Engine works, but can it be optimized? Or maybe a new one?

[qubek]

If you take a look into the two answers above, they are contradictory, but at the same time both make sense.
Finally, the decision will probably depend on the amount of free time I'll have. There is still a lot of other things that MUST be done to the car, so we’ll see.

But there is another thing in this  discussion that seems interesting to me.

The issue with a stock crank. There is a lot of people, especially in the US, that will never ever use a non-counterweighted crank in a high performance type 1 engine.
On the other hand, if I remember well some old German magazines I’ve seen in the past, the use of stock cranks was quite normal.
Johannes Persson’s engine in the topic above used stock crank (if I remember correctly). Sure, it had lighter pistons, but still….

And looking into the counterweighted cranks we can buy today their quality is inferior compared to a stock crank. This concerns forged cranks, but I have also heard that there are problems with stock welded ones.

So how is it really? But don't start with “Gene Berg has once said…” or “Everyone knows that…” please

[Zach Gomulka]

In the US it's cheap & easy, so why not? A buddy of mine has a basically stock engine in his bus but with a c/w crank, single Zenith & header. It's got to be the smoothest running VW engine I've ever heard, I'm hoping for the same results with my new engine, but much faster throttle response.

[Diederick/DVK]

a number of DFL guys ran stock cranks in their 1776cc for quite a while with no issues. but, with all due respect, it'll always be one opinion against the other.

[Torben Alstrup]

I only have one thing to say to that:
Why do we see so many stock cranked souped up 1600´s 1776´s and 1914´s with totally destroyed crankcases and occasionally broken cranks then ?
T

[Udo]

Sorry Torben , i never had a broken original crank . you must watch if it is ok and do a good balancing with a straight flywheel

Udo

[Torben Alstrup]

I have never experienced it on "my own" engines. (I wouldnt dare to build one like that except for race) But as said seen it on several high rpm stock cranked street engines.

We did have a Bugpack 69 mm counterweigthed crank break on us about 8 years back. That wasnt even a high rpm engine, but a super torque set up. The engine had about 70,000 km on the clock. On the way home from Spa, it broke just after accellerating up to freeway speed. Judging from the wound, it had suffered damage some time earlier and this accelleration was the drop that made it break. Luckily the guy was quick at the clutch and key, so only crank and cam was damaged.
So anything can happen, even if one think that every percaution has been taken.
T

[Chris bugster]

I would suggest building another engine as well as improving this one. Those Dynosoar/SuperFlow heads that you had off me should go on the next engine that you put together, but 103 HP is really not enough especially as you are not following your diet. It's nice to drive, but doesn't have that rush at the top end. It feels pretty much the same as what the dyno showed-flat.
re-Dellorto 40s I remember doing a 1914 back in the 90s that made 165HP@6500 with 40 Dells and 36mm vents. It had 10.5 squeeze and a 130 Engle and the heads were ported versions of your ones. They looked something like a S/E- port, but had a 40intake and 35 exhaust.

[Chris bugster]

BTW- Hello everyone. thanks for letting me in. Can I smoke?

[Frallan]

Czesc Chris,
Why do you want to smoke?
Do not smoke, it is bad for you and the children around you :-)
Maybe we can bring up some old memories and chat in another place?

[Chris bugster]

HI Fredrik. Where are you in the world? It would be good to catch up. Where would you like to chat?

[Fiatdude]

I have broken MANY stock cranks and would never trust the investment I have in an engine to one --- IMO

[Frallan]

HI Fredrik. Where are you in the world? It would be good to catch up. Where would you like to chat?

Just saw you on Facebook. C u there. No more OT here. Sorry guys.

[qubek]

I would suggest building another engine as well as improving this one. Those Dynosoar/SuperFlow heads that you had off me should go on the next engine that ...

Speaking of which. As this topic is pretty much exhausted, maybe a new one - 'How to build en engine around a set of old ARPM super flows' - would be interesting?

