Leakdown Results Smog Story
#1
Burning Brakes
Thread Starter
Leakdown Results Smog Story
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...
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...
#3
Nordschleife Master
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".
#4
Rennlist Member
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".
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.
#6
Burning Brakes
Thread Starter
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?
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?