Buick 320 block interchangability question 37 to 47

[MNRoadMaster]

Thanks in advance for the help here. I have a 47 Road Master that I've rescued from the scrap heap here (sitting since '71) with the 320 which I'm refusing to change over to anything but another 320. The original engine melted down and I found a good block with crank, rods and cam out of a 37 Century in very nice condition although frozen when I got it.(320). Will it work (with all peripherals bolting on) and bolt up OK? For some reason I thought I heard it would not work. I believe that I should be able to use the domed pistons and head (after having it checked and a valve job) out of the melted down engine I believe as they look OK. I've really been enjoying the posts here an modifying these engines although at this point I have to get something that functions on the cheap right now. These engines are getting hard to find aren't they!

Thanks again!

Don

[BigRivy]

Look to see if it has the right engine mounts. I think the later engines have side mounts and the earlier ones may not. Make sure the '37 crankshaft has the same configuration on the rear flange. Usually automatic and standard transmissions have a different sized rear hole. The one for a pilot bushing is smaller and the one that will fit the nose on the torque converter on the Dynaflow, which is larger. You might also look to see if the early block is drilled for all the oil filter lines that would be nice to keep. Do the oil pans look to be interchangeable? Make sure if they are not, that the sump is in the right place to work with your existing crossmember and steering linkage.

[MNRoadMaster]

Thanks for the reply BigRivy!
Well as I understand it there were "plenty of smaller changes" including motor mounts and the fuel pump is different for sure. I have found these things out so far. Ahhhh - the crankshaft...I would suppose that this would be the same as it is all pre - dynaflow (1949 or so) Camshaft also the same? Not sure on this. I hear that it is likely that the water pump is different (a likely change in pully / fan or generator?) and of course the 37 pistons are flat but I believe that the 47 domed ones (assuming both to be standard) would work fine. The pan seems to be the same. As it appears to be a matter of trying to figure out modifying motor mounts and other issues I will be looking for a different block etc. Someone has said that there might be someone in need of a 37 block for much the same reasons I want a 47 block (46 47 48 - maybe 49?) and perhaps they are even harder to find. So it is looking like my best option is to try to find the latter engine / block for this.... I keep finding ones that have already went to the recycling scale within the past month or year. Yikes!
I'm still determined to keep the car with an original 320...

[alleycat]

Basicly, all 320's are the same engine. But at about 47-8 things started to change. Buick was going to introduce the 263 in the then totaly new Super for 1940. This engine "fixed" every problem the 320 and 248 had and also contained improvments that would be difficult to do in the other engines, it also made more power to boot! Buick got massivly shut down and the engine did'ent see the light of day untill 1950. Too bad, because with the entire Super package Buick likely would have changed the automotive landscape. Buick knew they were not going to get any engine anytime soon. So they started sneeking the 263 changes into the 248 and 320 by about 47-8. The changes; oil line relocations, bigger, relocated water pump along with a deck with fewer holes and redirected coolant path for improved cooling. Side motor mounts. Domed pistons! Insert rod bearings. Your 47 could have some or all of these changes, Buick barely or not at all published these changes or when, they just sorta "appeared". But for sure all changes were in place by 49. All were for the good, and seriously improved the 248 and 320. Engines earlyer than 47 would not have had these changes and, for the most part, cant be done. Piston, rod, crank, cam, etc, all the same. If you've got the newer engine, its the one to use. You may even have a newer engine than you think in that Roadie, it could have been switched out years ago for a newer than 47. Its hard to tell from the outside. Look things over reeeal careful like. alleycat

[MNRoadMaster]

