Got some head problems

Some troubleing noises are coming from my engine its a 73 6 cyl 250 C.I.D. in my 65 stang. After replaceing trans and flexplate i put the motor back in and it runs very ruff. So I decided to do a compression test cylinders 1,2,5,6 are at around 70-75 psi. Cylinders 3,4 are only at 25 psi and when i crank over the engine it has a hollow sound. So after i found that out, I removed the valve cover and checked all the springs, rockers, valves, etc... nothing seemed to wrong with the valve train. im not blowing smoke so it not the rings what the hell could make the valve not close all the way[img]/forums/images/smiles/icon_bicker.gif[/img] im stumped. The only thing i havent done is take off the head and look. Is thier any thing i can do to see if I burned up a valve, or bent one, or if its not closing all the way and free it up agian. Any help would be appretiated.

It sounds like the valves may be hanging open.

I had a similar problem with a car I bought that had a "fresh" rebuilt engine. It would not run smoothly. The old 6 cylinder valve springs were installed on the head and they had gotten very weak over time. I was able to easily push down on the retainer and the springs would collapse. I installed new ones and that solved the compression problem.

You could try to add a tablespoon of oil to each cylinder and run the compression test again. If the compression increases, then you have ring problems. If not, it is valve related.

Off topic, many years ago I visited the San Dimas water park. That place was a blast and one of my favorite all time memories.

Good Luck!

_________________
Dennis

65' STANG

393W NA, Toploader 4 Spd, 3:70 Posi,
CI Custom SFT, ProComp Heads, Vic Jr. Intake, 750dp, 10.2 CR

3370 lbs, 12.012@114.51 MPH on DOT's in full street trim.



<font size=-1>[ This Message was edited by: dennis111 on 5/18/07 7:26pm ]</font>

Tarnish builds up on the valve stems inside the head where you can not see. Once it gets too thick, the valve does not seat..

For the cost of a gasket, take the head off, pop the valves out, buff the tarnish off, and put it back together.

F.Y.I, any 250 CID head all the way up to 1986 will fit well on your engine, incase you decide to get a replacement head... look around, or ask, folks have them, probably get one for under $100.00

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2007-05-17 20:49, 1965Mustang wrote:
Some troubleing noises are coming from my engine its a 73 6 cyl 250 C.I.D. in my 65 stang. After replaceing trans and flexplate i put the motor back in and it runs very ruff. So I decided to do a compression test cylinders 1,2,5,6 are at around 70-75 psi. Cylinders 3,4 are only at 25 psi and when i crank over the engine it has a hollow sound. So after i found that out, I removed the valve cover and checked all the springs, rockers, valves, etc... nothing seemed to wrong with the valve train. im not blowing smoke so it not the rings what the hell could make the valve not close all the way[img]/forums/images/smiles/icon_bicker.gif[/img] im stumped. The only thing i havent done is take off the head and look. Is thier any thing i can do to see if I burned up a valve, or bent one, or if its not closing all the way and free it up agian. Any help would be appretiated.
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>


Adjacent cyls with that low of a compression test result make me wonder about the head gasket.


[addsig]

Check with these guys
http://fordsix.com/forum/viewforum.p...90c1d9c248a90f
its a good site for these 6cyl.
tim
[addsig]

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On 2007-05-18 05:56, GregP wrote:
<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2007-05-17 20:49, 1965Mustang wrote:
Some troubleing noises are coming from my engine its a 73 6 cyl 250 C.I.D. in my 65 stang. After replaceing trans and flexplate i put the motor back in and it runs very ruff. So I decided to do a compression test cylinders 1,2,5,6 are at around 70-75 psi. Cylinders 3,4 are only at 25 psi and when i crank over the engine it has a hollow sound. So after i found that out, I removed the valve cover and checked all the springs, rockers, valves, etc... nothing seemed to wrong with the valve train. im not blowing smoke so it not the rings what the hell could make the valve not close all the way[img]/forums/images/smiles/icon_bicker.gif[/img] im stumped. The only thing i havent done is take off the head and look. Is thier any thing i can do to see if I burned up a valve, or bent one, or if its not closing all the way and free it up agian. Any help would be appretiated.
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>


Adjacent cyls with that low of a compression test result make me wonder about the head gasket.



</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

That was my first thought as well.
[addsig]

Thanks for the ideas i tried them First I tried some engine flush it helped a bit the compression is cyl 3-4 came up 10 psi. Then i tried the oil in cyl to check the rings nothing different with compression thats good. So Im not totaly sure but I think its the head gasket so ill replace it and see what happens. Thanks for the help guys Ill let you know how it turns out.

head gasket or valve job/clean up !!!! also check between the #3/#4 exhaust ports for cracks as they tend to crack their !! good luck!!! -mel-