2007cc build thoughts

[EBSTEVE]

I'm looking for some thoughts if someone sees a problem with what I have planned.
This will be gong in my bug to drive from time to time but not daily, I am wanting it to be a reliable motor that has enough HP to have a bit of fun driving.
I already have some of the parts marked with the *
* AB case 10mm studs opened up for 90.5's and full flow
90.5 B pistons
*78mm scat crank
*5.4 rods balanced and clearanced
*W110 Engle cam
*041 heads (40x32) ported single spring
shooting for around 9:1 compression
*Dual Weber IDF's, I may rework some DCNF's

Plans changed, I bought some 92mm thick wall B pistons and a set of AA 40x35.5 heads that were ported by Brothers machine. (can reuse my old mild ported heads on my wife's motor).
Now I am rethinking compression and cam if anyone has any thoughts.

[jfats808]

Everything looks good. 13lbs chromoly flywheel, kep stg1 and kushlok. I believe scat 78 cranks are actually 78.8? Anyway looks like a great build for even a daily. I'd probably have the cylinder bases turned down say .030 and shim if you need to. Or if you have a machine shop close, just have them turn down the bases to size after mock up.
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2276 IDA's 86C 11-1 DD

[GTV]

Since you don't yet have pistons and cylinders considering upgrading to 92's or 94's. You can get them where they "slip in" to the 90.5 case register. With both sizes the heads would require boring to the 94mm cylinder OD. Obviously that makes the 92mm cylinders 1mm thicker, and less susceptible to warping should you ever overheat the engine.
Secondly, have the exhaust valves increased to 35.5mm, and dual springs. Quality port job... You may find it is much more cost effective to buy a new pair of heads, like the CB Panchito's, rather than to have the work done to your existing heads.
The 110 cam will work, but there's better choices out there today. Especially at 2+ liters of displacement, you can have more cam.
I would choose the IDF's, they fit in a beetle's engine compartment a lot easier (assuming that is what it's going in). What size are they?
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EMPI Power Rules!

[EBSTEVE]

Both sets of carbs are 40's

[GTV]

If you're keen on keeping the 40's then keep the cam and displacement you've outlined. There's nothing really wrong with it (other than the small exhaust valve) but there is potential for improvement. If you want a lot more power sell both sets of 40's for some 44's, go 94 bore for 2165cc (no more cost than 90.5's), and upgrade the heads (new Panchito's are cheap compared to head work).

Will you need a heater? Do you already have an exhaust, or have one in mind?
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EMPI Power Rules!

[mark tucker]

5.5 rod or cut the cylinders down

[modok]

brazil 041 heads suck. I think you should use a split cam with more exhaust duration, or get some panchitos!

Mark is right, if they are mahle B pistons the pistons will be down the hole .100, so you should fix that, deck the case .040 or get longer rods.

if they are AA pistons then neverfmind it will fit perfect.

[EBSTEVE]

Glen, do you have a suggestion of a split cam?

I know bigger heads and carbs will increase the power but I have to draw a line somewhere, is this completely the wrong spot to draw it?

Once I mock up the motor I will see if I need to change the deck height, it's there an advantage to machining the jugs, either easy would be an option.

As for piston size I can get the heads cut locally (by a reputable shop) for 90.5's but he is not setup for 94's so that is why I am going 90.5 vs 92 thick walls.

Thanks for the thoughts so far, please keep the info coming.

[modok]

Machining the cylinders would have the advantage of actually making the engine narrower a small amount, which might be good, the downside, is if you replace a cylinder or all of them later you will have to shorten them again, rather than just replacing.
decking the case would represent no additional work if you'd done it at the same time the case was done, but I guess too late.

If you have a lathe, do the cylinders
If you have a milling machine, do the case
If you have nothing, get a job
(whatever floats your boat)

A lot of people "think" you can't run bigger exhaust valves with heater boxes, and I don't know if it's really true, but assuming it is, you could use more duration instead of a bigger exhaust valve. I think it makes sense, and will work, and should be done a lot more often than it is. Not really a fan of the brazil 041 because they don't flow very good numbers for how big the port it, but that's a separate issue. I would prefer to endorse the idea more along the lines of put in ONLY a bigger intake seat, rather than use brazil heads, but in either case a split cam is the right direction.
I was thinking crower 61004 or 61005, it doesn't have to be crower brand but just so happens they have around a 8 degree split.

