VCCA Home Forums TECHNICAL - GENERAL Trucks and Vans 1946 1/2 ton 216 Compression

Ran a compression check today and then did the tune up.
1-120
2-118
3-120
4-100
5-120
6-118
Squirted oil into # 4 and it came up to 120
What does that indicate?
Also anyone have any recommendations for the coil wire into the coil. It went in after we had to squeeze the end.
I don't want it to drop off, like the original one did once.
It now acts like it starts correctly. Had some problems before.

Generally, an improvement in compression by inserting some oil into the cylinder, indicates problems with the rings.

Looks good except that number four ought to be re-tested. Place some oil into the spark plug hole and re-test. If the reading comes up you got worn rings. If it still stays low you got worn valve. Or out of adjustment valve. Then try and re-adjust the valve. (Most of the time it is worn out.) A reading of 20 below the others is not acceptable.

Remove the end of the coil wire. Look at the metal clip that you placed onto the wire. It should be bent out of shape and/or cocked to one side. Remove it and with a needle nose pliers straighten the clip. Then put it back onto the wire, press into place and check to see if it is aligned properly. It should then "snap" into place.

A 20 pound variation does raise concern especially when you add oil to get a response like that. At this stage I wouldnt be pulling the engine out but would start putting some $ ready for a rering and decoke at least.
Tony

Tony,

I hope this isn't a dumb question, but I suspect it is. I'm not familiar with decoke in regard to the engine. From blacksmithing I know that coal will turn into coke, which is a lighter form of coal. I was curious if the decoking you speak of is removing some type of carbon buildup in the engine, that has somehow turned into a hard type coke surface???

I know I can google, I will after I post this...just that others may also wonder what decoking is in regard to the rebuild of Chevy engines.

For extra credit, is this something that also needs to be done for the 283/327 V8 family also, or was this something isolated to the 216/235/261 family?

Thanks for any help, sorry for my ignorance. I am looking for a '41-'46 and not sure if I will get an original or <gasp> conversion. At minimum if I go original I will need to re-gear the rear end. I also know of a '39 that has a 262 V6. It is located in the same city I own property I'm building a home, Kelseyville, CA. It's a pretty clean conversion from the pics, I haven't seen it in person, it has fiberglass fenders...I have my heart more set on the '41-'46. I see a '46 with a 327, auto, a/c, elec.fan/etc...it's tempting but still kind of lean towards original.

I've read your threads Keith, I am green with envy! I love putzing around and fixing things...seems you posted a pic of it in the shipping truck or container when you first got it. I'd love to see a pic of it again. I'll check some other threads. Geez that '39 is pretty cool also in it's own way, but since I don't have cash at the moment, it's not hard to wait for a '41-'46.

Alan

Aland
The decoke I refer to is simpley remove the head and clean the combustion chamber and ports doing a valve grind while it is apart.
When doing compression test and adding oil makes that much difference to the readings generally means the rings are leaking, to fix that it will be neccessary to remove the head so while it is off I do a full service (decoke).
Tony

Thanks for the replys. I will not be driving it very much, so I do not plan on doing anything with it right now. Also do not know how long I will be keeping it. No plans to sell it right now. Just want to drive it around town. Plan on putting seatbelts in it this Thursday when my buddy comes over.

In that case you may not need to do much for some time. I suspect you will see blue smoke out of the exhaust before you need to worry in a hurry.
Tony

No blue smoke yet.

In that case going on your previous post just drive it until the blue smoke appears in your rear vision mirror. Depending on your age and how much you drive it you may not have to worry about it.
Tony

KK,,

This issue with the low compression cylinder will bug you until you bite the bullet and fix it. Do the following soon to hedge on offsetting the misery:

a. Drain the radiator and take the hoses off. Easy.

b. Ease off the valve cover and side pan. Real easy.

c. Take the valve train out and the push rods. Make a cardboard with holes in it for the push rods. Keep them in order. Keep the valve train in order. Wire it together before you lift it off. Extremely hard to do. Be careful.

c. Drain and Ease off the oil pan. Sorta tough. But you can do it.

f. Ease the manifolds off the head. Easy. Wire it where it will be out of the way.

d. Remove the head off. Easy. Heavy but easy. Watch your back and don't strain yourself.

f. Position # 4 piston at bottom of travel. Easy. Since the head is off do that with starter or use a stout screw driver on the balancer hand crank protrusion.

g. Ease the rod cap off # 5 rod (just seeing if you're paying attention ) make that #4. Easy. Keep the shims and cap in take off order. Hard but important. Be a man.

h. Turn the crank and tap the piston and rod out the bottom of the cylinder. Easy. Be sure to mark the piston to make sure you don't put in back in the wrong cylinder. Just kidding.

