[Michel Buchs]

Hi

I am repairing my 400 block of my 75 Formula 400 Pontiac. Not rebuilding it but wanted to repair some "small" problems that now became bigger. (broken exhaust studs, rusted waterpump, bad carb etc.)
I think it's all still original, although surfing on the net and trying to identify my heads I got confused!
First I have this two date casting on the heads: E055 and D215. I think that makes them 75 heads, doesn't it?
But on the middle exhaust port is on both heads a big 6X. Looking at the Pontiac Heads ID # here on this site ( http://www.boyleworks.com/ta400/psp/heads.html ) it shows that it's a 75 head?
Shouldn't it be "5C 1975 350/400/455 cid D port 2.11/1.77 98" to be a 75?
I meassured the valves and I got 2.12"/1.66". So what do I have here now?
This is a pic of the heads:

http://home.datacomm.ch/6o4o/poncho/Dscn0124_small.jpg

What's the best thing I can do to remove the broken studs in the heads?

And another question, since I removed the water pump and 3 bolts are broken in the timing chain cover (I can't remove them!! They almost seem welded!) should I replace the cover and also the timing chain? This engine has 115'000miles on it.
Or is it time consuming (as said before, that's my first time I do something like that!) to replace the timing chain? (I already got a new one)
Here a pic of the broken bolts on the cover:

http://home.datacomm.ch/6o4o/poncho/Dscn0062_small.jpg

Here some pictures of the cylinders and the cam. No idea how well it looks like?! Maybe anyone can tell me?

http://home.datacomm.ch/6o4o/poncho/Dscn0063_small.jpg

http://home.datacomm.ch/6o4o/poncho/Dscn0118_small.jpg

Anything else I should check before putting all back together? Other tips?

Thank you for any help! My first time I am doing something like that (or working on an engine!) so I hope I didn't do anything wrong or will do anything wrong here!

bye

[Michel Buchs]

Hi

I am repairing my 400 block of my 75 Formula 400 Pontiac. Not rebuilding it but wanted to repair some "small" problems that now became bigger. (broken exhaust studs, rusted waterpump, bad carb etc.)
I think it's all still original, although surfing on the net and trying to identify my heads I got confused!
First I have this two date casting on the heads: E055 and D215. I think that makes them 75 heads, doesn't it?
But on the middle exhaust port is on both heads a big 6X. Looking at the Pontiac Heads ID # here on this site ( http://www.boyleworks.com/ta400/psp/heads.html ) it shows that it's a 75 head?
Shouldn't it be "5C 1975 350/400/455 cid D port 2.11/1.77 98" to be a 75?
I meassured the valves and I got 2.12"/1.66". So what do I have here now?
This is a pic of the heads:

http://home.datacomm.ch/6o4o/poncho/Dscn0124_small.jpg

What's the best thing I can do to remove the broken studs in the heads?

And another question, since I removed the water pump and 3 bolts are broken in the timing chain cover (I can't remove them!! They almost seem welded!) should I replace the cover and also the timing chain? This engine has 115'000miles on it.
Or is it time consuming (as said before, that's my first time I do something like that!) to replace the timing chain? (I already got a new one)
Here a pic of the broken bolts on the cover:

http://home.datacomm.ch/6o4o/poncho/Dscn0062_small.jpg

Here some pictures of the cylinders and the cam. No idea how well it looks like?! Maybe anyone can tell me?

http://home.datacomm.ch/6o4o/poncho/Dscn0063_small.jpg

http://home.datacomm.ch/6o4o/poncho/Dscn0118_small.jpg

Anything else I should check before putting all back together? Other tips?

Thank you for any help! My first time I am doing something like that (or working on an engine!) so I hope I didn't do anything wrong or will do anything wrong here!

bye

[denpsim]

Did you check compression before removeing the heads. Was it consumeing very much oil. The heads are 1975 6X april 21 and may 5, valves are 2.11 and 1.66 you can drill the broken bolts and use an ease out wich you can pick up at a hardware store. with the amount of miles on the engine and as far as you have gone, rebuild it. Just a little time and a lot of money thats the fun of owning a Pontiac, if it was cheap it would be a SBC.

