Rebuilding A Flathead

[Bingster]

After reading this forum over the years, I've gotten curious as to the possibility of rebuilding my '47 Desoto engine.  It seems like a no-brainer that it probably needs it, and it would be better in the long run to have it as fresh as possible for the time when I am not so fresh.  If I plan to keep the car for another twenty years or so, it'd be nice to have at least a partially rebuilt power plant.

I'm not taking it out. I'm not than ambitious.  I was reading over the repair manual, and it seems doable to do pistons, rings, valves and other things that I can get to with the engine in the car.

However, there are an awful lot of special tools described in the manual from that era and for that particular engine that I don't have and probably cannot get.  So how much can I get done at a shop like grinding valves, truing pistons, etc.?  And I suppose there are enough contemporary tools to do the tasks of the old? Mainly removing parts and replacing them.

 

[P15-D24]

You need to pull the block. Before investing in a rebuild you need to get the block magufluxed for cracks, and to properly do the valve seat, cam bearings and cylinder walls. Other wise your throwing good money away. Reassembly is not complex, but lot of nits to get you in trouble like the correct way to install valve guides and the proper spacing on all the rings. Need a ring expander, torque wrenches, good set hand tools engine stand. Also learn about plasticgage, feeler gauges and good dial (or digital) indicator.  Take your time, follow the manuals and ask questions when you get stuck and it will be an enjoyable experience.   

[knuckleharley]

I guess it MIGHT be possible to remove and re-install the crankshaft with the engine still in the car,but it's not something I would ever try and you are going to need to have the crank either reground or polished. Count on it.

The kind of rebuild you are talking about is the kind people used to do to be able to get by for a few years. Primarily rings and bearings,and lapping the valves. More of a "refresh" than an actual rebuild.

Since new pistons,rings,bearings,valve springs,valves,oil pumps,etc,etc,etc are going to be practically impossible to find 20+ years from now,you are nuts if you don't pull the engine and have a machine shop familiar with flatheads do a complete professional rebuild for you and be done with it. Even now you might have to overbore your block more than necessary or sleeve it because you might not be able to find pistons and rings the correct size.

Same with the crankshaft and camshaft. Yes,you WILL want to get the camshaft rebuilt while you have the engine apart. Or exchange it for one that has already been rebuilt. The chances of getting this done locally are pretty slim. You will have to send it off to someone like Delta Cams to get it redone. They can also redo your crank if it is flat and needs to be welded up and reground. Chances are they will have fresh ones already done and you can use your old ones to avoid core charges.

Contact me when you get it all apart and find out what you need. I MIGHT have rings of the correct size,and I might even have pistons of the correct size. Right now I don't know what I have because the hard drive on my old computer died,and the so-called automatic backup to a portable HDD I was using ended up not being so automatic.

You plan on keeping this car forever,so do what needs to be done the right way and not have to worry about it in the future. You will be glad you did.

Edited September 4, 2016 by knuckleharley

[Don Coatney]

In my youth I twice tried to do a crankshaft bearing exchange with the engine in the car. Failed both times. I have had good luck doing a valve job on overhead valve engines with the engine in the car but never tried to do so with a flathead engine.

[pflaming]

I think the previous two posts, while accurate, are overstated and discouraging to a novice. I started my first engine refresh with an empty tool box and zero knowledge. I bought tools as I needed them ALL readily available. Sidebar, expensive tools are not required and there are possible about six or so tools that are really helpful, just buy these as singles not full sets. Remember, O'Rielly's, have an excellent selection of very speciallized tools, free to use.

Parts, buy one or two old engines, they are every where at a dime a dozen and you will likely find most every part you need. Here I may get some slack. To me, if the old engine has 40 #'s of oil pressure when motored by the starter, why fix what works, and if the cylinder walls are nice and smooth, why tear down lower? 

For me, there is one mandatory step. Block crud! Once my engines are stripped, that is, the head is off, I remove the freeze plugs, the water pump, and the water distributor and I spend at least an hour cleaning out the crud with a high pressure steam cleaner. I help things along by poking into all the water holes with a stiff pointed rod and as long as the water is colored I steam clean.

The two most important items that protect the engine are water and oil! Accordingly my eyes are always on the oil gauge and the temp gauge. 

My overriding point is this, it is better to do it right once, yet let's not overstate what is so simple to learn, and wrongfully discourage newbies by implying perfection is required. 

Finally, pulling the doghouse, then the engine, makes this task SO much easier. Hang a winch on a rafter or a GOOD tree limb and begin a great journey. IMHO. 

