Some engine questions from a new Model A'er

[ryanheacox]

Hi all,
I've just recently been getting more involved with the Model A hobby since my grandfather passed away about a year ago and I've got a few quick questions.

First: The engine makes a light but pronounced thunk when cold (I'll attach a youtube link if I can), its been like this for years now and hasn't gotten any worse (even after I logged about 1000MI on it last summer) but we could never decide on what might be causing it.

Second: The radiator likes to bubble over especially when under loads like climbing hills, I also think that I can smell exhaust gas in the radiator neck and it tends to loose water yet doesn't leak any. I think it could be a warped head since the head gasket was replaced about 4 years ago but I'd like to get some opinions before I start tearing stuff apart. After a hard run (like 30-50 miles with plenty of hills), oil also leaks around the head gasket and #4 plug.

Third: This isn't a question so much as some more info. As far as I can tell, the engine still makes good power and it's pretty quiet once warmed up thoroughly. It pulls just about any hill in 3rd at about 35mph and it'll push right up to around 60 on level road. This engine is also completely stock as far as I know, babbitt bearings, stock head, plugs, everything.

If anyone could give me some feedback on this that would be great. It's getting harder and harder to find old school mechanics that know this stuff in my area.

Link to engine noise:https://www.youtube.com/watch?v=jjI6z-qHc5w

Thanks,
-Ryan

[Rowdy]

Ryan, I hate to say it, but likely the thud ins the center main bearing. Hard to tell without hearing it in person. Have you ever checked the clearances and adjusted them. Likely the head gasket is the cause of the bubbles, but could be that the pacling nut on the water pump may need tightened. Rod

[1930artdeco]

When you pull the head off be sure to check that there are no cracks between any of the valves and a water jacket. Especially the exhaust valves as that is where they seem to like to crack. And welcome to the club.

Mike

[ryanheacox]

Thanks for that very quick response. That confirms most of my suspicions. Everyone I've talked to says that it'll go another hundred thousand miles on that knock but I think I'll check the clearances on the mains and the condition of the babbit. Anyone know of anyone that can repour bearings in CT if it were to come to that? The block has also been cracked and patched with lead in the front near the timing cover so I might also start looking around for a spare block.

[Tom Wesenberg]

You sure have a nice looking car, but I didn't hear any bad noise.
I did hear an engine running at full retard, which can overheat the engine and cause loss of coolant. I wouldn't run full retard more than a few seconds. A shop can use a tool to sniff the coolant for exhaust gases.

[ryanheacox]

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Thanks Tom. Like I said, I'm kinda new to this. I might know my way around a Model A better than a typical 18 year old but I still have a novice ear and eye. There is a shop about a minute from us that could both sniff the coolant and resurface the head if need be. Also the timing was a little messed up in the video but has been reset as per Les Andrews instructions.

[Wick]

Ryan retorque the head,it probley hasen't been done in 4 years....this could very well stop the water loss. Pull the plugs and see how there burning. Sometimes when a head is cracked water will leak over night into a open valve port. Hard to first start and when it does it blows All the water out of the exhaust pipe! Makes a black mess on the garage floor. Also you can leave the plugs out over night and in the morning spin her over...if water has leaked from the head gasket,it will blow it out the spark plug hole! I know...I was standing too close when one did this.
Welcome
Wick

[ryanheacox]

Wow, all this advice is fantastic. I'll retorque the head this weekend while I'm home. Also, I know all too well about the black mess on the garage floor... When we got it out about 3 weeks ago, there was black gunk scattered across the floor. It seemed to start easily though, especially for sitting 6 months. I think the starter only cranked over twice and she fired right up. I will also try taking all of the spark plugs out and cranking it over the next morning. I've also been meaning to do a compression test.

[1931 flamingo]

On loosing water when climbing a hill, ck the gasket under the radiator cap.
Out of curiosity what year/model A do you have.
Paul in CT

[ryanheacox]

Paul,
That gasket has been checked and double checked. In fact, a new cap was ordered to see if that would solve the problem, no luck. The only thing that has seemed to help is that rug doctor anti-foam stuff, I read about it awhile back on some Model A site and it seems to help quite a bit. I have (its really my grandmothers but it seems like its mine, I drive it and keep it rolling) a 1930 3-window Fordor, two-tone blue and black, if you live in CT you may have seen it. If you look at my first post, there is a youtube link near the bottom. I will say it drives better and better the more it gets driven, I'd just like to make sure there's nothing seriously wrong since I've already put 150 miles on it this year and plan on putting quite a bit more on it.

