NEED ENGINE HELP!-UPDATED AGAIN

[bordin34]

I think I have a valve sticking on my 400. The engine sounds like there is air being compressed and it backfires. When I remove the spark plug wire from that cylinder it quiets down. Could I have a valve sticking and is there an easy way to help solve this. The cylinder is the second one from the front on the passenger side.

[Todd Wilson]

I'd pull the valve cover and see if thats the case. Maybe move the rocker back and forth to try and free it up some. If you can get the thing to work some then I would run some marvel mystery oil thru the car. A jug in the gas tank and possibly one in the oil and then plan for an oil change in a day or so. Or run it for an hour and change the oil. If that seems to take care of it I'd run some mystery oil in a tank or 2 of gas.


Todd

[bordin34]

Threw the oil fill hole I can see the one closest to the hole moving. Would a stuck valve quiet down when there is no spark to that cylinder.

[jwc]

Try a compression check on that whole side and see if the readings are all the same.

[firefighter3931]

When I remove the spark plug wire from that cylinder it quiets down.

That's usually a good indicator that something is wrong. A compression test and leakdown test is in order. 


Ron

[bordin34]

I removed the valve cover and everything appears to be moving normally. However I noticed that one of those clear fuel bowl sight plugs was falling apart and as soon as I got it out it broke. I got all I could out of the hole but some may have fallen into the bowl. Is there any skill or new gaskets needed if I take off the bowl to clean it out. I also bought new spark plugs and will see what those do.

[bordin34]

I also found out I have 452 heads.

A short vid of it cranking look toward the bottom left and you can see both intake and exhaust moving.

[dukeboy_318]

id say somethings messed up, do a compression test like firefighter3931 said and see what the readings are.  sounds like you might have to pull the head though

[firefighter3931]

You could have a burnt valve or bent valvestem....either of which can cause the issues you are describing. Get the compression tester on it and see what you've got. 


Ron

[bordin34]

Ok thanks, now I gotta borrow a compression gauge from somebody.

[dukeboy_318]

jegs, summit or jcwhitney have em

[bordin34]

I changed the distributor cap with one I had and I unplugged all the wires from the old one so I forget where the number 1 wire goes and can't put the rest of the wires on unless I know where the number one is. Any help. I still can't start it to see if that is the problem, waiting on fuel bowl sight plugs.

[caddman]

bump the starter till the timing mark is at the zero line, the rotor will be pointing at the number one spot on the cap (might want to mark the cap).  the symptoms that you described are the exact same thing that i had with my 318 (just this week even), with mine it was a dead lifter that beat the lobe off the cam.  I watched your video but couldn't really see much to say if they were moving.  good luck to ya.

caddman

[dukeboy_318]

I changed the distributor cap with one I had and I unplugged all the wires from the old one so I forget where the number 1 wire goes and can't put the rest of the wires on unless I know where the number one is. Any help. I still can't start it to see if that is the problem, waiting on fuel bowl sight plugs.

number on should be marked on the cap, after that use the firing order to determine which ones go where

[bordin34]

There is no number one on the cap.

[dukeboy_318]

then remove the spark plug from the number on cylinder and bump the starter till it brings the piston to top dead center, rotor should point to number one location, then put cap on and place the wires in the proper firing order.  This only works if the distributor hasnt been removed.

[firefighter3931]

then remove the spark plug from the number on cylinder and bump the starter till it brings the piston to top dead center, rotor should point to number one location, then put cap on and place the wires in the proper firing order.  This only works if the distributor hasnt been removed.

To further expand on this ; make sure the timing mark on your balancer is lined up at Zero on the timing cover tab. You can stick a small piece of wire into the spark plug hole to make sure the piston is indeed at top dead center and not bottom dead center. Once you've determined that it is in the firing position (piston top of bore) look to see where the rotor is pointing on your distributor cap....this will be #1 cylinder.

On a big block the distributor rotates counterclockwise and you simply follow the firing order and route the plug wires. Firing order is : 1-8-4-3-6-5-7-2



Ron

[dukeboy_318]

of couse if you forget to write this down, its shown on the intake manifold if its the stock intake.

[bordin34]

I did just the finger over the hole with the number 1 and my number 4 is in the same location it was in before so I guess I found my number one.

[bordin34]

A different cap didn't solve my original problem. I swapped spark plugs from a know good cylinder to the number 4 which has the problem and that didn't fix the problem. I swapped the stock coil with a blaster and that didn't fix the problem. Could new wires or electronic ignition box solve the problem?

[Charger-Bodie]

before you throw alot of $ in parts at it do a compression test!

[caddman]

by the symptoms you described, I would just about put money on it that you are facing a mechanical problem.  the carb back fire is being cased by the exhaust not escaping the cylinder.  that is unless you have some plug wires flipped then you have 2 plugs firing at the wrong time.

