1972 Dodge Colt

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jacko241 said:
How did you find out that you had compression by leaving those nuts loose? What made you try that?
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Great question!
Not really sure, but during the work on the valve cover, I think, I just loosened them on #1.
Just to see if I could see, hear or feel something.
Bingo, I had the 180 psi number on the gage.
I had just a little interference on the #1 and #6 exhaust rockers.
So I just kept grinding and checking till everything cleared.
Just a small rub.
You can see in this picture the marking I placed on the high spot to check for rub.
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To follow up on the post.
Remember these are anodized roller lifters.
Smith Brothers push-rods.
300 lbs open pressure on the springs.
Bronze wall guides.
"If" I was hitting any of that stuff I would see chips, grind marks and maybe broke parts.
Here is the inside of the valve cover at #1 and the top of the rockers.
Nothing, no marks.
When I installed the steel cover, I had a huge pressure drop on compression test.
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slantracer said:
Great video by the way, but sorry that you are having trouble. How about changing to a set of the old black roller rockers and see if it fixes your problem? If you don't have a set of rockers I can ship you a set to try.

Mark
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Thank you Mr. SlantRacer!
I have a set of those old black roller rockers I am saving for the "killer" 210 engine.
Don't want to use them up on this old junk engine.
You know I watched the video, I look beat.
Maybe some energy drink or coffee would help me.
I am glad a few posts ago I said, I "may" have found the problem.
"may"
This is a better video, with loose rocker cover nuts!
 
I thought the double gaskets would indicate if it was an interference issue with the valve cover or an issue with the head when you tighten the bolts
 
qkcuda said:
I thought the double gaskets would indicate if it was an interference issue with the valve cover or an issue with the head when you tighten the bolts
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I wasn't giving grief for your comment, sorry if it sounded that way.
I appreciate any ideas to fix this problem.
I don't see any interference issues.
Only the little bit I cleared on the adjuster end to the side of the cover.
 
jacko241 said:
Possible crack in the head that opens up when you tighten those bolts?
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I really don't want to guess, but it seems that way.
It's just hard to believe 2 little 1/4-20 studs and nuts could cause that much problem.
Talking about an 80 lbs head bolted to a big cast iron block.
 
Hyper_pak said:
I really don't want to guess, but it seems that way.
It's just hard to believe 2 little 1/4-20 studs and nuts could cause that much problem.
Talking about an 80 lbs head bolted to a big cast iron block.
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I agree, but if you are certain that there is no interference with the valve cover, I can't think of anything else it could be.
 
Stan, at this point, just for the heck of it, I'd try a set of stock rockers.
 
Also Stan, have you started the engine without the valve cover to verify #1 fires? You have something barely touching up there, not enough to leave a mark, but just enough to affect what's going on with #1.
 
Hyper_pak said:
"If" I was hitting any of that stuff I would see chips, grind marks and maybe broke parts.
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Not sure I agree. Here's why. ALL you're doing is tightening down some fasteners and it makes a difference. You have all the rest tight, but when you loosen those two, that's when you get good compression. Also, when they are tight, you STILL have compression, just a very small amount. So that means something's touching "just barely enough" to affect the compression on that cylinder. Also, when you swap out the steel valve cover, it's not as tall so it affects it even more. You're touching "somewhere", there's just no evidence. Have you inspected the adjuster nuts REALLY GOOD? Those would be really difficult to see witness marks since they are a dark color. Maybe even try some modeling clay on the rockers on the tops of both ends.
 
Is the head ported? Does that bolt/stud in any way shape or form get into an intake port?
 
Stan, I would definitely install a stock set of rockers and check it before removing the head. Then you will know if it is the rockers touching something when you draw it down, or if it is actually something to do with the bolts. ( which I can't imagine) You could clean everything well and put a little bit of clay on those two rockers or the valve cover and turn it over and see what you got. Good luck!
 
408 swinger said:
Is the head ported? Does that bolt/stud in any way shape or form get into an intake port?
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That would be easy to test. Just apply some regulated air pressure to the stud holes. All that would be though is the equivalent to a vacuum leak. That wouldn't have that big an effect on compression. Might not have any.
 
