Alright so my buddy bought a 1953 chieftain a few months back we knew it was gonna need some work but what we didn’t know is he kinda got beat on the motor. It’s got a 389 out of a 59 bonneville in it and it’s only got compression in 4 cylinders. So we toyed around with the idea of swapping a crate engine in along with a few other swap ideas and decided for now for his budget our best bet might be to just rebuild what we got. Now I have never rebuilt an engine in my life I am highly mechanically inclined and have done a ton of fabrication and mechanical work in my life just never had a need to rebuild a motor before today. What kind of difficulty am I dealing with rebuilding that specific motor? What about the trans and the rest of the drive train how do I know how tired they are and if we’re just diving into a rabbit hole? Are there advantages to certain kits or parts versus others or bores or any of that kind of stuff? I have the theory behind everything for the most part just not sure how the technical application goes. Anyone that feels like helping in the most technical way possible would be greatly appreciated.
If the engine has been sitting for a long time, the rings may be stuck on the four cylinders without compression. If so it may be possible to get them to loosen up. If the engine does need a rebuild, it's really not that much different than any other make. Get a copy of the factory shop manual for a 1960 Pontiac and it should have most of the information you'll need. Used ones show up at swap meets or on eBay, or you can get reprints in either hard copy or digital format.
So I didn’t do the actual compression test a shop he had taken it to did and was like “ hey this is what we found you need a rebuild or a new motor “ if I redo the compression test and find those numbers what exactly am I looking for?
So prior to him buying it the guy we got the car off of was supposedly dailying the car out of necessity. He told him upon purchase it ran strong and all this shit it just needed a carb refresh and a hei setup to really wake it up. We found out that is not in fact the case at this point we can’t even get the thing to turn over it was running and driving at time of purchase though. Where would I even start with trying to diagnose some of this stuff?
Oh my. get a vacuum gauge and look up online how to read it, single best diagnostic tool you can own. get or borrow a compression tester, again look up online how to use it correctly do dry and wet compression test with a good fully charged battery make sure your battery and battery cables , system etc are good clean and up to the task of cranking snd starting your engine . make sure your ignition tune up , and carb are in good working order . good gas coming from a clean tank as has been stated get a shop manual for your engine , they can be purchased cheaply enough or even found online . will be the best investment you make as far as trying to diagnose this issue . start with a vacuum gauge and go from there
In Pre 60 Pontiac's the 59 389 is a pretty sought after engine so you have something there even if you can't get it right. Some one will want it. Most certainly do as suggested and try to get it running.
Thank you guys so much next time I see him I’m gonna do the testing and see what I can figure out and get back to you guys! Been using this forum for a while as a general sounding board a finally made the plunge and joined you guys are all awesome!
When was it purchased, and how long has it been sitting since then? Also where has it been sitting, in what condition? Are you saying the engine is now frozen solid? Or is this an electrical/starter issue that's making it not turn over? Before you even buy any new tools, consider taking the valve covers off and tapping on the tops of each valve with a hammer. You don't have to hit them hard, in fact, you don't want to. It will be easy to tell if the valves are stuck. On a good, unstuck valve, the spring should compress a bit when you whack it and basically pop the hammer back away. A sticking valve will move in sometimes but not pop back out, or when you tap it it'll sound like hitting an anvil instead of hitting a spring. If you have compression on 4 cylinders they aren't all stuck, so the difference should be apparent. If valves are sticking you may need to have the heads redone, but that doesn't necessarily mean the whole engine needs a total rebuild. The wet and dry compression tests will also give you a lot of info, once you know the valves aren't hung up (a stuck open valve will give basically 0 compression reading). Start with those things and report back.
Ok so test say's there is issue with compression. Next test would be to do a leak down test. This is done without turning over engine to see what gauge reads. Instead each cylinder is brought up to top dead center and compressed air (100 psi typical) is introduced into cylinder via spark plug hole with a tool that has gauges that will show pressure being applied vs pressure cylinder will hold. How does this differ? Well with air constantly being pumped in one can listen if air is escaping tail pipe (bad exhaust valve) or air escaping (wide open) carb (bad intake valve) or from oil fill source (bad rings, piston, cly walls).
The Vacuum gauge won't help until after IT ACTUALLY RUNS. 1. make sure that the battery is charged so it turns over good. 2. if it turns over get your hands on a compression gauge (doing the Autozone/O'Reillys pay the deposit, use it, take it back and get the deposit back is good here) Pull all eight plugs out, prop the throttle plate and choke wide open and crank it and let it hit on the gauge five times. Write down the reading and go to the next and on down the line doing it the exact same way every time. High and low should be within 10 lbs for a "good" engine. If it does have four dead holes you might want to take the valve covers off and see if the valves are moving when you crank the engine over. 3. make sure that the distributor is in time and that the firing order is right. This one is backwards to Chevys and someone may may have tried to wire it for a Chevy. I don't know if a 59 had a timing gear with plastic teeth but real Pontiac V8 engines are famous for loosing the teeth on the timing gear. I drove a mid 60''s Pontiac on the front end rack of the dealership I did front end work one day and the timing gear crapped out when I went to start it. The old dude who owned the car had a fit until the engine mechanic showed him that there was no way I could have done it. The car knew exactly where to have a timing gear issue. If you aren't sure of something ask before you do something. It's a lot better to ask because you don't know than ask how to fix something you screwed up. Pontiac V8 engines are pretty simple as American V8 engines go.
You sure you have the Schrader valve in your compression gauge? What kind of numbers are you getting in terms of compression and in which cylinders?
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