Engine Assessment = 322

[KAD36]

I thought I would pass on some info on the tests I ran on my engine and see what you guys think of the condition and if I should do anything further to it for now. I cleaned up and repainted the whole eng compartment (pics soon), put new rockers, lifters, shafts and pushrods in it. Cylinder head and valve job done about 15000 mi ago. Lower end all original. Some blowby on hard to moderate acceleration.

This is a 322 in a 55 Super, with about 95K on the clock

Compression Test after engine run and all warmed up, all plugs out, carb wide open:

Cyl / Pressure First stroke / Final Pressure

1 80 125

2 90 135

3 90 135

4 90 125

5 90 130

6 90 125

7 60 125

8 90 125

Min Spec 170 PSI

Note - when I added a few oz of oil into the low cylinders, they came up about 10-15 PSI

Idle: 475 in drive +/- 10 rpm

Vacumme: 16 in fluctuating +/- 1 at 550 in N

Dwell: 29 deg

Some questions:

1) While I was glad to see the compression within about 10 lbs of each cylinder, it bothered me it was so low compared to the minimum spec in the shop manual. Should this be something I need to look further into?

2) What is the vac spec on a 1955 322 and how does mine compare? I expected about 19 inches of vacuume and a steady needle. I'm guessing the needle fluctuation is the low cylinders?

3) Why does Buick state to not use Dwell in setting the point gap in 1955? I just stumbled upon this information and have used a dwell meter for years to check the points.

4) How about the idle - whats a reasonable variation? The manual says 450 - I can't believe thats in N because in Drive that drops to under 400. I was always told to watch the radio antenna, and if its not shaking, thats a smooth idle.

Any thoughts?

Thanks

[JohnD1956]

A few questions if I may:

I always thought a compression test was for three compression strokes, not two?

Were you using a screw in guage or a hand held?

What do you mean by "blow-by" on hard aceleration? Is this just black smoke you observe from the tail pipe?

The 450 low idle should stay at 450 when putting it in drive on the dynaflow so while low, it does seem to fit the application.

JD

[KAD36]

Hi Johh - the final pressure was the max it hit after about 4-5 strokes.

I was using a screw in type gauge, which I calibrated off my shop air regulator before I used it.

Blow by is the amount of vapor I observe coming out of the oil filler cap and road vent tube. Its kind of gray in color. Plugs have been running a little black lately - I think I may need new points as I have about 10,000 miles on them. Tail pipe blows gray if you put your foot into it.

[JohnD1956]

Did you use the original heads when you did the valve job 15K or so ago? Or could these be heads from another model with lower compression?

I used to think I had a problem with my engine ( the 56) a long while ago when I observed smoke coming from the vent tube. That was at the bottom of the motor, not from the oil fill caps. Eventually, with more regular use, that just seemes to have cleared up.

As for the grey smoke on aceleration, I would look to make sure your choke is not sticking. Has the carb been rebuilt?

Another seemingly useless question, how much use does the car get? Is it to the local store and back? Where it may not get a chance to really run and heat up to operating temp? Seems to me that the key to a Buick is to get it out there for a long haul and let the systems get fully heated. That blow by may be imputities in the oil that just do not get a chance to evaporate on short runs?

JD

[KAD36]

More good questions.

My original heads were both cracked, and the reworked ones were from a 1955 Roadmaster with about 50K on the clock that I found in a yard one lucky afternoon. I had a Buick dealer do the work - not sure if he put the .015 gaskets in or not. He was an old car nut also, so I hope the right ones went in.

Choke is not sticking, in fact the cover screws were loose and the climatic control was way on the lean side, so now I have it set 2 marks to the lean side.

The carb was rebuilt (not by me!) back in the late 80/s sometime and has not been touched since. I use STABIL in the tank, run 93 octane all the time, put fuel cleaner in occasionally, and have the timing set at 7 1/2 deg (no detonation).

The car does not get the use that it once enjoyed - 600 miles round trip to college 12 months a year. Its now lucky if it sees 500 miles a year. The past 2 years, it has been laid up with either a complete Power Steering rebuild, or this rediculously underestimated "couple of weekends" job I started almost a year ago with the valve train and engine detailing. I bet it hasn't seen 150 miles in the past 2 years.

