HELP!! need experts advice on 440 trouble.

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SC69DART

SC69DART

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Hey all FABO members.
I would have posted this under an "Engine" forum but I see every forum topic but engine? Anyhoo, read on and share your years of wisdom.

I just got this motor together, the short block was balanced, decked to zero and blueprinted, the RPM heads are off the old motor and worked fine on it, the cam is hotter than what was in the old motor, its a solid lifter Lunati with more lift but not crazy (.566/.586) and 280/288 duration.

Everything torqued down good, gaskets were better than average..it went together great.

Now, ever since it first started up I have this annoying noise coming from the passenger side that sounds like a header gasket leak...I have switched out the gasket twice and filed the flanges flat. I asked a friend for advice and he said maybe I had a burnt exhaust valve because it does sound like an exhaust leak so we compression tested that side of the engine:

cyl.
2: 160 psi
4: 155 psi
6: 160 psi
8: 160 psi

I don't think the 5 psi difference would indicate a valve problem but maybe you all know different. Is there anything else that can make a sound like an exhaust leak...it almost sounds intermittent but then again the cam is rough...bad plug or plug wire? maybe the cylinder is going dead now and again?

The plugs are all new but the number 4 plug was especially clean, like hardly any carbon on it at all.

Any thoughts would be great before I dig into pulling the head...which is essentially like pulling the motor when its a 440 tucked into my Dart with headers. If the compression numbers look ok to you all, can anyone say for sure that the valves and heads are not the issue here?

Thanks,

Greg in SC
 
I don't think valve but I would get some baby powder crank it up and then dust that side if there is a leak maybe in a tube or joint you will see it blow the powder out of the area. Just a thought.
 
Its an easy enough thing to try, maybe take the fan off or put up a cardboard blocker to keep it from blowing off.

Thanks,

Greg.
 
....crack in headder that opens up when hot........I dont know, just throwin stuff out there,,,,heat crossover passage to ntake/ not sure if you have those....bad threads on one plug or the little spark plug washer/(gasket) (you might not have the either) maybe an arcing plug wire (probably not) misaligned hedder opening/gasket opening to head.
(prolly not though).........cylinder PSI is just fine IMO.
 
Inspect the pushrods to make sure they are not contacting the heads where they go through. A lot of times if that happens, the noise is very similar to an exhaust leak.
 
Thanks for all the ideas, Im preparing cold coronas and will start checking each item you have all thought of, this community is great. I wish there were some good ol' Mopar boys around my neck of the woods who could just come over and listen to it. I live in Clover, SC...is there any rare chance that somebody from FABO lives near me....Cold Beer and $50 cash to diagnose this noise!! How cool would that be.
 
My best guess is there is something between the intake or exhaust valve and seat on #4 cylinder causing it to not be closing properly.
This could be why the plug is cleaner than most and why the compression is slightly lower on this one cylinder only.
Doing a leakdown test will tell you for sure.
If you don't have a leakdown tester, you can always us an old spark plug, break out the porceline and weld an air fitting to it, put the engine at TDC and pump compressed air into it. If you hear air leaking out the exhaust, the valve is faulty or hung up, air leaking through the intake/carb, intake valve faulty or hung up, air through the oil filler cap, it's the rings or piston.
I've seen bits of gasket material etc. caught in the valves do this before. It doesn't take much.
Hope this helps,
Let us know how it turns out.
Tom.
 
Is there anyway to pull the valve spring and spin the valve to clear any potential problem on the seat? In other words compress the cylinder, remove the spring and spin the valve with pressure from the cylinder on it? Man I'm gettin' deperate! I hate it when things done right don't turn out right...I knew I should have tore the heads down and inspected them before putting them onto the new short block but I figured "hey, they worked ok on the old block so why mess with them....Murphy's law I guess. You guys are great for pitching me all these Ideas, I will try to keep a cool head and go through each one at a time.
 
I have to ask, after you first got the engine up to opperating temp, did you shut it down, pull the headers, valve covers, etc., and retorque the head bolts?
Its an obsolute must with aluminum heads! A real pain in the a$$, but you would'nt believe how much they loosen. You could already have a blown head gasket.
 
kocuda said:
I have to ask, after you first got the engine up to opperating temp, did you shut it down, pull the headers, valve covers, etc., and retorque the head bolts?
Its an obsolute must with aluminum heads! A real pain in the a$$, but you would'nt believe how much they loosen. You could already have a blown head gasket.
Click to expand...

