My engine blew up today....

I guess that all comes down to who you choose. I could ship the engine out for a complete rebuild, but the price tag and my curiosity keeps me away from that option.
The heads and carb are dropped of at a private enthusiast, who has bought himself the nessesary equipment. The block is at an official machineshop, and they offer seperate services, as well as specific jobs.
I have asked the machineshop to do the mesurements, and tell me what size pistons/bearings to get. Then i will order the parts, and deliver the pistons to the shop.
I plan to do the assembly myself - with help from friends who have tried this before....

I finally got word from the machineshop. They say that the block is already bored 0.060 over, and i need even bigger pistons.
WTF - it is never bored according to my own measurements?. I just checked the old pistons, using my regular calibers, and got exactly 103 mm on the skirts. The bore is suppose to be 103,18 mm acording to my calculations.
I can't figure out how he can get a 0.06 overbore, but if that is right i am going to need 400 pistons in oversize - i think he is wrong, and i will call him monday to check.
Somehow it is not a good sign - i mean if he can't even measure the bore correctly.......

It seems that the 400 pistons is the same as 386 +060 overbore - anyone who can confirm this ??

Well you burned holes in your pistons so you'll need new pistons anyway! I highly doubt your motor was bored 60 over. I thought you had a nice original car???

Your motor should have plenty of meat on it for another bore even if it is bored 60 over. The only real problem may be getting pistons

Yes a 400 is a 60 over 389. The problem you may run into is valve relief notches on the 400 pistons. 389s don't have them. I don't know how much it will lower your compression but it may or may not be a bad thing depending on what you're going for. If you can't get 93+ octane or you don't care to, then lowering the compression might be a good idea, especially if you may have already had detonation issues.

Look on the tops of the pistons. They're usually stamped std or .040 over or whatever if it's been rebuilt.

and yes standard bore in mm is 103.1875

I would go to the shop and ask them to show you the measurements. They may be mistaken

Exactly my thoughts. I get 103,0 on the bottom of the piston skirts, so there is no way in hell they could have worked in +060 holes !. They must have gotten the wrong measurements.
Unfortunatly the old pistons have no marks on the top, but if they were oversized it should be visible using standard calibers - which means they've got i wrong .

However, just out of curiosity, i guess that you could continue with oversize pistons for a 400 - should it ever get that far.

As you pointed out - the car does not look like it did THAT many miles.

It's probably standard bore. Maybe they mistook it for a 347 or a 370 or something. I don't know

Good point, you should be able to get some 20 over 400s i guess if you needed to.

Finally some good news - i dropped the new bearings, pistons and cam of at the machine shop. After waiting for what seems to be forever for the parts, it is a great feeling. When the lost package was finally found, it got stock on iceland under a cloud of ash . The new distributor is still missing, but that is no showstopper, since ive still got the old one.
I changed my order to have the engine delivered as short block - to save some time, and get running asap.

The beast is back. I had it started yesterday, and ran for about 2 minutes in two runs of 1 min. I could not start it, and it would not turn over on the starter - i handcrancked it, and i belive it did feel sligtly harder to turn than before the start up (cold). New battery, and let the engine cool down, and it started again. I am going to do a new run today - i hope that it is going to survive the breakin . I got about 4000 $ on the rebuild so far - about 2500 on the machinework alone - so if it has to be taken apart again i will be lucky to have it running next year.

I used Redline assembly paste on the cam, and MoS additive in the oil, and did my best to follow the breakin procedures . 20 mins at 2000 RPM, but since i don't have a tach i might have been slightly higher.

It sounds good, though, so i am causiously optimistic .

An interesting thing about the pistons (FELPRO). The machine shop called, and said that the new pistons were .5 mm lower than the original ones. I ran that through the compression calculator, and along with the valve reliefs it should yield about a 9,5 : 1 - perfect....

Christian- Nice looking motor! I guess the only way to get a decent paint job is to take the motor and trans out! Awesome job, man! I do have one question though, and not being picky, just curious.....why the silver heads and intake? Perhaps you were going for the aluminum look or are they actually aluminum? Either way, a VERY sharp looking motor you have there! I wish you a long and happy motor life, with all you have been through to get there, you deserve it! Good job!!!

Thanks !

No, it is the all original cast iron heads - i just used some alu spray. I saw this on a Buick owned by a friend of mine. I think it makes a nice contrast, and there is an abundance of silver heat resistant paints on the market. - unfortunatly not so with pontiac blue . I used pure aluminium spray (99.5 % Alu), so it should be corrosion resistant too.

I guess you could get away with painting it in the car (i brushed the pontiac blue on), but you would still have to remove all accesories and the exaust manifolds.

Christian, what a great looking blue and silver thing of beauty to fill up that black hole. It really came out looking great. My mechanic told me to drive as normal and change the "break -in oil" after the first 500 miles. That was 200 miles ago and now she runs even better on 10W-30. Good luck with your new engine. Jim

Thanks !

I am at about 60 miles now - and it is running better and better.

Ok, i am now at about 250 miles. Things are running great, and i am sorting out the last small things.
I have started to open the throttle a little, and it is definatly fast ! - and there is a lovely sound when the
secondaries open up. I havent heard the slightest sign of detonation - just running standard 95 with lead replacement additive.

A small problem, that i am going to have to adress, is a drop in oilpressure when turning right. I know this has to be the pickup tube sucking air. The old pickup had a o-ring pivot point, and would automaticly drop to the buttom of the oilpan - the new one is fixed (and obviously too far from the bottom of the pan). I hope that i can reach it through the drainhole with a screwdriver, and pry it a little further down, when i change the break-in oil.

The old jetaway seems to be a lot more happy to change down when i get on the throttle - not sure if it is the new fluid, or maybe it is just the lincage from the carb that is adjusted a little differently.