adam.dudenhoeffer

I am in dire need of some help on this one. I consider myself mechanically inclined but I have found myself in unfamiliar terrrirtory...

My 4runner (1987 2.4L 22RE) is making a lot of noise and is pouring smoke from the PCV valve on the valve cover gasket. The noise from the engine is primarily a loud valve tap but is ocassionally accompanied by the sound of marbles being thrown within the cylinder. I was having some overheating problems (I was sure not to let her get too hot) so I replaced the thermostat, changed out the coolant, and the replaced the fan clutch. I was letting the truck idle in the driveway while purging the cooling system when it started to make some horrible noises (the sound of marbles in the cylinder). Since the initial occurence the marble sound has primarily gone away but the tapping of the valves is very loud. I took a short video of what is going on - http://www.youtube.com/watch?v=8Ms0vlFT70A.

I have been told to do a "leakdown test" on the cylinders to begin my diagnosis which has once again brought me to a standstill. Ive got the leakage tester but I am unsure how to close the valves on the cylinders and what procedure to follow from there.

I appreciate any thought/ideas/suggestions that you all may have.

Thanks,
Adam D

scope103

Ouch! That does not sound good.

You could start with a compression test; I don't think you're going to like what you find.

But you said you've already got the leak-down tester. Do you have the instructions for it?
Here's the one for a Harbor-Freight version: http://manuals.harborfreight.com/man...4999/94190.pdf

The valves are closed .... when? At TDC, at the beginning of the power stroke. Set the timing mark on the Harmonic Balancer to zero. Two of your cylinders will be at TDC. Which ones? Slide a chop stick in the spark plug hole to see if you touch the top of the cylinder (#1 will be at TDC). But you're not done yet; one of those cylinders is at the top of the intake stroke. The easy way to tell is to remove the distributor cap and see which cyl the rotor is pointing to.

The other two cylinders will be at TDC with the crank rotated 180 degrees. This is not easy to tell with just the timing mark; it's a lot easier to do with the valve covers off (when you just look at the top of each valve). But you can do it with the chopstick.

Keep in mind that a leak down tester is supposed to pressurize the cylinder you're looking at. Which means the engine is going to try to turn over if the cylinder is not perfectly at TDC. So leave your 1/2" "breaker bar" on the crank bolt, and tie it to something that won't move. It won't pull too hard if you're at TDC, but once it starts moving it can do some damage before it stops.

Fink

OP, are you related to Kimberly Dudenhoeffer?

Fink

adam.dudenhoeffer

Scope, thanks for the quick reply. I am going to get the leak-down test done today to see if I can diagnose where the problem is. The instructions for the leak-down test will be very hlepful. I am going to pull the valve cover to ensure that I am getting the cylinders completely closed when performing the test. I am under the impression that the rings are blown - if this is the case is there anything I can do to salvage the engine? Just bought this truck less than 2,000 miles ago and the previous owner said that top-end was rebuilt less than 25,000 miles ago. The truck currently has 389,000 miles on it which brings me to the next question... is she worthy of a $2,000 investment from here.

Fink, to the best of my knowledge I am not related to Kimberly.

Thanks,
Adam

scope103

No.

According to Kelly Blue Book (which I think runs notoriously high), your ForeRunner is worth --- wait! KBB doesn't even go that old! If you run a 1991 Forerunner (4wd?) it could be worth $1340. (In running condition, obviously)

If you had owned that vehicle for years, loved it, knew all it's good sides, then you might want to take care of it when it broke a ring. I'd probably do that for mine. But you have no attachment to this vehicle, and even once you sink $2000 into a repair you might still end up with a POS. And where does $2000 come from? If you learn anything from this site, you know that a ring job doesn't just involve replacing the rings. On the way you'll find lots of 24-year-old parts that are just not going to make it, and you'll have to replace all of them too.

All that said, there are lots of people who take perfectly busted vehicles, sink oodles of money into them, and end up with a very shiny, perfectly running, 24-year-old trucks. If that's your idea of fun, go for it. But expect it to cost you in the end.

adam.dudenhoeffer

I took off the valve cover and discovered a timing chain that was more than loose and was accompanied by a broken timing chain guide. Im going to start there and see what happens. Thanks for the input. Ill keep yall up to date with my diagnosis.

92dlxman

valve stem seals? i've heard of non oem seals being less than good and with your rebuilt top end i suspect they could leak combustion gases into the valve cover? just my logic

92dlxman

maybe get gutsy and remove valve cover and COIL WIRE and have a friend crank it over for a very short period of time while you watch for any blow-by. into the valve-train area