[bordin34]

I haven't spent a dime in spare parts, they all came with the car when I bought it. I am just trying to do some troubleshooting until I can get a compression gauge.

[dukeboy_318]

id say youve got a stuck valve for sure

[Charger-Bodie]

id say youve got a stuck valve for sure

or burnt...or bent

[bordin34]

So, I gotta pull the head if the compression check is bad?

[Charger-Bodie]

yes and if you do need to do so, it would be a good idea to remove them both and have a good valve job done atleast.

[bordin34]

That head is gonna be a PITA to pull with all the A/C stuff running over it.

[Charger-Bodie]

It wont be that bad, just take youre time , keep youre cool ,keep the parts and fasteners well organized and youll have it done and be proud of it.

[pettybird]

Both Autozone and Advance Auto have compression testers in their loan-a-tool programs.

[dukeboy_318]

pulling the heads arent bad, theres two ways to do this, one simply remove the valve cover and lremove the many bolts holding the head down and slowly pull it off being carefull not to drop it or any of the push rods or the easiest and safest is to remove the rockers and rockershaft and pull the push rods then remove the head.  I prefer the second method. and like reccomended above, pull both neads and have them worked on.

[bordin34]

I started the engine today and it started fine with a couple pumps of the gas pedal, then stalled. After that it wouldn't start or stay running unless I was between WOT and half-throttle. It also puffed blue smoke out of the exhuast like nobodies business it was like I just did a burnout but out the exhaust, it is about 42* here though. Could bad rings cause the original problem.

[dukeboy_318]

not likely, its most likely in the valvetrain,  just my two cents but id stop shotgunning it and find out whats truly wrong before guessing, get a compression tester from autozone and then we can go from there

[bordin34]

This doesn't have anything to do with my problem,but I just bought a 0.8ohm resistor for my blaster coil and it only has 2 prongs the one on it now has 4 prongs. How can I make it work. And I bought some XR5 spark plugs what gap should I put them at. I have a chrome box, blaster coil, and stock distributor.

[bordin34]

Here is a video of the sound that it makes.

[dukeboy_318]

i think i can hear the valve train clicking, thats not a good thing, i hate to say it but, i think the only way you're going to know for sure is to pull the heads, better to do so now than trying the wrong solution and havingthe motor break a valve which could fall down into the cylinder and make contact with the piston and cause the motor to blow a rod through the bottom end.  Had that happen on my aunts car a few years ago, not pretty or cheap

[bordin34]

Thats what I thought, but I would think that if it was the valve train clicking, it would click regardless if that cylinder was getting a spark or not.

[dukeboy_318]

it could be something where the decreased pressure  caused by the plug not firing might be silencing the clicking sound.  unless you want to drive around on 7 cylinders, id pull the heads and have a look see.  keep me post, let me know if you need pics of anything

[bordin34]

I don't know how accurate the factory oil pressure gauge is but at idle the oil pressure gauge is 7/8 to the right and at 4000rpm it is fully to the right, could this be relevant to my problem?

[firefighter3931]

What are the compression test results ? 


Ron

[bordin34]

Today I replaced the spark plugs with NGK XR-5's and ditched the Champions that were in there and were oil and richness fouled. I like NGK plugs because my friends golf cart had one that was literally partially melted and the engine still ran with that plug. I turn the key and the car starts up almost instantly and seems to idle much better and at a higher rpm. I think that was by misfiring problem. Then while it was running I happened to have my worklight on and saw smoke coming from the header on the "bad" cylinder so I believe that a bad header gasket on the head is my puffing sound. Anybody have gasket recommendations?

[Charger-Bodie]

Today I replaced the spark plugs with NGK XR-5's and ditched the Champions that were in there and were oil and richness fouled. I like NGK plugs because my friends golf cart had one that was literally partially melted and the engine still ran with that plug. I turn the key and the car starts up almost instantly and seems to idle much better and at a higher rpm. I think that was by misfiring problem. Then while it was running I happened to have my worklight on and saw smoke coming from the header on the "bad" cylinder so I believe that a bad header gasket on the head is my puffing sound. Anybody have gasket recommendations?

"percys dead soft alluminum" header gaskets!! I have had great luck with them.

[Tilar]

If your dual exhaust does NOT have a crossover pipe between the two sides, You can take a rag, And with the engine running, Hold the rag tight and square and place it over the exhaust on the side that you suspect the problem. If you have a valve leaking you will be able to see the rag being sucked up into the exhaust pipe just a little bit.

[bordin34]

The car has 2.5" duals with an H-pipe so I can't do that. I could literally see smoke puffing out of the header.

[dukeboy_318]

like ron said, what are the results of your compression test?   

[bordin34]

I didn't do one, the car seems to be running fine now.

[dukeboy_318]

glad to hear, hopefully you solved your problem and wont have any more issues with it.  merry christmass ya'll