I don't know about that. I worked as a line tech for a LONG time and I've done cylinder head work a LOT. On the line at the Ford dealer in Macon, I never once saw a factory TSB or anything that said aluminum heads required a retorque. Never. There are some special head bolt torque deestruckshuns, but that's all.
 
StrokerScamp said:
I don't know about that. I worked as a line tech for a LONG time and I've done cylinder head work a LOT. On the line at the Ford dealer in Macon, I never once saw a factory TSB or anything that said aluminum heads required a retorque. Never. There are some special head bolt torque deestruckshuns, but that's all.
Click to expand...

toque to yield bolts...
 
I'm getting closer to a cause...I think. I found that when I pull #4 plug wire the noise goes away...that was cool. I also picked up on a "chirping" noise coming out of both exhaust pipes...I have no idea. And....last but least, condensation drips from the exhaust joints behind the mufflers...it was 91 here today so the "cold exhaust system/hot exhaust gas theory" don't really fit. Anybody ever feel like throwing a hand grenade into the back seat of their car and getting some marshmallows? One head bolt was checked from each side after break in and it they were tight...short block source told me that would be fine. If I found them needing torque then I should go through all of them....maybe a mistake. Does any of this help???
 
Sounds like the exhaust guide grabbed the valve and has too much clearance. Would pressure up the cylinders, removes the springs (with piston a TDC) and check for movement.
 
This is all tending towards one thing......removing the head :O(
Burnt valve, bad valve guide, leaking head gasket....all head related.
 
The header leak theory has been ruled out so it leaves the head and the intake, I sprayed carb cleaner all around the intake and its good, too bad I have to screw with that now. I have decided to pull the heads tonight and have them gone through. When reassembly time comes, I will check back with you guys because I thought I did it right but I think not checking all of the head bolts after break-in was a mistake. I think I will get some new ARP head bolts also.

Are their any suggestions out there for going through the heads? I have a Lunati cam kit with the springs, retainers etc... but what of the valves and the seats and guides? If you all were building an engine that was going to be 10% strip and 90% street (mustang killer) what would you have done to the heads?

One FABO member said if the heads are decked on the block side then they have to be cut on the intake side too, can you confirm that and how much of each would need to come off each side. These are RPM heads, maybe milling them isn't even necessary.
 
If the heads or decks are cut, you also need to cut the intake manifold. Make a simple drawing for illustration. Draw the front of an engine with heads and manifold on. Draw a centerline down the center of each head or down the port face. You will see that lowering the heads on the centerline (cutting) actually brings the heads closer together and they move downward. The manifold become too wide for the new angle, thus riding higher on the intake ports.

The actual difference might be very subtle, depending on how much was cut, and the bolts might actually line up somewhat, but if the heads are ported and gasket-matched, a misalignment would affect flow across the mating surface.

Maybe one of the engine builders here could better explain this.
 
Here is a question:

When you set your intake on the heads, how much space should there be? It seems as though there is a lot of side to side play, is it ok to double gaskets or what could be used to take up some space before tightening it down? These are RPM heads and RPM intake, the deck was cut to zero so like Fishbreath said the intake mating surfaces should actually be closer but not the case, I wonder now if the heads have been milled on the intake sides.
Anyway: it was #4 that was causing the noise, pull the plug wire and the misfire/exhaust leak noise stops...when I pulled the intake I can see the bolt right next to the #4intake runner is stripped and there was oil around the port? I can only figure that oil was being sucked up the stripped hole and into #4 runner, an oily air leak? I will replace the gaskets and see what happens.
In the meantime I looked into a few other ports and see what looks like a collection of gas/oil laying on the backsides of some of the valves? I dipped into it and it feels a little slippery but smells like gas, I cant believe that anything could be puddled in there...gas or oil. So even if fixing the stripped intake bolt and replacing the gaskets takes care of the noise/miss I fear I will be pulling the heads
 
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