Parts list for a turbo build

[westypoo]

Well today was a sad say. My wbx turbo motor in my super Beetle let go today. I think I broke a rod on #1 cylinder. The spark plug that I pulled from their is smashed. Fortunately I guess that it happed while decelerating. As soon as I heard the weird noise I put the clutch in and shut the car off. Of course this all happed on a busy 4 Lane road. So I was in the turn lane and fortunately I had a friend with me and we pushed the car to a safe spot so I could see just what might have happened. I tried to turn the motor over and it wasn't turning over. So I got the car home. Tried turning the motor over with a socket wrench and it turned one way, then turns the other then way, then stops. Tonight I got the motor tore down to basically a long block. Tomorrow I'm gonna drain the oil and coolant and pull the heads off. I have a spare wbx that I'm gonna put into the car and run it all motor for the time being till I get this broke one built up again.

So I guess it's time I look at what needs to be done to build a bottom end that can handle boost. What is all you experts suggestions for what I need to do. This will be my first ground up build and I just wanna do it right. I guess I might as well get bigger pistons/cylinders and up the size as well for how little the cost difference is.
Questions are
what rods should I get?
Are the piston/ cylinder kits off go westy good for a turbo application?
Stock crank good?
Thanks guys for any input.

P. S. THE Motor IS A 2.1 WBX w/ amc heads, WAS running 8lbs of boost, running fuel and spark control thru megasquirt.

[Chip Birks]

What kind of rpm was it being run to? Boost did not break that rod. Not 8psi. Sounds like the motor was probably on the tired side to begin with.

What kind of power are you looking for out of the new motor?

Good luck with the new build Wes!

[syncrogreg]

Bad luck mate. Have you thought about supercharging instead? That way you can keep the rpm down and still get great power. I would love to build a wbx with a blower.

[AMBROSIA]

Stock rods are a known weak point from what i'm told, even in a stock engine.
Marco Mansi uses I-Beam Rods in his builds.
Don't worry about the stock crank, it can handle lot's of hp being a forged unit.
I've heard mixed reviews about the gowesty oversized pistons and liners, so do some research before deciding.

[westypoo]

@chip max rpm was 5800/6000. Nothing too crazy. The oil pressure was on the lower end of things for sure. But I'll surly post pictures of the damage.

As far as the new motor goes..... I'd like it to hold 15-20 lbs of boost, put in 96mm piston/ cylinder kit, better rods, keep the stock crank, reuse the heads and go from their. Does this sound worthy? What are good rods that I can get? Do they even make better rods for a WBX?

[syncrogreg]

Easiest option for rods IMHO is to get T1 rods from scat as they will resize the bushing to 24mm before sending. I would not bother with rebuilding standard rods, good money after bad I think. The stock crank is a stout unit for sure but you might consider a rebuilt and counterweighted DPR to cope with high rpm. Is the new engine to run over 6k?

[Piledriver]

SCAT T1 I beams, not Hbeams. Mucho stronger, 3/8" ARP1000 bolt option.
The Hbeams don't have sufficient meat at the small end for safety margin.
SCAT will do setup for 24mm pins for a few $ extra.

Tencentlifes trick... buy the rods a touch long (they come in 5.4/5.5/5.6 and IIRC 5.7" lengths) then shave the piston crowns as needed to set deck, since you can't shim etc a WBX like an aircooled.

[Joe vw]

Sorry to hear this. It's likely you dropped a AMC exhaust valve (known junk) or a rod stretch bolt let go. Possibly a broken piston from detonation.
The stock bottom end doesn't need much to upgrade. Was this a stock used long block?
Some factory engines had very loose clearances for the mains and others were good. I would get the crank mains ground (just for tighter clearances).
Unless you are running a wild cam no counterweights are required to 6000 rpm just a good balance job.
The stock rods can be rebuilt with arp or 1.9 bolts and the small end profile milled to shave weight. The stock rods are not that weak, it's just the weight of the small end and the pistons that are attached to them. Low oil pressure due to sloppy mains (on some) and crappy stretch bolts combine to cause problems.
More economical are aftermarket I-beam type1 rods - CB, Scat or AA resized and rebushed for 24mm pins .
I would also do the oiling mods as posted on this forum including o-ringed oil pump.
The Go Westy pistons are J&E and up to the task of more boost. Keep your deck at 1mm and don't do anything drastic to lower compression.
Just make sure your tune is good. Maybe some dyno time when your done. Keep us posted

[Piledriver]

The stock rods big ends go all egg shaped on 2.1s after ~100K miles.
Initially thus just causes low oil pressure. Eventually it causes ventilated blocks.

