The Stovebolt Site Forums The Shop Area Engine Shop 1953 216 running rough

Hey! I'm new here, my wife and I recently acquired a 1953 3100 with (as far as I can tell...) the original motor. We love it, we think it looks awesome (It needs some body, paint, and trim TLC, but overall it's cool.) and my wife and I need it to be relatively road worthy. It's drivable as is, but it has a miss, and possibly a faint knock. The motor mounts are pretty deteriorated, so it rocks a lot when it misses, but it shouldn't miss like it does.

Here's what I know:
From the previous owner's receipts, I know it was rebuilt in 2013, and from what I can read on the machine shop's scribbled receipt, they bored out the old Babbitt main bearings and put new ones in, reground the crank and cam, replace pistons, rings, rod bearings, main bearings, cam bearings, timing gears, oil pump and (of course) gaskets all around. It also had a 12v conversion.
After this and some other work to get it drivable, the previous owner's teenage son drove it as a daily for several years until he went to college, then it sat (except for "grocery store trips" 1-2 times a month to keep it running) for 3, then I bought it.
They replaced the carb at least twice, and I replaced it myself after I got it, thinking that may have been the cause. I have also changed plugs, wires, points, condenser, coil, and rotor button (probably unnecessary, but they're like $5). The cap looked fine and I couldn't find it locally anyway. Plugs gapped to .035, point was gapped to .016, but I brought them in to .013, as the dwell angle was only about 28 degrees, .013 brought it to (a still low) 33 degrees. Re-timed the ignition to 5 degrees advanced using "static timing" settings described here and also adjusted the valve lash back to spec.

No changes how it runs. I will also add it misses when it's running faster than idle as well. I also noticed that the idle gets REALLY rough when I adjust the idle speed below 1000 rpm, and wants to die.

I know it needs a choke cable, as the one on it broke when I installed the last carb (it's on its way.)

Click here for the video of the engine running. at about 2:40, I move to the camera to the exhaust (ignore the cracked muffler and the tail pipe piece dangling from the frame! We're getting there.)

I appreciate any help you guys can offer, I've read about several other things that can cause this, and while I don't WANT bad news, but I'm willing to hear it if it means I can get it fixed.

Thanks in advance!

Sounds like you know your basics as far as being able to work on the old beast. I would work my way through the three requirements for an internal combustion engine: compression, ignition, fuel, and start with compression. A regular compression test and if all aren't within 10% follow up with a leak down test. If all is well then the expensive tear down and rebuild is off the table and it's a cheaper but sometimes hard to find solution. Since it does run a vacuum gauge can be a very useful tool as it can monitor functions like valves, timing, and whatever it takes to get the vacuum up to at least 18 inches. If anyone in your area has an old engine analyzer scope then it would be a two minute solution but they are getting rare since new vehicles have on board analysis.

My first thought was about the Motor mounts, they probably need replacing very soon, that rocking is not good.

Have you done a compression check? Lots of people are going to start screaming about doing a leak down yes, but a compression check will get you some decent results quickly and either find a problem or eliminate a source of the problem. If the engine was rebuilt several years ago, and there have been multiple carbs on it with no improvement it is probably something else. Do you get any water coming out of the tail pipe?.

First- - - - -even before doing a compression test, pull the valve cover and do a valve adjustment. A tight valve will mess up a compression test and send you chasing down rabbit holes looking for more serious problems. Try doing a search on this site for "companion cylinder valve adjustment". It's the method I've been using on race engines for 50-something years, and it's very reliable.

Next step after checking compression is a power balance test. With the engine set at a fast idle with a tachometer, 1000 RPM or more, and a vacuum gauge attached to the main vacuum port (not distributor vacuum) disconnect one spark plug wire at a time and record the RPM and vacuum drop. A good cylinder will show a definite drop in both RPM and vacuum while a dead one will show little or no change. A burned intake valve will actually show a rise in RPM with the plug shorted sometimes, due to less dilution of the intake mixture with exhaust gases.

Last item- - - -using an unlit Propane torch with the gas valve open a couple of turns, check all the gaskets in the intake system for vacuum leaks. When you find a leak, the engine should smooth out while it's pulling Propane into the manifold.
Jerry

Welcome to the site ! You give an excellent description of your engines problem.

