Stuck valve?

[Mark D]

So took the car out to my club meet on Monday night. Had a decent ride out, but noticed on the way back some rough idle at the first stop light. Pulled over to give a visual under the hood, found nothing glaring at me, so I jumped back in a got a progressively worse ride on the way home. Lack of power on acceleration was most noticeable, also engine shake. Tonight I got time to stop down the garage and run a couple tests.

Here's a vid of the engine running and a shot of my vacuum guage hooked up to the carb.

Got my compression guage out and did a test on all 6 cylinders. Here's what I got: 1+2 = high 80's, 3+4 = high 70's, 5+6 = 0. Plugs in cylinders 1-4 are clean and dry, 5+6 where muddy and fouled.

She gave my wife and I a great ride this past weekend and we did a good 80 mile round trip. Wife says she noticed something but I really don't recall anything out of the ordinary.

I am guessing I might have a stuck valve? But I am only a year into this and would like to hear your thoughts & suggestions. Have I given enough info?

Edited March 21, 2012 by My48Ruby

[drillmastertommy]

Sounds more like a head gasket gone if 5+6 have no compression.

[Dodgeb4ya]

Looks like maybe the head gasket blew on 5-6. Could be stuck valves on both 5 and 6 too- kinda unlikely unless it sat a long time or bad gas.

Good even compression is 100lbs up to about 130lbs.

Bob

[Mark D]

Jeez that wasnt on my radar at all. I have been looking at getting a spare head gasket. Looks like I need to accelerate that plan.

[garbagestate 44]

here's an "interpret your vacuum gauge " link.

http://www.secondchancegarage.com/public/186.cfm

[Mark D]

Here's the chart I have been using. Top right image is what I was thinking matched closest. Just ordered my replacement head gasket. Searching now to see if I can find a local shop to shave the head while its off the deck.

Vacuum Gauge Chart.pdf

[Mark D]

Just called Gary Roberts and he's got a head gasket in stock. Planned a half work-day tomorrow so I'm driving up to his place to grab it and head back home to start my first ever head gasket replacement.

I read up on the torque sequence in the manual last night, picked up a new torque wrench and some copper gasket spray, any other pointers I should know about before I tackle this job? I'm going to reuse the head bolts for the time being, and source new for the engine rebuild I've got planned for next winter.

[greg g]

be careful removing the temp gauge sensor. make sure you note how the thermostate is installed. Open the petcock in the block or remove the drain plug to get the coolant out of the head and top of the block.

Pretty easy job to do. I might suggest if you have the time toget the head checked to assure it not warped. This will also give you a chance to check the top of your pistons for any of the typical ring damage.

If you are planning performance upgrades in the future is every thing checks out OK you could have the head milled while it off. At the least you will want to clean the threads of the head bolts before you reinstall.

If your are just going to check swap the head gasket, it usually about a 2 hour job single handed.

[Mark D]

I'm searching for a local shop that can take a look at the head while I have it off, but I had planned to pull the engine this fall and do a refresh when I get to wherever I am going to store her next fall. Depending on timing and cost, I might consider a mild shave while the heads in my hands, .030 over seems to be what a majority of the folks are doing according to my search results here. Is there a datum point on the head where measurements are typically taken to see if the head is OEM thickness? I recall this briefly being discussed in a thread, but don't recall an exact answer.

I'm scratching my head now as I reread your thoughts on the temp sensor... for the life of me I can't recall this being threaded into the head. Pretty sure its lower on the rear of the block? Gotta stop at the garage on the way home from the office tonight, will investigate when I grab my manuals from the shelf.

[drillmastertommy]

I certainly couldn't claim to be any kind of guru, but after a recent search for a gland nut so I could refit my temperature gauge sender it seems that all the Dodge/Plymouth flat 6's had the temperature outlet on the drivers side rear of the cylinder head.

There are a few different thread sizes but my 53 218 has a gland nut which screws directly into the cylinder head which you then pass the capillary bulb through with a screw fitting securing it.

When you've disconnected everything and double checked there's nothing in the way and you go to lift off your head, just remember it weighs around 40lbs!

[Mark D]

And with each challenge learn something new thankfully. Stopped at the garage and found the temp sensor is in fact where stated by Greg. Just haven't had a need to notice it before I guess. Thanks for the weight tip drillmaster. I would never have guessed 40#...

[Mark Haymond]

And remember to retorque the head after the engine is warmed up.

[Dodgeb4ya]

Make sure you identify the exact engine problem before you do anything else!!

