What wrong with this.. (pics)mustang

[94GT347]

Just curious, did you pull any of the valves out of the heads at any point?

Even though you torque the rocker nut to a certain value, you still have to shim under the pedestal to get the correct valve lash. I'm sure someone has already taken the time to detail the procedure on here. I'd try a search.

I agree with the other poster.....if nothing obvious, go back together with it. Very doubtful you have a ring issue on 3 cylinders.
If it was a cheby, you could just swap sides on the heads. Then you could verify if it is a vlave or short block issue by comparing new compression readings to the old ones.
Ford has a "special" insert in a bolt hole in one end of the head that makes it side specific. You may be able to back it out and put it in the other end?

 

[Fox_84]

Just a suggestion but when you torque the head bolts down, are you going in a circle or are you starting in the center and working your way outwards? If you have a haynes or chilton manual it will show you the order to start in the center and work your way outwards and do so correctly. I really dont feel this is it though.

I dont have a lot of experience with the 302, on my second one, but I do have much experience with engine work.

There is most likely 2 things it could be.
1st you may have rings that are sticking or the gaps are in align with each other and they shouldnt be.
2nd you may have a couple of burnt valves or valves that are adjusted tighter than they should to be.

Rings Sticking. You can put a teaspoon of Marvel Mystery Oil in each spark plug hole and circulate that and usually rings will free up. But since you had pistons out, I doubt it is that.
If you have the gaps on the rings on a single piston in align, you can loose compression here. The gaps on each ring should not be in align with each other.
As far as valves, it is hard to explain to you how to adjust them, but this is what I fee it is. I figure the valves have been tightened too far.
Your primary problem, I will have to agree with others, it was probably not internal, but you will just have to go from there once you figure out your comperssion problem, because that is definitely not right.

 

[mustangsally93]

Just a suggestion but when you torque the head bolts down, are you going in a circle or are you starting in the center and working your way outwards? If you have a haynes or chilton manual it will show you the order to start in the center and work your way outwards and do so correctly. I really dont feel this is it though.

I dont have a lot of experience with the 302, on my second one, but I do have much experience with engine work.

There is most likely 2 things it could be.
1st you may have rings that are sticking or the gaps are in align with each other and they shouldnt be.
2nd you may have a couple of burnt valves or valves that are adjusted tighter than they should to be.

Rings Sticking. You can put a teaspoon of Marvel Mystery Oil in each spark plug hole and circulate that and usually rings will free up. But since you had pistons out, I doubt it is that.
If you have the gaps on the rings on a single piston in align, you can loose compression here. The gaps on each ring should not be in align with each other.
As far as valves, it is hard to explain to you how to adjust them, but this is what I fee it is. I figure the valves have been tightened too far.
Your primary problem, I will have to agree with others, it was probably not internal, but you will just have to go from there once you figure out your comperssion problem, because that is definitely not right.

Well the pistions were never out. Also I did a gap feeler and all the ring were fine. Also no marks on the pistions walls. We also put a but load of oil on the wall and worked it in. the heads were never missed with other then them being off. So in the morning I well redo the rockers and tighten them down less. The heads bolts are done right in the order they should have been done.

 

[custom89stang]

i know its been a while, BUT do i dare say go back to square one? and every step of the way, make sure you get consensus on everything you do (torque specs,etc)?

 

[74courier]

if it was like my car when i got it the heads wernt tourqed right and the pushrods where a lil to short with about 30mins of work i had a good running motor again and close comp ratios between 125-137[most read at 125-129]. id get a pushrod length checker from summit or a local parts store.

 

[mustangsally93]

ok ok Well in about 4 hours Im going back to work on it. I really don't know why the size of the push rod matter but ok I well check. And I well tighten the rockers to 15-20 and not 25-30. Also could it be the head gaskets Im using. I'm using trick flow head gaskets and not oem. Could this do anything????

View attachment 478296

 

[mustangsally93]

I dont know why it posted three times

 

[mustangsally93]

ok

 

[getusummm]

I was under the impression that the 91 or 92 and later head bolts were of the torque to yield variety and should not be reused. The cam is very easy to time, just line up the marks on the sprockets.

 

[bluevenom867]

I was under the impression that the 91 or 92 and later head bolts were of the torque to yield variety and should not be reused. The cam is very easy to time, just line up the marks on the sprockets.

Yes you cant reuse torque to yield bolts.

Sould get a set of ARP bolts,even used they are far better than a factory bolt.

 

[Mustang5L5]

That's right, you can't reuse the '93's head bolts. Once they are off they are done.

Maybe that's why the compression was down on the end cylinders? Possible the head was slightly lifting there???

 

[Black1987Stang]

Im also thinking its a rocker problem, i had redone my stock heads, cut the valves and seats and never then never shimmed the rockers so in one cylinder i had like 9psi of compression hah, i put in one shim and went back up to 150. i no u didnt get ur heads worked on just saying though. U said u had the cam out, are the dots ligned up? once u get the heads on, turn each cylinder to top dead center and hook up compressed air and see where air comes out, if its the intake or exhaust pipe then u no its the valves, if its the breather or oil dipstick its the rings...btw did u try a wet compression test too

 

[JRPony]

That's right, you can't reuse the '93's head bolts. Once they are off they are done.

Maybe that's why the compression was down on the end cylinders? Possible the head was slightly lifting there???

Technically, TTY bolts are one time use only, but they will still provide equal clamping force the second or third time that their used. Its the shear /tensile stength that is reduced. What I'm saying is, reusing TTY bolts will not reduce compression #'s.

 

[bluevenom867]

Technically, TTY bolts are one time use only, but they will still provide equal clamping force the second or third time that their used. Its the shear /tensile stength that is reduced. What I'm saying is, reusing TTY bolts will not reduce compression #'s.

They will if the bolt stretchs and the head lifts....

 

[mustangsally93]

Well this morning I missed with it more. Also Im back in kansas so a freind is taking my heads to a shop to find out if those are all right for sure. Then this weekend I'm going to use oem head gaskets and arp head studs. I know the rings were fine because I used a feeler gauge. And if the heads come out fine it has to be the head gaskets or the head bolts?? Right?

 

[CRASH7772]

How do I adjust the rockers??? We don't know how to..

http://www.fordracingparts.com/download/instructionsheets/FordInstShtM-6564-All.pdf

 

[mustangsally93]

http://www.fordracingparts.com/download/instructionsheets/FordInstShtM-6564-All.pdf

thanks I well use that next weekend

 

[JRPony]

They will if the bolt stretchs and the head lifts....

TTY bolts are designed to stretch. This is what happens when the they are angle torqued. And the head will not lift during a compression test.

 

[bluevenom867]

TTY bolts are designed to stretch. This is what happens when the they are angle torqued. And the head will not lift during a compression test.

All bolts stretch thats why its a clamping load,there like springs.
A TTY bolt once stretched doesnt return to its noraml length though,and looses some of its strength,making is useless...

If it lifted during running though,you already have a weak gasket.

 

[mustangsally93]

Well this morning I missed with it more. Also Im back in kansas so a freind is taking my heads to a shop to find out if those are all right for sure. Then this weekend I'm going to use oem head gaskets and arp head studs. I know the rings were fine because I used a feeler gauge. And if the heads come out fine it has to be the head gaskets or the head bolts?? Right?

Well what do you guys think about this? Right or wrong?