compression ???

[wayfarerstranger]

i ran a compression test on my 1950 dodge # were from 1 to 6 cylinders 100 ,100, 55, 45,100, 85 looks like there is a problem somewhere , looks lIke this is my power issue ... no water in the oil does smoke some , but it doesn`t bellow out ,, car cranks and runs smooth time i turn the key . but does lack power .. hoping it`s just a blown head gasket any thoughts ?? thanx CHANCE

[greg g]

Might be the head gasket between the cylinders where there isn't much material between the paired cylinders like three and four. Did you do a wet test with oil squirted into the low cylinders? If you do and there is an increase, it likely worn or broken rings. If the readings don;t change it either the gasket or valves sticking or burned.

[wayfarerstranger]

I DID put some oil in the 2 down cylinders .. on one it came up for a second or two then went back down on the other no difference it seems ..

[Jerry Roberts]

It's not very much work to pull off the valve covers and turn the engine over to see if a valve or two are stuck . Much less work than pulling the head .

[wayfarerstranger]

thanx jerry i think thats what i`ll do tomorrow ...

[wayfarerstranger]

car has 40 lbs oil pressure on the gauge inside the car test results from cyl 1 to 6 cold 100,100,50,45,100,85 hot wot 100,80,55,35,95,100 wet 125,125,85,35,125,100 everything increased with oil which is normal i guess with pouring oil ontop of the piston on the two low readingd 3&4 cylinder one went up one stayed the same i know the rings are worn it`s an old engine , but could the main problem still be the head gasket ?? also poured the water thru the carb before i did the cold & wet test.. any input ..thanx chance

[Mr. Belvedere]

Have you done a vacuum test? That can also help determine if its a valve problem too. If so what reading do you get?

[wayfarerstranger]

not yet i`ll do one and let u know , i know i need to go ahead & pull the head & see what i got . i just hate having the car unmovable ...

[RALPHDEI]

If the problem isn't the head gasket, pulling the head won't tell you anything. If oil in the cylinders didn't raise the compression,(use plenty of oil 30W or 40W) then valves are probably the problem. As was suggested a vacuum gauge will pin point the problem.

[38plymouth]

I just put a different head on my car. It ran great before I did it but after it popped really bad and barely ran. I did a compression test and one cylinder was at zero. I looked down the plug hole and could see a valve was stuck open. I sprayed some pb blaster down onto the valve and let it soak for awhile then I tapped the top of it with a screwdriver and popped back into place. When I started it it ran great. I still don't know why it stuck. I would think your compression would be zero or damn close if it was a valve. When I had the head off I soaked the tops of the pistons overnight with seafoam, the carbon came right off. I'd try pouring a bunch of seafoam into the plug holes and spin it by hand and then let it sit overnight and see what happens.

[Mr. Belvedere]

What the heck is seafoam?

[Don Coatney]

What the heck is seafoam?

Follow this link.

http://www430.pair.com/p15d24/mopar_forum/showthread.php?t=3197&highlight=seafoam

Some swear buy it, others swear at it.

[Mr. Belvedere]

If the valves are way out of adjustment, or if burned or pitted and therefore not making a good seat then you could have low readings. However, if they are stuck open even a little you will get a zero read on the tester. A vacuum test may help determine whats going on.

[wayfarerstranger]

when i started these test , i wasn`t sure of the tester i had so i bought a new one today it works a lot better .. ran test hot & cold engine #`s about the same 120,120,70,50,120,120, i did put some oil in the 2 low cyls they came up about 20 lbs just for a second then went back .. as i let it idle the white smoke got worst never stopped pouring out of the exhaust .. since these 2 low cyl`s are side by side and there is so much smoke and it is white . i`m amost sure i`ve got a blown head gasket . it has 40 lbs of oil pressure & if the rings were stuck i don`t believe i`d have that ? also bad rings usually produce dark smoke .. i borrow a vacuum gauge from auto zone & do that vacuum test . i had one but loaned it out and never saw it again..

[wayfarerstranger]

well MR, BELVEDERE i did my vacuum test and it seems to me normal runiing steady at 18 , when i reved the engine it drop back to about 5 and when i let go it jumped to about 23 the back to 18 which is normal .. i`ve got a chart that shows what the vacuum gauge will do in response to different problems .. doesn`t seem to have any valve problems or any other problems at all .. also " re- don c. " let it run with the oil cap/filter off didn`t see any blowby or spitting oil even put a piece of paper over it no oil splatter at all . when i cut it off a little smoke came up but that normal .so that indicates probably no ring trouble .. engine cranks time i hit the starter and runs steady no shaking or jumping ,, just low compression in 3 & 4 cylinders . must be my first response to the problem blown head gasket .. what do you think ? thanx ,, chance

[Lou Earle]

White smoke and adjacent cyls having low compression are definite signs of blown gasket and there is one other sign- All other cyl are high in compression - I bet you have a rebuilt engine that was installed and run the first few times and the head was NOT re torqued and it- the head gasket blew. I have had 3 cars to do that. If you have a torque wrench just for fun see what the head bolts are torqued at I suspect about 45 to 50.

Remove head and install new gasket - about 4 hours.

Lou

[wayfarerstranger]

lou , thanx for the input I`LL GO CHECK THE HEAD BOLTS ///

[wayfarerstranger]

all head bolts are tight .. guess i`ll pull the head ...

[Lou Earle]

did you check them with a torque wrench? On mine I found several at 50 pounds when they should have been at 70- I set my wrench on 50 pounds and tightened a coupel soem . When set on 70 almost all tightened. Anyway that head just must come off

Lou

[Lou Earle]

When you pull the head take a look at the ridge or edge of the cylinder and feel of it. If thee is no ridge ring- that is the cylinder wall is smooth to the top or just barely a feelable ring that indicates a fairly new engine. I am sure there are several other things you can check when the head is off - valve seating etc . Some others need to make suggestions.

Lou

[Normspeed]

Inspect the valves for obvious damage but personally I would not remove them just for inspection.

You'll also be able to see if the rear water jacket area is clogged with cooling system chili. If so, consider removing the water pump and inspecting the water distribution tube.

Can you spot the bad valve in the photo?

[wayfarerstranger]

thanx for all the input , i`ll keep you updated ..

[Mr. Belvedere]

Yep, your first impression is usually right, probably is the headgasket esp. since it is two adjacent cylinders, and with white vapor smoke. Strange that you have completely normal vacuum though. I'll be interested to see what you find when you pull the head.

[wayfarerstranger]

thats what confusses me and why i try to get feed back on this forum. car cranks on the first turn of the key , cranks better and easier than my 49 woodie with a rebuilt engine in it ? runs pretty smooth just shakes very little . probably because it needs fine tuning? sometimes i crank it & it starts to smoke other times hardly any smoke till i gun the engine ? sometimes it smokes when i start it up i rev the engine up it smokes like crazy then backs off to nothing ?? & it looks white to me ? i guess it could super pale blue but to my eyes it looks white ..no noise at all except the exhaust needs a little help .. then the compression 4 cylinders @ 120 & 2 of them about 50% down & side by side, and the vacuum @ 18 the needle on the vacuum gauge flickers but doesn`t move away from 18 and according to the chart i have that could be plugs or points ? and its strange that it doesn`t give a reading for a bad head gasket ? or anything else . thought the gauge might be off so i put it on my 49 woodie rebuilt engine and it went to 20 steady so i guess its ok . i don`t mind pulling the head i just like to know what the problem is before i start tearing things up ..

[Lou Earle]

It should start easier- after all it has considerably less pressure to contend with.