What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Compression test question-done

lak2004

lak2004

1/2 ton status
Joined
Aug 31, 2006
Posts
3,806
Reaction score
0
Location
Durango, CO
So i forgot to do a compression test before I started pulling stuf yesterday :doah:. I want to finish pulling the intake and distributor today, but i already pulled the carb.

I can do a compression test without the carb correct? Will I need to plug the fuel line or can I pull off the fuel pump? I am doing a tbi conversion so it has to come off anyway.

Thanks
 
Last edited:
Even if the carb was on there you would hold the pedal to the floor while you cranked it so that as much air goes into the motor as possible. Having the carb off just makes the whole deal a little easier.

Go ahead and remove the fuel pump before you test the compression.
 
Should I block it off as well or will that matter since there will be no pump?
 
Ran out of time today so I couldnt go get a block off plate for the fuel pump. If I pull the distributor and manifold will i still be able to do a compression test? I already pulled the battery out the other day so I will have to turn the engine over by hand too.
I have already sold the carb, manifold and distributor so I need to get them shipped out by tomorrow sometime.
 
Um, No you can't do a compression test the traditional way by turning it over by hand. Just can't get enough speed to get a realistic reading. I would just set the battery close and wire it back up and crank with the starter.
Dont need the manifold or dist. for the compression test. Keep in mind that the dist turns the oil pump, so without it you risk dry bearings and lifters without oil pressure. Might work if you keep the revolutions to a minimum.
 
I can just set the batt on the tire and throw the dist back in in the morning. I can do it with just putting the dist back in and not running the spark lug wires correct?

Damn I shouldve done a compression test weeks ago when I was complaining about other crap on here :doah:
 
You don't need the distributor to do a compression check. In fact, you should pull the power from the distributor while you are doing the compression check (you don't want the truck starting :eek1:)


You do need to use the starter to spin the motor fast enough to get an accurate reading.
 
Yes you can do it that way, you don't need the wires, only the distributor to keep oil flowing through the engine.
 
38377k5 said:
You don't need the distributor to do a compression check. In fact, you should pull the power from the distributor while you are doing the compression check (you don't want the truck starting :eek1:)


You do need to use the starter to spin the motor fast enough to get an accurate reading.
Click to expand...
Normally I agree, but without oil flowing through the engine, lifters are not going to be at full pressure, among the other issue of no oil flowing to bearings without a distributor in place.
 
Ok so i should just intall the dist without any of the wires then? That what i was planning on doing but I just want to make sure I dont screw anything up.
 
lectric80 said:
Normally I agree, but without oil flowing through the engine, lifters are not going to be at full pressure, among the other issue of no oil flowing to bearings without a distributor in place.
Click to expand...

Oops, I forgot that the distributor drives the oil pump.

You should install the distributor, but you don't need to mess with the cap, rotor, plug wires, etc.
 
Well got the compression test done on the side that has been fouling plugs really bad. In short looks like the heads are coming off and I will be doing some work. My 2,6 and 8 cylinders all had 90-95psi dry and then 105-110 wet. 4 had something like 45 dry and 60 wet :doah: So piston rings are in order and while I am at it I think I will just do a rebuild.
 
You must log in or register to reply here.

Latest Posts

Top Bottom