Engine: Will the same head fit both the 170 and 185 CI flathead champions?

[jjesien]

I'm new to SDC as of Friday. I have a 47 M-5pickup and just pulled the engine to see about rebuilding it. The spark plug hole at the back of the head is stripped out. The engine I pulled is 1956 vintage and from what I read here in the forum is 185 CI. I also happen to have another champion 6 cyl. that is a 1947 vintage (170 CI?). Can I use the head off the 170 CI and move it to the 185 CI? I want to stay with 185 to get as much power as I can.

Thanks for any advice you can offer,
John

[Chipmaker]

Why not repair the head you took off?NAPA and outher part houses have repair kits.A tap to thread to a larger size then a incert to bring it back to the standard plug size.

[jclary]

First of all...Welcome to the SDC! Secondly, I'm not going to attempt to give you much advice 'cept to suggest that you sift through any suggestions from the motley crew here on the forum. I own both engines, but don't eat, breathe, and sleep this stuff enough to claim to know the details of how and where the 170's differ from the 185's.

There are some who could assemble these things blindfolded, but I am not one of them. If your 170 is an OK and complete engine, perhaps it could be kept in reserve as a spare. Even if the heads are the same, these engines and parts are common enough that, with a little patience, you should be able to locate one without much difficulty. From discussions and conversations I have stumbled across in the past, dancing around in my head, is that the cast iron blocks and heads in these old flat head engines tend to be a bit nodular and under the stress of torque, time, and heat cycles...they tend to "wear in" together. Mating another head to your block might require a good check for fit and a little shaving (machining) might be required to get a good seal for your head gasket.

It is possible to install a heli-coil (sp) as a thread repair, but I have personally not done this on a flat-head engine. You have a great looking truck. Besides the engine, if it does not have an overdrive transmission...see if you can find one. That would make it more highway friendly. In fact, a good working 170 coupled to an overdrive transmission, would be better than a 185 with a standard three speed. Having a 185 and overdrive would be a bonus.

Again...Welcome and happy Studebakering!

[jjesien]

Thanks for the responses so far. If I don't get an answer about the head here on the forum in the next week or so, I may go out to the barn and pull the one off of the 170 CI engine and compare them side by side. I was hoping to avoid pulling it apart if I didn't have to. I was fortunate enough to pick up the engine at the local Spokane swap meet for $50 several years ago. A guy had pulled it out of his M5 to replace it with a modern V8. It is complete from the carb to the oil pan including transmission (no overdive though). I thought it would be good for spare parts... As for the transmission, I am very interrested in the possibility of putting a Tremec T5 behind it if possible. I've been searching the forum to see if anyone has done this on an M5 pickup (behind a flathead 6). So far, I was able to locate a thread on an install someone did on their Avanti. That was full of great info.

[Studebakercenteroforegon]

To answer your question...Yes, they are interchangeable. You will note that the same head gasket will work on all Champion flatlead sixes - 1939 through 1960.

[t walgamuth]

I'd be in favor of helicoiling the head you have, after all you know what it is. A helicoil is not a weak spot. I'd plull it get it skimmed and repaired and replace it. It is the simplist head in the world to remove. I think you could even get away with repairing it without removing it.

[RadioRoy]

One of our engine experts might chime in here, but I wonder if the older head will have lower compression, or poorer swirl characteristics.

I will third or forth the recommendation of fixing the newer head.

As additional incentive against pulling the head off the older engine consider this. The majority of flathead engines that have had their head removed, end up dying a slow miserable death due to rust and neglect. Pulling the head off a mostly usable flathead engine and then leaving it to sit is the kiss of death for that engine.

[wolfie]

If you have never done one dont let anything about a heli-coil scare you. I have ran them in many engines with both steel and aluminium heads and have never had one fail. They are really quite simple to install and I have done them successfully on dirt bike heads without pulling them down. I would personally pull your head to prevent any shavings from entering the engine but I have seen people pull those shavings with a magnet and have success. Good Luck, Steve

[Dwain G.]

