engine and drivetrain Cylinder Leak Test Question (Long)

[gregh]

I recently bought a 72 2002tii ~ 95k to ~105k miles on original engine and head. The car has probably averaged less than 1000 miles per year over the last 10 years and less than 100 miles for the past 2 to 3 years. Old spark plugs (I have no idea how many miles were on them) showed sign of dark black soot - didn't appear to be oil fouled. There was an anti-fouler plug cap installed in one of the cylinders.

After warmup (2 to 3 minutes or a mile on the road) the car runs really well and pulls strong. No smoke on deceleration from (3 to 4k RPM to idle)- though there is some backfiring. Some black smoke on acceleration.

I have driven it less than 150 miles so I'm not sure if it's burning oil. Though there is evidence of several external oil leaks (exhaust manifold studs - etc).

Compression Test 1 - Approximately 4 years and 1500 miles ago - 150 psi across all cylinders - done by a shop.

Compression Test 2 - Leak down compression test completed today - 140 psi, 140 psi, 140 psi, 145 psi - done by a shop.

The embarrassing part is the percent air leaking - 58%, 53%, 45%, 51%. I have yet to follow up with the shop to make sure they did the test wet and dry to determine where the leaking was occurring - but the owner of the shop said it was leaking past the rings. CD's guidance suggests anything above 20% is not good.

My question - am I doomed to a complete engine rebuild? Could I have stuck rings on all four cylinders? I am having a hard to reconciling how well the car drives and pulls with the % leak numbers.

[tkent02]

The rings couldn't possibly seal correctly after all that sitting. Put good oil in it, tune it correctly and run the heck out of it. Then learn to test this stuff yourself so you are not at the mercy of someone who wants to profit from your ignorance by selling you an engine you don't need.

[c.d.iesel]

agree'd - change the oil AND filter , new gas in the tank, DRIVE for 250 miles and then retest.

your alright - just service it and drive it !

ck all valves COLD - 0.006"

[bevans6]

Strip and totally clean the carb. variously gummed up passages can make it run rich and easily account for the sooty plugs. Do plugs. points, timing, drive it for a while and see.

Brian

[SteveJ]

Yes, but the numbers are even across the board which is good.

The big killer is when you have REALLY low numbers on one or more cylinders.

You'd be suprised at how poor the numbers can get and the damn thing will still run. After you run it for a while, look for other tell-tale signs such as smoke- blue or white, oil usage, etc...

[TobyB]

run it hard for a while- like months- and if nothing else seems wrong, forget about it!

But if it still bugs you, for $70US you can buy yourself a leakdown tester and test it yourself.

The only way it's a problem is if you get a large leak through a valve- that tends to get worse with time, not better.

But the rings will settle in as you drive- to a point...

t

[gregh]

(nt)