The Stovebolt Site Forums The Shop Area Engine Shop Replacement Cylinder Head- 55.2 235

The topic has been brought up many times, but I just fell victim to the Stovebolt Crackosaurus...

The machine shop called to let me know the head off my 55.2 235 (head #3835913) had a crack in it between the valves, so I now need to find a replacement. The owner did not have an immediate replacement from his suppliers, but checked around and I also called the few folks I know that keep these engines. No luck there either, so I'll be going to market for one and don't know what to look out for.

Is buying another cyl head strictly 'buyer beware'? How can you possibly know what you are getting if it is not from an engine/machine shop that checked/magnafluxed it?

I know that prices sometimes lean toward buying another entire engine, but am I about to just be throwing money & hoping it doesn't land in another cracked head?

I'd also really appreciate some guidance on what year ranges of 235 cyl heads are compatible with the block I have (CON 4 H55 3836233), and I hope you all are having a great Monday.

Thanks!

Brad

1954-62 will all interchange.
1956-62 are set-up for an electric temp sender. If you use one of these you will need to pick up an adapter for your mechanical gauge.

Brad the head with the last three numbers 848 is the best head as far as ratings that matter. If it were me, I would get the engine shop to find it if they are willing. They would guarantee the head. It may cost more, but sadly, these heads have about a 50% bad due to cracks rate. It might be higher, but I don't recommend trying to find one yourself unless you are feeling lucky. I have 6 235's sitting around and when I get to them, I expect less than 3 to have working heads. Maybe someone here will know of a good one and hook you up? 54-62

I should have mentioned a 1953 235 head will also work but will require using the older two bolt valve cover.

Brad, check your PM inbox.
Jerry

No, I don't feel lucky Deve-- especially since the head I did have "looked" flawless to me & your 50% success prediction. That is exactly what I was afraid of going it alone. I definitely don't need another busted one.

I'll see what the shop can find or if they are willing to look anymore. I remembered seeing an 848 head by JimBow(?) or someone else with 20K posts not too long ago in the swap, so maybe I'll get lucky.

Thanks

Brad

Brad, I've got an 848 head stashed away- - - -come and get it so Alan can check it out.
Jerry

There is some lag time in my refresh, but I checked the PM & responded after posting...


WILCO!

Thanks!!

Any reason such a crack could not be Brazed?

Seems like Brazing (with approproate pre-Heating) would be an easy and forthright fix, and durable.

All good things come from Stovebolters who stick together!

Brass will not stand combustion chamber temperature. The crack is between the valve seats. It might be repairable by pinning or arc welding the crack with nickel welding rod but then both valve seats would have to be replaced. That's about a $200.00 fix or more, plus all the other machine work involved in rebuilding the head.
Jerry

Is there certain cylinders that the head seems to crack in?? I know the '53 engine I had was between the intake and exhaust in number 5. Didn't need no magna-flux to find it....

John

The crack between valves was not visible to the naked eye (I called back to double check on that), but as smoked as the rear intermediate main bearing was-- I would not doubt if it was in the same area as your '53, John. Mine was not leaking water YET, but it would be soon after the cleaning.

I'm not quite out of the woods yet as far as having a replacement head to install (almost though- VERY fortunate Hotrod is close by- THANKS x10!), but the scarcity of good cyl heads we all need for these Stovebolts brings up the question:

What is our plan going forward to maintain their availability/maintain the hobby? It is a pretty doggone essential part of the engine, and I'm just curious what ideas are out there to pass the hobby on... Who's stepping up to be the go-to guy if repair is the only option? I saw some aluminum milled heads for 235s, but they had 'race' and HiPo adjectives listed in their descriptions. The casting operations I looked at that could prototype would be astronomical expensive... Can a Stovebolt cylinder head even be made- trademark/patent-wise? I know somebody here has thought about it- maybe even made one.

I hope I'm not bothering everybody being curious- this is probably not the last Stovebolt I'll be owning- so it'll come up again I'm sure.

