First build

[Rick122]

Hi, I'm gathering all the bits to do my first VW engine build.

** Before I list the parts, I live remotely and don't have access to anyone that can machine the case within 1500km, hence the reason for not going straight to an easier-to-build big bore. I am a mechanic and have built my fair share of motors before and have made my own EFI and turbo setups, so I'm not afraid to tinker and learn from others.
I'm also not made of money, and our dollar is atrocious at the moment compared to the US or UK, so I have bought some of these parts from the classified's here, not parts houses. I hope that I have not ended up with a poor performing build by doing this, which is what I would like feedback on.

The main parts I have are:

- AS21 twin-port case, single relief. Stock, with very little wear. I believe it was a replacement motor and as far as I can tell, it had never been rebuilt before. It ran well before I pulled it apart and everything measures within factory specs.
- 74mm counter-balanced 8 dowel crank. Unknown brand or if it's 4130/4340
- 88mm machine-in cylinders and pistons - AA. I bought these new.
- 5.4mm rods. The seller couldn't tell me what brand they were but they look like stock ones that have been stroker clearanced to me. They were bolted to the crank.
- 042 Mofoco heads, 40x35, single springs. I jumped on these because I got them for price cheaper than a set of cheap 35.5x32's and they were already machined for 90.5/92mm. They are new.
- Engle 120. I bought this second-hand and it supposedly had little use.
- Straight cut cam gears. These came with the cam and I got them as a set for cheap.
- Scat pro-street 1.25 ratio rockers. Bought second-hand from a good friend. He gave me some chrome moly pushrods too.
- Scat lightweight lifters. Bought with the heads. They are new.
- 200mm Lightened flywheel. New
- CB maxi-pump 2, #1791 with filter. New
- Scat 8mm Chrome Moly head stud kit. New
- Twin Dellorto DRLA's
- Pertronix distributor
- Empi 1-5/8" Comp stinger w/muffler
- and new case bolts etc.
All up this has cost me roughly $2000US

I had previously started building an Speeduino EFI setup for it, with injector bosses welded into dual port manifolds and distributorless ignition and I have an AMR500 supercharger I was going to put on later but not sure on that yet as it might be too small for the motor.

I guess what I'm worried about is that the large valves/ports and W120 cam might be too big for such a small displacement, resulting in poor torque down low (it has big tyres and the gearing suffers because of it). I can't do anything about the other basic components but would a smaller cam, eg. C35 still work ok with these heads? Or am I worrying too much? In the end I think I'd be happy with 110-120hp.

[66brm]

What's it going into? My biggest concern is the cam, rockers and springs, valve float is a big possibility.

[Rick122]

'59 Baja with big tyres.
Do you think it needs dual springs, or a smaller cam?

[66brm]

If you are off-roading in tight trails at lower rpm then a smaller cam would suit, if you're doing hwy miles then look at dual springs

[sideshow]

Smaller cam or at least stock ratio rockers, assuming you are building a big tire (high gears) with street manners. Most would suggest better single or the more common duals with big valve/cam combos like yours.

[Rick122]

Thanks for the suggestions. Would a w110 or C35 be ok with the single springs if I set say a 6k rpm limit? Yes it's a street car which will see little off-road.

[sideshow]

That is a more tradition mild build. I would guess that you want great idle and off idle so aim towards that design.
And because you have bigger valves, higher than stock rpm range, more aggressive valve timing, I still would choose cheap dual or better singles.

[Rick122]

Are the singles that come with the mofoco 042's not good?

[sideshow]

It isn't a show stopper and something that can be changed after build insitu
Watch for erratic map signal or really any poping up the carburetor throats

Anything can be made to work, somethings just last longer and bring more joy.

[Rick122]

Thanks sideshow. I've bought a c35 cam.

[Tom in PA]

Keep us updated on the build. Was the C35 a new cam? Mixing new lifters with a used cam can be a recipe for disaster. Be sure to use a good, high zinc break in oil when the time comes. I'm a big fan of Brad Penn. Down the line, a smaller header would likely be beneficial but not mandatory. I think it would likely help the bottom end but run whatcha' got for now. Not a game changer.

Tom

[Bad Bob]

CB sells DRLA venturies as small as 28mm. I have 30mm in my street car. With big tires and low rpms, go with the 28’s. Don’t start playing with the jetting until you get a wide band sensor/gauge. Life will be much easier.

[Rick122]

Thais for all the advice and suggestions. I've got most of the bottom end completed, but I'm still waiting on parts to arrive (flywheel shims, cam plug etc.) before I can bolt the halves together. C35 cam is new, new scat lifters, straight cut gears fitted. 74mm crank fitted without any clearance issues, just a tiny bit for the rod bolts which turned out to be Empi 5.4. I've done the HVX mods. I've decided I'm going to fit the supercharger. I've ordered some copper head shims in 0.040" and 0.060" barrel shims from CB. I won't know until I can work out the deck height but I'm hoping the 0.100" will give me a bit lower compression.

[Rick122]

Can anyone assist me with the deck height?

I've fitted the 60 thou shims, which gives me 13 thou deck height (to the top of the cylinder).
The head chambers I was told were 55cc, but they've been taken out an extra 10cc by machining to the inside diameter of the barrel.
If I plug all this into the calculator using 65cc, I get a 7.7:1 compression ratio. But all the info I read says that I should have around 30-50 thou deck height?
Should I measure the step in the head and count it as being part of the deck height, or as part of the cc? Counted as being deck height results in higher compression ratio according to the calculator?

[Bad Bob]

You better find out for sure what the volume of your chambers are. It’s easy to do with a syringe and a plate of lexan or acrylic. If you have a step cut in your chamber, that counts as part of the .040 clearance you need. Measure the height of the step and the chamber volume and you will know for sure what your C/R is. No short cuts here!