compression test

[the gimpey one]

So after saturdays fiasco i am going to get pretty serious on my engine. I would like to do a compression test. Couple of questions:

1. Do i need to check timing and valves first?
2. Can someone walk me thru how to do a compression test?

I want to do this before the hamom coming up but it will just depend on time. I gotta install a ps pump and replace some tre's first.

 

[dohcdelsol93]

first, mark all spark plugs so you know how they go back on.

then remove all spark plugs.

pull all plug wires back where they will not spark.

put compression gauge in 1st cylinder

have someone in the car turn it over about 3-4 times at WOT

jot down readings and go through the rest of the cylinders one at a time.

your looking for 1 or more cylinders that are more than 25% greater/lesser than the others.

If readings are weak you have issues.

If two cylinders next to each other are weak it could be a head gasket.

If you put oil in the cylinder of a weak piston and the reading jumps up you have a ring/cylinder/piston issue.

if all are ok i would probably still check the valve lash before putting back on the road.

I would definatley check the timing before adjusting the carb out.

It was dark, cold and wet when i adjusted the carb before we left the wheeling spot so chances are my lack of patience and daylight combined with a soaked a/f did not help matters much

 

[Southeast Overland]

Dat's just about it. The only thing I would add is watch the compression rise as the engine turns over. 3-4 cycles should max out the compression but if you keep an eye on the gauge you will be able to tell when you've reached your highest compression. Accurate readings are good readings.

Now I'll turn this thread back over to the guy who did a diesel swap in his sleep.

 

[the gimpey one]

lol. I am gonna start the tre's this week. Power steering next week. Then Compression. What about my valves? Should i make sure they are correct before compression test?

 

[Southeast Overland]

lol. I am gonna start the tre's this week. Power steering next week. Then Compression. What about my valves? Should i make sure they are correct before compression test?

You can - but I'd probably run the compression test without adjusting your valves to get a baseline - then adjust your valves and run a compression test again and look at the difference.

 

[dohcdelsol93]

Now I'll turn this thread back over to the guy who did a diesel swap in his sleep.

this was actually the first swap i've done to a vehicle without the consumption of large amounts of alcohol. It's also the first i've done since my son was born.

 

[Trollhole]

Need to keep the butterfly's open on the carb.