Inliners International Forums General Discussion Engines 54 pontiac 239 rebuild?

Hello,

I have finally discovered that my inline 6 - 239 in my 54 pontiac is shot and needs a rebuild(keep in mind, I have never driven this car) It will cost me about $1500 CDN to do it. My question is, can someone tell me if this engine is worth rebuilding? are they reliable? is it fast enough for a cruiser? Should I just pull it out and put something else in? (if so, what?)my knowledge is a bit limited but I am willing to try anything. And as always I am fairly budget minded.

Thanks
Mark

Mark;

I don't know a thing about the 239 Pontiac engine, but I do know a little about engines, re-building same, and engine swaps.

It's an old engine, and if parts are available, should be rather easy to re-build (it sounds like you've done some research if you have the costs).

Reliable? sure, if you treat it well, and drive it within it's design limits - which brings me to your question of 'is it fast enough for a cruiser?'. Define 'fast' - cruise all day at 65mph? If so, that might not be the best idea, and the brakes and suspension will be a little past their limits.

Last, 'pull it out and put something else in'. You will have some major surgery to perform to install it, and you'll have to match a transmission to the new engine.

If I remember, that year Pontiac is an open rear, and fairly strong, so the rear end should hold up; but a higher ratio might be desirable.

If you car is standard shift*, and you have a limited budget along with limited knowledge, then re-build the engine and use that as learning experience.

*I mentioned the transmission because if it is automatic I think that would make it an early Hydromatic which may have it's own problems, and will probably cost more than the engine to repair.

Just my .02 - but you did ask...........

Thanks for your input,

The 54 waas the last year of the closed driveline so I would need to swap that if I changed everything else correct?

I am leaning heavily towords rebuilding this one as itr apparantly only has 15000 miles on it and I just don't really have the know how to do major surgery if you know what I mean.

Yes, I can get a kit to rebuild it, is 6V to 12V something I should swap too?

About the tranny, is there any way of finding out if it is decent as I will be pulling it as well or is that something I should rebuild as well?

Can I get a higher ratio tranny? or is that something i specify when rebuilding it?

thanks again

1) US-made Pontiacs were open driveline all through the '50s; I'm not sure about Canandian cars, except that as far a I know, the body and running gear were the same as US with different trim

2) If the engine has only 15,000 miles on it, and still turns over, you may be able to bring it back to life. Drain and refill the oil, try to get it running, see what oil pressure it holds, listen for any knocking noises then run a compression test. Your biggest problem will be stuck rings.

3) 6V to 12V is fairly easy, however I run 5 old farm tractors with 6V with no trouble as long as the temperature is over 25 degrees

4) Is the transmission standard or automatic? If it's a standard, it's probably OK.

5) You change the gear ratio in the rear, not the transmission


My recommendation - If it's a stick shift, do your best to get it running and see how it moves. You said you have little mechanical experience and this is a great way to learn. Pontiac parts may be a little harder to find, but the electrical system will be GM (Delco), carbureator parts should be available, and the brakes should be common between Pontiac, Olds, and maybe Buick of that era.

Hey Ducky,
I have tried over the past year(slowly and when it was warm enough up here in Canada) to get iot to run, I had it turning over but no fire, my compression was less than 10lbs on every cylinder, so I popped the head off just last week and poured solvent on top of the pistons and it all ran past the rings on all cylinders. This is why I have come to the decision that the motor is coming out.

I have done all the brakes and most of the body work(i do what I know best) I rebuilt the carb as well and I can definately get thos parts

I would like to "Hop it up" while I have it apart a bit, is there anything I can do?

The tranny is manual, 3 on the tree, should I just leave it in the car and not pull it with the motor?(I assume there is only 15000 on it as well)

Should I change the gear ratio in the rear end? is this something I would do now? BTW how do I do that?

Dear Mark;

That was a fine car in it's day & can be again.

With a little work it will start.

There is plenty of parts for the Hydro too.

Good luck, John M, #3370

John, Ducky....1954 Canadian Pontiac is basically Chevrolet with different trim and a flathead 6. Soooo...anything powertrain related think Chevrolet. For higher ratio rear end gears use 54 powerglide gears, I believe they are 3:54 or something close to that. Very few 53-54 Canadian Pontiacs left, most were scrapped out for Chevy parts.

Dear Mark;

Dry cylinder walls will read 10#.

If the valves look good, put a little STP on the cylinder walls & change the head gasket.

That will give you the compression you need.

Getting the spark & fuel to it is 'a snap', you can do it.

Make sure the trans has oil too.

Good luck, John M, #3370.....

The valves do not look good either unfortunately, half of them at least.

I got the fuel there and there was air, but it wouldn't go, so I just made a decision that if it does run asis, it wont run well.

Hmmmmm....You can learn something everyday

If the Canadian Pontiacs had a closed driveline that was basicaly the same as Chevy, where did the flathead 6 come from? - it had to be a GM engine already in use.

M;

It is a Pontiac engine from USA.

Are the valves split or 'cloverleaf' & are they available in Canada?

Are the pistons tight at TDC?? See if you can move them (sise to side)in the bore with your fingertips.

J...

The pistons are tight at first glance but I leaked them down and the solvent passed right by at different places(i didn't pay attention to TDC though)

The valves don't seem to be "cloverleaf" but I am not sure, they look like basic valves.

M;

At TDC see if they "wiggle around", that's the test for rings etc. Solvent can leak through good pistons/rings. How much ring ridge?

If the valves are not split/cracked they may be okay (have compression) to run. Look & see if they (tops) are even (parallel) with the top of the block.

Put some oil on the cylinders before you start turning things etc.

JM......

I did lube up everything before I started trying to get it going.

a few of the valves are burnt and crumbled, where you can see right past them.

Okay; Their easy to change if the seats aren't to bad. What about the pistons??

J.....

5 look brand new, aside from some soot and one has a bunch of white ash on it. other wise they look great, the engine is only supposed to have 15000 miles on it, so I am hoping I can save some of the parts to reuse, also save me in the long run.

What I have decided I am going to do is pull the motor and tear it down for a rebuild, it is the easiest way to learn and hopefully I will get a good engine out of the deal.

Can I upgrade anything, like the cam or carb or anything?

You don't need to pull the engine.

Are the pistons tight at TDC?? If so the rings & cylinders are usable. How much ring ridge??

J.......

Hey John,

I haven't checked yet, and I am not sure how to check the ring ridge(sorry, I am green)

What sort of HP am I lookin at if I rebuild this motor? Am I going to be hapier with something else?

M;

On each cylinder you will see a space at the top that is 'unused'. This is because the top compression ring can't travel any further up. It's nickname is the "ring ridge". This is the smallest part of the cylinder and the space just below it (where compression rings set @ TDC)is the largest due to heat/wear.

With your finger tips try to move the pistons at TDC and see if they are tight.

The 1954 Pontiac engine you have is 115 @ 3800 RPM. Making all this work (stock) is a big enough project for a beginner. You can do something different on the next one.


JM.....

when my pistons are at TDC they do not wiggle at all.

the "ring ridge" is not super evident to me, is measured by how much of the wall is not touched by rings at the top of the stroke?

thx

M;

Okay then; Just replace the valves that are bad and a new head gasket & "your all set". This can be done with the engine in the car.

Once you get it runing then you can see if you like the car etc.

Good luck, John M., #3370......

PS: It's measured by the difference between the used & unused portion (diameter) of the upper cylinder, ie; the unused portion being smaler.