1980 Pontiac w/400 engine question

What's up people,

I just got me a 1980 Trans Am with a 400 engine. There are a few problems, but I plan on fixing them. One thing I really don't understand is if you are looking at the engine between the intake and the left side cylinder head right by the bottom of the valve cover in the middle is a little hole. Actually it is like that on both sides. The hole is about 1/8 thick by about an inch and a half to two inches. If I have it running for a little bit, when it reaches about 200 degrees water starts coming out of the little hole. Now here a some things that I have heard. One is that the notches are supposed to be there since it is like that on both sides. The second thing i heard about the water is that it could just be rain water coming in because the shaker seal is bad and is just sitting on top of the engine and when the engine heats up, it boils causing the water to expand. Then i have also heard that it could be the head gasket. I checked the oil and the oil is perfect. It has the color that oil is supposed to have. If anyone can give me an answer or tell me anything, it would help. Thanks.

Dan

If the hole you are describing is a freeze plug in the head, it should not leak. There is no place on a 400 engine that should leak coolant to the outside. If you could post a picture of the leak, it may be helpful.

Sorry, but I must interject here.

The holes you describe are "cavities", there to make installing a non-EGR intake more difficult on an engine equipped with EGR (Exhaust Gas Recirculatrion). There is no expansion plug in the middle of the head. There are two 1 3/8" plugs in each head, one at each end. There is a 1 13/64" expansion plug on the driver's side, towards the rear, opposite the heater hose nipple on the passenger's side.

Your surmise is correct, water gets down in there and boils up. I would use a paper towel and soak as much out as you can. Take steps to eliminate the water running down in there.

Any idea what year the engine is? It's gotta be betweeen '73 and '79 if it has EGR heads. There's a number cast into the center exhaust ports, usually two digits. Example: 6X, 4X, 5C... I can narrow it down for you if you wish. No '80 T/A came from the factory with the 400. The only Pontiac V8 offered that year was the little 301, most of them "turbos".

Jim

Sorry, but I must interject here.

The holes you describe are "cavities", there to make installing a non-EGR intake more difficult on an engine equipped with EGR (Exhaust Gas Recirculatrion). There is no expansion plug in the middle of the head. There are two 1 3/8" plugs in each head, one at each end. There is a 1 13/64" expansion plug on the driver's side, towards the rear, opposite the heater hose nipple on the passenger's side.

Your surmise is correct, water gets down in there and boils up. I would use a paper towel and soak as much out as you can. Take steps to eliminate the water running down in there.

Any idea what year the engine is? It's gotta be betweeen '73 and '79 if it has EGR heads. There's a number cast into the center exhaust ports, usually two digits. Example: 6X, 4X, 5C... I can narrow it down for you if you wish. No '80 T/A came from the factory with the 400. The only Pontiac V8 offered that year was the little 301, most of them "turbos".

Jim


Ok I know i looked at it today and it did say 6X, I do believe that is a 78 head. now when you say soak it up with a towel or something do you mean when it actually does boil over? Because you cannot see the water when the engine is cold. I do know that the engine did not come with the car. I thought however it was the 301 and the 350 that came with the 80. I don't know, I could be wrong. As far as taking steps, i know i need a new seal to put around the shaker and there is actually a hole that i can attach a hose to, so i need to go buy one. Thank you for the reply and i will try it as soon as i get everything back together. I took the valve covers off and when i tried to take one of the bolts of, it broke in the head. I am taking care of it. I got someone coming over tomorrow to see if they can drill it out and tap it. It did piss me off. I will let you know if it does work. Thanks again. Wait one more question. Is there anyway that it can be the head gasket is bad and the water is going up? Like i said the oil is fine and hasnt been touched by water. Let me know. Thanks.

Dan

If that cavity were compromised into the water jackets, you would have massive overheating and water in the oil. Do a "leakage" or "leak down" test on it, and you'll know immediately if there's head gasket problem. Pontiac engines aren't prone to head gasket problems, but it CAN happen.