[ryanheacox]

Also, on a bit of an unrelated note, the clutch chatters quite badly. I have a new disk, pressure plate, throwout and pilot bearing for it. However, some people I've asked say that this might not fix the problem. And is it easier to pull the rear end or the engine to do the clutch (if the engine needs work this might be a no brainer...)

[BILL WILLIAMSON]

Ryan, Dog here, black crap on the floor does not necessarily mean an abnormal problem, they just do that from condensation in the Kzhaust plumbing.
Buster T.

[robw]

Are you overfilling the radiator? Mine foamed a bit, till I lowered the level to just above the tubes.

[Rusty Homestead Fl]

I'm with Tom. I was taught to start the engine at full retard (spark lever all the way up) let run for a minute or so, and then drop lever to mid way. I know it sounds cool at full retard but the engine may be happier with more advance.

[BILL WILLIAMSON]

Originally Posted by Rusty Homestead Fl

I'm with Tom. I was taught to start the engine at full retard (spark lever all the way up) let run for a minute or so, and then drop lever to mid way. I know it sounds cool at full retard but the engine may be happier with more advance.

Minerva was extremely HAPPY & bright EYED when retarded & goin' VOILLE, VOILLE, VOILLE, VOILLE & warmed up QUICKER. FULL retard IS for starting & idling! HALF advance IS for half road speed & FULL advance IS for balls out flatland!
Bill W.

[Tom Wesenberg]

Originally Posted by ryanheacox

Also, on a bit of an unrelated note, the clutch chatters quite badly. I have a new disk, pressure plate, throwout and pilot bearing for it. However, some people I've asked say that this might not fix the problem. And is it easier to pull the rear end or the engine to do the clutch (if the engine needs work this might be a no brainer...)

My clutch chattered worse than a paint shaker when I first bought my 29 Tudor. A new disc, light sanding of the flywheel, and a good used pressure plate made it as smooth as an automatic. I removed the rear end to do the job, and after unclamping the U bolts and reinstalling them, it also fixed the left leaning problem.

[KGBnut]

I can't say for sure, but that 'thud' could be timing gear. A loose one can give you a sound like a rod knock. I just swapped mine out a few weeks ago and the sound went away.

Wasn't a bad job at all. About two hours of light wrenching, and that was really taking our time.

[ryanheacox]

Bill, thats exactly what I've heard, the quicker you go, the more advance you give it. Tom, thats reassuring about replacing the clutch, thank you. And about the timing gear, that makes sense, he always said he thought the noise came from the front end and I don't think he ever touched the timing gear. Was the noise yours made a light thud when cold? About 4 years ago, the car had a terrible knock and it turned out to be the front generator bearing had seized and the shaft was pitted and rattling around so I can't rule anything out.

[KGBnut]

It was more of a knock than a thud, but it was most noticeable at low idle. As soon as you revved it up, the sound went away.

It can be caused either by a worn (or loose) timing gear, or a problem with the Camshaft Thrust Plunger/Spring. They are in the same place in the engine, so if you open it up, just check 'em both.

[antiquepa]

My car would also throw water when on hills or hard pull, I was told by an old timmer they run cooler with just plane water, which solved my problem..be sure to ad a rust probiter and rember to put anti=freeze back in when the cold weather sets in..!

[ryanheacox]

Yep, that sounds about right, anything above a quick idle seems to make the noise pretty much go away when cold and when warm its barely noticeable. About the water, I've heard the same thing and I intend to switch out to distilled water now that it's not getting down to freezing at night anymore.

Thanks everyone for the advice, I had no idea how quickly I would get responses. This is great.

Oh, how do I go about removing a broken window crank? A friend of mine was riding in the back and it broke off when he started to put the window down. I was a little annoyed until I saw it was a very, very thin casting.

[Tom Wesenberg]

Originally Posted by ryanheacox

Yep, that sounds about right, anything above a quick idle seems to make the noise pretty much go away when cold and when warm its barely noticeable. About the water, I've heard the same thing and I intend to switch out to distilled water now that it's not getting down to freezing at night anymore.

Thanks everyone for the advice, I had no idea how quickly I would get responses. This is great.

Oh, how do I go about removing a broken window crank? A friend of mine was riding in the back and it broke off when he started to put the window down. I was a little annoyed until I saw it was a very, very thin casting.

Most handles you push in on the escutcheon, then push the pin out, or loosen the screw.