So there is a set of heads as mentioned above:
ARPM super flo, seats are 44x37,5 (if I remember correctly), there are no valves. The heads need some work.
Now I know that they are quite outdated heads, but I'd like to use them

So what engine would you build around this heads?

The conditions are as follows:
1) I'd like to be fast enough to race modern cars, not just Beetles. The faster the better, but I don't need to be the fastest man in the town. I don't expect too much, especially that there are two other conditions:
2) The car should be able to be street driven. Now, before Udo mentions that super flows overheat - I know that. I don't need this car to be a daily driver (I have other Beetles) and I won't use it on autobahns (the nearest is more than 100 kms away anyway). This car would be something like a Saturday night special. I just don't want (yet) a pure race car that can be used only on a race track, few times a year.
3) The engine should be relatively simple.

I thought about something with a rather short crank, 94 mm cylinders and maybe some light pistons. Something less diesel-like compared to what I have now

What do you think? I know that there are many ways to skin a cat, but I'm interesting in hearing you opinions


 

[TexasTom]

How about this:

Mag case, 78mm crank, 5.352 (porsche length) rods, K10 or FK87 cam w/ 1.4-1.5 rockers, 94mm Ps&Cs, your ARPM heads, IDAs or 48IDFs, 10.5:1 - 10.75:1 compression, pump gas

Should build reasonable steam.

[qubek]

Why such short rods? I actually thought about 5,7s. Of course, I have no personal experience, so it's just my thinking

[TexasTom]

Snappier engine for the street: increased acceleration from tdc will improve airspeed and low end power.
Also, nice and narrow to fit engine compartment.

[qubek]

Well, I think it would be a good idea if I had different goals.
But, as I already heave another street car, I think more about power then snappy low end in this one.
Plus modifying the engine compartment will not be an issue - it's not a nicely preserved original Bug. Unless I underestimate the problem. Still, in this case, it is more important for me to heave an engine which works better, than one that is externally smaller.
In addition to that I was thinking about using other pistons then mahle - something lighter and with wrist pin positioned higher. Chris uses Venolias in his engine and I like the concept.
This is why I was thinking about long con-rods

[Torben Alstrup]

The heads dont work well with the valve set up. It revs a lot, but not enough power due to too large ports for the valves. Replace intake to 48 mm. Get more stroke, like 82 mm (Then it is also easier to get the required CR.) Since its also for the street I wouldnt go too long on the rods. 5,6 or so. High pinned light pistons, good. Get one of JPM´s new Raptor cams. if memory serves # 13 is good for what youre aiming at, but would have to double check that.
T

[TexasTom]

I think more about power then snappy low end in this one.

Then you should go 4" bore! 

[Zach Gomulka]

Going back to the original topic here...

To stay relatively inexpensive, and get some substantial power gains without further shortening engine life... I agree the crankshaft should be changed to a counterweighted unit. Now, at the same time why not get a 74mm crank for 2054cc? This small increase in stroke would allow you to re-use your stock stroke "A" pistons, and stock rods (with clearancing). Along with some port work, 1.25 rockers, and maybe a slight bump in compression, you would have a completely different engine under your lid.
Something to think about

[TexasTom]

Excellent point, Zach ... love the 2054 for a driver engine, one of my favorite combos.
Why not take just one more tiny step and go 76 on the stroke and step into some 2110 shoes? Just a little more clearance needed and an extra .040 on the cylinder shims.

[qubek]

Guys! Guys!
You know where such "one more tiny steps" lead to. You have to draw a line somewhere and for me it is not to disassembly the case. Just think how many parts you need to measure, replace, rework etc in the process. This would be a full-fledged engine rebuild. No point when you have plans for a second engine anyway.

[TexasTom]

Fair enough ... 

[Zach Gomulka]

I'm just sayin swap the crank, that's all It would be a great power gain for your dollar. It would take a little time, sure, but in my opinion would be worth it.