Engine: OHV 6, myth?

[HawkBuilder]

So, we all know that the heads on the OHV six had cracking problems. But this one guy told me that Studebaker recognized the problem and that the for the last casting run of those heads they went to a better alloy and that those heads don't crack. Myth? ... like the '61 GT Hawk?

[StudeRich]

No, I think the story goes a bit more like this: they improved the Molds changing the Water Jackets in the Castings to provide slightly better cooling, moved the Heater outlet fitting to the rear, and some improvement was made, but you still have to keep the RPM at a reasonable level by changing to Higher Axle Ratios or you may still have problems.

The 3.73 Rear Axle Ratio was more than a one to one Ratio Transmission, OHV Six Lark or Zip Van (even Lower Ratio) could handle at sustained higher speeds above 55-60 MPH, THAT is what kills them.

[Skybolt]

I may be mistaken, as it is late, but didn't they move the heater outlet to towards the center of the head. I believe it was always at the rear until the last castings.

Len

[Ron Dame]

I've never known which head was which, but I have a few with the outlet at teh rear, and one with it on the front (on my 185 OHV that I am running)

I may be mistaken, as it is late, but didn't they move the heater outlet to towards the center of the head. I believe it was always at the rear until the last castings.

Len

[Skybolt]

I've never known which head was which, but I have a few with the outlet at teh rear, and one with it on the front (on my 185 OHV that I am running)

I think you are right as photos of my 63 full flow OHV show it at the rear, but I have no more OHV, or six cylinder stuff to compare, but some of the other engines photos I looked at this morning, the 64 has the outlet at the front. I guess the center would interfere with the distributor and wires.

Len

[StudeRich]

You are correct Len, I get confused as to which is Newer also, Front or Rear, but whichever is Newer maybe Front Heater fitting, is the Improved '64 Head, but I don't think there ever was a foolproof Fix.

It's the little Engine that COULD! It actually Ran TOO Good! With it's canted Valve Semi-hemi combustion chambers, larger Valves and long Ram Intake, it ran so good, they got Too Hot unless RPM was kept quite Low.

I remember THAT a Guy who made a Video of his Lark OHV Six running on a Calif. Freeway right before he pulled it to install a V8, it had a 4 Barrel Carb. and it went like a scalded Cat!

[mbstude]

You are correct Len, I get confused as to which is Newer also, Front or Rear, but whichever is Newer maybe Front Heater fitting, is the Improved '64 Head, but I don't think there ever was a foolproof Fix.

It's the little Engine COULD! It actually Ran TOO Good! With it's canted Valve Semi-hemi combustion chambers, larger Valves and long Ram Intake, it ran so good, they got Too Hot unless RPM was kept quite Low.

I remember a Guy who made a Video of his Lark OHV Six running on a Calif. Freeway right before he pulled it to install a V8, it had a 4 Barrel Carb. and went like a scalded Cat!

I think that video was Len (Skybolt)

[Skybolt]

You are correct Len, I get confused as to which is Newer also, Front or Rear, but whichever is Newer maybe Front Heater fitting, is the Improved '64 Head, but I don't think there ever was a foolproof Fix.

It's the little Engine that COULD! It actually Ran TOO Good! With it's canted Valve Semi-hemi combustion chambers, larger Valves and long Ram Intake, it ran so good, they got Too Hot unless RPM was kept quite Low.

I remember THAT a Guy who made a Video of his Lark OHV Six running on a Calif. Freeway right before he pulled it to install a V8, it had a 4 Barrel Carb. and it went like a scalded Cat!

That was me. If you want details I can provide what I did.

Len

[Bills R2]

Is there a ready market for these heads? I know of a couple but unsure of the years.

[Ron Dame]

I'd like to know, Len. I love the 185 crank in my OHV 6, my original intent was to keep it looking stock, yet it it still is hampered by the Carter AS. Ove course the 4 3/8" stroke limits RPMs, but I do wonder what could be gained with better flow.

That was me. If you want details I can provide what I did.

Len

[HawkBuilder]

Hey Ron- you put a 185 crank in your OHV 6? I had heard that it couldn't be done- some sort of clearance problems. What pistons do you use with that?