I did put fresh oilin last month, and shoveled about 3 inches of crud and rocks out of the oil pan at that time. Oddly enough, most of the "smoke" comes out the oil fill rather than the vent tube, and I cleaned the passages and mesh up in the valley cover when I had it all apart. I get more of the smoke if I hold it in drive with the emergency brake, and bring the throttle up while leaning under the hood (tires blocked and I'm standing next to the car rahter than in front of it!).

[JohnD1956]

I'm sure the 56 engines were the same in all models except for the Special with a stick shift. But that is not the case in 55, is it? I don't have a manual for 55 but wasn't the Super a lower compression motor to begin with? Even if it wasn't, I think the pressures you recorded are close enough to each other to rule out a bad cylinder.

So you may have some sticky piston rings, with the resulting air pressure stiring things up in the oil pan compartment. But I would think the smoke you are seeing under the hood is still due to condensation inside the engine block. The coloring of the exhaust pipe gas is another matter.

Of course blue on hard aceleration is oil. I would think if you had weak rings, you'd be seeing oil burning through the exhaust. The grey /black I would think is carbon deposits.

Since I believe in Buicks, my recommendation would be to get this car out and drive it an easy 100 miles without worrying about anything else in the engine. To me "easy" means get it on a highway and bring it up to cruising speed. 50 miles one way and 50 miles back, then see if you still have that smoke coming from the breathers.

If not, consider changing the oil again. If so consider breaking down the lower half for a rebuild. But I'm thinking you won't have that problem after such a ride, at least till you stop using it again.

Good Luck

JD

[KAD36]

John - the 1955 series 50,60 and 70 Dynaflow cars all had the same high compression. You're right on the series 40. Hows your 56 engine compare for steadiness of idle and vacuum?

thanks

[JohnD1956]

Well Ken, my 56 has a very smooth idle. But things get rough quickly. I've done a ton of work to my car but I fear that my torque converter and flywheel are not in balance. This is because I did not know that the units were balanced together at the factory and therefore should be realigned if ever separated. A rebuild with a different torque converter all but guarantees I am out of balance here. But it is not all that bad really. I do have a vibration and every time I look into the book I have with the 56 Technical service Bulletins I see another possibility that I want to check. The latest is a vibration in the fan shroud between 1,400 and 2,000 RPMs, due to the shroud being too thin.

I have not taken a compression test on the car and I also had a valve job done on my original heads. But I do get some blue smoke on a start up occasionally and will use some oil on long hauls. Since I drive it less than a thousand miles per year, I'm not sweating it.

If I ever do have the motor rebuilt, I will make absolutely sure the engine is balanced with the converter on there.

[KAD36]

Hi John - an update - I finally had a chance to get the car out for a good run yesterday - took it on about a 70 mile drive on I81 - 65- 70 mph the whole way, with a few short bursts if you know what I mean. I have some Marvel and Stabil in the gas tank, and some CD2 in the oil.

Once nice thing about cold weather is you get no bugs on the chrome.

When I got home, I pulled a few plugs and they had cleaned themselves back to tan, and I picked up another inch of vacumme and a much steadier needle (17.5 in +/- 1/2 at 550 in Neutral)

Blowby is still there, but anything sticky appears less sticky, and anything sooty appears to have burned off.

Guess she just needs to get out more....

Thanks

[NTX5467]

Sounds like things are better than you might have suspected?

The oil smoke from the oil cap can well be "blowby", which could also be a normal situation considering that all crankcase vent systems back then were "road draft" rather than PCV. In other words, of the road draft tube might also be gunked-up inside, it'll not have the desired volume of air flowing through it and let the blowby come out the easiest place. I used to see mechanics take the road tube off the car, put it on the floor, get the welding torch out and "light off" or "burn out" the accumulated deposits in the baffled tube--sometimes with spectacular pyrotechnics, so everybody knew to stand clear. Back then, fixing or repairing was the operative orientation rather than replacement.

All engines have a certain amount of blowby, especially back then and when they get "miles" on the piston rings. When they are new, it's not significant, but as they age into the upper half of 100K miles, with possibly so-so maintenance, it can happen and be evident via the oil fill cap's vents.

In the earlier years of PCV adaptation, on Chevy small blocks (for example), they utilized the same location where the road draft tube bolted in, but used a cone-shaped piece of sheet metal to plug the hole and serve as the place where crankcase vapors were vacuumed from the engine, with an inline PCV valve that was attached (screwed into, maybe?) the base plate of the carb. Air still entered the crankcase via the oil filler tube cap. Something of that nature could probably be adapted to most any early engine without much cosmetic "damage", I suspect, but also result in longer engine life and less temperature-related deposits inside the engine.