RustyRatRod said:
That would be easy to test. Just apply some regulated air pressure to the stud holes. All that would be though is the equivalent to a vacuum leak. That wouldn't have that big an effect on compression. Might not have any.
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Agreed. I don't have a slant head to put eyes on at the moment. Wondering where those bolts/studs are in correlation to a port. Just spit ballin'. All the focus is on the valvetrain. I know there isn't any real torque on a valve cover. Just maybe enough to open a crack somewhere?
 
408 swinger said:
Agreed. I don't have a slant head to put eyes on at the moment. Wondering where those bolts/studs are in correlation to a port. Just spit ballin'. All the focus is on the valvetrain. I know there isn't any real torque on a valve cover. Just maybe enough to open a crack somewhere?
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Man I don't know. I ain't seein it. I think it's gotta be the rocker(s) touching somehow.
 
Rick Covalt said:
Stan, I would definitely install a stock set of rockers and check it before removing the head. Then you will know if it is the rockers touching something when you draw it down, or if it is actually something to do with the bolts. ( which I can't imagine) You could clean everything well and put a little bit of clay on those two rockers or the valve cover and turn it over and see what you got. Good luck!
Click to expand...

I was going to suggest a dab of grease on top of the adjusters.

Is the cam hydraulic or solid?
 
408 swinger said:
Agreed. I don't have a slant head to put eyes on at the moment. Wondering where those bolts/studs are in correlation to a port. Just spit ballin'. All the focus is on the valvetrain. I know there isn't any real torque on a valve cover. Just maybe enough to open a crack somewhere?
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That's what I said earlier. If it has been ported crazy, maybe the metal is thin enough that it would open up under light torque.
 
jacko241 said:
That's what I said earlier. If it has been ported crazy, maybe the metal is thin enough that it would open up under light torque.
Click to expand...

The valve cover bolt on the intake side of the head lines up between the number one intake and exhaust valve. Probably into the wall between the two runners if I guess. However if the head was cracked there-(Into the exhaust or intake port) I don't see how that is going to change a simple compression reading? That area is a long way from the combustion area of the head where you make compression. Still a valve hanging open is my guess. An exhaust if it is not popping back into the carb. Good luck!
 
I will try and comment on all your inputs, thanks for scratching your brains.
First off I made a template of the inside of the valve cover.
There is a lot of room under the aluminum cover.
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Also that head is off the engine now and I am moving the springs over to the next head.

Rusty:
Stock rockers will be tested on the new head, same tests.
It ran great with the cover screws loose, I posted a video of it running on all 6.
I see no interference under the cover, the adjusters or tips don't touch.

408 Swinger:
The problem head was heavily ported and repaired by a pro where the water jacket was ported into. On number 1 and others. It has 1.88 Intake and 1.5 exhaust valves. The first valve cover stud is between the #1 Exhaust and Intake ports. Right between.

Rick C:
Head was off yesterday. I will do a test with stock rockers as soon as it's back together.

Justinp61: Solid lifter Racer Brown cam.

Thanks Mopar Friends!
 
Hyper_pak said:
I will try and comment on all your inputs, thanks for scratching your brains.
First off I made a template of the inside of the valve cover.
There is a lot of room under the aluminum cover.View attachment 1715904737

Also that head is off the engine now and I am moving the springs over to the next head.

Rusty:
Stock rockers will be tested on the new head, same tests.
It ran great with the cover screws loose, I posted a video of it running on all 6.
I see no interference under the cover, the adjusters or tips don't touch.

408 Swinger:
The problem head was heavily ported and repaired by a pro where the water jacket was ported into. On number 1 and others. It has 1.88 Intake and 1.5 exhaust valves. The first valve cover stud is between the #1 Exhaust and Intake ports. Right between.

Rick C:
Head was off yesterday. I will do a test with stock rockers as soon as it's back together.

Justinp61: Solid lifter Racer Brown cam.

Thanks Mopar Friends!
Click to expand...
Hope you get to the bottom of it. Good luck!!
 
This is for the valve cover conspiracy group.
Rollers on #1 with grease on tips and adjusters.
Last picture is cover installed with no valve cover gasket.
No transfer to the underside of the cover.
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I know you pulled the head already but did you run the engine or do a compression test previously with the valve cover OFF and the nuts tight on the studs? That would quickly eliminate the valve cover being the problem.
 
I have the new head built up with springs and retainers.
Did a piston to valve clearance test today and I have more than the other head.
The older head was milled quite a bit.
To make up part of it, I will use a steel shim in place of the composite one.
Couple of days now.
 
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