The Oddball Build

[Millionmph]

So, got new case a while back, then parts, and parts... so far:
New case
New 85.5 p and c set
2280 cam
74mm crank
cb intake center section
34 pict and svda
1.25 rockers
bearings, seals, dowels timing gear, lifters yadda yadda;

currently in car is a 1500 sp with the new intake, carb, dizzy, rockers, with the tri mil hotdog for exhaust.

Going to be reusing all that stuff on the new motor, for budget reasons; It will be a single carb, single port motor;

So, that in mind, build is going as follows:
All the parts above, the questions are:

Heads are staying stock 35.5 32 valve sizes, will be 'ported', ie the old bowl blend, 3 angle job, backcut intake valves, intake matching etc.
When setting this up what is better? to 0 deck the piston and step the head or set the piston below deck and leave the head 'as is' for quench?

Looking at 8.5 to one for compression, thinking 9 might be too much for that cam?
would 92 octane work with that?

I might be able to spring for a new cheap header the old 4-1 glasspack jobby, would that be better than the tri mil hotdog I have or pretty much the same?

For the carb, its mostly rejetting, resizing the vent prolly to get the most from it. its currently with a 137.5 and 60 idle which works good on the above sp.

Also, putting just the 1.25s on the intakes, thinking that would work better than 1.25s on both intake and exhaust?

Take note, this is the budget, so there wont be any dual port heads, dual carbs, turbos, etc, already know that would make more power, but what i got is what i got, so if thats yer reply then dont. I already know what Im looking for in this build just need the above answered only.

Also, how come cant get lighter advance springs for VW dizzys like you can with others? Looked everywhere can't find them. Will be curving the dist to match this combo and looks like will be making my own springs on the lathe.

One other question is, I bought the CB gear with 4* adv/ret option, best to leave this cam straight up? Car seems to have a regular open box with 4.12 gearset??? in it, 1st gear seems real steep and the rest seem to be 'normal' although it still seems to rev high 31-3200 at 60mph 4th with a 205 60/70(cant remember, but tall) 15 tire. Thinking with that tire at 60 should be more like 28-2900rpm

[BFB]

I think its a shame to do all that work only to choke it with a carb that flows as much are as a coffee straw. But that’s just me, I can’t stand those carbs, some ppl seem to really like them though and more power to them! Heh heh .. pun?
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.  
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1

[Dusty1]

Aircooled dot net won't sell you a 2280 cam any time soon but they can tell you about it. They say,

"This cam works best with a compression ratio of 8.25-8.4:1, but you can run it in the 8-8.25:1 range too.

You can use 1.25 rocker with this cam, if you use HD Springs and Bolt On Rocker Shafts!"


Maintaining low RPM flow velocity is a concept that is becoming archaic as carburetors become a thing of the past. Still, if we're using a carburetor or carburetors the old rules apply. The old rules say to keep intake tract or port volume necessarily low to maintain low RPM flow velocity. That's part of the reason "built" motors idle lumpy, a choppy vacuum signal at low RPM. We see dual plane manifolds in the V8 world as a solution to low RPM flow velocity. If we're using a four barrel carb on a V8 we can use a manifold that separates the primary and secondary venturies of the carburetor. Clever! There's almost nothing like that in our vintage aircooled world. Except maybe for the old Holley / Weber "Progressive" two barrel. We could conceivably split an old Progressive into a dual plane setup but let's not get ahead of ourselves. It's a carburetor that never really worked properly on anything except a 2.3 liter Pinto.

Which is to say your combination should work well without over- thinking or over- working it. I would keep the compression ratio on the low side. The only thing predictable about gasoline is it will become higher priced and lower quality. It disrupts my fun to money ratio when I pay an extra buck or more per gallon for premium gasoline every time I fill up.

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[modok]

I think you won't need lighter springs in the distributor, maybe heavier ones just as likely, but not totally sure what it would like best, maybe others are more expert.

Already have said about the 1.25 rockers, but will say again easy to try both ways and see yourself.
For the max compression IMO, cylinders 2/4 8.5, cylinders 1/3 8.0
Yeah that's odd, but it doesn't run equally on all four anyway and everybody knows THAT, they just haven't though of what to do about it yet.

How you cut the heads and establish the deck height is not critical since it's stock bore.
If it was bigger bore then I might want to machine it in such a way as to leave max metal in the heads, but stock bore it's just not a real concern, any way is fine that gets the piston the right distance from the head.

Although the intake is a performance limiter.... the exhaust system still will make a difference, a good system will help overall performance a lot, maybe even more so than if it didn't have a restrictive intake. The more intake vac there is at WOT, then the more you want to have the exhaust pull more vac to match it.
Longtube four into one will probably be best, and with a long collector length. That worked best on my big SP
Far as a hotdog, I don't know never tried one.

Cam timing I'd think straight up is fine, or no more than 2 degrees advance. I don't think extra advance would be of any help.

[Dusty1]

In between Subaru conversions, a 175hp EJ25 in a sand rail and a 500- plus hp STi w/ Subarugears in a Super Beetle... I tuned a '70 single port in a buggy. I can't believe how stout that thing is. I wish someone took a video. I'm fairly certain I was hopping the front wheels off the ground between first and second gear.

That's a tried and true performance recipe, shave as much weight off the vehicle as possible.

We're talkin' a mostly stock '70 single port built on a "B" case. Solex 30 PICT2 carburetor, 009 distributor, merged exhaust w/ single QP and "J" tubes.

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[Millionmph]

Hmmm after that input, will be setting my CR at 8.4 to 1 and try just running 1.25s on the intake side;
Wondering how Modok has never tried a hotdog? lol
If anyone else has any input on the empi header glasspack setup vs the hotdog, let me know, the hotdog is getting crusty/pitted and like the look/sound, but wondering if the header glasspack makes more power, if its significant enough would go that route
If I scrounge more, might splurge and try one of those cheap 39mm pict carbs on it as well

[Dusty1]