The Stovebolt Site Forums The Shop Area Engine Shop 216 pistons

Hello.
The chevy manual did not really go into this, but I just pulled off my oil pan and head so the upper and lower part of piston is exposed.
I am wondering about the process of removing the piston?
The block is still connected to engine mounts and tranny, but like I said, head is off and oil pan is off and entire front end is disassembled.
Also, after removing, what type of adjustments will be required when re-installing pistons?
Thanks,
Judson

When i rebuilt my sbc, it was pretty easy. I just unbolted crank shaft and pushed out the pistons (after marking every bolt/part so i knew where they went back in). My opinion, i would pull the motor out if you are going that far. You might as well get the block cleaned, honed, check for cracks and do it right. Also, it will probably be easier to put back together on a stand so that you are not trying to do things upside down. Just my thought on the matter since i have never put an engine together while still in a vehicle. Everyone else could tell you better about that.

Chris

Advice is not worth so much when we don't know what kind of truck you're working on.

I've gone through a motor both in place and on a stand. It is really irritating having to work on the motor from underneath, but if the motor isn't too beat up from the start you might get it back on the road a little faster.
In any case, what you will have to do directly is check the cylinders for wear/tapering, to decide if they will need to be rebored. In that case the motor comes out. And gets cleaned and done right. Once you drop the crank, you will want to check the bearing clearances, rods and mains, with plastigage. You can search on these words and read up on the methods.
You really want to take a lot of pictures and keep all your removed parts in very good order. Read the service manual. Search these pages.
Oh, and also, I have always had a machine shop do my valves. Most of these old trucks will have pretty beat up seats and valves.
Good Luck,

Karl

If you have a ridge in the top of the cylinders you will want to remove it before you push the pistons out.

Big thing with disassembly is to keep all parts that go together, together. Piston, connecting rod, rod cap any shims ect and what bore you remove it from. Same on the head, if you took it off, and remove the push rods keep, mark which hole you remove them from front to back and also the lifters if you remove those.
To remove pistons you will probably need a ridge reamer to cut the ridge out of the top of the cylinders. Probably could rent one of those if you don't have one.
John

If a cylinder has enough ring ridge to make the pistons difficult to remove, it probably needs a rebore and oversize pistons. Cylinder wear happens mostly in the top 1 1/2 inches of the piston travel and more than 3-4 thousandths of taper wear makes for a VERY short lifespan of a re-ring job. The constant flexing of the rings trying to keep up with the changing cylinder diameter destroys the tension of the rings in a hurry. At 2500 RPM a ring in a taper-worn cylinder is flexing 5,000 times a minute!
Jerry

The constant flexing of the rings trying to keep up with the changing cylinder diameter destroys the tension of the rings in a hurry.

Well, except for the odd few million engines manufactured with tapered cylinder walls, very common up to about 1935.

Did that include the 216 engine the "new guy", Judson is trying to learn about.

How many of them tapered 5-10 thousandths in the top inch and a half of the piston travel? Name some or those engines, please, and I want to see cylinder dimensions while you're at it!
Jerry

Here we go again!

I am waiting for this fascinating answer too.

Easy boys, its a trap. Look away from the cheese.

Just to put everyone at ease, I'm actually not working on a truck. My 216 is in a Chevy special deluxe-1941-but I guess that 216 stovebolt was the engine used back then-truck or sedan.

In terms of the specs of the piston rings and cylinder bore diameter, Im not interested-yet. Im only trying to collect the information Ill need as I get into this project. This will be my first rebuild. Ive already restored most of the interior, but now its time to get the car running. In fact, that would have been my first step, if not for the working conditions of the car which included about 20 mice nest in and throughout the body. It came out of a barn in New Hampshire.

So, thank you everyone for your input. I appreciate this forum and respect this site because I know the participants know about engines, and that is where I am at. Im not just trying to have someone restore this car for me, Im trying to do it myself and learn in the process.

Ill post more question later.

Thanks,

Judson

Judson,
did you look at this manual? 1941 Chev Shop Manual for Cars and Trucks I think you will find a lot of information here.

I am curious as to whether you had to remove part of the steering or crossmember to get the pan off?

I did this exact same work about a year back on my 41 Special Deluxe, dropped the pan, removed the head, and got the motor into fine working order while lying many hours on my back under the thing. With lots of help from the folks here.
I removed the pitman arm assembly and lowered the tie rod to get the oilpan off.
Karl

Hi Truckernix,
I did look at the manual, yes. It has been helpful.
No, I did not have to remove any part of the steering to get the pan off. At first I thought I would have to, but after unscrewing everything (it actually has screws for oil pan to block) the pan slipped out without having to remove anything additional.
Judson

Karl,
This is helpful, as I am doing the same thing you did a year ago. When you removed the head and oil pan, what type of servicing/repair did you do in order to get your deluxe running?
Judson

Well, Judson, first I would point out that I can follow the history of the car since it was new - it was bought by my great grandfather and driven most of its miles by my great aunt, the original buyer's daughter. It was sympathetically driven during its 76,000 miles and has been running the whole time, although very little the last 35 years. I had done a compression check before I started, so I knew what I was up against.
I sent the head to a machine shop for a complete rebuild including new valves, seats, and guides. I pulled the pistons without ridge reaming first, but I did ream the ridge later. It is surely wise to remove the ridge first, you will probably be able to feel the ridge with a finger.
It really is important to keep the rod caps and shims in order for each rod, and when the time comes also for the bearing caps. I plastigaged all the clearances, rods and bearings. In my case I could get by with removing on average one shim from each bearing, sometimes one shim from each side.
You will probably need to replace the rear crankshaft seal, the rope seal. I got good at replacing the rope seal because it didn't work the first time and leaked pretty freely the second time too. Read up on this procedure really well. It is not so fun lying on your back.
I changed motor mounts. I rebuilt the vacuum shifter. I rebuilt the Carter carb.
My engine runs great now, but it always ran smooth even when it was missing. I believe I had some little success because the motor was always well treated, I had no damaged bearing surfaces, and I got a lot of help from these pages.
If you have the pistons out, it is simple to check the cylinders for tapering using one of the old rings. Search that topic for the exact process, the technique with the used ring is not in the service manual. That will tell you if the block needs reboring, and if it does it will need to come out.
Karl

There are certain clues when you take an engine apart. For instance, the pistons will have a wear pattern on the sides just from running. In my case, the pattern was skewed across the vertical, not symetrical, on one piston. That turned out to be caused by a slghtly bent rod.

I often think the 216 is maligned more than it should be. For practical purposes it was a good engine. Not a high horsepower or rpm engine, but for cruising around not bad.

John

thanks guys. this gives me alot to work with. I will keep working on it and follow up. Judson