compression test, how do these #'s look Options

[toon1]

Did a compression check last night how so these numbers look to you guy's....

Cyl. # 2 145psi
#1 125
#4 130
#3 140

the motor was cold when I did the test..

[Dr. Roger]

QUOTE (toon1 @ Jan 10 2006, 01:25 PM)

Did a compression check last night how so these numbers look to you guy's.... Cyl. # 2 145psi #1 125 #4 130 #3 140 the motor was cold when I did the test..

test should be done warm.

20 lbs difference is not terrible. just not great. but warm that puppy first.

[toon1]

I am having problems getting the motor to run right. I had a freind take a listen to it, he thinks there might be a rocker problem. I am going to pull the motor out to adress that and replace the exaust gaskets but he said to do a compression check first. The sound he hears is not major or very loud there is just something little off. He knows more than I so I am taking his advice. What do you all think?

[r_towle]

I agree that if you are going to pull the motor, you might as well do a compression test...

But it is meaningless if you do it wrong...it will send you down the wrong path.

First, get the car up to normal operating temp..you cannot do this by leaving the car at idle...

If you cannot drive it, you need to at least rev it to 2k rpms for like 15-20 min.

then do the test.
First do it dry...
Then a bit of oil in each cylinder and do it again..

Record both readings for your buddy with and without oil..

The oil will seal off the rings,,,so if you have poor compression doing the dry test, and it bumps up after you put oil in the plug hole, you may need rings.

If there is no change, you could either have a valve problem, or cylinder leaks...

Now, I would also say that before you go any further, describe the problem here, in detail and get some help...

These cars have quite a few abnormal issues that we have all run into and fixed with no problems...

I will say one thing...this vw flat four motor will run perfect even if its low on compression, leaks , etc....it still can be tuned to run very smooth...

Rich

[SLITS]

#1 Question....Why would you pull the engine for a rocker problem? The whole assembly can be accessed.

[sean_v8_914]

...914 owners love jack stands
if you leave it on jack stands it will be perserved longer

[toon1]

I have a fear of commitment and if the car stays on the stands it just seems right, LOL. My buddy told me it would be easier to check the valves by pulling the motor.

I know I can pull the rocker covers off while it is in the car but he said it is easier to turn the motor over with it out. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[Joe Ricard]

hi jack

[toon1]

to describe the problem I am running into, the motor will fire, when it fires cold it will instantly go to 3k, I can eventually get it to idle but it is rough and real rich. Pulling the plugs last night, they where black. The timing has not been set at idle, that could be one of the problems. There are exaust leaks that will be fixed ASAP. I tested the fuel pump before it went in and it put out plenty of pressure. I ohmed out the FI system as a preliminary check via the pennington book things checked ok.

[SLITS]

Everything else being equal...the engine will easily turn over if you lock one wheel with a bar or ?, put the tranny in gear and turn the other wheel...whatever direction you wish.

If you pull the sparkplugs it will turn even easier.

Alternatively, you can put a wrench on the alternator pulley nut and as long as the belt is reasonably tight (I press down on it while turining), you can turn the engine with it.

And I assume your going to play valve adjustment to see if you have a tight valve or a really loose valve from a bent pushrod. Since there are only 4 lobes on the camshaft...it stands to reason if one cylinder's valve is in the open position, it's opposite is on the heel of the cam...no timing marks, rotor position, etc to worry about..Open one, adjust it's opposite.

But, with that all said....it's your and your buddy's time.......

[toon1]

thanks for the advice, I did a valve adjustment when the motor was out of the car and everything looked and adjusted ok, nothing out lof the norm. I rotated the motor until I felt compression, brought the piston to TDC checked the posistion with a light through the spark plug hole and set the rockers.