Roll a paper towel up small enough to cram it into the cavity, and "wick" the water out that way. Just be sure to use "good" paper towels, so they don't come apart in there. Not to worry, that is a "no place of importance" in the head.

The valve cover bolts shouldn't be "bottomed" in the hole. Try to use a chisel or punch to "turn" the remnants before drilling and tapping.

No T/A had a 350 Pontiac (ever), and none of the 2nd gen cars had the 350 Chevy. A few were built (mostly '81s) with 305, but I believe they were California only (could be wrong about that). 400 Pontiac is among the best powerplants used in T/As of any year (IMO, but it's shared with most "car" people).

Jim

If that cavity were compromised into the water jackets, you would have massive overheating and water in the oil. Do a "leakage" or "leak down" test on it, and you'll know immediately if there's head gasket problem. Pontiac engines aren't prone to head gasket problems, but it CAN happen.

Roll a paper towel up small enough to cram it into the cavity, and "wick" the water out that way. Just be sure to use "good" paper towels, so they don't come apart in there. Not to worry, that is a "no place of importance" in the head.

The valve cover bolts shouldn't be "bottomed" in the hole. Try to use a chisel or punch to "turn" the remnants before drilling and tapping.

No T/A had a 350 Pontiac (ever), and none of the 2nd gen cars had the 350 Chevy. A few were built (mostly '81s) with 305, but I believe they were California only (could be wrong about that). 400 Pontiac is among the best powerplants used in T/As of any year (IMO, but it's shared with most "car" people).

Jim


Ok well I did take the heads off anyway. Well actually i took one off and the valves needed to be adjusted, so i just decided to take the other head off too. I am going to take them to a machine shop so they can do it. And i guess whatever else needs done to them. Thanks.

Ok well if anyone wants to know the progress on the heads, here it is. They are still in the shop. The guy just called me yesterday and told me that all but 2 of the valve guides were shot and 3 valves were shot. So pretty much they told me 250 in the beginning, it is now going to cost me 400-450. Just to let you all know.

They always do. I had (still have) a set of 6x heads that I tried doing a port & polish (but not so polished) before getting a valve job. I had nicked some valve seats and was told the price was about $600 and I didn't want to spend that much. I pulled some other heads off a 350 in a boneyard and by the time it was all over I spent at least that much with unrefined heads to boot. Ugh.

Unless they've been modified, there are no "adjustments" to the valves. Torque rocker nuts to 20 lbs.

Sounds like a rather extensive (expensive) job. 6X is a decent head to start with.

Mikeemon,

Do you still have those heads? "Knicking" seats isn't uncommon while porting. It's usually best to "rough them in" before porting, and fiinish-grind them when you're done. There's a lot of myth and superstition involving Pontiac heads. Maybe your shop isn't as well "versed" or comfortable with them as they are other makes like Chevy and Ford... Where the exhaust seats are concerned, they need "oversizing" anyway, as the 1.77" valve is standard procedure to "pick up" a Pontiac motor with those heads.

FWIW

Jim

Yes, I still have them. One area of confusion was the valve seats. I ended up paying for hardened inserts. Was this neccessary? The shop that did it is no longer around and this was all done about 15 years ago.

Sorry, dude. No. It wasn't necessary. 6X is an EGR head. It came from the factory with induction-hardened exhaust seats. All Pontiac heads did, '73 and newer. SOME '72s.

We still hear it from time to time, that you MUST use "hard seats". Not so. If you're going to "push" the limits of "lean" and timing, pull a load AND run the lowest possible octane, hard seats would be a good idea in a pre-'73 headed Pontiac. Our performance engines with iron heads don't get them unless there's previous damage and they're needed to repair. When that happens, we replace all 8 exhausts, but we use a seat insert that is a smaller ID than "stock". We then "profile" the inside of the seat to make it a venturi, increasing velocity at the exit and thus more flow.

FWIW

Jim