First, I wonder if the previous owners' (PO) re-builder truly had "bored out the old Babbitt main bearings" . Your 1953 3100 (216cu ?) had precision replaceable main shell bearings , and it would have been very unusual to have the saddle bores in the block further "align bored" . More common practice is to simply use new shell main bearings to match the new crankshaft grind. { Perhaps the re-builder meant they just bored out the six lower connecting rod bearings to eliminate the direct-babbitt, and then used replaceable shell bearings for the lower connecting rods ?}

Second, you state the PO had the cam re-ground ? After the cam regrind, did the PO then also have the problem with the rough idle and shaky running (thus chasing the carb replacement 2 times) ?

What I am getting around to precisely asking is , do you think that engine had those problems when the previous owner had the truck, or do you think they are recent to your ownership? That alleged rebuild in 2013 seems very extensive and almost expert, but "scribbled" shop worksheets are odd. I wonder also about those motor mounts , I would have used new ones on a 2013 build that was so "well done".

Ok, let me try to hit everything.

I did do a compression test while I was changing spark plugs. I got 115, 115,120, 120, 120, 120. However, this was before I checked and adjusted valve lash, so it might be off then. There were a couple of valves that didn’t have a whole lot of lash if any at all. (No they weren’t open, I double checked everything before I adjusted any of the rockers.)

I do have a vacuum gauge, which I attached to the vacuum port at the carburetor that goes to the vacuum advance, so I suppose I need to try it on the line coming out of the intake manifold? At the carb I got about 17-18 inches of mercury. I suspect someone around here does have an old engine analyzer, but finding who might be challenging.

I have not gotten any water out of the exhaust.

Motor mounts are in process. The ones on it are deteriorated to the point the metal parts can be separated. In fact, I was working on them today, but I ran out of time before I could get one off. Nothing some penetrating oil and a breaker bar can’t fix.

As far as the bearings go, it’s not really specific on what exactly they did except replace them. I’ll double check the receipt when I get back to the house. Work done at Blanes motor supply in Dallas (we bought the truck from a guy in Frisco and trailered it home)

Soggy, I believe that’s likely what they did, bored out the 6 Babbitt journal bearings and used replaceable shell bearings.) I also believe the PO had those problems when he owned the truck, we haven’t owned it very long. However, I’m not sure if the motor ran before the rebuild. It was non-running when he bought it.

Another quick question since I’m not 100% sure. When I pulled the old coil, it was a 6V model, despite the 12V conversion, so when I replaced it I put a coil from a ‘55 on it as those are 12V. That is correct, right? I did notice it has a resistor mounted to the firewall as well.

Thanks guys!

Here's an attached picture of the parts and labor "receipt" from the rebuild. Cleaner writing is from the PO.

Totally agree with HRL and Soggy. On the valve adjustment, since it is already running, you could just warm it up and do a quick check with the engine running. I have done this many times, it is a bit messy but works even though a bit shade tree. If the valves, timing, compression, vacuum and all the other factors are correct, it may be something bigger than what is going on now. My first thought here is what kind of valve grind was done, to what specification?

A vacuum leak will shake like that at idle but generally smooths up with increased rpm. Your miss stays pretty consistent throughout the rpm range. That would lead me in the mechanical direction. A valve not sealing properly or spark not arriving at a plug or at the wrong time.

As been said, pull the valve cover and go through adjusting all the valves and leave the VC off when you test it again.

You want to verify oil to the rockers anyway.

Good luck
Dave

To correct my last post, I meant to say what kind of Cam Grinding went on, not valve grinding.

marknbacon,
The way that rebuild on your 216 engine is described , it appears as a premium A+ "done everything a 216 could need" job. It seems very extensive (likely expensive) and worth bragging about that high level of engine work. But then the actual receipt and its itemization sure leave out a whole lot of vital information.

Your posted video sounds (on my computer speakers) a bit like symptoms of "marbles in a beer can" detonation. BUT it is very hard to diagnose engine noise via video, so I would just be guessing the cause of the rattle/knock.

I advise that you keep checking all the simple stuff before you dig into that engine deeper. Eliminate the easy things to check. Look at the ignition distributor vacuum advance pot, see if it is moving on acceleration .Take distributor cap off and feel ign. rotor "snap" back on the centrifugal advance weights in the distributor. Hook a vacuum gauge to the intake manifold and observe the needle dance at various rpms (your video showed a weird disconnected line where maybe the vacuum wipers were connected?) . You already ran a basic check of valve tappet lash (I run that check with engine running @operating temp, low idle.) You can play with that ignition timing a bit more by advancing the degrees that are labeled on the little scale of the octane selector. Make sure your ignition point faces are clean, they can be coated with stuff when new. The compression test, power balance test from HRL ,and changing the motor mounts are all worthy efforts if you keep that engine.