Thanks for the reply here alleycat! I appreciate this post as well as others of yours - you are an excellent resource indeed! With this info the 37 block is out of the running here, even though it is in excellent condition.
Well, my melted down engine has the domed pistons and the machine shop tells me that they are in excellent condition with at most 2 thousandths wear so I will be using these for certain. The replacement '48 engine does not have the insert rod bearings and I will be removing shims in an attempt to bring it back into specs. From reading the odometer on the donor car and looking the engine over, along with the compression as bad as it is (50 - 70 range) etc, I believe that the 10,000 on the odometer likely is an accurate indication that the engine has indeed at least 110,000 miles on it. Indeed a lot of miles for a car of this vintage. When I got the engine I pulled the pan to clean it out as best I could. At that time I tried to get the bearings to the correct specs without success using plastigauge. I was recently told that plastigauge ia not a good option, perhaps because the babbit is soft. *My next question alleycat, is if you have any advice on this*: I currently plan on using a 1/8" by 2 thousandths piece of shim stock to assist in getting the proper shim placement for adjusting the clearances. As I understand this, I will adjust things such that the engine binds with the shimstock in it and when it is removed - the clearances should be pretty close.
No, I do not have a viable option for reboring etc at this time. Yes, this car is my daily driver. (I figure that these thoughts are going through someone's mind here)
That being said, it's a craps shoot regarding what I will find when I pull the head off as far as the amount of ridging / wear there. My gamble is that I will find standard diameter pistons installed. Hopefully, after the ridge reaming and honeing it will be close enough. I have had the good fortune of making a new friend who has given me a low miles late 40's 320 head for this endeavor, and another buddy of mine is going to give it a basic valve job for me as a favor. I believe that the timing chain and gears out of the melted down engine are likely good as well because of the piston's being in such good condition, so I will use them as well. Of course, I will also be doing what I can to replace the seals as well, so if you have any information or advice on this please feel free to pass it along! I think I can do the seals with the engine still in the car - can't I?
Hopefully, I can get the old engine to run decently at least...
Thanks again alleycat!
Don

[alleycat]

You will very likely find not much or any ridge in the block. The rings and then the pistons would start to self destruct at about 60,000, which is likely the reason for the low comp. Believe it or not, you can mix n match parts almost unmercifuly and the engine will be happy. I had to do as much back when I HAD to be on the campus bright n early monday morning. Plastiguage does not work so well in used babbit bearings because the babbit does not wear evenly. I would slap 'em in, get a "snugish" fit, heavy oil, and "off to the races"! However, I like a babited rod. They do require more work to set up, but they can be set up deadly accurate and with todays oil & filters, go FOREVER! When you valve job the head, keep the seats narrow, like .060, there is only about 40lbs keeping the seat seal. Buick liked wide seats, carbon would deposit on the seats and hold the valve open. The narrow seat makes it harder for the carbon and increases the lbs/surface area. Good luck on the seals, it can be real no fun. alleycat

[MNRoadMaster]

Thanks again for the reply here alleycat!
Well the engine has 110 rounds on it so looks like it's quite the craps shoot. at least I have good pistons.
So how do I know when I have this "snugish fit" right? I take this to mean by feel only. Do I do one - take it back apart keeping the shims organized - then do the next one? You think that the ribbon of shim stock is a bad idea?
So babbited rods - even though the babbit is soft last longer than inserts??? It just sounds counter intuitive....Not a first time on that...
Thanks for the numbers to give my friend on the valves - I am certain this will be a huge help indeed! This sure makes sense to me. Would they be more apt to burn? Of course I tend to adjust them fairly regularly...
I guess I will have to get a 6 pack to use as a "carrot on the end of a string" for the seal job won't I....It is a good thing I am so stubborn.

Best regards, and thank you alleycat!
Don

[alleycat]

I don't know exactly what babbit alloy is in the rods but "soft" is kinda a relative term. Clevite 77 insert bearings are "soft", were as Michigan bearin gs are "hard". The clevites have a higher imbedability, which means that a hunk of crud will tend to bury into the babbit and thus not eat up the journal, unlike a harder babbit. Way back when just about everything had babbited bearings, oil was what was pumped out of the ground, and filters mostly a joke, a LOT of crud went through the bearings. Since the bearing was considered more replaceable than the crank, the bearing(s) had to absorb a huge amount of abuse. So, the babbit was softish to absorb the junk and since the bearing was never to ride on the journal but in oil, everything was good. And if you look at a original babbited bearing, you'll see that it's pounded full of junk. Considering what it went through, I seriously doubt that a insert bearing would have lived as long.

Since there are probably 50 different types of bearing babbit alloys, oil is so vastly much better as well as filters, the outlook for babbited bearing rods is very different and much better. If a person is starting a total rebuild, the block squeeky clean and modified for full flow moderen oil filters, crank turned to a handy undersize, a harder babbit could be used. The bearing can be sized to fit the journal very accuratly, without shim stock. The babbit can be poured right out to the edge of the rod, with a proper sized fillet on the edge to match the radius in the corner of the crank journal. This is a very important detail. How the bearing fits up to the edge of the journal and the rod clearance side to side is what determines the oil pressure in the bottom of the engine. Edge control. A lot of space down there and it'll take a lot of pump to catch up. And since nobody is making insert bearings specificaly for the str8, that means that the only bearings for the insert rods is NOS or bearings that just happen to fit, made for other engines, and they are smaller. In this instance, the babbited bearing has a real advantage. After the rods are done, send 'em to a coating outfit like Calico, have 'em coated. Coulde'nt be more perfecto.