Good luck Dennis

[Reed '75_T/A]

I've heard of other people with "original" 6X heads on a '75 400 but everything I've read only lists the 5C heads for '75 so who knows. Unless your timing crain cover is cracked, warped or otherwise causing problems it shouldn't need replacing. Just clean it up, paint it, and voila, good as new. The timing chain is definitely worth replacing and should only take about 5 minutes once you get the cover off. As far as your stuck screws, vise grips & WD40? You can buy stuck screw kits from any hardware store as mentioned above and that should work too. The broken studs in the heads - are they screwed in or pressed in? If they're screwed in, where are they broken? Can you still unscrew them? If they're pressed in, your screwed (pun intended). If that is the case, I guess now is a good time to switch them to the screw-in type.

[ April 20, 2002, 01:05 AM: Message edited by: Reed '75_T/A ]

[Held for Ransom]

Reed, have you ever tried getting out the broken bolts in the timing cover? I sorry, but it is easier to buy a new one. Even if you have to order it from the States. GM part number is 527291. While you are at it, replace the timing gears and chain. If you want to change the cam, I would also do it at this time (maybe a replacement "S" cam). The broken exhaust bolts need to be heated up and quenched in penatrating oil a few times. Then, if enough of the stud is sticking up, weld a nut on the end and slowly try to remove. If that don't work, try drilling the center out and use an Easy Out to try and remove. Or take to a engine rebuilding shop and see how much they would charge to recondition the heads and remove the broken studs. As for the block itself, how much do you have for a rebuild? The piston tops look pretty clean, so maybe leave all that for a later date.

[Michel Buchs]

Thnx for all the answer! I really appreciate that [img]smile.gif[/img]

Ok first, I didn't check compression myself.. it was done by the previous owner I think many years ago. I found some paper with the compressions (but can't find it anymore!) and there one cylinder hat 4bar, some 5, 6 and 7 bars as much as I remember. Don't know what that has to mean! When I bought the car it smoked for weeks when accelerating hard! It smoked REALLY bad! But after some miles that's gone now... it doesn't smoke and drives fine, just had big problems lately with backfiring trought the carb when accelerating (never on idle) and sometimes very bad idling problems (& smoke) on stops after a hard acceleration. I think the carb is gone... probably ordering a new one from Classicindustries. Hope they are all tuned and working fine.
And since my friend is buying the car I want to do the most important things on this engine so he can enjoy it for some time. Don't have the tools to do an engine rebuilt.. maybe later, when I have the tools and time and he the money [img]smile.gif[/img] But he just wants to enjoy it.
I hope it lasts! [img]smile.gif[/img]

The stuck screws in the cover we tryed with WD40 and the biggest vise grips we found, no movement! I will buy a new cover! I saw nice used ones on Ebay for 20$! I will probably get one of those! Although I saw that on some covers the 3 bottom screws are IN the cover? What is that? Should I just get nuts there and fix the waterpump like that?

We have no hardware store here that carrys such tools like stuck screw kits! Only thing they carry are drills and that's all.

Exhaust...
I saw great like new looking exhaust manifolds on the internet for a 75 for 20$! I will get one of those since I want this car to keep original and the old exhaust manifolds are gone (exhaust flange screws are so badly rusted in the manifolds that it all looks like one piece!)

The head bolts are all screwed in?! Didn't see any pressed in of the ones I removed! All were screwed in and all broke IN the head, not sticking out at all. At least 2 of them are open.. I mean, you see the screw on the other side of the head... the thread is open, not a dead end. Just the one in the middle goes into the head.
So how do I heat them up? With a butan-fire_burner? WD40 is penetrating oil? I mean, then just put WD40 on it when it's hot? No risk of fire?
What's better now, welding a nut on it (they are a little bit deeper inside than the head surface) or drilling it with a left-handed-thread?

What's an "Easy Out"? this left handed thread?

I also thought if I have to remove this timing cover anyway I will change the chain! 5 min? I read to put cyl. 1 to TDC (both marks on the timing wheels showing 12 o'clock) and then remove both wheels. The cam won't move in this moment a little bit and change the timing like that? (heads are removed) Just never did that and don't want to degree this cam! No experience with that at all!

