440 Valve spring replacement with head still on engine?

[DocMel]

Gents.   Havent posted awhile, Colorado weather being the way it is

I've been tracking down a rough running engine over the winter, not really going at seriously till the weather got warm.  Like today....

So today I take the valve covers off to check out my valve train (hyd lifters).  Sure enough, one of  the number 4 cylinder rockers (the rocker toward the water pump) is loose.  The valve spring is collapsed, allowing at least a 1/4 play between the rocker and pushrod.

So............How can I replace the valve spring with the head still in the car?  (Or can I?) 

 I've  replaced a valve spring before with a head out of the car, and I sure dont want to remove the head now in place to replace the valve spring if not needed

Its on a set of 440 source heads, if that makes a dif


So I take off the passneger side valve train assembly, and righ there

[73440]

I believe you make an air chuck modifying a spark plug to allow air to hold the valves closed till the work is completed up top.

[DocMel]

Thanks: I'm familiar with that trick.   Really my question deals with how do I keep downward pressure on the springs till I get the keepers on?   

 Will the typical valve spring compressor work with the head still on the engine?

[734406pk]

I have done this job on many engines in the past both gasoline and and Diesel. I have used the air pressure trick to hold the valves closed but i have found an easier way. Remove the sparkplug and rocker shaft on the effected cylinder. Rotate the crankshaft to position the piston to BDC. Use 1/8" parachute cord and feed a few feet into the spark plug hole. Carefully rotate the crank towards TDC (valves are closed) until you fell the cord press against the intake and exhaust valves. Now you can use a spring compressor to change the spring(s).
I've used this spring compressor quite often:

http://www.nationaltoolwarehouse.com/Overhead-Valve-Spring-Compressor-P230649.aspx?zmam=31282435&zmas=50&zmac=750&zmap=LIS16550&gclid=Cj0KEQjwjoC6BRDXuvnw4Ym2y8MBEiQACA-jWRSfqMcYWXK0YsQg6NTKX7jtGHhzlTIlFedN-K0FMbwaAp9j8P8HAQ

For a BB Mopar dedicated on-engine valve spring compressor, Hughs Engine has this:
http://www.hughesengines.com/Index/products.php?browse=category&level0=Ti0gVG9vbHMgJiBCb29rcw==&level1=VmFsdmUgU3ByaW5nIENvbXByZXNzb3JzICYgVGVzdGVycw==&searchmode=partnumber&page=2&partid=24354

You can buy the tool, use it then resell to someone else if needed.
Hopes this helps!!

[73440]

I like that idea 734406pk.

[734406pk]

I like that idea 734406pk.
[/quote

Thank You! It's not my idea originally, but something i learned many years ago from some very smart instructors. No air compressor needed and no risk of sudden air pressure loss. You know what happens then... lots of cursing! and pull the cylinder head anyway... Been there!

[73440]

Exactly!!
And tie a big knot on the end. or a wrench.

[1 Wild R/T]

You have a problem that isn't the valve spring.... Likely the valve is stuck in the guide... A weal or even broken spring will still close the valve on a non-running engine, the fact the valve is open points to bigger problems....

[734406pk]

You have a problem that isn't the valve spring.... Likely the valve is stuck in the guide... A weal or even broken spring will still close the valve on a non-running engine, the fact the valve is open points to bigger problems....

  It's highly possible. Do your homework on the cause.

[Chryco Psycho]

Or all of the springs could be under rated & may break too .
 You definatly need to know why it broke !
 Change the spring check valve movement & do a compression test with the new spring to make sure it is normal

[DocMel]

I can actually move the valve up and down about a 1/4 inch.  The broken spring allows for me to move to valve a tad up and down .  I cant explain why the spring broke, 

Last time I ran it before the symptom started, (the last time I drove it on the way home), I was pulling out from a gas station.  l
Symptoms were just like a non firing cylinder, which turned out was the case

I dont run it full out, and I dont have a hot cam, so I am not sure what may have been the cause of the break. 

I thinking a flaw in the one spring.       Ill reinstall a new one and see if it run

[1 Wild R/T]

Thing is the valve being open means it's very likely the piston & valve made contact, amazing the keepers didn't pop out & drop the valve.. As Chryco said, put a spring on it & check compression...  Good Luck...

[734406pk]

Thing is the valve being open means it's very likely the piston & valve made contact, amazing the keepers didn't pop out & drop the valve.. As Chryco said, put a spring on it & check compression...  Good Luck...

 

[Chryco Psycho]

Not always , the piston moving upward will usually close the valve with air pressure , but still amazing / lucky the locks did not drop out 

[4 speed fish]

I would pull the head and check everything.i would also check all the pushrod on that side.