Vorsicht

So I failed CA smog twice after trying all the usual fixes (plugs, wires, vacuum checks, rotors, caps, etc..). My hydrocarbons were double the max allowed. Given my car has 96K I thought what the hay, I'll do a leakdown test and rule that out. Here are the results and some questions for y'all.

Cylinder 1: 88% leak
Cylinder 6: 5%
Cylinder 2: 5%
Cylinder 4: 13%
Cylinder 3: 5%
Cylinder 5: 78%

I did cylinder 1 at least 5 times to make sure I was at TDC. Sure enough crankcase notch and pulley notch aligned and primary rotor at notch (cylinder 1).

It looks likes a top end at the minimum. Needless to say I'm not happy but I'm also not surprised. So before I dive in a few questions for the gurus:

1. Would these figures be the cause of the smog failure (my guess yes).

2. What do these numbers mean? Am I looking at a total rebuild. My guess is I have to tear the thing down to find out what's causing the mayhem at numbers 1 and 5. Could valve-guides alone cause such a loss or is it more likely rings or blown head Gasket?

Look forward to your comments...

CalvinC4S

Those numbers are not right. Borrow some cats from a local lister and retest HC's.

ca993twin

As long as we are all guessing, I'll throw in my two cents... a few bent valves from an overrev. And I think that can cause the HC failure. With any luck, the pistons are OK. If I am correct, you'll need a valve job (plus a few new valves), new guides, and perhaps a set of rings "while you're in there".

race911

Why not? Done more than one engine back in the Olden Days of mag case "Rebuild Of The Month" club that looked similar on a leakage test. My own car, the faux RS, was right at 80% leakage from the (aftermarket) valve spring breaking.

Unless you've got aftermarket valve springs that have failed (see above), this is certainly the most likely scenario. But does it matter? Did you listen to where the air was coming from? It's either massively coming through the intake and/or exhaust, or the filler cap.

In any case, if this is a DIY thing, bust it down and send the heads to Steve. If you heard air through the breather, pull the PC and send them to him as well.

Final comment--there are no "head gaskets" in the classic sense on these engines.

vincer77

The fact that 5-6 are low would have lead me to head gasket failure - but these have separate sealing rings.

Vorsicht

Regarding the air sound: As far as I could tell using just my human ears I detected most sound coming from the exhaust. Nothing from the filler tube. On number one I heard air noise from exhaust but it 'seemed' like it was coming from 'inside' near the head. Where is the breather?

Yes, I intend to do a DIY teardown. When sending stuff up to Steve does he remill the valves and seats or just the seats and then new valves?

How does one evaluate the pistons?

Steve Weiner-Rennsport Systems

Sounds like possible bent valves.

Peter,....call me tomorrow. This one is too complex for the forum, much less e-mails & PM's.

CalvinC4S

If those numbers where right, the original poster would have other things to compain about then high HC numbers at the smog check.