.

Heads and carbs?
Depends on the size engine you decide on.(you’ll want thick walled cylinders)
Your 043s and ICTs are probably good to 1835. After that the ICTs will start holding things back.

In my experience, the mid stroke cranks require all the weird math and shimming for deck etc. so to eliminate that cornfusion stick with stock 69mm or jump straight to 82mm.
_________________
Volkswagen!
Turning owners into mechanics since 1938.

“Let he that is without oil throw the first rod”
(Compression 8.7:1)

[DrKamikazi]

So my post may have been a bit confusing in some parts. I don't have ICTs anymore. We switched over to weber 40 IDFs. Nsracing were you thinking I had ICTs as well? Or do you think I should replace the IDFs with kadrons?
I love the idea of a being able to use a stock size cam and rockers, would that keep stock pushrod length stock on the 1776? What about a bigger displacement?
I have been researching a 1904, would I need to change up from the 043 heads? Just need bigger valve size or what would want to change above 1835?
Also what is the general thought on strokers with stock size cylinders? Waste of time? Seem to read people that are really happy with them, but then some people think it's not worth the time. Maybe those people want big fast racers tho.
Thanks everyone!
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SOLD-Layla - 1978 Riviera, 2.0L, FI
1971 hightop, 1776 dp, dual Weber 34 ict

[nsracing]

Dual WEbers do not really breathe very well w/ stock valves. For a heavy bus smaller carbs will run better. The WEbers can be detuned..smaller venturis and jet accordingly. But you have gotta a way to keep track of the changes in the Air-Fuel ratio...lambda systems or EGT setup to see where it is.

Increasing the displacement is fine. Just know how much fuel it will need. And driveability is something to consider - it is a bus. Don't expect it to behave like a street car if you put all the stuff on it. Low and midrange is where you want the power for a bus.

Hope this helps.

[DrKamikazi]

Thanks that for sure helps. I am definitely looking for low range power and torque. Want it to drive like a bus, not some high power street racer haha. Would dual kadrons be the best thing to look into for the bus?
What about single carb? I am leaning towards this if I have to sell the Weber's as we spend alot of time in varying climates (ie half the year in cold high elevations).
Also I pmd you nsraceing about 1699 engines, but maybe could discuss it here so someone else could find it if they are looking for that info. 😄
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SOLD-Layla - 1978 Riviera, 2.0L, FI
1971 hightop, 1776 dp, dual Weber 34 ict

[Alstrup]

Idf´s are fine. Kads are OK. Stock carbed large displacement bus engines are getting popular, but needs to be built a little specific to work well. Talk to Modok or Brian E.
043 heads can be many things. There are at least 3 different base heads that has 043 as the first 3 digits. So you need to inspect closer.
A high roof tin top is not just kinda heavy, it also pulls a lot of wind. So you definitely want a larger than stock displacement than stock to help make some usable torque.
Stock cam, - why? Because its cheap? No, today we can do so much better.
There are several different 40 Webers, so you need to determine which since they have each their working enviroment so to speak.
At the very least I would opt for a 1776 displacement, prefereably even more. Even though it is slightly more problematic to build than most, one of my favourite bus combo´s is the 1955. A 2007 cc is easier to build and works well too. As for which cam to chose, that really depends on the rest of the engine. But good bus cams are generally in the range of CB 2280, 2239, 2241, Web 119, 218, FK41, Pauter B6 & C7.

[DrKamikazi]

Thanks, that is some good cam info to help get me started. Like I mentioned the cam and valve train effect on the engine is where I need to learn the most. Other areas I get much better. I will research those cams some more. Stock cam was a thought not because they're cheap but because they're proven reliable and because like I said a stock engine width for the tin and stock sized valve train seems like it will make it easier when trouble does occur. But we can always carry a few spares if we end up with different pushrod sizes and rockers.
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SOLD-Layla - 1978 Riviera, 2.0L, FI
1971 hightop, 1776 dp, dual Weber 34 ict

[Brian_e]

A hightop baywindow is like a brick in the wind!!

I vote for the most displacement you can afford. I drive a lowered '71 bay with a 2332cc. I would hate to see what a highroof and anything smaller than 2000cc would drive like in real conditions. Crossing the prairie trying to maintain 60mph in the wind. Or a long high elevation Colorado pass.

I built an engine for this stretched baywindow limo with an extra 2' added to the top. Your engine needs would be similar, but not quite as much.

Here is the combo I did for the limo. It has over 30,000 miles on it now. Still pulling strong.

New aluminum case
84mm crank
92mm thick walls
CB panchito heads w/ CNC chambers
web 218
9.0cr, .043" deck
1 5/8" sidewinder
40mm IDF's, 34mm vents
KEP S2, daiken super disk
huge oil cooler

No matter what you build, it will need to have really good heads, with very fast airspeed in the ports, and a mild cam. I am huge fan of the Web 218 for buses.