[Mark D]

Poor / no acceleration.

No compression at 5&6

Fouled plugs at 5&6

Engine roll at idle

Heavy exhaust smoke

Vacuum guage results...

What else do you suggest I look for to help eliminate potential other results? I am all ears.

[Niel Hoback]

You might try a fortune teller, but I bet you get the same answer.

[Dodgeb4ya]

Check #5 and 6 valve movement action- no valves sticking up and seat and face condition and that they completely seat. Look at the head gasket area between cylinders 5 and 6, and check the cylinders for excessive scoring just for the sake of checking. Carefully remove the built up carbon off the pistons and valves with a sraper-be gentle and use a vacuum while scraping to prevent carbon gunk from getting into the valves/ports and down around the pistons. Clean the block deck too.That should bout do it!

Bob

Edited March 23, 2012 by Dodgeb4ya

[steveplym]

I'd pull the head Mark. I had just about the exact same problem two years ago. Found a break in the head gasket between 5 & 6 cyls. Had the head checked to at that point and had to get it shaved off a bit. Was not real straight and warped just a tad. Haven't had any problems since, knock on wood.

Car ran real rough and would pop back through the carb on accel. When you have the head off you can check the valves too while you're there.

[moose]

Wish I was closer Mark, this is a fairly easy single handed job, but a second set of eyes never hurts. My first time doing this I had some help, but you've got all the info from this forum so you'll do OK. Give me a call if you run into something.

[Mark D]

Thanks Bob & Steve - I'll have your notes handy on my I-pad when I start this project later this afternoon.

Moose - Would have been great to have you looking over my shoulder just for the confidence factor, but understand the drive. I got your cell number so if there's complications I'll drop a call. Just praying that the bolts all come out without any issue.

I had all of my literature out last night "cramming" for this. I think I am well prepared. One question I do have is how to break the head away from the block. I assume with 63 years of compression it is not going to be loose when I pull the head-bolts. Is there a proper way to free the head from the block if its stuck? Perhaps a little bump on the side of the head with a rubber mallet? Do I dare pry it up? I don't want to damage the surfaces at all. A little guidance would be great.

[Young Ed]

Yes a little smack with a mallet will be fine or put something in 1-2 head bolt holes(just in the head) and pry sideways.

[Rusty O'Toole]

If the head is stuck turn the starter and let compression *pop* it free. On Fords with aluminum heads and studs the heads could get stuck on and you started the engine and let it idle till it got hot, then the heads would come loose.

If you shave the head check the bolts do not bottom out, you may need to add a washer to each bolt. At least run a tap down each hole and blow it clean. Head bolts can be reused several times with no problem. If you want to check them, line them up and see they are all the same length. If some are stretched all should be replaced.

[Mark D]

Well gents the majority was correct on this one. Pictures show that this was something thats been going on for some time now. I am amazed that she had drove so well. Seems as thought my trip with the wife last weekend put her over the edge. Looks like the exhaust valves at 5&6 will need to be replaced. There's tons of scale built up on the tops of the valves, but the seats and the edges of the valves seem to be in good shape. Rather than tear into that now I will defer it to the fall. I've descaled the head and the block, vacuumed out the crap and wiped everything down with a degreaser.

My biggest issue now is that 20 out of 21 head bolts came out fine. Some needed to be muscled, others turned out with no issue. The third to the last snapped off just above the block. So thats my challenge for tomorrow. I tried to get a nut to twist onto what remains, but no success. I guess my plan tomorrow is to purchase a decent set of drill bit and an easy out. Start small and work up the size. Am I on track with that strategy?

Here's the photos of the damage.

[Mark D]

Forgot to mention the good part, all cylinder walls are in great shape. #4 has a slight score in one spot, but not really what I would call bad. Also wanted to mention that I had a great visit with Gary Roberts this afternoon. Highlight of my day was getting to see his dads car collection! Amazing, just amazing. Photo of their '41 Plymouth Pickup attached, the rest are still stuck in my phone.

[Niel Hoback]

I have never had an easy out work. They always end up broken off and I'm lucky if I get the stump out. I would try a lot of pentrating oil, heat, maybe that 50/50 acetone trans fluid mixture and then more heat. Kroil if you've got it, PB Blaster and anything else you can get it. Easy outs are one of those "good ideas" that just don't work, for me, anyway.

[Mark D]

I've got a buddy telling me all about the "ez-brokes" as I write. Seems I need to find a welder tomorrow.