[Red Coupe]

This is a thread about how to rebuild a Pontiac V-8.

I decided to post this thread after looking all over the internet for information on rebuilding Pontiac motors. There is no one thread devoted to this one topic. While it's true that rebuilding any type of motor shares many common techniques, each brand has its own special ins and outs. It's time to have a thread dedicated to Pontiacs only.

I'm not claiming to be a Pontiac expert, and there are many engine rebuilding topics that I’m not going touch on in this thread. The hope is that those of you with more experience rebuilding Pontiac V-8's will add to this thread, fill in the areas I missed, and add your own tips and pointers.

Let's get started.

First of all, it's a good idea to begin with a plan for your motor. Do you want a drag car that barely runs on the streets, or torque monster that will rule the streets? Trailer queen, or daily driver? Restification or concours?

Since the original 400 in my 1969 GTO was long gone, I decided to do what a guy probably would've done back in the 1970s if he grenaded the original motor -- find a 428, install a better cam, swap over the GTO intake and carb, and go with better heads.



Our rebuild subject is a 1969 Pontiac 428. It is a so-called YH motor, which means it came from the factory with 46 heads, two bolt main caps, and a mild cam. In keeping with my theme, this motor was rebuilt using the 69 GTO intake and carb along with the hotter 068 cam.





Doesn't look very clean on the stand, does it? I was hoping that the innards would look better than the exterior.





Next we pulled the intake and carb. Although the motor was not overly sludgy for its age, the oil was tired and smelled fried. This motor may have run recently, but could not have been running very well.





After the water pump came off the motor really started showing its age with some nasty pitting on the timing cover.





We pulled the heads off, looked at the cylinders, and there it was -- pitting, scratching, everything that says time for rebuild.





Now that we were committed to a total rebuild, it was time to get organized. The first thing we did was number the rods and the main caps so they could be reassembled in the right order. We didn't have number punches, so we used a series of dots to mark the rods and caps. Works fine as long as the marks are clear.

We also made sure to bag and tag all of the many small parts that we removed from the engine. We made good use of the digital camera, taking as many pictures as possible so that we know where and how to reinstall the parts during the reassembly.





The rod journals were looking sort of rough. Although things looked bad, we couldn't catch a fingernail on the journal surface, which was a good sign.





I forgot to mention that the oil pan had lots of nasty grit in it. By the looks of these rod bearings, that grit had found its way through the motor.




Here's a closer look at one of the cylinders. You can see the pitting and you can see where water accumulated down in the cylinder. No doubt this block needed to be bored.





Not that any more reasons were needed, but here is a shot of one of the pistons showing scratching on the side. The other 7 were no better. Since the motor was going to be bored anyway, these pistons were junk.

I’ll be posting more soon.