OHV 6 Weak Spots

[allen04084]

I'm pretty familiar with the 259/289, but not so much with the 170 OHV 6. What should I expect for issues and/or what do I look for when evaluating a vehicle for purchase with one of these? I'm on the hunt.

Thanks everybody in advance - this is a fabulous site, oozing with knowledge! Tim

[DEEPNHOCK]

Here's some info....

http://www.studebaker-info.org/text3/ohvsix.txt

(copy)

MArch 2004 -

Studebaker Overhead valve Six cyinder engine -
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Its not a great engine, being a conversion of the flathead done in a
hurry it seems without sufficient pre production testing.
But the head cracks can be welded.

I have three OHV 6's and havent had any problems with the heads cracking.

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I have had lots of exposure to the OHV six. First off, the engine is
not that much different from the '59-'60 flathead from the deck down.
Items such as the pistons, crankshaft and rods are virtually
identical. The heads were prone to crack and Studebaker knew this.
Subtle changes were made in the area between the valves, which is the
area most prone to show cracks first. Typically burned valves were
also an issue, caused by carbon flaking off in the combustion chamber,
caused by excessive oil consumption. This carbon would get between
the valve face and seat, which would start the whole process. There
are other weak links in this engine, other than just cracked heads.
Carburation was always an issue, with both the AS and RBS carburetors.
They tended to run rich and load up, especially when cold. The heat
transfer tube for the choke, inside the exhaust manifold tended to
crack in one of the dimples, allowing exhaust to enter the choke
stove. Pistons were changed in '63 which included a longer skirt to
reduce piston slap. These skirted pistons tended to develop cracks in
the corner radius of the skirt. If the skirts broke off, the piston
cocked in the bore, cracking the cylinder. I have seen two that
failed in that manner.
The '59-'62 pistons without the skirt are generally the better way to
go during an overhaul on a '63 or '64. The piston slap issue was of
more concern beginning in '59 when the wrist pin bore was positioned
lower than the '58 and prior Champion sixes. The pistons lost some of
their stability in the bore as a result.
The oil drain-back holes in the pistons tended to get plugged with
carbon, leading to excessive oil consumption early on. The '64 used a
set of piston rings unique to that year. The '39-'63 used the same
ones.
-----------------------------------------

According to DD's Studebaker six book, the later heads were worse
because the engineers added more metal where there was too much already.


----------------------------------------------------
At one time someone had written a complete article about the OHV 6
cylinder heads, in Turning Wheels. (Perhaps someone with an index can
look it up.) As I recall he mentioned Studebaker had added more metal
in the area between the valves, and in the writer's opinion it made
matters worse. I had heard a story at one time that mentioned the
U.S. Goverment stopped using the Zip-Vans earlier than originally
anticipated, due to the short supply of replacement cylinder heads.

I had owned twelve different cars with these OHV sixes and all had
similar problems. I do recall the heater hose came out in a different
spot on the '64 head. Perhaps it came off of the front, and the rest
off of the rear.

As far as being slow, they were much quicker than the flathead they
replaced. Had it not been for the inherent problems, I had always
felt they had more than adequate power. Compared to a '59 with
flathead six and automatic, an OHV with automatic was a rocket in
comparison. At Bonneville they ran one for days on end at around 100
MPH. I believe Paula Murphy was the principle driver of the six
cylinder Commander. This was during the Granatelli speed trials.
-------------------

I have never owned a car with the ohv 6, but I have a friend who has one that
he has driven for years. The car will cruise down the interstate at 70mph with
no problem and has adequate pep around town. The only thing the owner of the
convertible for sale seems to have right however is that the engine does not
need to be lugged at all. These engines do have a bad reputation and it is
mostly deserved, but taken care of, driven with care, they can last for a long
time.
Joe Roberts
----------------------------
I have had just as many with cracked heads on automatics, as I did on
sticks, three on each. This idea of it being lugged will crack heads
is bull. You cannot effectively lug an automatic. Poor coolant
maintenance, low coolant level, deposits from hard water and burned
valves will crack a head before anything else. From my experience the
OHV 170 will need work when they get into the 50 to 80K range.
Usually rings for sure, and sometimes valve work. I have never had
any problems with the lower end. Many times the ring lands of the
piston get worn and will be out of tolerance at about the same time.
The cylinder bores never wore all that much and would take at least
one fresh ring job. KK
--------------------------------------`

[StudeRich]

Regarding the longevity of these OHV Sixes, there is an amazing gap between Love and Dislike!

I never trusted them because of all the horror stories of cracked heads, that is until I owned this current '63 Lark Regal 2 Door Sedan that someone overhauled or rebuilt before I owned it. It came from Grants Pass, OR and I know nothing about it's history.

What I do know is; this thing is strong and as durable as it gets! Runs like a Gazelle!
This one was a direct manual 3 Speed and now is a T-96 Overdrive with the original Twin Traction Model 27, 3.73 Ratio rear axle.