[1930artdeco]

An easy way to determine where a noise is coming from is to use a really long screwdriver or stechiscope. Put it where you think the noise is coming from and listen. My engine has a knock from the oil pump. We thought it was a rod but after shorting out all of the cylinders it was still there. With dads three foot long screw driver we isolated it down to the oil pump where.

Mike

[ryanheacox]

Tom, thats what I was hoping it was, I was worried about having to remove the entire panel. Mike, I was going to try that with some pipe but the only length we had was about 20 feet long and buried in the garage. I'll be home from school this weekend and I'll report back here with anything that I find.

[ryanheacox]

Ok, time for an update.

I went around the engine with a metal bar trying to see where the noise got worse. It seems to be worst right in the middle of the engine on the passenger side, noticeable on the driver side but much louder on the passenger side. That's where the oil pump is right? Also, it really didn't change much at all until I disconnected cylinders 3 and 4. Any other combination didn't have much affect on changing the knock.

The other discovery that I made today was with the repro distributor body. I was checking the gap between the rotor and the points and found that it was hitting two of them and wearing a groove into them and it had a .035 gap with the other two. I have since switched back to the old distributor body.

Also, about the window crank. I can't really push in on the escutcheon at all. Any other suggestions?

Engine running on all cylinders- https://www.youtube.com/watch?v=XsNVInUvqD0

Engine on the front cylinders only- https://www.youtube.com/watch?v=1NVbqyIQlMI

[columbiA]

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Quite often if the center main is loose,the noise will be much less when the center cyls are grounded & not firing.

[Dick Webber]

Don't get too muscular when you torque the head. Water outlets crack pretty easy.

With respect to the clutch, if you replace it have the flywheel resurfaced too.

Don't ask how I know this . . . .

[ryanheacox]

Sorry I haven't gotten back quicker, it's finals week...

Took the car to the Rhinebeck show on Sunday, seemed to run well, its been knocking less and hasn't bubbled over since I flushed the radiator and put in distilled water and water wetter.

columbiA, I grounded the center cylinders and the knock didn't change at all. If it were the center main, wouldn't it be noticeable regardless of whether the engine were warm or cold?

Dick, I will keep both of those in mind. Thanks.

[Mark in MT]

Ryan: Another possibility is piston slap. This happens most when the engine is cold and the piston is at its smallest. Aluminum expands twice as fast as cast iron. Once the piston grows to fit the hole and more oil is thrown up onto the cylinder walls, the engine quiets down. Piston slap occurs in high milage engines with worn pistons and cyliinders. The B engine in my coupe has been slapping for about 10,000 miles, it is still running its original pistons, standard size, the taper in the cylinder was .007 about 16,000 miles ago. I just warm it up slow for the first few miles, then go for it. If I ever wear it out I will rebuild it.

[BILL WILLIAMSON]

Originally Posted by ryanheacox

columbiA, I grounded the center cylinders and the knock didn't change at all. If it were the center main, wouldn't it be noticeable regardless of whether the engine were warm or cold?

Dick, I will keep both of those in mind. Thanks.

Ryan, I diagnosed a center main knock for a friend on an older, barely run, rebuilt engine by grounding out #2 & # 3 cyls at the same time. It was then perfectly QUIET. He found the shim pack on the center main was totally un-disturbed! Adjusted it & it was perfect!! SOMEBODY FORGOT TO ADJUST THE CENTER ONE!!! Bill W.

[RHD]

Ryan.
Listened to the video and I would say your knock is 100% timing gear and the engine will go along way with slight a knock like that. It is not a serious as it sounds. There are oversize gears available for a replacement in the future. If left for too long, i.e. a few years, there is a chance the gear will eventually strip. (This depends of course on mileage). Always use fiber gears where possible and it is really best to replace both gears at the same time. The crank gear is travelling at twice the speed of the fiber gear and even being steel, they can wear considerably.
A main bearing will give a rumble, not a knock.
Ryan. I have sent you a private message.
Les.

[Drive Shaft Dave]

I am not hearing any bad noises either. it sound's like you have a nice running engine the way it ticks em off, so to speak. By the way I listened to your video about twenty time's I couldn't get enough of it , sweet sounding engine, beautiful car.

[28 fast faton]

That sounds like mine did before I changed the timing gear. If the clearance between the two gears is too large, you will get the clunking noise at idle and deceleration. It purrs like a kitten now.

[ryanheacox]

It seems like the general consensus is that it's most likely the timing gear and that the problem isn't nearly as bad as I had originally thought.

