What wrong with this.. (pics)mustang

mustangsally93 said:

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

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I honestly think swapping out for new head bolts is a good idea. Im not 100% convinced you are having the compression problem soley because you reused the old head bolts.. However, I do know that its not really a good idea to reuse the stock head bolts.. that can cause problems.. So, its a good thing you are switching to ARP

i would do a compression test without the rockers bolted down...... if the numbers are the same it is not a rocker arm issue, if you have normal numbers without the rockers, then you know without a doubt where the problem is

I would also get a good set of ARP head botls.......only like 35$..


jason

jason

mytight95 said:

i would do a compression test without the rockers bolted down...... if the numbers are the same it is not a rocker arm issue, if you have normal numbers without the rockers, then you know without a doubt where the problem is

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You need to elimnate the rockers as a possible issue.

Not trying to stir up anything here but i don't think the head bolts are the problem myself, i have used the same one's 3 and 4 times and never had any problems what so ever, just torque them down about 5 pounds more than usualy and everything has been great!

keep doing that and you will find their breaking point

Seriously guys cmon....those aer the stock pedastal mount stamped rockers. Why are yuou giving him instructions to adjust for ROLLER rockers. Honestly the guys at the dealership just blown them down with impact guns and dont even torque them, and those ars run fine for years. there is NO need to "adjust" non-adjustable stamped stock rocker arms. just torque them down to the (35lbft if i remember correctly). BUT can you prime your oil pump to pump up the lifters??? to put proper stresses on the valve train, though they would all be shut if they werent pumped up. Anyways either there is something wrong with your sequencing of the head bolts or maybe you have some crank rings...for that low of compression. i seriously doubt its the rockers at all if you just torques them down.

mytight95 said:

i would do a compression test without the rockers bolted down...... if the numbers are the same it is not a rocker arm issue, if you have normal numbers without the rockers, then you know without a doubt where the problem is

I would also get a good set of ARP head botls.......only like 35$..


jason

jason

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ding,ding,ding- i think we have a winner! compression test without rockers is needed. arp bolts or studs needed. do it..do it

Ok,so now let me ask you this...

How you get the air into the cylinders with out the rockers on (to open the intake valve)?

And even if you could (theres one way,but its a PITA) if they are out of adjustment (i.e shims) then it will still give you problems.

don't thread the gauge into the spark plug hole until right before the cylinder you want to test is on the compression stroke. it will pull air through the spark plug holes....... I don't think i am wrong in saying you can do it this way.... i have been shown to do it that way by my father, and our mechanic


jason

mytight95 said:

don't thread the gauge into the spark plug hole until right before the cylinder you want to test is on the compression stroke. it will pull air through the spark plug holes....... I don't think i am wrong in saying you can do it this way.... i have been shown to do it that way by my father, and our mechanic


jason

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Yup,thats the one way I was refering to,however you cant get a real accurate reading when cranking it over.Because the psi numbers will get lower as it cranks cause its not drawing more air in like if the valves opened normaly.

i doesnt look like you had the heads milled after you took them off. if you heads are warped .010 the you will msot likely see the low comp. # on the end cylinders.

what ur doing sounds good...once u get the heads back on I would hook up compressed air line into the sparj plug hole via the compression tester fitting or whatever...this is without the rockers on and piston at TDC? (all the way up), turn on the air and see wheres its leaking from if it does leak at all...rings, intake, exhayst etc...
I never heard of checking rings with a feeler gauge?? if u got space between the outside of the ring and the cylinder then u got problems then...maybe u were thinking of the piston to wall clearance?

Hey, fellas.

I’m the guy helping MustangSally with his Cobra. I skimmed through the other posts so forgive me if I ask any questions that have already been covered.

I won’t pretend I’m an expert of 5.0s, but I have done headgaskets before. This is my first time wrenching on a 5.0. Thus far, the experience has been very strange.

As Sally stated, this motor ran STRONG before he pulled it. The short block has never been apart, just the cam and heads.

I used the feeler gauge just to see if a chunk of ring was gone (going off what the speed shop that first tested it said). I could only see the top half of the rings with the engine in the car. No, it’s probably not the best method, but it’s all we had in his garage.

The pistons are just fine, contrary to what the speed shop said.

The cam is installed properly. I’m 100% positive. Ford made it moron-proof with the alignment dowel on one end.

Here’s what I think the problem might be: The head bolts were reused.

I assume these are torque to yield head bolts and were thus stretched after Ford installed them. I am wondering if we are bottoming the now longer bolts out inside the block before they have clamped all the way down. Short of ARP fasteners (head studs, anyway), I’ve never heard of a factory head bolt that could safely be reused.

Also, a tap was never run through the head bolt holes to clean them out.

In addition, when Sally reinstalled the heads, he torqued them to 85-95ft-lb for the final step. The manual actually said 85-95º past the second torque reading (55ft-lb or so IIRC).

When I retorqued them (now the third time on this set of bolts), I could not get them a full quarter turn past the second torque value (maybe an 1/8 turn at best). Sally’s 260lb ass couldn’t turn them all the way either. We thought the bolts would break.

I think the fasteners are shot and the head isn’t nearly as tight on the ends as it should be (notice that all 3 cylinders that are low are on the ends).

Could loosening the bolts in the wrong order warp the head? Is there a correct order? Opposite of the tightening sequence?

Your thoughts?

Well,I say...get the thing back together with ARP bolts now.

Then you can see if anythings wrong.

:SNSign:

:yup:


jason

I was wondering what cam you put in it. Some cams use a 351 pattern and some use a 302 pattern. If it uses a different pattern from the stock 302 it may require you to run the spark plug wires from the distributor in a different pattern to the cylinders. Just a thought.