Hi Jeff,

Welcome to the fray! 😉

Here's a discussion on the old VCCACHAT forums that talks about this subject: Engine swap for 1929

Cheers, Dean

I guess the first question I would ask you boss is, why replace the engine? Just rebuild it. The parts are available. It would be an excellent time to swap to insert bearings and aluminum pistons.

Posted by: @rustoholic

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Hi Jeff,

Welcome to the fray! 😉

Here's a discussion on the old VCCACHAT forums that talks about this subject: <a href=" removed link " target="_blank" rel="noopener">Engine swap for 1929

Cheers, Dean

Thanks Dean!    That thread focuses mainly on the 1929 engine, but does hint that '31 to'36 have a lot of similarities.

Jeff

Posted by: @tiny

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I guess the first question I would ask you boss is, why replace the engine? Just rebuild it. The parts are available. It would be an excellent time to swap to insert bearings and aluminum pistons.

My honest answer would be that he doesn't want to spend $5-7K on rebuilding what we have.  The car was slated to go up for sale before I ended up taking it all apart.  You could make a sound argument that the car is worth more with the correct engine in it, but we're already into it for quite a bit over current value, and it's hard to justify putting a bunch more money into a car that you may not be able to sell.  The previous owner cobbled the engine together because he had no intention of driving the car any distance on the road.  It just needed to run well enough to go on and off of a trailer at car shows.  My boss was not aware of this when he bought it 10 years ago, and has only driven it a couple times, as it had a severe overheating problem after running no more than 10 minutes.  

This particular engine would need more than a rebuild if one wanted to get it back to 100%.  The thrust surface on the crankshaft is worn way beyond spec, so it needs a crank, and the coolant passages on the cylinder head have been enlarged by corrosion, so it really should get a replacement head too.

There's a rebuilt 1935 engine for sale by a VCCA member withing reasonable driving distance that's tempting, which was why I wanted to find out if the pre-1937 engines will interchange.  We have the word out in the local antique car circles looking for another 1931 engine, but no luck so far.  It also makes things tougher when you say " I'm looking for a good engine, but don't want to pay much for it".

It's possible that we end up just putting this engine back together with new gaskets and market it as a museum piece like the previous owner used it, although that's going to be an ultra small group to try to sell to.  We did mostly fix the overheating problem before I pulled the engine out.  The radiator was clogged with junk that was coming out of the passages in the block.  The engine had a knock at certain loads, so I decided to pull it for a thorough inspection.  Some of the rod clearances were a bit loose and I removed shims to get them back into spec.  I excavated all the rusty junk from the water passages, and that should keep the radiator from getting clogged again.  Even with the bad crank and corrosion on the head passages it would likely live forever being used for short trips and shows, but I wouldn't try to take it on any tours or high speed highways.  The boss also has a 1931 cabriolet that's a nicer car, so this roadster is down near the bottom of the priority list and there's no rush to get it back together.  I'm just investigating options so I know what to keep an eye out for if any good deals happen to come our way.

Jeff

He can easily spend more on modifications putting an engine in that it wasn't made for than he'll spend rebuilding what's there.

@bigmoparjeff I don't necessarily agree with Tiny's opinion that mods would cost more than a rebuild. If you are not in a hurry, just wait for the right engine. 

I cannot figure out why it is so expensive to rebuild these engines. Parts are reasonable if you know where to look and are patient. Machine work such as cylinder boring and head reconditioning are no different than a modern engine. Crank grinding cost is usually based on the number of journals. Once again, no different than a modern engine. My advice, if you decide to rebuild, is to source your own parts and have them on hand before you start.

When a purchase turns out to be "under water" it is almost impossible to bring it back. Good luck.

Mike

@bigmoparjeff I just noticed an engine for sale in the classifieds here on the forum. It is identified only with the number 836573. My books don't have any casting number info that includes that number but you could check it against your engine. May someone will come along why knows. Once again, good luck.

Mike

#836573 is a 1932 Chevy engine block number.

I think the 1932 engine will interchange directly with the 1931 but may be different engine mounts.  One major change between 1931 and 1932 was the move from a side draft to a down draft carb,  The 1931 manifold and carb can be used on a 1932 engine if you wish to retain the original appearance.