Another question... sorry for the many questions...
This timing cover I saw has all that "It comes with the divider plate and the 2 sleeves that keep the oil and water seperate." What are this 2 sleeves? (he sandblasted it) The 2 rubber sleeves that were in the divider plate? Should I get there new ones always or reuse the old ones?
Any tips on that?

thnx for help again!

bye

Michel from Switzerland

[Michel Buchs]

Oh, I forgot something... this 2 exhaust manifolds I saw that I want to buy, they have the No. 496002A & 499624B on it, mine do have the exact same No. but I am not sure about the last letter.. is that of any significance?

[Lemans1]

OK, you have some very common problems, which, unfortunately, will not be "easy" to fix. Do-able, just not easy. Using a left handed drill bit is very effective, but you may have a hard time finding them. Even here you have to get them from a machinist supply company. Never found a store that has them. An "Easy Out" is a hardened tapered tool about the size of a tap. It also has a "twist" to it that is reversed. Basically you drill a hole in the broken bolt, then insert the correct sized Easy Out, and turn it counter-clockwise. The harder you turn, the harder it goes into the hole and tries to turn it out....unfortunately, they break. If they break, your screwed. Drilling them then becomes far more difficult. It is your best chance though. The other alternative is drilling them out completely and intalling helicoils. And on the "open" ones, you can drill a hole all the way through the broken bolt and use an Oxy/acet. torch to burn the bolt out of the threads. This is something that takes practice and you might want to let a professional welder do it.
Also, on the timing chain, you dont want both timing marks at 12:00!! The cam gear should be at 6 and the crank at 12 so they are pointing at each other.
Good luck with the timing cover! Replacing it would be the easier way to go. You may find (like I have in the past) that when you go to remove it is "welded" to the broken stud. I destroyed a timing cover one time because of that. Tried everything to get it off. It came down to brute force. Once it is off though, welding a nut to the stud proved effective in getting the stud out of the block. And for the rubber sleeves, if yours are not cracked up and brittle, re-use them. But thats not likely as old as they are.
Good luck with your project, it will definitely try your patience!

[Michel Buchs]

Thnx for te tips! [img]smile.gif[/img]

Yeah, I heard that about the torch too... you just put the flame trought the drilled whole till the bolt just becomes reddish hot? And then what? That won't melt the head-threads?!
I saw a place on the internet where you can order this left handed drills!

http://www.harborfreight.com/cpi/cta...emnumber=38180

And they are cheap!

I definatly will remove this cover and cut it up if I have to! It's just aluminium... looking at the moment at ebay for a good one. I just see some have a different bolt pattern or have the 3 bottom bolts IN the cover? And some seem to be made out of regular steel? (rusted) Mine is out of aluminium.

Do I have to get for sure a pulley puller to remove the balancer or does it also work with the hands? I just read I can push it on without special tools if I am careful. So what about removing? (just looking what tools I need to get)

[denpsim]

Michel, I have a timeing cover for a 76 455 should fit your 400, e-mail me your address will let you have it for shipping i will check it out tommorrow and make sure it is good. My son took this engine apart, so we could store it. it is dirty you will have to clean it though. As for the water jacket sleeves I just bought some on e-bay.

-----------------------
Dennis

[Lemans1]

With the torch, yes get it hot to the point it just starts to liquify, then tap the O2 and blow it out the other hole. Dont let too much of it melt or it will heat the threads and melt them too. It takes some patience and practice, but works very well when you get used it. Just take your time and do it rather slowly.
As for the puller, I would say definitely, without a doubt you will need one. If it has never been off, and even if it has, it would probably be impossible to get off without one. They are cheap and available in any auto parts store.

[75 T/A YS]

6X Heads were made for the 400 mill in 1975, nobody is brave enough to update their head charts [img]/infopop/emoticons/icon_smile.gif[/img]

http://www.pontiacs.org/modules.php?...iewtopic&t=409

75 T/A YS

[johnta1]

6X Heads were made for the 400 mill in 1975, nobody is brave enough to update their head charts

Maybe you need to try my site?
[img]/infopop/emoticons/icon_confused.gif[/img]

Had them for a few years now.
[img]/infopop/emoticons/icon_cool.gif[/img]

johnta1
Pontiac Power RULES !!!
www.wallaceracing.com