Now just to make sure, to change the timing gear I remove the generator, and four of the pan bolts in addition to removing the timing cover bolts, right?

Also, does the oil need to be drained before doing this job?

[Tom Wesenberg]

Originally Posted by ryanheacox

It seems like the general consensus is that it's most likely the timing gear and that the problem isn't nearly as bad as I had originally thought.

Now just to make sure, to change the timing gear I remove the generator, and four of the pan bolts in addition to removing the timing cover bolts, right?

Also, does the oil need to be drained before doing this job?

Correct, and don't forget the hidden bolt near the generator mount.

If you have pieces of the timing gear in the oil, it would be a good idea to pull the pan and clean off the oil pump screen as well as the oil pump.

[ryanheacox]

Ok, thanks Tom.

Yesterday, I pulled the car into the garage, adjusted the brakes and when I started it up to go test them, something was wrong. I've spent most of the day today trying to diagnose and fix the problem to no avail...

The car will no longer idle with the spark retarded and even with the spark advanced it idles rough and sounded to me like it was running on only 3 cylinders. The exhaust doesn't smell the same either, and it's smokey, like it isn't burning the gas as well.

Also, at a fast RPM, around 1600-1800, the engine seems to run fine however, disconnecting the front two spark plugs doesn't do much, it does make some difference but if the back two plugs are disconnected, the engine will die.

I replaced the condenser, rechecked the timing, cleaned the sediment bulb and took apart, cleaned and reassembled the carburetor, all with no change. It also has plenty of oil and water.

It's very strange to me that it ran perfectly fine and then 25 minutes later it was noticeably much worse.

Any ideas guys? If it helps, I can post a video later on.

[Tom Wesenberg]

An air leak will make the engine run lean and give a bad exhaust smell. That's my first though, either an air leak or plugged idle circuit making it run lean and smell different.

[700rpm]

In my experience these engines can make a variety of alarming noises which sometimes are serious and sometimes OK to just live with. The only way I've been able to tell which is which for sure is to open up the engine. In my most recent surgery, I found a bunch of things that needed attention but I didn't find the source of the original problem (a slight ticking noise, which I now think is #4 piston wrist pin, given everything else I saw when I had it apart. But I'm going to live with it, for now).

In your case, Ryan, I think it may be a retard/advance problem. Hard to tell though from a video. If it is a center main, simply taking it up, which you can do with the engine in the car, might solve the problem. And if it is the center main, you aren't going to get another 100k miles out of it.

Take your time, read a lot, talk to everyone you know who has a Model A, join a local club, and have fun.

[ryanheacox]

Tom and Ray,

Thanks, I ordered a carb gasket set, and engine gasket set with a modern head gasket last night and will replace the gaskets in the carb when they come in.

I did a rough compression test by sticking my thumb in the spark plug holes since I don't have an adapter to fit a compression gauge to the spark plug holes on the A engine. It seems like the front two cylinders have very weak compression when compared to the rear two (the fronts would barely move my thumb while the rears would suck it in and blow it back out). So it looks like I will be opening up the engine to do some closer inspecting when my gaskets come in.

[ryanheacox]

Just uploaded a video to Youtube showing how the engine runs now. For comparison, please look at the previous videos that were uploaded.

Rough Running Engine- https://www.youtube.com/watch?v=jXgSLx3jDnw

[Fred K-OR]

How is the water? Is it getting lower and maybe running into the first two cylinders? Is there water in the oil? When you started it, you could tell something was wrong just the way it sounded when you turned it over. Almost sounded like you had a couple of spark plugs out. May want to check this stuff. You may be correct with the head gasket.

[ryanheacox]

Fred,

The water level is the same as it has been since I took it out for the first drive after changing it and the oil is at the same level (albeit slightly darker) as when I changed it and is not creamy or coffee colored.

Whether I'm right or wrong, the head is coming off and the gasket is getting changed.

Also, the gasket set that I bought is coming with a modern head gasket as opposed to the copper clad felpro one. It was advertized to stop "virtually all coolant leaks"... Any thoughts on that vs. the original style?

[Greg Jones]

That new fangled head gasket will stop all coolant leaks, virtually, only if the head and block surface are co-planar, i.e. flat. I quit using them, had bad luck with them but that is just my experience. As they say, YMMV.

[ryanheacox]

Well then I guess I'll have to be extra careful when I check the head for level. If it does blow, I guess I'll switch back to the original style.

[ryanheacox]

I was right with my suspicions, it was the head gasket, blown between the 1&2 cylinders.