"Ultimate" Heater Box Motor

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"Ultimate" Heater Box Motor

Post by Clatter » Wed Apr 12, 2017 10:04 pm

So, yes, ultimate heater box motor is indeed an oxymoron..

Seeing some old HotVWs builds, it shows how limiting 1 3/8 exhaust really is..

I broke the big motor in my Oval (again :x ) and my 12-year-old wants to help build another.
Was going to do a type 4..

I have a whole pile of t1 parts here, and we have to build this one around a set of heater boxes (German OG ones) so Mom will ride in it.
This is one for some mild miles, but as much fun as is practical.

So far, I have a counterweighted 69 crank, 8-doweled with a Scat gland nut.
(A high school kid might drive this one day soon).

Some 90.5s are here, as 1776 is generally accepted as the biggest before you choke a set of heaters.
(And I'm getting really sick of the issues with 94s and decked case-savers, etc.)

I'm on the fence if I should get a 1700# Kennedy balanced up,
Or maybe just a normal Brazilian Sachs, but maybe a Daiken, or "copper" disk?
It sure would be nice to run a light plate..

He heads are some really "nice" stock-valve (35 x 32) G03s that I spend about three full weekends on.
The chambers are opened up, and the ports done according to Fisher's book.
The valve job is pure artistry by my local guru here.
The fins are even detailed..
Think I should go ahead and buy some really nice Manley or SI valves, with thin heads, and swirl-polishing and all?
Or would that just be pissing money into the breeze?

There is an Engle 110 sitting here.
Was thinking Web 218..?
Would aluminum pushrods be light enough to run single springs with a Web 218?
Not really sure ti retainers would be sanity for this build.
Duals are sitting right here, as is the cutter...

For now, I have a set of K-dogs with bigger vents, vacuum port, etc.
Got an OG SVDA, too.
There is this set of Weber 36s my neighbor is trying to sell me...

I'll have 1 3/8 header, doghouse, t-stat, all tin, sump, full-flow, etc. etc.
Was even going to do full Hoover HVX mods on it,
And that requires stock rockers.
Was even thinking of using a set of old Courier Mazda feet, just to get the oil flowing,
And honor the memory of Mr. Hoover..
The aluminum pushrods would allow plenty more oil, with the clearance at start-up.
There is also a set of Autocraft 1.4s sitting right here too...

So, Any input from about valves, cam, clutch, valvetrain, etc?

Was thinking about 8.4(?) CR?
Maybe more?
More cam?

There comes a point of diminishing returns on a build like this.
My gut tells me to just throw it together old-school - duals, steel pushrods, 110..
Tough and done. One the cheap. Stuff is all sitting right here..

Anybody got a sanity check for me?

Would a more 'new school'' build be worth the effort and $$ ?
Or is something like this just not worth really messing about with...

:? :? :? :?
"Oh, You don't need to do all that... The valve seats are just going to fall out of it anyway!"
- Doug Ellsworth

Beginners' how-to Type 4 build thread ---> viewtopic.php?f=1&t=145853

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Re: "Ultimate" Heater Box Motor

Post by farmer » Thu Apr 13, 2017 7:40 am

Well, here´s my shot at it.

I was going to say mini stroker, but since you have the 69 CW crank, use it.
Next, Kads are ok and can actually support more hp than the average dual 36és, but get the 36és. Then your mom will drive it too, as it can make the engine much smoother in the lower rpm range.
Stock heater boxes has a hp limit around 120 hp. you can choose where you want the power partly by displacement. I have bult 118 - 120 hp 1914´s with stock heater boxes and 1 3/8" headers, but with a detailed muffler part. They pull max hp just over 5000 rpm and flattens out and drop fast after that. You are correct that a 1800ish displacement can make a more harmonious engine. So lets stay at 1776.

Apart from the obvius balance job I would lighten the flywheel 1 kg.
Clutch. a good stock 200 mm - should - hold, but will be on its limit if youre lucky, so a 1700 lbs would be the safe bet.
I also like light rods, so maybe lighten and rebuild a set of stock rods or buy a set of Unitech. They are usually in the 525 - 540 grams.
Cam. The W110 will do. I don´t like it, but it will work. The 218 is definitely an option. It will not pull the same upper end power as the W110, but it will pull flatter and be very easy to drive. (Some actually call it boring because they do not really feel the cam "coming in") I use it a lot for especially bus engines. My next option would be the Web 163. it is slightly above the W110, but you do not feel it when youre driving. That would be my choice.
GO3 heads are 39/35 mm valves (?) I think you mean GO1 (Also IF they really are GO3´s you will need to upgrade the exhaust system. 1 3/8" exh simply do not compute well with a 35 mm exh. valve) If your cylinderheads are GO1´s and "that good" you will hit 110 hp with lots of torque, no problem. CR 9-1. sea level 8,4 is simply not enough to make an efficient DCR. Make sure you get a good and tight deck height. Good SS valves are always nice.
Personally I do not like the Mazda style adjusters. I would go Porsche style in a heartbeat.
Ally PR´s, definitely :) With the 163 set them for 0,05/0,010 mm cold. No more. I run loose zero on most engines, it works very well and they run very quiet.
With that much displacement under the relatively small carbs you should use 32 mm venturies in them. I sometimes machine the carb top to match 40 mm stack (sort of like a Spanish 40 IDF) It work well and can aid in decreasing the midrange IDF AFR dip as well as help the carbs to assist with a couple of extra ponies.
Muffler. If you make the pipe from the collector flange to the muffler cone up a bit like many of the good mufflers (Magnaflow, Dynomax etc) and use a muffler that will support the power (by that I mean NO friggin sgl quiet crap muffler, you need more/better) you can make a good scavening effect from the header, which will also aid in the engine run relatively cool also under higher constant load such as freeway rides.
An SVDA distributor is a good choice. Sometimes it can be a real challenge to make them work with carbs since not all carbs have good vacum. The 36 IDF´s - should - be good since they are originally from an Alfa Romeo engine. (Unless they are an aftermarket buy of course. That can be) If that turns out to be a challenge I can recommend the CB black box. With a little seat time you can really improve driveability, engine temperature control and fuel efficiency.

