76 2.7 with 110lb even comp. why ?

[brianvb]

My car feels under powered and measures an even 110lb compression. What can I do ?

[brighton911]

Any history on the engine? A "big" cam could give you a low cranking pressure, do you know what's in it? Are you holding the throttle wide open during cranking, if not, there's your answer. How about your guage, known to be accurate or compare readings to another. Any oil consumption issues?

[E Sully]

I would consider 125lb minimum, 110 is very low. You can do a leak down test to see if air is escaping past the valves or rings. Have you removed the valve covers to check valve clearance and head studs?
How do the spark plugs look? Are they clean or black?

[earossi]

Without data, which you lack in your posting, my "guesses" are just that. First, the probability is very low that every cylinder would be equally down on compression. So, the previous posters remarks about checking the accuracy of the compression gauge is right now.

But, you did say that there is a loss of power as well, which does correlate with poor compression.

Have you recently done a valve adjustment on the car? If you have, I would recommend going back and repeating that step. You may have adjusted the valves so tightly that you are, in fact, lifting every valve "slightly" off its seat, which would explain not only your low compression readings, but the fact that they are all the same. And, since the valves are not sealing off, you are decreasing the amount of air needed for combustion.

If compression does not change following a valve adjustment, then I would do a leak down on the engine. If you have a valve off its seat in every cylinder, your leak downs should be horrible! Probably in excess of 10-15%.

[Jcslocum]

Proper Compression test in my shop is:

Hot engine
All sparking plugs out
Fuel Pump Off
Ignition grounded
Throttle held Wide open
Fully Charged battery (on charger is always good if you can)
Make sure tester has good o-ring for proper seal
Crank engine until the needle stops moving up (I do this 3 times and average readings)

The fact that all read the same makes me think something is amiss with the tool or procedure.

[tctnd]

Check cam timing.

[cgarr]

Originally Posted by tctnd

Check cam timing.

^

This, Timing can change compression huge