As for adjusting the bearing in your engine; start at one end, pull out the shims untill the cap "bites" the crank and it won't turn. That will be about zero clearance, put about .0025 back in. Don't look for absolute perfection here, the bearings are used. Do the other 7. Shim stock, aluminum foil, whatever, it works. Don't use paper, I tried that...alleycat

[MNRoadMaster]

alleycat...
I’ve been delayed a bit with the engine rebuild because I shattered my finger but it’s getting good enough to do this with a splint……In the interim I found an industrial engine stand that will actually hold this engine that I can borrow for the job. Well alleycat - I can find bearings for the 320 as well as others I believe from CARS or Bob’s Automobilia however re-babbiting is a whole different can of worms. I did look up calicocoatings and that is a very interesting company indeed! I will have to see if it is cost prohibitive as we are doing this on a shoe string. I now have the valve job done on the head (Thanks for the info) and a good crank / camshaft / rods and pistons / rings. We’ll see how bad the cylinder walls are ridged with 110 rounds on the engine. I could be surprised, but I’m not counting on it. I found the ’37 320 and the parts seem to be in very good condition – I bought a block which only had the pistons / rods cam and crank frozen. I damaged the pistons taking them out but the other parts look to be in most excellent condition. I’m planning to use .0010 shim stock cut the width of the bearing by ¼ inch. One of the good things about this engine design is the removability of shims to compensate for wear. Hopefully I will have enough removable shims to get it back into specs.
.0025 sounds kind of loose doesn’t it – Factory Specs are: Main Bearing Clearance, Inch: .0007-.0025 is what is quoted and Rod Bearing Clearance, Inch: .0008-.0018 is the specs. I don’t know why I would be shooting for the loose end of specs here…Perhaps you can enlighten me…
Also I hear that I can convert or modify this for a full flow oil filter – I have an adaptor with lines here but no clue if or how I can install it. I believe I can put a FRANTZ filter in place of the original bypass filter. Why couldn’t I have both as I do in my more modern cars? As you say good oil and filtration would really make it last much longer, which is good because I put plenty of miles on this car.
How are these 3 piece manifolds supposed to go together??? I tried repairing the broken center piece repeatedly and I’m done beating that dead horse. I’m glad that there are new manifolds available for this however expensive they are. It appears that there was some sort of metallic gasketing material between the manifold pieces where they sleeve together. Any info or ideas here???

Thanks again for the help here!!

[alleycat]

Oooh! A finger smash! That ALWAYS got my attention. Did it many times. On to the bearings...Buick always did use very close bearing clearance, which I like, but no filter and oil "out of the ground" I don't. I don't know how those bottom ends lasted. The way I describe setting up a babbited rod bottom end is if you want to be really deadly accurate, get max load capacity and use the best light weight oils out there. And it must have a full flow oil filter. The partial filter that runs into the rocker shaft just is not enough, I would certainly retain it, but the bearings need their own. So, I would try to get about .0015 or so bearing clearance, with used bearings there is just too much junk embeded into the babbit to get much closer without chewing up the crank. Use 30 wt oil. If you end up going all new in the bottom end then things are different. Putting in a full oil filter is not to difficult. The oil pump is on the right side. The oil feed up to the main gallery is about 2" long. The main gallery runs the lenth of the block and has little feed plugs tapped into it for oil supply to other stuff, easy to spot. The oil supply up to the main gallery has to be diverted. Put a plug in the supply line, brass works nicely, a tight fit, about 1 1/2" up in the line. On the pump side of the supply line, drill into the block and into the line. Thread it for whatever type of take off line you want to use. Banjo fittings look cool and period but not so easy to find. Get a remote filter set up. Bolt it onto the frame somewhere. I use a Ford or Chevy set up just because the filters are EVERYWHERE, and OK to really good filters can be had easy. Drill and tap another hole on the other side of the plug for the out put side of the filter to pump into the main oil gallery. Run the lines, check for leaks. Yer off to the races!

Be REALLY careful with the exhaust manifold. Most are broken and they are like hens teeth. I don't know if anybody is making a really good replacement center section. Years ago I repaired one by cutting off the "sleeves", machining new ones, and brazing them on. Worked fine for as long as I knew. alleycat