I'm asking these OHV 6 questions cause I have a shop doing a rebuild on one that I want to use in my 62 Champ. I bought the block from a rebuild shop that got stuck with it back in the 90s (year unknown, but it is full flow) and the head came from a 64 Commander. Its actually a little late in the game to switch cranks, but I'm still curious.

[Ron Dame]

It can be done! You must use the 195(3?)- 1958 pistons. The only clearance issues are at the bottom of the bores, where the rod could contact the block. 10 minutes with a die grinder fixes that. With no other changes, you'll be running about 10.2 compression ratio too

Hey Ron- you put a 185 crank in your OHV 6? I had heard that it couldn't be done- some sort of clearance problems. What pistons do you use with that?

I'm asking these OHV 6 questions cause I have a shop doing a rebuild on one that I want to use in my 62 Champ. I bought the block from a rebuild shop that got stuck with it back in the 90s (year unknown, but it is full flow) and the head came from a 64 Commander. Its actually a little late in the game to switch cranks, but I'm still curious.

[Skybolt]

I'd like to know, Len. I love the 185 crank in my OHV 6, my original intent was to keep it looking stock, yet it it still is hampered by the Carter AS. Ove course the 4 3/8" stroke limits RPMs, but I do wonder what could be gained with better flow.

The best thing was I didn't do anything major, mechanically, to the engine. As sixes were new to me I played more with what was outside, you know, bolt on stuff. So, to start I port matched the manifolds then had the head checked, valve seats cleaned and lapped and a light surface to make it square. That was the extent of engine work. Next, all new gaskets and seals. I mainly wanted to know what the baseline for the engine was, mechanically, before I did any modification to it.

If anyone wants to know why I didn't do a rebuild it was that the engine was rebuilt for the past owner and didn't have many miles on it. I knew the gentleman that did the rebuild as I bought parts from him before he past away a few years back. The engine was a 63 that resided in a 62 Lark. I bought the 62 car for the running gear and swapped the engine. overdrive transmission, 4.10 differential and Saginaw steering box in to the 59 Lark.

I upgraded the ignition. Better plugs to match the Mallory CDI with matching Mallory coil. A modified distributor with electronic trigger. Accel 8.8 spiral wires.

Carburetion was a Holley 4bbl Economiser using adapters to step it down to the single port in the manifold. A lot of blending and smoothing but it all worked well.

The exhaust was NOS parts from different years as the engine was from a 63 in a 59. Front from a 63 rear from a 59. I used a Magnaflow muffler. I still have the setup If anyone is interested. At most it has a couple of thousand miles on it, maybe less, as I since I have owned the car, got it at just under 30K miles and now has 34K on it. I drove with a modified Flathead for years before I put the OHV six in.

I could drive it fast because I setup the brakes and suspension to take advantage of more power but that is another story.

As you can see all I did was increase the flow in and out of the engine and make sure it burnt all the fuel mix. The rest was up to the engine. I did have plans for more work and still have a couple of parts left over to do so but I don't think I will play with sixes anymore, as it was just curiosity before I put a V8 in, which was the original intent. A diversion with sixes for a few years. The OHV engine was sold a few days after the video was shot and I donated all the other six cylinder engines, new bearing sets, gaskets and parts to a high school Auto shop program.

Len

[Dwain G.]

I don't have any documentation of casting changes done to the OHV6 head to prevent cracks, just what I once read that an inspection of the castings revealed they actually had too much metal in some areas and not enough in other areas. But that's hearsay. Maybe something would be revealed in an engineering drawing if one exists.
Here's what I do know. The 1961-63 head is casting #1550582 and part #1553551 with heater outlet at left rear. This head eventually superceded to the '64 head.
The 1964 head is casting #1560959 and part #1561582 with heater outlet at front. Casting numbers are found under the valve cover at rear of head, date code at front.
Service letters from 1965-'66 announce a cylinder head exchange and remanufacturing program. They were screaming for cores!
A 1967 service letter announced they had obtained a source of new cylinder heads and would be phasing out the remanufacturing.
It would seem logical that hot water for the Climatizer should come from the rear of the head, so why did they move it to the front? Well, there was a January 1964 service letter that offered a field fix to improve Climatizer performance. It involved moving the outlet from left front of head to right front.

[doofus]

Hawkbuilder if you want another "ohv6" cyl head PM me, Doofus