The Stovebolt Site Forums The Shop Area Engine Shop 216 with zero compression on cylinders 5 and 6

I have a 49 PU with original 216 which I only drive once every month or so. When I tried to start it a few days ago it first made a loud clanking noise then a popping noise but it did start and the noise went away. The next day I only got the popping noise but it would not start. I checked the compression and on cylinders 1-4 it ranged from 60 to 90; however, on cylinders 5 and 6 I had zero compression. I removed the oil pan and valve cover and saw no obvious problems. Any suggestions as to what to look for before I go further. I had the heads reworked about five years ago and at that time I replaced the rings.

Thanks. JD

Stale gas will cause valves to stick. Valves can stay open to where you bend them or a push rod. Watch the rocker arms while you crank.

Stuck valves & bent pushrods. Been there, done that. Time to pull the head & do a valve job. Get some help, those 216 heads weigh a ton.

Check for proper valve movement, particularly on cylinders 5 and 6. Also look for bent pushrods, which usually happens when the valve sticks. It's also possible you've blown a head gasket between cylinders, but the valve are much more likely to be the problem.
Jerry

Thanks for the guidance. I'll check out the valves and probably get the heads redone.

JD

If the valves are in good shape other than being stuck you can probably get by without grinding the valves. I had to drive the valves out of my 216. Then using a gun cleaning bore brush and "chemtool" solvent I cleaned the guides. I wire brushed the valves and cleaned the carbon out of the combustion chambers. I lapped the valves & reinstalled the head. Runs like a champ.

Zero between five AND six sounds like a definite head gasket.

I know gambling is illegal, but I'll put $50 virtual Stovbolt Dollars on it!

JD5 let us know how it pans out!

It's possible to have valves stuck open on more than one cylinder at a time. Are you sure you want to make that bet?

i have bought 2 tractors for under 500 bucks been given countless
lawnmowers and i traded a 22 rifle for a wood splitter all with
nothing wrong with them but stuck valves. all run good now.
thats my bet. philip

Valves can often be freed without pulling the head. Remove the rocker shaft and check all the push rods for bends. Remove the plugs and squirt in some Marvel Mystery Oil or its equivalent and let it set. Hit each of the valves with a hammer about once a day and squirt in some more ucl. After about a week or so, run a compression check again. Worth a try before pulling the head.

What crenwelge said!! All you're out is a little bit of time, and if it works...miles ahead in the sweat equity department.

I noticed something strange, to me, when I had the valve cover off my 3800's 235. There's a picture in my Webshots album. Aside from all the crud in the valve gear, you can see that most of the valve spring retainers are nice and wet, but at least two are not only dry, but rusted.

I've only run the engine for less than an hour since I've had it, and I plan to lubricate the valve gear thoroughly, probably with grease, before I get the carburetor back on.

Is it possible that lack of lubrication at the interface between the pushrod and valve lifter havecaused so much wear that the pushrods stuck through the lifter arms? That would cause a clanking that would go away when the ends of the pushrods break off.

Sorry, it sounded less likely as I typed it. I am interested in hearing about anyone else who has had the dry valve spring retainer problem before.

You need to add a link to your album. As for a dry valve train. Anywhere it's not oily, it's not getting oil. Grease won't do you any good. You need to find where the blockage is & fix it.

curious as to the findings, jd.

back in the day, i had a ford 351w in a pinto,(sorry about that guys), LOL, and was drag racing it at the local dragway.

after one run it began to run rough, so i pulled the plugs, looked good. pulled the valve covers, turned it over several times, and all was working properly.

stupidly i drove it home from the drags, about 15 miles away, since that is how i got it there and it was late and nobody to tow me, and checked the compression out the next morning, and 2 adjacent cylinders were no compression.

so i pulled that head, and it wore the head and the block between the two cylinders about .250 of an inch.

so i would suspect a blown head gasket as a possibility, but dont know a thing about 216 6 cylinders.

just dont drive it until you find out exactly what it is.

leonard

In reply to TINY and my "$50 Virtual Stovebolt Dollar" bet.

As LEONARD has just explained to us his experience, this is normally what a head gasket blowout does, it loses compression in two adjacent cylinders.

To have valves cause the same thing, you would need a valve from each of the two cylinders to fail at the same time and happen to be right next to each other!
Possible, but the odds tell me less likely.

Thats why I've got my coin on the Gasket.

The head will have to come off to inspect the valves anyway, but it will pay to closely inspect the gasket between those two cylinders VERY closely before paying someone a lot of money to reface a heap of valves that don't need doing!

Valve Gear Pics

Two of the last three pictures show the valve gear. I wasn't considering grease as a permanent solution. I'll probably pull the head off as soon as I get it running with the new carb.

The valves should probably get new seats anyway because of the unleaded fuel issue.

How do you deal with that in Oz?

You're mistaking "common" for "normal". While it's not uncommon for the head gasket to be at fault it's also not uncommon for valves to stick open on more than one cylinder especially when you consider that many of these old rides have been sitting for a long time with old gasoline in them. I speak from experience because every valve in my 38 had to be driven out after running it on old gas (bent two pushrods in adjoining cylinders). Plus there have been numerous posts in the past dealing with stuck valves. Which is more common? Beats me but I like better odds than betting on a head gasket over stuck valves. Especially considering the symptoms outlined in JD5 original post. You might be right but then you might be wrong.

Tiny,

JD5 said the motor was running the day before, then wouldn't start the next and has had the heads rebuilt not long ago.

Buy me a burger with your "$50 VSD" if you're right.

If I'm right I'll buy you a virtual burger!

all the best..........

RE: Unleaded fuel.

We run a product called Flash-Lube.
It's a lead replacement additive that you add direct to the tank when you re-fuel, or as I run, an under bonnet vacuum feeder.
This attaches to a port on the carby and feeds the product into the engine at an adjustable rate.

Or........fit hardened seat inserts!

I've read several posts in different forums from folks who put hardened seats in only to have them fail, causing severe damage to the head. One was outlined in the Generator & Distributor magazine of the VCCA that happened to a 30 something firetruck. I've never personally experienced or read of an incident of head damage from unleaded gas. I used unleaded in my old '70 Harley (pre unleaded engine) for years and many miles with no damage. I've been running unleaded in my 38 since '04 with no damage. The general consensus that I've seen is you don't need to worry about using unleaded unless you work the engine hard for an extended period.

No skin off my nose cob.

I'll have mine with Beetroot, Vegemite, Dead Horse and a couple of pickles!

That should leave enough dough for a slab of KING BROWNS !

Hooroo..........Doc Bob
(can decipher thru link below!)

Tiny,
yep an unfortunate part of leaded petrol being abolished is the extra expense to the owners of vintage vehicles.

The valves and seats do wear at a greater rate due to the lack of the lead barrier between the two as they peen away at each other, but not at an alarming rate!

I have heard of inserts failing....mainly due to the task being normally handballed to the Apprentice to do, while all the higher paid tradesmen do the rest of the work!

I have not converted any of my engines........just fit stainless steel valves and run the flash-lube to keep the valve guides lubricated, as this was one of the jobs that the lead in the petrol USED to do.
Funny that.....new heads, unleaded fuel, no valve guide lubrication = sticking valves!

The flash-lube also fights against pinging caused by the lower octane rating of the unleaded fuel.
My bog standard 179 cu.in. HOLDEN six pings its ring out without the flash-lube, even though I run nothing but quality High Octane "Premium Unleaded" in all my vehicles.