ChefYota4x4

iTrader: (5)

Well, it can also tell you about valves and whether or not they're seating properly, etc. The leak down is more specific, but just to start off, for reference for ya, here's a decent write up on "Compression Testing".....

It will tell you if your engine has good compression. An engine is essentially a self-powered air pump, so it needs good compression to run efficiently, cleanly and to start easily.
As a rule, most engines should have 140 to 160 lbs. of cranking compression with no more than 10% difference between any of the cylinders.
Low compression in one cylinder usually indicates a bad exhaust valve. Low compression in two adjacent cylinders typically means you have a bad head gasket. Low compression in all cylinders would tell you the rings and cylinders are worn and the engine needs to be overhauled.

Checking Compression

Compression can be checked two ways: manually with a compression gauge or electronically with an engine analyzer. The manual gauge method is the more common method available to most do-it-yourselfers.
To check compression, all the spark plugs are removed. The ignition coil is then disabled or the high tension lead is grounded. The throttle is also held open. The engine is then cranked for a few seconds using a remote starter switch or a helper while a compression gauge is held in a spark plug hole. The maximum compression reading is noted, then the process is repeated for each of the remaining cylinders. The individual cylinder readings are then compared to see if the results are within specs (always refer to a manual for the exact compression specs for your engine because they do vary from the ballpark figures we quoted earlier).
If compression is low in one or more cylinders, you can isolate the problem to the valves or rings by squirting a little 30 weight motor oil into the cylinder through the spark plug hole and repeating the compression test. The oil temporarily seals the rings. If the readings are higher the second time around, it means the rings and/or cylinder is worn. No change in the compression readings tells you the cylinder has a bad valve.
With electronic testing, a computer analyzer "estimates" compression in each of the engine's cylinders by measuring slight variations in engine cranking speed. The results correlate well with actual gauge readings and can be completed in a matter of minutes without having to remove any spark plugs. What's more, the analyzer prints out the results of the compression test making it easy to see and compare the actual numbers.

myyota

What would ever make you move to comifornia ?. I wish i knew someone with an M60, i would love to shoot one. Being that im in Idaho its legal for me to own an M60, i just can`t afford to buy one.

ChefYota4x4

iTrader: (5)

Here is a write up on "Leak Down Testing" by Car Craft Magazine.........

http://www.carcraft.com/techarticles...ter/index.html

KatKrazy

Chef,

Great post. Here's some more info though. The block was bored out .020 over. Pistons and rings are new. I realize they can still not have seated properly, but I can't see them being "worn"

Further, the machine shop I took it to is a 1 man show and is highly respected in my area by a lot of gear-heads. He had the head in hand and checked it for "flat" and gave it the once over. He said it was much newer than the block and said it looked good.

He is human though, so he can be wrong. I will start with a compression test on all cylinders and see what happens.

ChefYota4x4

iTrader: (5)

Well, sure, I hear ya... But, respected or not, it's FREE to test your compression and at least RULE IT OUT, right? Then move on to 'this or that', so on.

Nearly a quart of oil every 3 tanks? I mean, .... it's not guzzling, but if you're not leaking, ....let's just say, "I WOULD, PERSONALLY, be driven nuts not knowing why I was using oil", lol. It's gotta be going somewhere, and it sounds 'slow enough' of a usage to maybe just be something like part of mine was...... My guy reused the same guides and with all the play I had in the guides, and using the same valves like he did(all 8), it quickly wore out the seals(theory of Tod of engnbldr, my machinist, etc.)... then, it was pulling in some oil like that and mixing with fuel, then on out the exhaust side. If I was using oil, it would be too hard to tell because of all the leaks, lol. Now, I'm not leaking a drop, so obviously, if I start going through oil.... I'll have to investigate like you're planning to do, ya know? You're using up to 12oz. oil every 600 miles or so, ....fair enough estimate? yeah, that would bug me, and especially with a newly rebuilt motor, ya know?

SURE you have no leaking that's coming from the bell housing, then running backward down the trans? haha. I know, I'm sure you looked it all over a hundred times... it's frustrating, no doubt!

PS> Just to be clear... the bottom end is basically fully rebuilt, ....the head(inspected and given the ok?) Or are they all new seals, guides, exhaust valves, etc.?

KatKrazy

the head was checked but never touched as far as valves and guides. The bottom end is new in the block. New crank, seals, timing components, clutch, etc.

If it's leaking anywhere, it is never hitting the garage floor. I only have 1 small leak that I know of and that is gear oil from the t case. I will look again but it has never dripped a drop on the concrete of motor oil.

ChefYota4x4

iTrader: (5)

Well, sounds like you've checked till your ears are turnin red! lol. I just mentioned the rear main tell-tails cuz they CAN leak back onto the trans and actually drip more toward the center of the rig. But, ...... you'd probably of seen that build up of oil on the bellhousing/2/backing plate. , etc..

KatKrazy

I'm gonna check again. thanks for the tips. I will post back my findings