1835 Single port build!

JRKman · Posted: Mon May 27, 2013 9:51 pm Post subject:

In a few years I'll probably build a larger engine with all the good'ns using the case from the motor that is in my bug now. This is just something I can build for a learning experience to replace the barn engine I am currently running. Literally was an engine a friend had sitting in a barn I had to use since the engine that came with my bug when I bought it crapped out.

These are my requirements for this build (in order):
-Reliability
-Affordability
-Learning experience
-Performance

Really as long as this thing runs as good as a stock 1600 does, then that is an improvement from what I have now.

Also, I'm set on the scat C25 cam. Ive read really good things about it and how it can run really good with 1.25 ratios also. Also I already own it,

Matthew · Posted: Tue May 28, 2013 4:21 am Post subject:

The c25 is a fine choice. Now concentrate your efforts on intake flow while maintaining velocity. Look at the Bill Fisher book for tips on the heads. I would enlarge the intake ports without hogging them out and have a nice multi-angle valve job done. Individual 1.25 rockers can be bought cheap enough. I'd add them to the intakes only.
_________________
1965 Beetle sedan
Click to view image

JRKman · Posted: Tue May 28, 2013 10:49 am Post subject:

Ya I've been doing a lot of`reading on single port head porting. I think opening up the intake port a bit, multi-angle valve grind, and the better flowing manifold ought to get air moving a little better.

modok · Posted: Tue May 28, 2013 4:42 pm Post subject:

yeah, the intake manifold and porting is going to be the key more than anything. I'd think maybe a CB 'stock" center piece connected to larger steel ends? I'd prefer steel tubular adapted from type-3 or from an old SP bugspray/dcnf manifold that are so common. I know they have aluminum ones but those just don't look all that great, the middle is good to be aluminum(for heat) but for the ends steel is better.

JRKman · Posted: Tue May 28, 2013 11:55 pm Post subject:

Can you give me a link or something to the steel ends. I dont see any anywhere.

modok · Posted: Wed May 29, 2013 12:16 am Post subject:

Sorry, I suppose this stuff may seem obscure if you don't know what it is, it's just junk to most folks
Type-3 FI manifold; the tubes on this are the correct shape and size, just have to cut em off and weld the ends on
http://www.thesamba.com/vw/classifieds/detail.php?id=1380746

and these are also very common too; manifolds for dcnf/bugspray onto SP
http://www.thesamba.com/vw/classifieds/detail.php?id=1274781
tubing on these is a little smaller, only 1 or at most 2mm bigger than stock 1500, but stout, and already has ends even

JRKman · Posted: Wed May 29, 2013 10:44 am Post subject:

I see what you're sayin now. The dcnf manifold might be a little easier to do but more expensive. I'll look into that stuff. Thanks

JRKman · Posted: Thu May 30, 2013 8:42 pm Post subject:

So I'm rebuilding my 34 pict right now. Got to thinking about jetting for the new engine and dont really know where to start. It'll obviously need an idle and a main jet increase but how far is the question. Also, should the air jet be changed as well?

Danwvw · Posted: Thu May 30, 2013 10:18 pm Post subject:

I am trying to learn a little about jetting too. It looks like the thing to do is to get one of the instruments that measures combustion gasses to analyze the mixture! I think they are called a "wide band" a company called AEM makes them. But jetting is an art form. Probably have to do it through buying a few different jets and trying them to see how each behaves. Trial and Error!
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

JRKman · Posted: Thu May 30, 2013 10:48 pm Post subject:

I'm gonna shoot for 28mm on the vent, 140-145 main, 60-65 idle, and 80 airs first. That should be around the right place. Anyone have any other opinions?
_________________
1969 Type I
House paint red
1835cc single port:
Scat C25, ICT's, SVDA

modok · Posted: Thu May 30, 2013 10:56 pm Post subject:

The main must go up in proportion to the vent for sure, but sine your also putting it on a bigger engine and smaller manifold.... who know, all the other stuff might cancel eachother out.

JRKman · Posted: Tue Jun 04, 2013 12:29 pm Post subject:

Just rebuilt a 34 pict and put it on my bug with my SVDA. Holy crap my car runs like a top now. Who woulda thought that stock stuff would run so well. Razz

Anyways now just waiting to send stuff to the machine shop. Will update once there is some progress.
_________________
1969 Type I
House paint red
1835cc single port:
Scat C25, ICT's, SVDA

JRKman · Posted: Sun Jun 30, 2013 5:40 pm Post subject:

So I'm gong to buy some pistons and cyls and now I can't decide if I want the thick walled 92's or to just go for the 94's. any opinions?
_________________
1969 Type I
House paint red
1835cc single port:
Scat C25, ICT's, SVDA

JRKman · Posted: Mon Jul 01, 2013 12:30 pm Post subject:

Ok you guys convinced me to get the 94's. Soon will be starting the build. Gonna port the heads here soon also. Will be posting pics.
_________________
1969 Type I
House paint red
1835cc single port:
Scat C25, ICT's, SVDA

JRKman · Posted: Mon Jul 08, 2013 12:32 pm Post subject:

I am now in the possession of pretty freshly rebuilt single port heads opened up for 94mm cyls. I've found out that cb carries single port manifolds for ict's for a reasonable price. That leaves the icts open instead of the 34 pict but I still haven't decided what ill run.

I also have the option to purchase a CW crankshaft for a reasonable price. Am I better off running the stock crank and spending the money on balancing or would you recommend the CW crank? Keep in mind this think isn't gonna rev more than 4500 rpm. I'm leaning more towards running the stock crank but am open for opinions.

-Josh
_________________
1969 Type I
House paint red
1835cc single port:
Scat C25, ICT's, SVDA

Quokka42 · Posted: Mon Jul 08, 2013 1:56 pm Post subject:

Use the ICTs, you're going to need the little bit of extra breathing for the larger engine.
_________________
There has only ever been one man who was perfect, and they nailed Him to a cross.

JRKman · Posted: Mon Jul 08, 2013 2:53 pm Post subject:

I got a nice assortment of jets for them too.
_________________
1969 Type I
House paint red
1835cc single port:
Scat C25, ICT's, SVDA

modok · Posted: Mon Jul 08, 2013 6:56 pm Post subject:

I'd run a stock crank, buying an aftermarket one may cause more problems than help anything.

ach60 · Posted: Mon Jul 08, 2013 7:52 pm Post subject:

modok · Posted: Mon Jul 08, 2013 8:56 pm Post subject:

If the engine is designed for lower rpm powerband then stock, then it would be a good use for a stock crank if I ever heard one.

I would put a counterweighted stroker crank in it and port the heads and use bigger valves too.........oh yeah, actually I did.
BTW I just drove that thing over 250 miles to the north sand hills, then beat the crap out of it, then drove 250 miles back the day before yesterday.
Blew a shock and reverse but that funny old engine runs like a clock.
The 1904 SP is not to be underestimated Wink

if it had ICT carbs I don't know if they would have flooded, boiled over, or broke off first, or if they would have kept working long enough to kill the engine with dirt Laughing

Long live the single dellorto also Very Happy

No offense to the "street carburetors" offroad is a whole different thing


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