Others here know more than me about that 6V or 12V ignition coil and the resistor , so perhaps they will add more....

All said, you are doing a great job of explaining the problem and actually trying to delve a solution. Get the simple test out of the way first.
I think a few of us may be reasonably suspecting valve timing, or cam stuff , or ??? ; maybe deeper issues that need a dial test indicator etc. Latter you could possibly pull off some engine side/pan covers and gaze at some engine internals ---- latter.
For now, keep it simple.

just as a matter of asking, have you checked to see that the plug wires are routed correctly for the firing order (1,5,3,6,2,4), and that none of the wires are laying directly on top of one another creating an inadvertent mis fire? Also, and this is just me, but .013 on the points would be a speck to tight for me regardless of the dwell. Try getting them back to .016 and see what that does. What is the delco part number for the distributor? The reason I ask is that it would not surprise me if the distributor had been changed. Stock 53 uses a different point cam then the later 55 and up so if the delco number came up to a 53 unit, you would be right as the dwell should be 38-45. However, if the distributor comes back as a 55 and up, the dwell would be in the 28-35 range and .016 on the points.

Soggy,
Yeah that's the impression I got when I read the receipt as well, however I wish there had been more detail as well as more legible writing. It was quite expensive, $2600ish I believe, which from what I've been reading, is in the ball park for an "extensive rebuild" on the 216.

I still need to tear into the distributor and take a look at the weights. I did noticed I would turn the distributor and release it, and the springs would take it almost all the way back, but I could move it about 2 degrees more if I nudged it, making me think there may be a dirty, corroded, or rusty part in it (under the "breaker plate?"). The vacuum advance is working OK from what I could see, and when I had it disconnected from the carb last time I did a vacuum test, the motor sounded almost the same.
And yes, I believe that's where the wipes went to, there is a little rubber boot on it, and it looks like pipe fittings fitted into the intake manifold. I may need to adjust the octane selector, I know the manual mentioned it a couple of times during the "tune up procedure." so I'll fiddle with it some. I can't really read the writing on it. I'll also grab some ultra fine sandpaper and make sure the points are perfectly clean.
I am kind of wondering if one of the push rods is slightly bent or something and I have a valve not opening all the way, or something causing a valve to not close all the way (but that would show up on the compression test wouldn't it?)

Yes, I would like to keep this as simple as possible. I'm not going out of my way to over-complicate things haha.

Dragsix,
as long as the cylinders are still in order 1-6 from front to back, then yes they are in the correct order. However, some of them are twist-tied together right after the distributor to keep them together, which might not be helping. Despite them being "radio suppressant" I don't know how effective those wires are at suppressing interference from each other. (not exactly a twisted pair are they?)

The distributor cap is from LMC, part number 36-1716, which is listed as the "47-53" version. Unfortunately, I have no idea who makes that part for LMC. At the "3 major auto parts stores" my options are either BWD or duralast, no delco, as they only go back to 1958 according to their parts site.

As for the motor mounts: after some choice words, a few thrown tools, and having dirt rain on my face, the truck now has new rear motor mounts. Things I noticed while working on it: the exhaust manifold to exhaust pipe connection is VERY loose (like the nuts and bolts are there, but not tight at all, and the piping is just loosely hanging there, although the pipe looks fairly new.) I didn't think to tighten them up just yet, however I'll probably want to throw a new exhaust pipe flange gasket on it anyway. I'm sure the old one has deteriorated to some degree.

Thanks again guys! I'll try to keep everything updated as I work on it and let everyone know if I ever figure out what's causing it.

Ok, so get the twist ties off and separate the wires with some plastic wire separators. That may very well be part of your issue. I am still courious as to the distributor. If you take the cap off, you will see the Delco number on the point plate. From there I can tell you exactly what you have.

Pulled the twist tie off, no wire separators yet, but they aren’t really touching anymore. No change.

Distributor is a 1112362.

Ok, that is 51-52 manual transmission. Just asking, how did you adjust the valves and what clearance did you use?