I found an SAE Transaction that was presented by a division of GM (possibly Chevrolet) as the test vehicles were two 1961 (?) Chevy 235 6-cylinder sedans used by GM for plant security. Probably the worst case scenario for low speed, low engine temperature use. It was amazing how much they found one PCV valve would clean things up inside the motor just by keeping the "blowby" and such vacuumed out of the motor. If one was good, two would be better . . . and they were. They also used this test to determine the more optimum flow rates for the systems.

As always, getting a vehicle up to operating temperature and keeping it there for a 100 mile (or more) highway, steady-state cruise, can help both the health of the vehicle and its systems and also the driver/passenger. Everything just tends to work better and possibly operate better each time it's done. Unfortunately, having a cell phone handy can be an asset if something might not be completely as it should be.

Just some thougths,

NTX5467

[JohnD1956]

NXTX has a good thought there with the plugged vent tube. You may find the tube is not plugged but the area it is attached to on the valley cover is. When you're ready to change the oil you might look at pulling the tube and cleaning it and maybe dropping some kerosene into the valley cover opening for the tube, to clean out any sludge built up in there.

JD

[old-tank]

That valley cover does get clogged. There is an aluminum mesh inside that cannot be cleaned with heat ( it will melt ), acids ( it will dissolve ) and common solvents will not touch the grunge. The cleaner that a machine shop uses to clean aluminum heads 'might" clean it.

The way that I have restored these units is to take them apart, which will involve cutting out the spot welds from the underside using a tool that you put in your drill. Once inside you will understand the cleaning problem. I use aluminum air conditioning filter material and then weld it back together.

Willie

[NTX5467]

From what my machine shop associate mentioned years ago, there are two types of "tanks" to clean things in. The "hot" tank for everything not aluminum and the "cold" tank for aluminum items. He went on to mention that putting aluminum in a "hot" tank would kill both the aluminum item and the tank--not good for having to refill and recharge the tank for that indiscretion. Many municipalities don't line that caustic stuff in their sewers (although it can help keep them clean too!), which can further complicate things.

It used to be somewhat exciting to see him set up a new batch of cleaner in the hot tank. He'd add the cleaner powder to the hot water . . . and then step back . . . when the eruption didn't happen, they he'd add a little more until the solution was at full strength again. Those were the days . . .

NTX5467

[Aaron65]

That motor sounds fine to me! Drive it and enjoy it...will a few miles on these things, there's going to be a little smoke out the draft tube here and there...the more you drive it, the better it'll run...

[old-tank]

Ken

I was sent this link and will pass it along to you and others.

Willie

[JohnD1956]

Oh Boy! Great information. Thanks OT

JD

[KAD36]

Great link Willie - thank you for forwarding. My Dad taught me how to use one years ago, but not nearly with all of these scenarios. My reading is a combination of 3 (with the 1/2 inch flicker - that looks exactly like the actual needle motion I saw) and 4 (17 at idle and only 22 inches on decel). This is a big help.

NTX - Could wear in the timing gear/chain set (ref your PM) cause valve overlap? I'm just curious about that bouncing needle.

Thanks also to everyone who took the time to respond - lots learned here!

[NTX5467]

"Valve overlap" is a designed-in situation on the camshaft--not variable. That is the time that the intake and exhaust valves are open at the same time. Generally, less overlap = more torque, more overlap biases the engine's power curve toward the upper rpm ranges--from a particular point of reference set of cam timing specs.

Significant wear on the timing chain and sprockets would result in "retarded" cam timing that would generally lower vacuum levels, but I suspect that if it's that loose, it could well have caused a situation where engine operation would cease. On the vehicles that I've had that we did a timing chain/sprocket replacement on, with normal wear of about 90K miles on them, it didn't make a big difference in the way they ran or vacuum levels.

As I recall on vacuum gauge diagnostics, whenever a weak cylinder fires, the gauge reading is lower when that happens. That would result in a quick and consistent drop in the needle on the gauge. Also, be cognizant that the environment inside of the intake and exhaust manifolds is not one homogenous, smooooth flow, but a total flow that has many pressure peaks and valleys as each cylinder does it's contribution to the total operational situation. This is why many vacuum gauges have a small pinhole in the fitting where the vacuum supply hose attaches to the base of the gauge, to dampen the vacuum signal so the gauge can become more useable.