[nsracing]

We have a 2007cc thread going now.... check it out.

The combo you have is close to what I have used in the past but w/ stock cam on the 041 heads for bus. Worked pretty good and lasted.

Cam choice should be to what the combo is meant for. A daily driver should not be running a racing cam. Mild is good in a daily driver. more reliable too.

[Mikedrevguy]

The first iteration of my motor was very similar-
78 x 90.5
C-35
Mild ported heads 40/32
kadrons.

First change: swapped out the Kads for 44's- no appreciable change what so ever.
Next change- DRD L-5s - confirms the adage- the power is all in your head. Bigly noticable change.

That first motor wasn't a bad motor, in fact, after all the changes I've made, I have all the pieces karts to out it back together again (after I get lifter bores sleeved) and I'm going to run that as a winter motor - maybe next winter?
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74 1303 (RevBug): plan for German Look
76 914 with 2260
79 VW Iltis
69 Bwajaja
"The wise speak because they have something to say; while the foolish speak because they have to say something." Plato

Illigitimi non-Carborundum!!

[EBSTEVE]

Mike,
Were the 40x32's you had ported?

I am leaning towards building it with the intention of swapping to ported 40x35.5 heads in about a year.

I am"restoring" a 61 ragtop my wife at the moment, the pan is at 95% and I plan on starting the body as soon as my engine is done. I can justify some heads for my car when I build her motor and put the 40x32's on her 1776.

[anthax]

I finished my 2007 late this summer, and love the engine.
It's quite similar to yours, but I have
C25 cam
CB 044 heads with single HD springs (40mmx35mm)
Alu case full flowed
Forged counterweigheted 78mm crank
Forged conrods 5,4" Scat
Mahle Forged pistons 90,5
26mm oilpump
Dual IDF 40 with 32 vents
SVDA dist.
9,8 static comp, around 8,5 dynamic comp

The thing I had to to was lowering the deck 0,8mm on the case to get the right distance piston to head. (1,2mm).

I have a great engine shop nearby that did crank balancing, lowering the deck on the case and 3 angle valve job.
CB heads sure do have very bad valve seat from factory. The man at the shop that did the valve job was surprised how bad it was done from factory.
Luckily he could fix them without putting in new seats.

My engine pulls like a tractor from 1000rpm, still strong at 4k rpm. Haven't tried more because the rings haven't finished the running-in process.

[Mikedrevguy]

[EBSTEVE]

Plans changed, I bought some 92mm thick wall B pistons and a set of AA 40x35.5 heads that were ported by Brothers machine. (can reuse my old mild ported heads on my wife's motor).
Now I am rethinking compression and cam if anyone has any thoughts.

[modok]

I very much like the web 110, it's quiet, and also more everywhere than engle 120.
If you have dual springs can try 1.25 rockers, I like to do intake only.
Should be able to handle 9-1 or possibly 9.5-1 compression.

[EBSTEVE]

So you only do the 1.25's on the intakes? Never thought of that how is that better than doing them all?

[modok]

Why not?
Well, a valve in most cases should be lifted around 0.3 times it's diameter, so, do the math on it, and you'll see it's not OUTSIDE the usual rules of common sense. makes a lot more sense than using a 32 or 37mm valve in this engine and lots of people do that, for some reason. Sure you can try more or less and see what happens. I tried lots of things. If it works just as well then there is no downside. Guides will last longer, rockers are two sets for the price of one, lash is less critical. Having more exhaust flow than needed can often upset the carburetors believe it or not. If you want to play with 1.25 rockers get the CB big mouth pushrod tubes, if you don't want to play with it then don't worry about it; it's a small difference.
Good heads, high compression, tight deck, really brings them to life. IMO that's more important than chasing the last HP or the perfect tune.

[luckystiff]

[EBSTEVE]

I mocked up to measure today...
The Scat crank is 78.3MM of stroke
The heads are 62cc's
Deck height is .106"
According to CB's calculator this gives me 7.5:1 compression ratio

I am thinking that if I swap the 5.4 rods for 5.5 rods that should put my deck height at .006 and if I shim the cylinders .04 that will put me at .046 of deck height and that puts me at 8.5:1.

thoughts?