I. Get some valve grinding compound and a handle rotator and polish the two valve heads. Taking the valves out is easy. See tool list below. Don't take the head to a machine shop. You don't need that much work done. Do it yourself. Easy.

j. Use a ridge grinder and cut the ridge out of the upper cylinder on #4. Easy even for you. See tool list.

k. Hone #4 cylinder.

m. Put everything back together,

Tools needed. Small wrenches and one big enough to remove the head bolts, screwdrivers, Ridge cutter, cylinder reamer, valve grinding compound, hand valve grinding tool (it's a rounded wood stick with a suction cup on each end), piece of cardboard for the pushrods, ring groove cleaner and valve spring compressor.

Materials needed: Valve grind gasket set, oil pan gasket (refer to Gene's advice on how to install. A little difficult but if Bob can co it, anyone can, gasket glue material (I forgot what color) Orange. Ask the man. One piston set of rings. You'll have to split a full set, 5 QT jug of oil. Buy it from Walmart and get their brand of 10w-30. It's good enough and the engine will not care, cement for the radiator hoses, two gallons of coolant. Or one gal of full strength and fill up with water. 50/50 is best owing to better water base One small bottle of Marvel Mystery oil for the valve train and a set of manifold gaskets.. Cheap.

The special tools can be borrowed from many parts stores or from your friends.

The parts will set you back about $50 to a $100 bucks. Remember the aim is to do this job fast, cheap and on your own.

Time to do the complete job. No more than 8 hours. With a friend helping: a week. With the missus handing you tools: 8 1/2 hours (The extra 30 minutes? Thats how long one could expect before telling them to go back in the house. That little bit of disrespect will cost you more than the whole ring job will. Think diamonds.

Note: Use a flat metal bar to check the head and manifolds. If you note any issues or have been having issues then a trip to the machine shop may be in order. Don't let them talk you into anything expensive, just get the head planed and the manifold trued. Tell them the missus is 9 months along and is a couple days overdue and the truck is your only means of rushing her to the hospital. You'll wait for the work to be done.

I may have missed something but not much that will hamper you for long or cost you much. Others will fill in whatever I missed.

Don't let this little job bug you. Good luck and "Get-er Done!"

Best,

Charlie

Thank you for your suggestions Charlie. I am 77 and don't want to do that work. I won't be driving it a lot so it doesn't bother me. My buddy and I took it for a drive today and it ran just fine. He helped me put in seat belts today.

Keith,

What type of belts did you put in your pickup?

Did you go just belt or 3 point?

My truck doesn't have them, and I want to put them in, I can't imagine driving a vehicle on public roadways without belts, but was thinking that just a belt might be more comfortable than 3 point.

And in reply to your comment about not wanting to do the work, I saw this engine on ebay and thought to myself what a great deal that is...these are relatively inexpensive. I have a 911 that will cost about $20k-$25k to have someone rebuild. I bet not too many people bid on that, but it has an opening bid of $2250 and $3250 BIN, probably street value is about $2500. I wouldn't think twice to get a rebuilt engine like that, it would be easy to have a shop drop it in for you. Always easy to spend other people's money though...

EDIT: oops, would help if I put the link, I hope that's not against forum policy...

https://www.ebay.com/itm/Chevy-235-Remanufactured-Engine/192691691248?hash=item2cdd51def0

In reading this thread you don't seem that you'll keep your truck for the long haul. I hope to have mine for however long I live. I want to make it as functional and roadworthy as possible, but want to drive and use it like a truck. I would definitely think about buying a refurbished engine if I didn't want to rebuild my own. You could always have someone drop a refurb in the truck and rebuild the one you have. Might be able to get core for yours also. But you could learn how to rebuild it...I hope to do $#!T like that when I get to your age, I'm only 17 years behind you...I want to build a log house...

Doesn't sound like your engine is that bad, other than the compression in the one cylinder...and it drives ok...don't mess with it.

I got my seat belts (lap belts) from The Filling Station. I used belts 74" long. I weigh 180 lbs and am 5'10 to give you a reference.
Don't know how long I will keep it, but am having fun with it now. I do have 235 and a 216 cores. I am in the process of cleaning out my garage and they have to go along with some other parts.

Keith,

I'll check those belts out at the Filling Station.

How much do you want for the 235 core?