Hope this helps.


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Re: "Ultimate" Heater Box Motor

Post by Clatter » Sat Apr 15, 2017 12:09 pm

Wow, thanks for the detailed reply, Torben.
Helps to have a skilled head involved..

You are correct about my typo - Heads are indeed GO1s.
Because I put so much love into them,
And plan on doing the same to the manifolds,
It makes me wonder if it would be worth it to get good valves.
The heads came with the exhausts that have a fat neck, right under the head of the valve.
The intakes are back-cut, and have a thinner area under the head,
But, I can't help but think a small-valve environment might take good advantage of the better flow good valves offer.
Because we can't make them bigger, perhaps it's a good chance to make them better...

Ever dyno good valves back-to-back against stockers?
Or maybe see differences on the flow bench?

The stockers are here, have a nice valve job on them, and are fine.
I'm probably just looking to waste my money... ;-)

Perhaps it would be best to source some Weber 40s for this motor?
Never thought that 36s would limit a 1776 with small exhaust.

I saw that they have cheap 'Porsche' adjusters for sale these days.
You have tried these and can vouch for them?

Would you run an Engle 110 (not that you would ever run an Engle 110 of course :-)) with just single springs and aluminum pushrods?
Meaning no other valve-train lightening mods..?

Like you say, displacement moves the power lower,
So maybe 1776 needs dual springs because of the revs?

So many different ways to skin a cat here. Part of what makes these motors so fun.
Thanks again for your time.
"Oh, You don't need to do all that... The valve seats are just going to fall out of it anyway!"
- Doug Ellsworth

Beginners' how-to Type 4 build thread ---> viewtopic.php?f=1&t=145853

Posts: 2391
Joined: Fri Dec 07, 2001 3:01 am

Re: "Ultimate" Heater Box Motor

Post by farmer » Sat Apr 15, 2017 1:57 pm

WRT the 36és being limiting might be a slight overexaderation. They would actually fit quite well together performance wise. One advantage with the 36és over 40´s is that the 36és are relatively easy to get really good fuel efficiency out of. Much easier than the 40´s.
The W110 and aluminum PR´s will be ok. Valve float will begin to be evident around 65-6600 rpm. Same set up with the Web 163 will turn 7000 no problem. but of course both have stopped pulling way before that.
With such an engine combo there will not be much idea in turning higher than about 6 grand.
WRT better valves. Perormance wise there is no difference between a stock vallve that has recieced some attention over an SS valve. The problem as I see it with these heads is that the valves and guides that comes with the heads are crap, end of story. So from that point of view I would swop to something better. If you take a stock valve and compare it to a quality valve, in the same seat, the quality valve typically flows 1,5 cfm better up to about 0,200" and 1 cfm better from ,200 to ,350". After that there is no difference. If the intake port is really good I have seen up to 2,5 cfm improvement. But that is rare.
The elephant feet sold by CB/ACN and most likely several others are quite OK. Over a period of about 10 years I have replaced 1 set total due to cracks. That is on about 130 engines.


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Re: "Ultimate" Heater Box Motor

Post by Lingwendil » Sat Apr 15, 2017 4:33 pm

With regards to the Porsche/Elephant foot style adjustors, I have had a set of these from CB Performance for about fifteen thousand miles now, and can heartily recommend them-

CBPerformance Elephant foot adjusters


They are on my 34PICT3, stock valve, heaterbox/1-3/8" econo header and glasspack equipped 1776. They look absolutely fantastic just as the day I installed them, and are very easy to adjust and well made. I installed these after losing a swivel-foot/courier style adjuster which also chewed up the valve keeper and retainer, and can honestly say I greatly prefer these to the courier or stock style. :D

I think the Torb has you on the right track for sure, heaterboxes are a must-have for me personally, and I'm not sure I would use stockers on anything bigger than an 1835 unless it was a mini-to-mild-stroker like a 1904 or similar where you are more concerned about low-end and less high revs.

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