I want a second opinion of my blown head gasket?

Hienkel429

Hi all, 

Just completed a compression test of the engine and am sad to say it is presenting itself as a classic bad head gasket but wanted some other opinions. I might be completely off base here. 

Here are the readings:

Cylinder 1: 132 lbs.

Cylinder 2: 117 lbs.

Cylinder 3: 45 lbs.

Cylinder 4: 70 lbs (This was the hole I had to chase)

Cylinder 5: 120 lbs.

Cylinder 6: 112 lbs. 

Thoughts and opinions are very welcome.  Factory minimum per book is 100 lbs. with 10 lbs. difference maximum. 

Thanks

- Ray 

lostmind

Usually they are closer to the same readings when the gasket is bad. Before you pull it down , adjust the valves on those two cylinders and recheck.

Ol racer

rAY,
Squirt some oil in the low Cyls, If Compression comes up its the Rings or valve seats worn...

RL Chilton

Well, I'm not the most knowledgeable, but for what it's worth, cylinders [1 & 2], and [5 & 6] all have good compression.  I grouped them like this to point out that even though [3 & 4] both have LOW compression (and are right next to each other), the biggest chunk of iron between any two cylinders is between 3 & 4, which is the least likely place for the gasket to blow.  

I agree with Ol racer and lostmind, I think it's more likely rings or valves.  If you're lucky, adjusting those valves might be the ticket.  If you're not so lucky . . . well, you know.  

Geoff

You haven't told us the model car you have.  This makes a difference as to cylinder spacing. 

Hienkel429

51 Hornet 308

Ol racer

FYI

If this car has been setting (and even though im not a fan of finding a cure in a bottle), I would try an additive in the oil & gas then run awhile and retest compression. Readings can change at operating Temperature.

Glowplug

Some conjecture .... Hudson engines are known from stuck valves when the engine is allowed to sit... also the valves will open and close then stick... so inconsistent results will occur.

Geoff

In the Step-down and Jet motors the cylinder layout is three pairs, therefore the likelihood of a blow between three and four is likely, but that does not stack up with uneven pressures.  If the gasket was blown you would have no cylinder pressure in either.   Unless the gasket was only leaking slightly and not completely blown.  I very much doubt that adjusting the tappets would alter anything.   You can check the  valve action by removing the side covers.    A somewhat brutal method of unsticking valves it to mix up some kerosene and oil, remove the air filter, speed the motor up and dribble the mixture down the throat.  You will get clouds of smoke, but the unburnt mix will coat the  valve stems and may assist in unsticking, if this is actually the problem.  Check visually first. 

RL Chilton

I went back and re-read, but for some reason I thought this was an earlier engine than a 308.  I'm getting older by the day! 

Hienkel429

Could another contributing factor could be how low the engine was on oil?  When I bought the car it was just a little low. I did not check the engine oil level after trailering it 400 miles.  After doing a compression test the other day the car left a slick on the concrete overnight.  I thought it might have been the oil pan or plug.  I rechecked the oil level and found it was about 3+ quarts low.  I wonder if this lack of oil could have contributed to weird compression readings.  Since it is a splasher motor, my logic is that maybe there wasn't enough to splash and cylinders were a lil dry?  I turned the car over a bit (can't run because fuel system is pretty much varnish) and noticed it was leaking oil from the timing cover so I figure the seal is shot.  

At this point I'm resigned to the fact the engine will come out sometime in the future for extensive repair and checks and is un-drivable as is.  I made notes to check valve clearance and deposits and make necessary adjustments.  Was hoping these issues (leaks, compression) wasn't the case but not at all surprised.  The last time the car was registered was in '79 and according to an oil-change sticker, it has done less than 7000 miles since 1969.  

Thanks for all of your assistance thus far. 

- Ray

Geoff

You seem a little misinformed - if it is a Hornet 308 it is definitely not a splasher motor.  In any case the low oil level would not affect the compression reading.

Hienkel429

Geoff... you're 100% correct.... probably left over bad info from reading up on Hudsons and history before buying.

- Ray 

maasfhcenturylinknet

Most likely the outer cly's will have more compression than 3 &4 due to the fact the cly head has already been milled two or three times reducing the CC's in the outer cly's.  Sounds like a valve job is needed.  If rings were gone you wouldn't have the pressure you have on 1.2.5.6.