The Stovebolt Site Forums The Shop Area Engine Shop what engine is it

Can anyone tell me how to figure out easily what engine I am dealing with??? It's a GMC six but I don't know what size etc. It has no oil filter on it also, any thoughts on that one???

Thanks Doug

none of the early engines had oil filters standard .... need the year of the truck to come close [228 or 248 maybe], but numbers off the engine are the only way to be sure, stamped id on the pad by the distributor and casting numbers, as well as date codes

Bill

The first three digits of the serial number on the pad behind the distributor are the engine size. Sometimes there will be a leading letter, just ignore it and look at the first three numbers.

That approach works as long as the motor was not replaced AND someone stamped the old number on the motor because the motor number was used to title the truck.

Thank You so much. Any thoughts on the auto trans??? It seems to be cooled by water??? And type of tranny fluid??? Thanks again, Doug

An automatic behind a GMC six is going to be something not original or its a Hydra-Matic. Far as I know nothing else was ever offered by GM. I'd have to crawl under my Hyrda-Matic truck to be sure but I'd bet its got lube running in coolant lines just like most modern automatics.

Hy dejmeister, welcome, when you ask questions please remember to tell us as much as you can about the vehicle you're asking about, that way we're not just guessing blindly. As OldSub has said GMC trucks of the 50s were only equipped with a Hydra-Matic automatic transmissions from the factory [the same is not true for sedan deliveries]. Some Hydra-Matics were water cooled, but more were not. Try to find and post your serial number, a lot of information can be gleaned from that, to identify both your truck and its original equipment engine, hope that helps.

I will post the serial numbers as soon as I find them. I am pretty sure they are H2o lines but I'll bust a fitting to make sure and let you know. As far as the tranny is concerned I believe it is a Hydromatic in that's what the shift bezel says. It's not four speed but three, w/ an OD tagged on after a short driveline. It is cable operated w/ a bunch of wires also. I have not cked it out yet so I don't know the maker etc. The owner says it does work. By the way the engine is a 270 I think but I'll need to scrape off the paint a

Thr Hydramatic had a water-to-fluid cooler mounted near the transmission, with lines resembling heater hoses carrying coolant to it. The 1950 Powerglide I'm currently working on has a similar cooler built into the lower radiator hose.
Jerry

I don't think you have a factory setup. Post some pictures of this thing so we can make some better calls on what it might be.

All Hydramatics were 4-speed. The shift quadrant on GMC trucks usually had 1-2, 1-3, and 1-4 positions, indicating how far the transmission would shift before holding any particular gear. 1-2 would correspond to the "L" position on most automatics. The 1-2 shift happens almost immediately after the vehcle starts moving, usually below 4 MPH. The overdrive sounds like an aftermarket unit of some type.
Jerry

That's what I thought. Nope it's H2o. It's plumbed into the heater line in the front and the drivers side of the block at the back on the other. wow There is an OD setup w/ a cable. It is right behind the tranny after a small driveline. Lots of wires going to it. I'll try to get some pics tomorrow when it's light so you can see what I mean. Thanks for all the help dj