Tom

@35mike You're right. It can be fairly straight forward if the stars are aligned for him. I'll edit my post from 'will' to 'may'. When one gets into fabricating it can get really expensive really quickly, the point of my statement. You also have the fact that a different engine doesn't necessarily mean a better engine. Been there, done that. If any other engine he chooses happens to have hidden issues, it's flushed money. If his current engine is a good core, he's dealing with the devil he knows rather than buying someone else's problems, another 'it ran when I parked it' fable.

@tiny Tiny, Your points are well taken.

I have a fun story about engine swaps. I had a friend who made his living as a self employed machinist. He grew up during WWII and was interested in all things mechanical since he was a child. One of his early jobs, as a young man was at a local garage. This was the sort of place where people came when their cars engine was shot and it was impractical or impossible to find parts to fix it. The boss would send Knobby (my friend) to the junk yard with a tape measure to find a suitable transplant.

As years passed, Knobby had his own auto repair shop and then transitioned into machine work, not automotive machine work, just general machine work. Knobby never had any money but he was a true Mechanical Genius. He was well known locally as the guy who could solve your mechanical dilemma. Gasoline, Diesel, Steam, electrical, he could do it all. He could fix your steam turbine and he could fix your magneto.

When Knobby died, I bought his property. It came just as he had last walked out of it. 10 lathes (15 feet long to jewelers size), 3 horizontal mills, 2 power hack saws, each the size of a Smart Car, and a giant radial drill the size of a VW Beetle. All of his machine tools were ancient.

The rest of the 40' X 80' building was packed with his lifetime accumulation of stuff.

What does all this have to do with engine swaps, you ask. Outside was his mowing tractor. It was a late 1940s B.F. Avery Model A. Knobby had fitted it with an engine and transmission from a 1965 Sunbeam Alpine. It was mounted in front of the original tractor transmission. I haven't done the math to see how many gears it has. Also in the yard was his early Datsun pickup which he had re-powered with an Isuzu Diesel engine/transmission from a Chevette. A couple of years before he died, he had sold a 1964 Ford F-250 that was sporting a 455 Oldsmobile engine. He had coupled it to a Chevy 3-speed. He made the plate to attach the Chevy clutch housing to the Olds. All these swaps were born out of economy. Someone had given or sold super cheap an item which was impractical to repair. Knobby, armed with his tape measure, kept his eye out for a free or cheap solution. In all these cases, the cure for the problem had come along.  

I wish you could have known him. He is a local legend. 

Mike

Cool story! Would have loved to know him.

I have no intention of making any significant changes to get a different year engine to fit.  It has to be a direct bolt-in, or it will have to stay with a 1931 engine.  The only change I would consider is modifying the throttle linkage for a downdraft carb, since my understanding is it would be a significant improvement.  The current carb on this car is in rough shape and needs the low speed tube drilled out and replaced.  We did our testing with the carb and fuel pump off the cabriolet, along with the gas tank and radiator.  The entire fuel system in the roadster is trashed from ethanol fuel damage.

The gaskets between the rear drums and hubs are leaking on the cabriolet, so I have to bring the drums to a local machine shop to have the gaskets replaced.  The owner of the shop is supposed to be well versed in the early stovebolts, and my have a stash of them in a storage trailer behind his shop.  I can quiz him on my dilemma when I bring him the drums.  My fear is that anything from him is likely going to be priced at top dollar.  Also, anything he has is probably core engines that will need full rebuilds, but it doesn't hurt to ask.

I'm well aware of the pitfalls of trying to swap to different year engines.  Back in the 80's, a friend of mine in automotive trade school helped a buddy swap engines on a pair of 1960's Pontiacs.  It wasn't your typical swap involving a donor car because the goal was to still have two useable cars when it was all finished.  After both cars had their new engines in place and accessories were being installed they realized that the starter mounting had changed sometime between when the cars were built.  The starter mount had been moved from the transmission to the engine block.  They ended up with one car that had a choice of how to mount the starter, and a second car with no provision at all for mounting the starter.  Knobby probably would have whipped up some custom mounting brackets, but my friend and his buddy ended up putting the engines right back into the cars that they came from.

Jeff

@bigmoparjeff I thought I was the only one who did that kind of bonehead stunt. No doubt Knobby would have had a solution. They were not always pretty but they always worked.

On the Ford pickup with the 455 Olds, the manual choke cable was routed through holes he had drilled through the air cleaner.

Mike