2276 engine build question

[Jellezwolle]

Hey guys!

I am new to the aircooled scene and have bought a 1970 early bay.

I wanna start building a 2276 engine for it, already have some parts and ideas!
Maybe you guys have some tips for the setup?

Here is the setup that I was thinking of:
2276 motor
94mm aa cilinders
82mm cw cb performance cranck
5.4” h beam rods
Cb 044 heads 44x37.5 CNC ported
Dual weber 48 idf carbs
Engle w130 cam
Straight cut cam gears

Hope to hear from you guys what you think!

[madmike]

I'd use thick wall 92mm cylinders,smaller cam too, buses need lower rpms cams
40X 35.5 heads will work too but if u already have this stuff, and use it,, it may just run a little warm/hot on the Autobahn?
_________________
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[74 Thing]

Which CB CNC ported heads?

I would look at a different cam. The 130 needs some compression and you can get better drivability and torque for a bus using a different camshaft.

[Ohio Tom]

Agreed a "130" cam is way to HOT for your application.
you will operate "under the cam" 99% of the time. It will be lazy and less than it could be. (unless you plan on drag racing?).

[Jellezwolle]

So if I understand you guys I would need a can for lower rpms. Is it just because of the cooling?
I want to make an extra oil cooler in it.

Would not be a problem that the engine won’t last 100.000 miles.. will be driving like 1500-2000 miles a year and to take apart a motor after a few years is not a problem.

My goal is to keep up with my buddy’s who all drive watercooled cars.

[Jellezwolle]

And I got a fk7 and a fk8 cam laying around, would one of them be a better choice?

[ALB]

[Jellezwolle]

[Ohio Tom]

A w130 is a hot cam. Not sure who says it's powerband starts at 2500.
that's not right at all. More like 4,000rpm for peak torque. 7500rpm for peak HP.

You plan on living there?

It's real simple really.
The bigger the advertised duration number, the higher in the rpm range the cam will "work".

Here is my rule of thumb: Rpms are where the cam is "on" or making peak power.

280deg = 2,500-5,500rpm
285deg = 3,000-6,000rpm
290deg = 3,500- 6,500rpm
300deg = 4,000-7,000rpm
310deg = 4,500-7,500rpm
320deg = 5,000-8,000rpm
330deg = 5,500-9,000rpm+

Pretty straight forward really.

Advacing the cam 4deg brings the numbers down 500rpm. retarding it takes them up 500rpm. So if you choose the wrong cam, you have some adjustablity.

The thing about cams with big duration numbers is they have lots of "overlap". Meaning both valve are open. When that happens, the motor loses dynamic compression at lower rpms and gets Soggy. Power is very limted in the lower rpms. This is why big cams want lots of compression to make up for the loss of dynamic compression. They they also want higher octane fuel and run hotter..
If all you care about is the upper range, then choose a cam with 300+deg. A mid-range hole in the powerband is not a big deal.


If you want some mid-range and lower rpm grunt, stay under 300deg and you will have a nice continually increasing powerband.

I have used cams all over the range in everything from 1641's to 2387 Turbo Pro-Mod motors. Pro-Stock, and everything in between.
I have seen plenty of customers choose the "wrong" cam for the application.
it is so common to "over cam" VW motors it's not even funny any more.

I end up advancing the cam to de-tune it so they are happy with the motor. This happens ALOT.

[Jellezwolle]

Thanks a lot for your reply! That’s some good info!
If you guys could choose a cam for the setup, what would you do?
Not A problem if I need to buy a new cam so have a free choice 😜

[Ohio Tom]

My recoomendation is a cam with 280-285deg duration.
Get something that gives you about .430-.450" lift at the valve.
Dual springs, HD pushrods.

It will make good low/mid range torque.
And it will be able to rev to 5,500/6,000rpm and still make power (not float valves).

Just my thoughs.

Steve Long Racing CAms; XR280 comes to mind.

[Alstrup]

It basicly comes down to WHICH heads and WHICH gearbox. That said, unless you are really chasing hp the larger CB cnc heads are not the best choice for a bus engine. If you chose one of those opotions it is paramount that you chose the right cam to go under them.
The fk7 is too lame for such an engine, and will not make the large valve heads work that well. Its a small engine cam.

[Ohio Tom]

Why is the FK7 "too lame" for this engine..


Duration kills bottom end performance. Why would someone do that when they don't plan on running it up high?

Big motors run just fine with smaller cams.
No need install a cam that is designed to work in an rpm range beyond his goals.


Ever felt a 2276 make 180ftlbs of torque at 2,500rpm?

Don't need a big cam for that...