73Fore54

I was on vacation last week cruising the beautiful Finger Lakes region, on the third day I noticed a drop in power and a slight out-of-balance shaking. Bad plug I thought. Changed plugs and wires, no change. Made it back home on 7 cylinders. Got out the compression tester, 0 psi . Yanked the cover, sure enough, valve spring #5 exhaust had busted into two, rocker arm was off. The valve was still up.

But I cannot get the valve to come all the way up by hand, and blowing air into the cylinder after lining up TDC it just whooshes. So the valve is probably bent. Hopefully the piston is only indented a little.

SO - I need to yank the head to check it out. Never did this before on a 454. If anyone has experience here, I would appreciate some feedback. Here are some questions:

1) Shouldnt I be able to blow air into the cylinder and close the valve by hand and hear it? Valve wont come up all the way... seems to bind (bent probably?) Needs to come up another 8th inch or so.

2) After looking at the general overall picture, I think I need to remove the carb and intake manifold along with the left exhaust manifold and alternator and upper rad hose to get the head off. Anything else?

3) What am I in for here when I try to take the head off? Any hidden springs or should it just pop off?

4) If the piston is gone, can I replace the piston and rings by taking off the oil pan to get to the rod bolts? Or am I stuck removing the engine?

5) Hopefully the piston is OK. if so, what else beside a new valve and spring? Valve guide? Whats the proper procedure to mate the valve to the valve seat? Does it need to be 'fitted' by grinding?

6) Perhaps I should take the whole head to a machine shop and let them do it? and if thats the case, just do a complete valve job? This engine was rebuilt and balanced in 1998, I have all the slips. And maybe has no more than 4k miles on it. The spring break was probably just a fluke. Engine has been running great.

7) Can someone send me the torque sequence and torque values for when I put the head back on? Also need the valve clearance settings. Dont have a shop manual (yet - anybody know where i can get one)

Any advice or tricks would be appreciated. This is a first time for me, would not like to have to repeat the work if I screw something simple up.

Thanks . . . . .

MN 72 454

Make sure the intake valve on that cylinder is also closed, or take that rocker off also. Then try the air trick. If it still wont seal up, that valve may be bent. You'll usually hear some air exiting by the rings and thats pretty normal. If it is bent, head removal is pretty straight forward. The piston will probably be okay, maybe just a little dinged up on top. Those heads a pretty heavy, so a helping hand wouldn't hurt for the removal. Keep your push rods and rockers in the order they were on the engine when you remove them. Were the two valve keeper keys still in the retainer? I personally would take the head to a shop to at least get it looked at. Maybe replace the springs also just for peace of mind. It's a lot easier now than again later and they're not really that much $$.

rob75383

...forgive me father, for I have sinned, it has been at least 6 months since my last posting...


I had my #3 exhaust spring break on my engine in 1998. It snapped off one coil at the bottom, so it still ran kinda okay.
Boy, did it cause me a big headache in trying to track down the problem. She ran fine up to half throttle, then would backfire through the carb. Lean pop some said, rebuild the carb others said, too much timing, clogged fuel filter, etc-- this was before I joined the forum --.
I spent a lot of time and $$ tracking down the problem.
Sounds like you've got it a little easier, though. You already know where the problem lies.

I was hoping to need just a new set of springs, but the guy at the machine shop said to magnaflux the suckers. Turns out that I had 3 cracks running from the #3 exh seat!! Two of which connected to the #3intake seat. The head was JUNK.

-I'm a teenie bit wiser than a newbie, (guess I graduated to HACK status), so my advice is to take the head, give it to your local machinist, and let him quote you what it'll cost to get you back and running. If you need to keep the heads for originality, then by all means, get the heads reworked.
If you're open to aftermarket stuff, add up the cost of the WORST case scenario (full set of valves, valve guide machining, pressing in new valve guides, spring seat machining, valve springs, keepers, retainers, rockers, magna fluxing, hot tanking, milling gasket surfaces, and most of all, hourly labor charges) you might be able to convince yourself into getting that new set of alum. heads, if you got the $1500+ to spend, that is.

Before you try to remove the head, remove a bolt from the water pump to attempt to drain the block as much as possible, to avoid dumping the coolant when the head comes off.
When taking the head off, you might need a block of wood and a hammer to dislodge the head from the block. I THINK the best way to do this is to put the block on the accesory pad on the front of the engine, and give it a couple of good whacks with a decent sized hammer. If possible, have a person help you, one person can pull on the head by the intake ports, while the other tries to dislodge it with the hammer. Once the head breaks free, expect to see a little coolant.
Like I said earlier, my advice is to take it to a machinist who you TRUST, and preferably have had experience with already, and have them look over you head. If you're lucky, you might just need a new set of valve springs all around, a replacement valve, valve guide machining/ pressing, and magnafluxing. Shouldn't cost too much $$

I might be wrong on a couple of things, so take my advice with a grain of salt... I aint no expert!!

Best wishes and good luck.

bigvette1

Pulling the head with the engine in the car can be done - but is really a hard job. Everyting around and attached to the head has to come off. Getting to the bolts especially on the drivers side with the booster is a trick and they are torqued to and somewhat sealed to 65 ft lbs. Little ratchets don't crack it. The stock 049 heads are heavy and weigh about 65 lbs-70lbs.

As others said - drain the block the best you can before pulling the head. God there is a lot of coolant that comes out. Take it to a machine shop and have the work done so they can check the rest of the valve train. If you think you dinged the piston - pull the engine. Trying to work around the suspension etc to pull the pan, get the rod out etc. on your back is a nightmare. My .02 cents worth. Best of luck.

73Fore54

Thanks you guys. This should not be too bad . . . I may actually get started on this tonite, after I double check that i cannot get the valve to close . . . . but it only comes up to within 3/8 of an inch of the other three exhaust valves, so its gotta be bent. So, when I get the head off and see if the piston is OK I will feel better. If its not then I'll be pissed, but deal with it.

bb69

I had to pull the heads right after I installed the rebuilt engine, and it wasn't fun. When that head finally lets go of the block, you better have a good back. By the time you remove all the pieces to pull the driver's side head, you are half way to pulling the engine. If the piston has to be changed, I would pop out the rad and pull the engine and trans together. It's a lot easier to work on an engine stand. I would also make sure you find all the pieces of the broken spring. This may require pulling the oil pan. The last thing you need is a piece of spring floating in the engine.

Good luck.

Ken

Wrencher

My guess is the piston will be fine, but unless you have a high lift cam, it's kinda' unusual to break a spring. Check your receipts and see what was used in the rebuild, and go from there. This is one part I never scrimp on. If it was quality stuff, have the machine shop try and match the spring (check and make sure they HAVE a valve spring tester) and replace the valve.

Hans