While the 185 is based on the earlier 170 engine, it is a new casting with several changes. It also became the factory replacement (service) engine for older 170's. There is a service bulletin detailing the special parts needed to fit this engine into earlier vehicles. The increased cylinder volume of the 185 (longer stroke) means more compressed volume and higher compression ratio. It emphasizes that cylinder heads with casting number 527172 or 529279 should not be used. Order cyl. head 536180 instead.
The first two heads are 'high compression' heads (7.5-1) and the factory didn't want to sell an engine that might suffer pre-ignition damage in the field.
Will your engine really do that? Maybe not, but it needs to be watched.

[irish]

Yes you can switch the heads but I wouldn't. If the heads are correct for each engine you will lose a 1/4 point in compression, and it's only 7.5:1 now. Any used head will warp to some degree, unless you're are going to mill the head you're less likely to encounter problems if you return it to the original block. Also you'll want to check the threaded hole in the side of the head for the temp sensor, they changed the size sometime in the 50's. I personally would use a heli-coil. Hope this helps.

Joe

[jclary]

All good points made so far. In your initial post, you said you pulled the engine "to see about rebuilding it." If you are relatively unfamiliar with the Studebaker Flathead six engines, perhaps you should share your concerns first. The reason I suggest this is because I know how tough these little engines are. I have one that has been running OK for nearly 40 years with only about 30 lbs of oil pressure at highway speeds once it is warmed up. Except for running out of gas due to an inaccurate gas gauge, and a fuel pump failing (around 1978)...it has never let me down.

Due to their solid lifters, they seem to be a bit clickity clatter , but if you adjust them too much for quiet running, you're in danger of burning the valves. If that stripped plug thread is your main problem, repairing the thread, flushing the cooling passages, changing the oil, and some fine tuning, and you might be good to go. Since you have it out...new motor mounts wouldn't hurt. On these old engines...sometimes less is more. Some of us have learned the hard way that excessive tinkering...turning this screw...or one more twist of "that" bolt...can launch you into some major trouble that wouldn't have happened if you'd left well enough alone.

What ever you do, keep us informed and have fun with it.

[Neal in NM]

From my experience (I repair spark plug holes too often) I would not let anyone use a standard Heli-coil. I would use a threaded insert, the kind with a shoulder. If a Heli-coil is not done just right they can creep down into the combustion chamber. Repairing the spark plug hole with a threaded insert is a legitimate repair, I have been doing it on newer F##d engines. Neal

[tbirdtbird]

Since I need to know the answer to this same question I hope an engine maven chimes in with a definitive answer...Gary Ash, etc....

[t walgamuth]

From my experience (I repair spark plug holes too often) I would not let anyone use a standard Heli-coil. I would use a threaded insert, the kind with a shoulder. If a Heli-coil is not done just right they can creep down into the combustion chamber. Repairing the spark plug hole with a threaded insert is a legitimate repair, I have been doing it on newer F##d engines. Neal

I like this suggestion.

[Skybolt]

Dwain is the man for your answers for most factory specs and answers. If he says it "then it is so". That said if you want the simple answer you should put a head form a later model Studebaker six on it but anything from the early 50's to 64 will work well. Many heads are out there and even the lower compression early heads can be bought NOS for not much money.

Yes, you could repair the thread of the plug hole but why go to the trouble if you can pick up a head cheap. I bought an NOS head for $25 a few years back and gave it and a few engines to a school for them to learn with. Just wait for a while, look around and ask some more questions. You may be able to pick up a whole engine free with the head you seek, or maybe a few dollars.

Your 185 was the new casting for the Flathead and so using later heads would yield the best results.

But as John said, it's some time best to leave well enough alone. Fix the thread and be done with it.

I have a tendency to play with every thing. Len.

For your enjoyment

A 170 cid Champion six. https://picasaweb.google.com/1166731...9EngineInstall

http://www.youtube.com/watch?v=s8WT36NQD3A