We may never know why some fail and others run forever, maybe the Cooling Jackets are badly cast or something on some, I do not know.
One thing that may help with the Head cracking, is most nowadays when a Valve Job is done, get Hard Unleaded Valve Seats.

[skyway]

Rich, I too have no frills 2 dr OHV 6 Lark std with 3.73; mine a '62.
I have an OD transmissions for it and wondered how the 3.73 be with OD.
OK in your experience?

[StudeRich]

Better than OK! Cruises just fine at 65-70 on the Interstate and also gets going plenty quick enough for me, haven't been run over by a Prius yet.

Sorry I do not have a Tach, but the Rear Axle Parts Websites like "Randy's Ring and Pinion" have: Speed, Tire size, Trans. Type, and Axle Ratio, to RPM Calculators.

The O.D. made a whole New Car out of it!

I never understood why a Dealer or Buyer would want to save $1-200.00 by not ordering a O.D. it would pay for itself in a couple months today, but of course at .25 cents a gallon, not so much!
But the less noise level, Oil saving, engine wear, overheating etc. would make it worth it in the longer run.

[sals54]

I've never kept an OHV 6 any longer than it takes to swap in a 259. The 259 will double the horsepower, give tremendously more enjoyment on the highway. (have you ever tried staying up with traffic in a OHV 6 while driving uphill for any extended time? No thanks.) The 259 will offer very similar gas mileage when kept stock and with proper gearing and OD, will cruise better, faster and more economically than the OHV 6.
I can't think of any reason to keep one in a car. It was a stop gap effort to upgrade the flat head, and never should have been put in these cars. By the 60s, traffic was moving much faster than the 50s. Freeways were being built at alarming speed, which made all traffic move much faster and the underpowered cars were falling by the wayside.
I won't own a car with an OHV 6, plain and simple.

[RadioRoy]

I never understood why a Dealer or Buyer would want to save $1-200.00 by not ordering a O.D. it would pay for itself in a couple months today, but of course at .25 cents a gallon, not so much!
But the less noise level, Oil saving, engine wear, overheating etc. would make it worth it in the longer run.

Probably because they didn't understand what the overdrive does and all the benefits it provides. Old car people today still cannot fathom what the overdrive is or does. Amazing.

[Jeffry Cassel]

Had one in a 64 truck (3/4 ton yet!) It was a dumb combination but can't complain about the little 6 at all.

[62champ]

Had one in a 64 truck (3/4 ton yet!) It was a dumb combination but can't complain about the little 6 at all.

Hmmmm, not a very common truck - total of 57 were produced for domestic sales - will not see too many of them - for obvious reasons.

IIRC, part of the problem with cracking heads were people lugging them in too high a gear and not letting them wind up in the gear below - or did I imagine that?

[64LarkLover]

My 64 has the OHV with an automatic transmission. At lower speeds in and about town its a real perky engine and joy to drive, but I notice when I reach 50 or 55 mph on a two lane that same engine seems like its starting to really wind up on the rpm. If perception is reality, how's my perception here? Any member feedback on highway driving with the automatic?

[PackardV8]

My 64 has the OHV with an automatic transmission. At lower speeds in and about town its a real perky engine and joy to drive, but I notice when I reach 50 or 55 mph on a two lane that same engine seems like its starting to really wind up on the rpm. If perception is reality, how's my perception here? Any member feedback on highway driving with the automatic?

The OHV6 torque peak, the point of maximum efficiency, is 2,000 RPM. At a guess, not knowing for certain your rear gear and tire size, 50 -55 would probably be 2,500 RPM, or above the torque peak. The OHV6 Champion has a 4" stroke, so it does not enjoy high RPM. You're not hurting it by driving 60 - 65; it's just telling you it would rather not.

jack vines

[StudeRich]

Most of these OHV Sixes were standard equipped with 3.73 Ratio Rear Axle Gears which explains their Perkyness, that was one of their major failure causes.
Without Overdrive, that is too Low a gear for the Engine to survive equaling TOO many RPM's which at 65-70 will very quickly cause overheating and eventually a Cracked Head.

Maybe someone with easy access to the RPM Calculator can figure out if a 3.54 Axle with a one to one Trans. would be as good as a 3.73 with O.D.

[christophe]

One thing that may help with the Head cracking, is most nowadays when a Valve Job is done, get Hard Unleaded Valve Seats.

That's what I thought too. So, when I rebuilt my engine a few years ago, I got hardened seats.
Well, I had to change the head this year as there was two leaks behind the seats.I don't know what happened for sure. Maybe the machinist goofed this one. But I didn't touch the seats on the new head, except for surfacing.
To me the OHV6 is good engine. I only wish Studebaker had designed an alloy head for it.
Nice day to all.

[TWChamp]

I only put 60 miles on my 63 Lark with a 6 stick and no overdrive, because I didn't like the high revs at 50 MPH.

[jackb]

Why roll the dice with so many negative (historically confirmed) issue with this engine ? If original and you live on back roads <50 mph...go for it. If you want to keep your sanity on the freeway.....