Is this possible???

[ljinx23]

alright guys, This may sound like it's impossible, but i've been trying to get this motor together for some time now, and after all the frustration and effort, It still didn't run. We tore the front cover off, and checked the degree on the cam;good. tore off the heads, no bent valves. But still no compression. This is a brand new shortblock, is it possible the company put the rings in wrong. I only have 60psi, on a BRAND NEW, NEVER RUN SHORTBLOCK!. I should be at 3x that if i am correct. If it is the rings, is there anything i can do to fix this problem by going through the company? I have all the records, and all the paperwork, of all the other problems with delays and so on. Help me out guys, I'm at a loss of words.

 

[donjohn]

what kinda block is it?

 

[ljinx23]

It's a 302 shortblock w/forged pistons from Central Coast Mustang. You should be able to find the company in any of the mustang books available.

 

[mackey]

Did you torque down the rockers right? What rockers are you running? Are the rockers running in the right order?

 

[94gtslow]

make sure to take all the plugs out, and have a good charged batery, so you can crank it fast.


I think mine compression is about 160 for each cylinder if i am correct.

 

[Killercanary]

The motor should be warmed up as well to make sure you have proper seal of the rings, but regardless I think you should see more than 60psi. Are you sure the rockers are not too tight and the valve is open? Are you sure that your compression tester isn't leaking? My O ring on my tester on makes it through about 5 cylinders before it gets cut up and leaks.

 

[ljinx23]

Yea guys, my mechanic and i double, and triple checked the rockers, and all seemed well. we even had another engine builder come in to make sure everything was in order. I then went and got another compression tester for that same reason Killer. And they both came up the same. Charge on the battery was good, because we put it on a charger for an hour, and i also purchased a new battery after this whole ordeal happened. I'm frustrated, lost, and ready to give up.

 

[fred-fred]

Have you done a wet and dry compression check? also have you done a compression leak down check? This will give you more of an idea wants going on. The heads that you are using are they new or used? Are the valves seating all the way?

 

[Killercanary]

I agree, at this point you'll want to do a leakdown test and see if the rings really are not sealing. Don't give up!

 

[ljinx23]

Ok,

this may sound a little silly, but what exactly is a leakdown test, and how do i go about performing it. and what is the difference between dry and wet compression test, or is one a leakdown test, and what will each one tell me? thanks again guys, u give me new hope

Lenny

 

[ljinx23]

anyone???

 

[final5-0]

It sounds like it is either the valve train or a problem with the rings for sure.

When the rocker is on the heel of the cam do you have the lifter just barely collapsed? You did not tell us if we are working with peds or stud mount rr's.

Hope the rings weren't put in upside down.

Later
Grady

 

[ljinx23]

I have the crane adjustable 1.6. stud mount, w/hardened pushrods, on my AFR heads. We double and triple checked the valvetrain like i said, and i don't want to pull the shortblock apart, because if they caused the problem, i want them to fix it, and if i go in there, they may not want to help. what should i do guys.

 

[final5-0]

I have the crane adjustable 1.6. stud mount, w/hardened pushrods, on my AFR heads. We double and triple checked the valvetrain like i said, and i don't want to pull the shortblock apart, because if they caused the problem, i want them to fix it, and if i go in there, they may not want to help. what should i do guys.

I would want to be able to tell the engine builder what I've done to come to the conclusion that I think there is a prob with the short block.

Sounds like you have proved the valve train is not at fault.

You have done a compression test that shows a prob. I think you have enough info at this point to start talking to your builder

A leakdown test would just be more proof on your side when you talk to your builder.

btw ...... I never have checked the compression on a fresh never fired engine but it seems to me that even though the readings would be lower than what you would see after the rings have seated ...... you would think they would not be as low as you have reported.

Let us know what your builder has to say.

Later
Grady

 

[final5-0]

Have you tried to put some air in the plug hole with both valves closed to see if you can hear air in the intake or exhaust?

Later
Grady

 

[ljinx23]

final5-0,

yes, i tried putting air in the plug hole, and didn't have air coming out either the intake or exhaust. and as far as the psi from unsealed rings, it should be enough to start the engine, correct. because the car just cranks, and cranks. distributor is correct, because we turned it 180 and then got backfire. we're gonna pull the motor this weekend and remove the heads to check for bent valves, and if they dont exist, what do i do?

 

[final5-0]

After you crank the motor are the plugs wet with fuel?

Do you see a good spark jump across a plug when you crank it?

Later
Grady

 

[ljinx23]

yes for both of those. After we crank it, i can light the plugs with a lighter, and when we arc the plugs to the frame, we get real good spark.

 

[final5-0]

Since you didn't hear air in the intake or exhaust then the I don't see how the valves could be bent or you would hear the air.

Why do you suspect bent valves?

Sure does sound sound like the pressure is leaking past the rings.

I really don't know if the 60 lb reading you got is enough to allow the motor to fire.

Have you talked to your engine builder to see what they say?

Later
Grady

 

[ljinx23]

No, i havent's talked to the company ( central cost mustang) yet, because i want to have all of the information, and then confront them about it. It's not that i suspect bent valves, but it's the only other possibility that we haven't physically looked at. when we pull the heads off this weekend, that should leave us with the anwser, because either there will be bent valves or not. If not i would think the only other thing that could cause the low psi would be the rings. If there are any other possibilities, that i am unaware of, please let me know anyone. and thanks for all your help final5-0.

Lenny