Edited September 4, 2016 by pflaming

[captden29]

Bing, I am in NC also and I have a few things you can use should you decide to tackle this. I have an engine stand, a ring separator, chain, torque wrench, and maybe a few other necessities. I have to look out in the garage. I can give you some of these things, at least until you are done if not for good. I will probably never use the engine stand again. the torque wrench will be a loaner I also have a brake drum puller should you need it.I do not have a dial indicator. with the info available on this site and elsewhere the rebuild should be done in no time. of course, money is an element. I do not have the manual for that year. you can pm me if my offer is a help to you. I am near Wilmington.    capt den

[Young Ed]

3 hours ago, knuckleharley said:

 

Since new pistons,rings,bearings,valve springs,valves,oil pumps,etc,etc,etc are going to be practically impossible to find 20+ years from now,

What makes you think that? I would guess as technology keeps improving it will get easier to make parts. 

[Bingster]

I can see all of the points mentioned. Obviously, it's more involved than the old "valve and ring job" from my youth. I always used to think that was like rebuilding an engine!

Right now I can't afford to have it done, but scarcity of parts in the future I have thought about.  A person could stockpile pistons and other stuff, but if an internal part goes or even the Fluid Drive the entire car could turn into a fancy lawn jockey! 

Of course, I won't run up the mileage of a regular family car.  But it would be nice to have it roadworthy to go to car shows and such.  Mmmmm.  And too, after reading some of the sad stories about guys having to sell their projects 'cause they can't do the physical work anymore, I would like to be able to enjoy the car while I am still fully mobile.  I've been working under the dash lately and have been thinking of you folks who said it's getting very difficult down in there.  I can definately understand that!

Adding an engine rebuild to the list puts the day that the car is driveable further down the road.  Well, I'll have to give this one some serious thought. Thanks for the ideas. 

[Jeff Balazs]

2 hours ago, pflaming said:

The two most important items that protect the engine are water and oil! Accordingly my eyes are always on the oil gauge and the temp gauge. 

A glance now and then should be enough.........eyes belong on the road.

 

[Plymouthy Adams]

2 minutes ago, pflaming said:

I will check after church and dinner and get back to you.

this should have stayed where posted..in the wanted section...and if you reply should be in PM.....

[knuckleharley]

6 hours ago, Young Ed said:

What makes you think that? I would guess as technology keeps improving it will get easier to make parts. 

With the enviro-nazi's and the fascist left gaining more and more power all the time,I'm guessing in 20 years it will be practically impossible to buy any part for a car,antique or new. I am predicting it will even be illegal to work on any cars build before the mid-70's unless you are a federally-inspected and authorized repair facility with all the proper test equipment and forms to fill out. Chances are you will be required to take it to a dealership to even get it tuned.

Don't like getting political on this site,but I also don't like the politicians getting me,and make no mistake about it,they are after total control over every facet of our lives.

[knuckleharley]

6 hours ago, Bingster said:

I can see all of the points mentioned. Obviously, it's more involved than the old "valve and ring job" from my youth. I always used to think that was like rebuilding an engine!

Right now I can't afford to have it done, but scarcity of parts in the future I have thought about.  A person could stockpile pistons and other stuff, but if an internal part goes or even the Fluid Drive the entire car could turn into a fancy lawn jockey! 

Of course, I won't run up the mileage of a regular family car.  But it would be nice to have it roadworthy to go to car shows and such.  Mmmmm.  And too, after reading some of the sad stories about guys having to sell their projects 'cause they can't do the physical work anymore, I would like to be able to enjoy the car while I am still fully mobile.  I've been working under the dash lately and have been thinking of you folks who said it's getting very difficult down in there.  I can definately understand that!

Adding an engine rebuild to the list puts the day that the car is driveable further down the road.  Well, I'll have to give this one some serious thought. Thanks for the ideas. 

This might be a feasible option for you. Try to find a used engine that needs rebuilding cheap,and then tear it down out in your shop and find out what it needs,and buy the parts as you can afford them. You will need to borrow/rent a bore gauge/micrometer with range rods or have someone that has one come by and test your bore for you to tell you if it needs to be bored and how much before you can buy the pistons and rings,but lots of people have micrometers large enough to mike crank journals.

The valves will be a stock replacement item,but you will want to add the expense of installing hardened valve seats on the exhaust side. Stock new valve springs aren't expensive,either.

