1947 to 1952 Engine Swap

**ailimac** · 02-22-2013, 04:10 PM

Help please. I am new to the forum and also new to Buicks (my last project was a 36 Dodge D2). I recently purchased a 1947 Buick Special Sedanette Series 40. The car needs a total rebuild. As far as I know it has the original 248 staight 8 in it, which I have already removed. I got some advice from another forum and was told I can use any 263 straight 8 from 1947 to 1952. So when I came across a running 1952 263 engine I bought it (stamped engine ID 56094594, casting number 13880207). I was told I would just have to switch the front mounting plate from the 47 to the 52 and remove the side mounts on the 52. My 47 has a manual transmission. Now I am told that the 52 engine, which had an auto trans on it won't fit the 47 transmission. Is this true? If so is there anything I can do. The auto trans from the 52 is available to me if I want to buy it but will that fit in my 47 without any major modifications?
And what about switching the front mounting plate. The harmonic balancer doesn't have any holes to use a normal balancer puller. I tried using a hydraulic gear puller but only got it to move 3/16" (on the 47). I think I may be fighting the balancer against the hydraulic jack now. Before I continue to try and get the balancer off I would like to find out if I can even use the 52 263 engine.
I would greatly appreciate any advice.
Pete

**JR9162** · 02-23-2013, 07:38 AM

Pete,
Use the front mounting plate from the earlier engine on your 263. Swap it out with the plate that's under the 263's timing gear. You may have to look at the 263 block, compare the holes in the two plates, and drill extra hole(s) in the earlier mount plate... Not a big deal. After drilling the hole(s), chamfer the edges slightly to remove any drilling burrs.
Use the 248's bellhousing on the 263 block. You'll need this because it's what the 3 speed tranny is bolted to, and there's rear motor mounts that attach to said bellhousing. The 248 bellhousing bolts directly to the 263 block.
If your 263 was originally equipped with a dynaflow you'll need to remove the adapter extension bolted to the back of the 263's block in order to bolt up the 248 bellhousing. The extenson was used to bolt the dynaflow tranny to. In this case you should obtain a 263 flywheel, which may need it's cener hole enlarged to physically fit on the 263 crankshaft rear snout. You'll also need to have a pilot bearing adapter machined to fit in the dynaflow equipped crankshaft, as the hole there is larger in order to mate to the dynaflow torque converter.
You can eleminate steps in the 3rd paragraph by using a 263 that was OEM equipped with a 3 speed. However, the 248 bellhousing is required. Early 248's had 4 engine motor mounts and a tranny mount. The latter 248 and all 263's have 2 motor mounts and a tranny mount.
To remove the front dampner, I used a gear puller that had claws on it. Once the dampner begins to move it should wiggle off the crankshaft snout. Practice with the 248 engine 1st and pulling the one off the 263 will be a snap. However, clearly mark them as you do not want to mix them up. John

**ailimac** · 02-23-2013, 02:15 PM

Thanks John. Sounds pretty straight forward. For a minute I thought I may have had to sell the engine. Once again, thanks very much.

Pete

**'51 Special** · 02-24-2013, 05:29 PM

Pete-
The reason for the issues with the switch the engine from the automatic to the three-speed transmission is that Buick used different crankshafts, depending on the type of transmission. The Dynaflow flexplate connects to the crank with machine screws, and the flange on the rear of the Dynaflow crankshaft is thicker to accomodate the threads for the machine screws. The three-speed crankshaft uses bolts through the flange, which are inserted from the front, with washers and nuts snugged to the flywheel.
I recently converted a 51 Special from automatic to three-speed. When faced with the same set of problems, I located a crankshaft from a three-speed 263, and avoided all of the issues with mating the automatic crankshaft to the three-speed. And, because I tore apart my 263 to switch cranks, I discovered it was running fine, but with six cracked pistons. Who knew?
--It may be possible to use the machine screws that originally connected the flexplate to the crankshaft to bolt up the flywheel. i did not try this as the machine screws are a good deal less stout.
--In order to bolt the flywheel to a Dynaflow crank, you will need to drill out the existing threads, and also remove the pan and rear main bearing cap to insert the bolts. I am unsure of the effect, if any, of the difference in thickness of the Dynaflow crankshaft flange (thicker) and the three-speed crankshat flange on fitting the clutch. It is pretty tight within the Buick bell housing.
-- As JR9162 noted, the snout of the Dynaflow is much larger than the front shaft on the three-speed, and you will need an adapter to mount a pilot bearing. I located a shop in Florida that makes these adapters for the nailhead v-8s, and was told by the owner that the adapter should work with the straight eights. Because I changed my crankshaft, i never followed up, but could probaly find the contact information if you are interested.
Good luck with your 47.
'51 Special

**ailimac** · 02-25-2013, 03:51 PM

Thanks for info 51.
Let me ask you this. What if I used the auto transmission instead of trying to adapt the manual transmission. Would it fit in relasonship to the drive shaft or motor mounts? Would I be looking at any major modifications down the line? The person I bought the engine from still has the auto trans and is willing to sell.
Thanks again.
Pete

**raycow** · 03-13-2013, 06:11 PM

Originally Posted by ailimac

What if I used the auto transmission instead of trying to adapt the manual transmission. Would it fit in relasonship to the drive shaft or motor mounts? Would I be looking at any major modifications down the line?