Now, as for the vacuum levels you are seeing, it appears that there is a wide variation in the accuracy of vacuum gauges these days (and back in the 1970s too). On the ones that I'd find, all of my readings seemed to be a bit low, but ones that my friends had seemed to be "right on" for the vehicles they were using them on. That has been my observation, from back then, but I know that only a handfull of companies are now probably making vacuum gauges (for inside the car or as diagnostic equipment). ALSO, be cognizant that vacuum levels can be affected by altitude and a few other weather factors.

I guess one thing I'm trying to say is that using any diagnostic test instrument is only as good as the calibration thereof. Even tachometers have a tolerance of something like "+" or "-" 4% of FULL SCALE, so there can always be some variation in what we see on our test equipment and what the engineers might have seen on theirs (which should be of higher quality, I would hope). Also be aware that production tolerances, as good as they might be, can also cause some variations between products built on the same assembly line on the same day, right after each other.

As much as we might strive to hit the "factory specs" in how we might try to tune our vehicles, using a "given" that all test equipment is equally as accurate as what the engineers used, then we might hit things "on the head" or we might be frustrated as it does not seem quite right when things are set to "factory specs". ALSO, be aware that ignition timing is only as good as where the keyway in the crankshaft (to locate the harmonic balancer AND the timing mark) was cut when the crank was machined--not to mention production tolerances in the making of the harmonic balancer itself (one reason that many early timing marks are on the flywheel??). Now, when everything works as it should, even when these various tolerances might "stack", then we can have some success with what we are trying to do, but when something does go out of whack (like where the keyway on the crank is machined), then you can beat your head against the fender with factory specs and nothing will work "as designed". Bad part about it is, unless you take the engine apart and compare these things, they can go undetected "forever".

My machine shop associate mentioned one case where the nose of the crank (for the keyway) was machined something like 15 degrees off. The vehicle's owner tried to tune it and it just didn't work right, unless they "tuned it to run the best" and ignored anything they were getting from the timing light or whatever. Later, when it was overhauled, that's when the crank keyway issue was discovered . . . and fixed with a new crankshaft. Magnify that with a balancer where the outer timing ring has moved, and things get flaky very quickly.

Many old time hotrodders set their ignition timing "by ear" at about 2500rpm, then checked to see that it would start easily without kicking back (if it did, then you retarded the timing until easy starting was restored). Not to forget about the "high gear acceleration" from a slow speed (with manual transmissions) without "clattering".

In those prior times of "brave men", there was a diagnostic technique where each spark plug wire was pulled out of the distributor cap to test for weak cylinders. It HAD to be done quickly, yet gently, but ALSO to make sure that no "circuit" was from your body, the car, or "ground" was made. You might be able to kill the motor and restart it rather than trying to do that with it running (highly suggested!!), too. When the "miss" and the needle movements you might be seeing coincide, you'll probably discover that it's the weaker cylinder that your compression test uncovered.

Another shade tree diagnostic "tool" that could be used is a shop rag . . . placed around the exhaust pipe at the back of the car. Make sure it's reasonably taut where it fits over the end of the pipe, but not too tight as I'll explain. I mentioned pressure pulses in the intake and exhaust systems, well when an exhaust valve doesn't seat well (due to "burning" or a degraded seat), when the valve is closed, the piston can be on the suction stroke so it'll also send a negative pressure pulse out of the exhaust pipe when that happens. Therefore, the rag will be sucked into the pipe, momentarily, when that negative pressure pulse happens. It'll happen very quickly, but it can still happen, if there's an exhaust valve problem.

Every mechanism has a "sweet spot" where it likes to operate and operates at its best. If that sweet spot is at or near factory specs, that's great, but if it's not, a little investigation might be in order (to find the spot and to find out why it's different than acknowledged specs). In tuning, that would include idle speed and mixture adjustment, ignition base timing, and timing advance with engine speed. BEFORE you do these experiments, make sure that you have a strong baseline of performance information and driving experiences of your and similar vehicles at factory specs.

One example would be the balancing act of setting the idle speed and then the idle mixture for "best lean idle" or "max vacuum". Taking the time to make the "back and forth" adjustments to mixture and speed until they are where they need to be (operationally). And, of course, set the distributor points and then the base ignition timing BEFORE doing any carb adjustments.

Maybe, somewhere in all of this you can get some information that might help in this situation.

Enjoy!

NTX5467

[KAD36]

OMG! Thanks againg for sharing all your knowledge. I printed this thread and link out and put it with my tune up kit for future reference.