Brad

The procedure for going from a bare casting to a usable cylinder head is a long and difficult process, and the foundries that produce iron castings have virtually all moved overseas where the enviro-nazis aren't quite so difficult to deal with. Even something as simple and traditional as a Lodge brand cast iron skillet isn't made in South Pittsburg Tennessee anymore- - - -"Made in China" is the going thing. Ditto for brake rotors. Casting a stovebolt cylinder head for the few hundred of us who would buy one would be an economic disaster for anyone who tried to do it, let alone doing all the years of "curing" a "green" casting by leaving it out in the weather for several years to stress-relieve before doing the final machining. Repairing cracks in cast iron isn't impossible- - - -it's just E$$$$$PENSIVE!
Jerry

Yeah I've seen on there where they show how to repair cylinder heads..... Requires a bit of doing, to pre heat a head for so long then weld it and allow it to cool very slowly.
Would these "pins" work for fixing a head?? That might be doable by an individual....

John

I guess we will build a backyard aluminum foundry and make aluminum heads??
Are the Wayne 12 port heads cast iron or aluminum??

John

Several people make them for the GMC and 250/292 engines in aluminum without issue. Just an problem of demand for someone to toolup and do it for the Stovebolt. I've already been asked by a few on Inliners to do it. If I could get 10-15 people committed I might look at it more seriously.

Bigger issue is what the cost of the finished product might be???

John

Well, it's a lot of work, don't get me wrong, but I own my own aluminum foundry and can do all the 3D solid modeling and patternwork inhouse along with all the machining. So I can probably make them cheaper than anyone else since I don't have to outsource any of it. But, it might still be more than the average Stovebolter would spend, that's probably why nobody has already done it. But again, if I had 10-15 guys really serious about one then I would take a hard look at getting something off the ground.

What would be the @cost, if 15 people sign-up?

Being somewhat new to Stovebolts one thing I've learned is how the cylinder head is the biggest obstacle to these powerplants obtaining the coveted 1hp per cubic inch plateau.

In developing an aluminum head could it be designed to increase it's efficiency while still maintaining reuse of as much of the existing hardware?
Or perhaps use a more modern rocker arm and manifold assembly such as whats on the later inline 6's & SBC's?
Just throwing it out.
Dave

Are we talking about a 12 port head or an aluminum version of the existing 235 type head??

John

I think most everyone will want the most bang for their buck in a cylinder head. Creating a 12 Port head would definatly do that, as would a head that could utilize as much OEM components as possible too. A 12 Port head may have a more limited target market because most Stovebolters are just cruisers and not hardcore hotrodders in the sense of using their trucks or cars for a lot of high performance driving, though some do. A 12 Port head will also require a new intake and exhaust configuration, which is no problem for some, but just an added expense for others. Maybe there is a market for both a 12 Port head and an OEM style that also has increased performance potential over the stock head.
That's why 10-15 guys giving input would be helpful to help direct what is wanted.

I want an OHC version..... :-) John

Keep the conversation rolling...

Good stuff.

Brad

Thanks Claude, I was afraid we were going to sidetrack your thread.

I'm pretty sure it would be possible to improve the breathing of the stovebolt head with some redesigning, but I'm wondering if something similar to the Chevy Vega might crop up. When the Cosworth twin cam head got added to the basic Vega engine, the lower ends started coming apart. The head was capable of developing more power than the bottom end could stand. A stovebolt engine has a relatively heavy crankshaft and only four main bearings, plus long, fairly flimsy connecting rods. That's not a good starting point for hotrodding, especially with something as expensive as a custom-cast cylinder head. I think more conventional modifications might give more bang for the buck.
Jerry

Nope. The discussion is very relevant because we can either: 1) Replace a faulty cylinder head, 2) repair one, or 3) make one.

Supply, difficulty, & ability are respectively the interchangeable barriers in this situation- at some point in time we'll have to figure something out.

Brad

On a comparative note Jerry, and I totally agree with what your saying, but this might be where 2 separate markets are coming together. A more conservative siamese port style OEM head design with improvements for the guy that is not looking to go too overboard. I have ported a ton of the GMC big port heads, and if you could blend those ports into the Stovebolt head, then I think you won't go to far out in left field giving a good increase potential without compromising the Stovebolt's shortcomings in the bottom end department. But on the other hand, this would be a great candidate for the GMC rod conversion and get rid of the "pinch" bolt rods so you could rest a little easier. Keep in mind that the Wayne head came along for the Chevy a full decade before the insert engines were even produced. With modifications they were a top contender back in their time.