It costs more to rebuild them properly, and put good bolts in than the stock rods vs. much stronger CrMo scat rods with the ARP2000 bolts and rebushed for 24mm, in your choice of length.

The length is extra handy as some of the aftermarket pistons have the wrong deck height, plus shaving the pistons is the most sane way to up your CR.

[Joe vw]

There is good reason the stock rods egg out, Usually it's after 150,000 miles. It is due to the reasons stated above.
A heavy Vanagon at 4,000 rpms to go 70mph is another.
Reasonable sustained RPM, good oil pressure, good bolts and shaving weight at the piston end will help prevent this.
As I said, New I-beam rods are the way to go for most cases but not the only way.
My NA 2.1 is getting a set of AA 5.5s I beams with 22mm pins and (short) Toyota V6 pistons dished slightly more to save (a lot of) weight and raise my compression.

[westypoo]

Well here is the update. So I pulled the motor apart yesterday and I must say Joe vw was correct. #1 cylinder broke off a valve. As I know what the motor to be, it's a bone stock 2.1 WBX with amc heads. I'm going to need to get a new head. It looks like you can buy them without valves. I'll do that cause I'm gonna go stainless valves anyhow. I do wonder if the valves in the amc heads are sodium filled. Witch are known to be weak I believe. Also as far a high revving motor.... Nope. 6k would be good for me. I just wanna use a stock cam. Would you guys suggest stronger outer valve Springs? I see that their duel Springs factory.
So I'll have pictures of the damage up in the morning. Thanks guys for all the help and insight.

[Piledriver]

Warning: The AMC valve seats are made from bubble gum...

AFAICT the rocker and ex/intake studs were the only non-casting metal worth using.

Valves, guides, seats, etc all trash grade.

Buy the heads bare and have them built with ALL new good quality guides/seats/valves/keepers/springs etc.

There are a few places that sell them already reworked, probably cheaper unless you do your own headwork.

[Steve Arndt]

We install probably 20 pairs of those AMC heads a year at our shop on customers vans. Zero problems so far. These are stock engines not performance builds.

Rocky Jennings built my engine. He replaces the exhaust valves with TRW and does a good valve job but otherwise the AMC parts are good now.

[Joe vw]

Here's my experience.
The Older AMC heads definitely had crappy exhaust seats. I have a set that have all 4 seats ERODED to the point that the valve sunk at least .100" that went undetected due to the hydraulic lifters. It just lost power. These Heads were from the late 1990s.
Have they changed since then? I have read they are better now, but since when?
I ALWAYS recut all the seats and replace the exhaust valves and Use reground VW or new intakes. If you don't believe me at least do yourself a favor and check the valve job with dykem and fine lapping compound. I haven't had enough mileage to determine the full lifespan of the newer exhaust seats, but I recall them cutting fairly hard doing a valve job.
Guides have always seemed fine, intake seats are fine, retainers are mush, As stated above exhaust valves are crap, VW springs are better, the keepers need to be ground so they lock on all heads.

Replacing the outer springs with type1 HD ones is a good idea, you have to be careful with the installed height and coil bind. The type 1 springs are 1.5" where the waterboxers are 1.4" installed. This can be fixed with BERG retainers for extra installed height, machining the spring seats or cutting the seats .100 deeper when doing the valve job (increases flow). With the turbo keep the exhaust seats wide enough to quench the heat.

If you are really concerned about the exhaust seats in a new set of AMC heads they can be replaced without any machining of the head by a competent shop usually 25$ per seat.
You must have been down on power with burnt valves - check the others just for the heck of it.

[Piledriver]

My set were from 2003, in a Vanagon, got 55K miles out of them.
All the valves were pounded ~2mm into the seats, still sealed fine as they were so soft... and the hydraulic lifters kept the issue quiet.

I was so enthused about the head quality I eventually gave up on the project after assembling the shortblock and setting up the rocker geometry with the custom cam... (This was also about the time $4/gallon gasoline hit, so the 15MPG from the automatic shed still doesn't appeal to me, although I still have it in service as dry storage)