Brian
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www.type-emotorsports.com

[jeffrey8164]

Not to highjack but that Limo is wild!
Love the Beetle graft and the quite respectable power plant.
I’m assuming only one set of drive wheels?
_________________
Volkswagen!
Turning owners into mechanics since 1938.

“Let he that is without oil throw the first rod”
(Compression 8.7:1)

[Brian_e]

Yes, only the rear set drive, but all 6 have brakes.

The engine works very good for what its is being asked to do. He can feel it struggle a little when a group of 12 "larger" bachelor-et's are loaded up. I would do a few things differently next time, but it is working great as is.

Another real important thing to pay attention to in a bus is the trans gearing. It needs to all be matched. Desired cruising speed, tire size, and HP the engine will make. It will take a bunch of power to keep a brick moving through the wind at 65mph. The engine needs to be operating near it's peak torque, and peak cooling speed to remain cool.

Extra power will keep the engine from having to pull 100% all the time. Smaller engines in a high load will be working their butt off most all the time. This will make the smaller engine run hotter and its lifespan will be shorter.

Brian
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www.type-emotorsports.com

[ALB]

[Brian_e]

For that same application I would add +2-4degrees to the cam duration, add some bolt-on 1.18 rockers, different valve springs, a step header with 1 1/2" up to 1 5/8", and probably have a crank built with a T4 center main.

Brian
_________________
www.type-emotorsports.com

[DrKamikazi]

Thanks for all the input! I guess it is time to do some cam research! Would it be best practice to figure out what cranks and bore and heads I want to go with, then figure out the best mild cam for the engine?

Also Brian I know that bus! My buddy used it at his wedding! Then we got jobs at Under Canvas in keystone and saw it several times! I was stoked to hear it fire up and hear that it was an aircooled VW engine still!
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SOLD-Layla - 1978 Riviera, 2.0L, FI
1971 hightop, 1776 dp, dual Weber 34 ict

[Brian_e]

Figure out a realistic budget. Then decide if you want to have the case machined for larger cylinders and a stroker crank. Also figure out what you realistically plan to do with the bus. There is a huge giant difference between a bus that is good for trips across town for ice cream and a bus that is good for trips across the country.

If you go the stroker route, you will need new heads and everything. It will be expensive, but it will also make the most power.

If you added a 74mm crank, kept your 90.5's, added a cam, good 37x33 heads, and some IDF's, it would be a huge improvement over a stock head 1776cc.

Are you still around here in SoDak, or was that a summer job?

Brian
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www.type-emotorsports.com

[nsracing]

That bus just gave me a wet dream what I will do in my retirement. Thanks man! I love that stretch -

If it were me - 78mm x 88m thickwalls, w/ Dual Kadrons, stock cam, 40 x 35.5 heads, mild exhaust. I dare anyone to challenge that combo cross country...in a bus.

I am hanging on the last Mahle 88mm thickwalls from the early 80's - i inherited from a shop that closed. I just don't have the heart to use them.

[DrKamikazi]

So we had a planned budget of around 3-4k...I almost bought a turnkey engine that the shop I was at happened to have stock for a 71 bus, but it was 4k they wanted and that was pretty much max I was willing to spend and it had all aftermarket tin I would have had to swap with my og tin. Thought it was too much for a too quick decision and a lot of work that we could have done ourselves. We figure if we put that budget all into just a longblock then reuse what we have on top we could come up with a much better engine.

You guys have me thinking much harder about a bigger displacement motor for sure, seems like the best way. I see alot of guys rocking stock buses across the country, but none of them have hightop.

Our initial plan was just to build a new engine. Then if we find out the old one wasn't too bad on the inside we could save it for a backup or sell it for someone that needs one to rebuild. This will cost more, but having a backup with our traveling would be pretty sweet. Or wed make some back selling it. Mainly it will save us a lot of time. If we go rebuild then we won't know what we are into till we get back to the bus in about 4-6 weeks. I know all the internals will have to go to the machinist, as well as the heads need a valve job, etc...
When the engine first started exhibiting really bad symptoms it broke a rocker shaft in half at the mounting stud, so that's pretty discouraging as far as what were going to find in there.
We would like to keep the Weber's now, then swap them out if need be down the road. I see lots of people that do that, is that good to do? I know carbs can affect cam choice.

Brian we are no longer in the black hills, just a summer gig.
Edit: how does the limo like that compression? In reading about that cam it seems like it likes a lower CR.
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SOLD-Layla - 1978 Riviera, 2.0L, FI
1971 hightop, 1776 dp, dual Weber 34 ict

[Clatter]

There’s kind of two philosophies in building these IME;
Heater boxes or no heater boxes.

Meaning stock 1 3/8” heater boxes..

You’re best off staying with stock valve sizes unless you can upgrade the heaters to a larger size.

And,

If you do indeed have bigger heaters,
Then it’s a very different motor you can build.

Since they cost so much,
It’s a case of
“Build it around the exhaust”
IMHO
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Bus Motor Build

What’s That Noise?!?

[Brian_e]

[Brian_e]