The Stovebolt Site Forums The Shop Area Engine Shop Engine Block Drain or a Bolt?

I wonder how many of you have the drain on the lower left rear side of the engine on a 235 or 261 motor or is the hole filled with a sealed bolt(like mine). I'd like to hear your experiances with the drain and where you found it(parts supplier) as I've checked the usual chevy parts links and haven't found that drain with the metal piece through it any where.

I have a bolt in my motor block and it doesn't leak but wonder if I should get the parts and actually use that drain on the fire truck. Thoughts or ideas? Thanks.

I've had engines with and without that drain fitting, not something that's used much - one should be available at a local parts place or rad shop, it's the same as the drain on most of the old radiators - it does as well to pull the plug you have and flush some water thru, sediment does tend to collect in the passages down there - or if you store the truck long term in the cold you can drain the block there to be safe against freezing

Bill

It is a 1/4 pipe thread plug. You can remove the plug & usually have to poke something in the hole to break the scale built up around it. It's a good way to drain & flush the system.

Near the bottom rear of the manifold-side of all my 261/235 blocks is a hole with this style of drain fitting.

Lower right of this photo.

Thanks guys. Now I know what fits in the hole. I hope to find the part that matches the originial that came with the motor in 1951. I've been to several of the local parts stores but nobody has an originial.

I am getting ready to flush the system, so I'll clean out that area of the block while I'm at it.

On '55 2nd and later, that style drain seems to only be found on the 235 used in the Forward Contol Chassis (box van), pickups and heavy trucks didn't have them according to the shop and assembly manuals.

Just to chime in,

On my recent rebuild of a 216, we replaced that drain-cock with a brass quarter-turn valve, (not sure what they're called, I call them "gas-style", 'cause you see them on gas lines sometimes). I hate the above-linked pet-cocks, even if they ARE original: I find them hard to use, I think they fail far too easily, and are prone to breaking off. Just my opinion, anyway.

During our install, we had to drain the coolant twice chasing down thermostat issues. We ran about a one-foot line from that valve, down past all the engine stuff. Now, when we need to drain the coolant, it's a simple matter of sticking a clean bucket under the drain-hose, opening the valve, and presto.

I know you're a stickler for originality, and good-on-ya' for it; but I know you drive that beautiful truck a lot, so I thought I'd offer this idea up. Let me know if you want pics, and I'll get some this week.

-Michael

Lets see the picture! Thanks.

Bill

Bill,

I bet you are right about that drain cock on later 235s. There were no drain cocks on the 1959 and 1960 261s that I worked on last summer. We put a drain cock in that existing threaded hole (because the engines were going into Advance-Design trucks).

Tim

Tim,

Thanks. I guess that is why it has the bolt in it as it is a 59-62 motor.

Bill,

Here are two shots of the drain-valve, as promised.

Hard to see, but the hose curves back toward the engine and down between the engine baffle and the bell housing.

Hope this helps you decide!

-Michael

Thanks. I have seen those type valves before. I'm going to hold out to see if I can find the originial version. I'm going to flush the systm anyway, so I'll pull the bolt and see what comes out from behind it!

Thanks.

Mike & Bill,

NAPA can get that valve - it's not cheap (Weatherhead-Eaton brass producs catalog). I am also using that valve as a shut-off in a fuel line before the fuel pump (in a 1954 truck that has no factory shut-off at the fuel tank outlet). It is an all-metal assembly, so there is no concern about rubber gasket/seal deterioration.

Tim

Bill,

Sounds fine, I know it will look perfect when you're done. Look forward to seeing it.

-Michael

Bill,

If you are interested in an original-style drain cock that matches some I have found on old radiators and engines, Eaton (Weatherhead-Eaton) sells one, catalog number 6788 (1/4" male pipe thread). This one has a "snout" that allow a piece of tubing to be attached (makes for cleaner draining directly into a pail/container).

Tim

NAPA: WH 6788

Dorman sells a similar fitting: 480-245

I'll check it out. Thanks.