I wouldn't worry much about the fluid drive trans. Not a  high demand item,and you can buy one pretty cheap in good working condition and just store it away in case yours ever goes bad. Which is pretty rare.

One nice thing about having a spare engine is once you get the parts or the money for the parts you can take it to a local high school or community college auto mechanics/machinist class and have students do all the machine shop and assembly work for free. If you take the car there,they will even pull your engine and put the rebuilt one in for free. All it will cost you is the price for parts,oil,hoses,clamps,etc,etc,etc if any are needed.

The only problem you might have is some instructors may have a "my students won't be working on antique and obsolete engines" attitude,so you might have to shop around for one more open-minded.

[Bingster]

Capt Den. Sent you a PM.  And I see now that you live in Wilimington.

[dale]

If the motor doesnt knock or use an awfull lot of oil you should be fine going about anywhere.  I used to keep some really bad cars on the road by just using a heavy top grade motor oil if you are just Summer driving.   Go thru the starter, generator, water pump,  Maybe a new aluminum radiator and belt and hoses and she should be reliable.

[dale]

Too bad you cant still get out the Sears catalog and order a rebuilt like the old days.. I ordered one way back in the day and it was a great motor.  It was even .060 over bored.

[Bingster]

I just drained the oil and it was like new oil only darker. Perfectly smooth and no sludge. It wasn't even thick. I'm assuming the the drain plug gasket goes back on with the little ring indentation facing inward?

[Bingster]

Don, this one's for you.  I just came across a four-page article in the downloads file about rebuilding a flat head. It's a '39, but the basics should be the same.

[Don Coatney]

10 minutes ago, Bingster said:

Don, this one's for you.  I just came across a four-page article in the downloads file about rebuilding a flat head. It's a '39, but the basics should be the same.

Why is that for me? I already have the books I heed to do that job. Believe you need to read and comprehend the books you found.

[Bingster]

It's for you because you like people to do their own homework before asking questions that they can look up themselves.

[Don Coatney]

4 minutes ago, Bingster said:

It's for you because you like people to do their own homework before asking questions that they can look up themselves.

Yes I do, Have you read all that information?

[knuckleharley]

1 hour ago, Don Coatney said:

Yes I do, Have you read all that information?

Don,Bingster was posting that as a recognition and a tribute to you for your efforts to get people to search the archives. It wasn't a challenge..

 

Sometimes you just have to take a compliment,say "Thank you",and move on.

[Bingster]

No, I haven't read all that info, but I have copied it and am very excited about reading it. 

[Don Coatney]

8 hours ago, knuckleharley said:

Don,Bingster was posting that as a recognition and a tribute to you for your efforts to get people to search the archives. It wasn't a challenge..

 

Sometimes you just have to take a compliment,say "Thank you",and move on.

 

8 hours ago, Bingster said:

No, I haven't read all that info, but I have copied it and am very excited about reading it. 

Thank you, I will move on

[rallyace]

As has been mentioned above, rebuilding an engine as simple as a flathead is not an overly difficult job if you possess decent mechanical skills and have a clean and dry place to work. Yes, several specialized tools are needed but they are available for loan from most of the chain parts stores and Harbor Freight can be a source for decent quality tools that you only use on occasion. I would purchase a dial indicator with a magnetic base and a 6" digital caliper as you will find a lot of uses for them. They will set you back about $50 or $60 at HF. Other than a gasket set, I would not buy any parts until the machine shop has finished their work as you may need oversized parts.  Start by reading up and making sure you have all of the information needed like specifications, clearances, etc. You will need an experienced machine shop for some of the operations.  Ask a couple of independent mechanic shops who they use. Personally, I avoid the ones that do a lot of racing engines as they put a one time customer at the end of the priority list.  I saw that there are some local folks who will provide advise and possibly assistance. Use this forum for help, these guys know their old Mopar engines. If you have the room, a couple of old engines to use for parts is a very good idea.  Just my 2 cents worth.  Mike

[Bingster]

Thanks Rallyace.  I've just poured over the article on rebuilding a flat head and the writer answered a lot of questions for me, mostly that some of the operations such a honing and boring and that sort of thing are more time consuming than too difficult.  I think I'd buy a used engine and work on that.  If I blow it at least I will learn what I did wrong. If it runs, I can always swap it out.  One of the things that this article brought home to me is to remove the feeling of doing all that work and finding it runs crappy or not at all.  There' a learning curve with everything and sometimes I get too impatient.  Anyway, thanks to all of you, I now plan to get another engine and give a go.