I agree that things could turn into 2 different prototypes. What do you estimate that the cost would be if 15 people committed to the project? Interesting discussion.

Not only is the crank heavy but so too is the flywheel. Would a lightened flywheel balanced to a lightened crank improve the bottom end? Couple that w/the GMC rod conversion 12 Port mentions, have we improved the bottom end?

I would fall into the cruiser category but with that said, if/when I need to excelerate, I LIKES to excelerate

Course as I type this post I'm awaiting word from a machine shop on the serviceablility of an 848 head I turned in. With that said I'm still highly interested in an alternative HiPerf or OEM spec aluminum head no matter the outcome...

Dave

I was just reading an article from back in 1954 where they were talking about lightening the flywheel and how much and where to remove material.
Another thing that wasn't explained well was they suggested you could enlarge the intake port out to the size of the alignment rings. But they didn't say what to do about alignment rings then.
I would think a wider market would be for a more or less stock type head with some improvements to its breathing.....

John

Stovebolt cylinder heads have some interesting geometric features that make it difficult to improve the gas flow much. Enlarging and smoothing the ports helps somewhat, but making those twists and turns to get the gases in and out of the head is the primary drawback to getting good volumetric efficiency and the siamesed ports definitely aren't a plus. Making what is essentially three 90 degree turns with the intake airflow before it gets to the cylinder is not a good thing, and the exhaust flow is almost that convoluted.

When David Healey chose to use a 6 cylinder engine from an Austin delivery truck in the sports car he designed in the mid-1950's (the Austin-Healey 100-6 and 3000 models) he encountered similar problems. He chose to use side draft S-U carbs, two or three of them depending on the series of car. The split exhaust manifold on the Healey was very similar to the Fentons we use on stovebolts, but the header pipes were the exact length necessary for proper exhaust tuning when the muffler and tailpipes were removed for road racing. Sneaky!
Jerry

From what other aftermarket cylinder heads cost from companies like Sissell and Fontana for the GMC and Chevy 250/292 race heads, it seems like the entry level heads from them are around $2500 with valves and springs. Unfortunately, they use very little OEM support products and intake manifolds, valve covers and exhaust are special and extra expenses additionally.
In my opinion, I think that this would be too expensive of a proposition for the Stovebolt guys to become enthusiastic about, but because these are more niche products than anything, I think that's why they have a big price tag. I think they could be made much cheaper and still have a good sound product that can appeal to many levels of performance, whether its one head style or two different ones.
Let's keep the conversation going and the ideas flowing. I'll start putting the pencil to it and see what I can come up with.

I think a basic head designed pretty much after the existing 235 head would appeal the most. The buyer could reuse the intake and exhaust manifolds, valve cover and hopefully even valves, springs, rocker assemblies and valve cover.
It would be nice to redesign it for more, but then you add additional costs of buying other parts ect... to complete it.
With an aluminum head one could run a little higher compression?? Maybe make them at 8.5 to 1?

John

Higher compression is just about a necessity with an aluminum head, as more combustion heat is shunted away to the coolant, leaving less heat energy available to be applied to the pistons and ultimately to driving the vehicle. On average, 1/3 of the heat released by the burning fuel goes out the exhaust, a third goes to the radiator, and the rest drives the car. More efficient cooling provided by an aluminum head actually robs power from the pistons.
Jerry

I remember Packard went to aluminum heads on their straight 8's. It was said because they wanted higher compression. The 1954 359 had 8.7 to 1 compression.....

John

Compression would be one thing I would improve upon with a new head. I also like symetrical things too, so I would eliminate the oddball different rockers and valve lengths and make them the same. And of course make a more modern combustion chamber design.

I pulled a 848 head off a '53 Chevy Bel Air at the local junkyard in Birmingham today. How often do you see one out there for the taking?!

Now we shall see if it is a good one...

1) Higher compression. (more HP)
2) Eliminate the oddball rockers (perhaps go with individual SBC types. more availability and better lubrication).
3) Modern combustion chamber design. (another increase in HP)

Now we're talking

Dave