Adapting the Dynaflow crank to the manual flywheel will be MUCH less work than trying to install a Dynaflow in a 47 or earlier car. You can do any necessary mods on the crank flange without having to remove the crank from the engine. On my swap I kept the threads in the flange and made new bolts that go through the flywheel from the clutch side.

Your major challenge with the Dynaflow is that it has no provisions for attaching the 47 rear mounts. If you compare the Dynaflow and manual bellhousings, the difference will immediately be evident.

Ray

**'51 Special** · 03-18-2013, 03:09 PM

Originally Posted by ailimac

Thanks for info 51.
Let me ask you this. What if I used the auto transmission instead of trying to adapt the manual transmission. Would it fit in relasonship to the drive shaft or motor mounts? Would I be looking at any major modifications down the line? The person I bought the engine from still has the auto trans and is willing to sell.
Thanks again.
Pete

Pete-Sorry to take so long to respond. I was off-line for a few days. Raycow is absolutely correct about the problems with stuffing a Dynaflow into your car. He didn't even get to issues with finding and switching in a later steering column, and that no one manufactures a floor shift conversion for the Buick manual transmission. Ray's suggestions for connecting a flywheel to the Dynaflow crank make a lot of sense, and would be a good bit simpler than what I did.

**ailimac** · 03-18-2013, 05:29 PM

Now that I have decided to go with the manual trans I began trying to get the trans off the old engine. I have been trying for 3 days and can not get the trans off the motor. I got it to move about 3/4 of an inch and thats it. I've been soaking the shaft thru the bell housing with rust desolver but nothing. I can spin the transmission around but the shaft stays stationary. I've tried prying it with an 8 foot bar. This tranny doesn't want to come apart. I'm trying not to destroy anything. Wednesday I am going to hang the engine by the transmission on an engine hoist and try and use the wieght of the engine and the pry bar to get it to separate. I am definetly going to video this, just in case I crush a leg or something.
I double checked all my manuals to make sure I didn't miss any hidden bolts or set screws but found nothing. As anyone had this type of issue before?
Pete

**raycow** · 03-18-2013, 10:45 PM

Originally Posted by ailimac

I've tried prying it with an 8 foot bar. This tranny doesn't want to come apart. I'm trying not to destroy anything. Wednesday I am going to hang the engine by the transmission on an engine hoist and try and use the wieght of the engine and the pry bar to get it to separate.

Don't apply force on the bellhousing to adaptor ring joint or you will damage the converter. The same goes for the case to bellhousing joint. I mentioned both of these because I'm not sure where you are prying just now.

The Dynaflow is unlike any other automatic transmission that you have ever seen or worked on. To get it off the engine, you will need to remove the bolts around the edge of the converter that hold it to the flexplate. There is a hole in the adaptor that will give you access to the bolts. Drain the converter first or else you will get very wet. There are two plugs on the converter about 180 degrees apart for this purpose.

Once you get the transmission off the adaptor, unbolt the flexplate from the crank. You will then be able to get to the inside bolts that hold the adaptor to the engine. The rest of the bolts are on the front side where you can see them.

If you want to get the converter off the transmission, you first have to take the transmission off the engine as described above. Then take the converter apart from the front.

Ray

**ailimac** · 03-19-2013, 12:59 AM

Originally Posted by raycow

Don't apply force on the bellhousing to adaptor ring joint or you will damage the converter. The same goes for the case to bellhousing joint. I mentioned both of these because I'm not sure where you are prying just now.

The Dynaflow is unlike any other automatic transmission that you have ever seen or worked on. To get it off the engine, you will need to remove the bolts around the edge of the converter that hold it to the flexplate. There is a hole in the adaptor that will give you access to the bolts. Drain the converter first or else you will get very wet. There are two plugs on the converter about 180 degrees apart for this purpose.

Once you get the transmission off the adaptor, unbolt the flexplate from the crank. You will then be able to get to the inside bolts that hold the adaptor to the engine. The rest of the bolts are on the front side where you can see them.

If you want to get the converter off the transmission, you first have to take the transmission off the engine as described above. Then take the converter apart from the front.

Ray

Im sorry Ray I didn't make it clear that I was trying to separate the manual trans from the old engine. I removed the 4 tranny bolts and am prying between the trans and the bell housing.
Pete