Bummer! That's a scary sight under the skin .

 

Yeah..the pissed off gearhead in me is saying either walk away, or try to see if it can be saved. At the end of the day though, it's going to need a lot more machine work than my budget had allowed. I could continue as planned and just utilize the down time to focus on other areas of the car while saving up for machining..because I do understand it's a numbers matching car that deserves better than its had the last decade plus, but its still a big chunk that I didn't expect to be spending.

That's even IF it can be saved via sleeving it.

 

Just drop a 455 in it. It will bolt right up. Ditch the 400. Someone will want the intake and carb and dizzy and if it has it's original alt, that alone is worth good $$.

 

I kind of agree. Listen, when it comes to muscle cars I'm definitely an originalist, so it pains me to say this, but it really sounds like the universe is telling you to dump in a 455 and be done with it.

 

It looks really scary. But who knows? After an acid bath, maybe it's workable (fingers crossed).

 

I agree, see if it can be salvaged, and if not, a 455 block can be substituted and use the intake, carb, distributor, etc - keep all those original parts, just swap the block. Document everything, so if the car is ever sold the reasons for the block swap can be easily explained and a prosective buyer would obviously agree that it was a logical move under the circumstances

 

Wow that sucks Brian. What a shame that the owner left it outside uncovered, it looked like it was a pretty clean engine! I agree with the others, if the 400 block is too far gone to rebuild I'd go the 455 route. I hope those big valve heads aren't junk but from the look of a couple of those intake ports????. Someone's at least had the heads off before, those aren't factory head gaskets.

 

Slept on it and feel a bit better about the future, IF the conversation goes the way I'm hoping with the boss man/current owner.

Already have a buddy who has offered up a rebuilt and known running 350 to at least get the car on the road while I look into the likelihood this block can be saved.

I agree with everyone else in regards to the 455 route. He suggested that when I sent him the text, and I know I'm probably being too stuck on saving the original block due to numbers, but like I said earlier..the pissed off gearhead in me almost wants to fix it both out of spite for negligence and to keep the numbers intact.

 

That is too bad bro... glad you have some options.

 

You should be able to take detailed pictures and talk to a machine shop for free and get expert advice. This will give you more info to make your decision. To me, it looks done, but I am not an engine machinist. What kind of shape is the car in?

 

Car is solid, and in great shape considering it has sat in a barn the last 10-15 years.

The engine he had let sit uncovered outside for at least a year. The oil that was in there (while not much) was thick and sludgy, but I drained the pan on it yesterday and swore I turned the hose on. It still had antifreeze within the passages, so I'll drain the system and roll it over to get a good look at the crank and bottom side of the block.

 

I would be VERY surprised if you can get the pistons out without breaking them. Not that they would be worth anything other than scrap metal, I bet the engine would clean up with a overbore.

It’s a good thing there was antifreeze in the cooling system, chances are you don’t have to worry about cracked blocks from freezing.

I have never owned a late 400, but I have heard from enough people they don’t perform nearly as well as the earlier 400s, or the 455. I’d suggest (as other have) finding a 455 short block and transfer all the 400 stuff. That way you have the added performance, overall cheaper to build, and the correct parts that 95% of the people who see it won’t know any difference. Win win in my book.

 

Just got a price for magnafluxing, cleaning and the one sleeve, and it's not as bad as I had expected. I won't be able to communicate with the boss man until next week about it, but I may continue stripping it down and noting anything.

I would expect the potential need for slight overbore, at which I'm outside my element here (bigger pistons, balancing, etc) but even if the block needs that..as long as it can be saved I'll feel better about it.

If it needs to go 455, it'll go that way only if the original block is toast (granted, it's still his car so it's up to him..but if I end up with it, that's the direction it'll go)

 

Chris, I have a running 69 400 if your interested. But I am in Florida.
Let me know.

 

If you got the coin and the patience, nothing wrong with seeing how far you can go with it.

 

Just went out and flipped it over and pulled the pan. It looks much better than the lifter valley does. There is some scaling on the rods and crank, pistons look pretty decent. There are some portions of the cylinder walls that you can still see crosshatch, but then another that looks pretty gross. Didn't see anything cracked, but once we get the stamps back over here we'll mark rods and caps, and try to get the pistons out.





Also grabbed a couple shots of the underside of the head, showing the valves.

 

I love the effort that you are putting into this car already. I really hope that this car works out for you as in I hope your boss treats you good on the sale.
About the motor. Anytime an engine sits outside is never good. My opinion keep the motor so you have it down the road for a purist. Put a 455 in it. Paint it Oldsmobile 400 gold. 99 percent of the people will have no clue. You will get awesome Oldsmobile torque that will make you smile.

So I asked on your previous post. Is that 69 a factory Burgundy Mist car?

 

I remember that question now, sorry.

I'm not sure, the picture I have of the data plate isn't a good one. There were no obvious signs of a repaint, so either its factory or someone did a good job.

 

wasn't there a detailed '68-'69 build on here that used STANDARD 360 MOPAR 4.0" pistons to create a 427" 400 "G" engine?

4.000" bore (0.125 over 3.875) x 4.250 stroke = 427"

IMO it will be more cost effective in the long run to maintain the numbers matching status VS. hunting the 455 not needing a rebuild (or its rebuild costs)

 

Knowing it needs at least a sleeve, and it may need some other work due to the amount of rust in a couple other walls, I may start looking into bored options. Primary goal is to save the numbers matching aspect. If it needs a bit more done (overboring) then so be it..but if it's avoidable it only helps the wallet.

I've never bored anything out, so it'll be a foreign process for me. That pretty much just calls for bigger pistons right? The rods and crank remain the same?

ill definitely do some digging once I know how the block looks and once I do sign commitment to purchase when he gets back. I've got other questions regarding the heads/cam/intake as well..but need to make sure the important parts are done first.

 

Hopefully the machine shop will have some good news for you. I'd be a little nervous about boring the cylinders 1/8", The cyl wall thickness can be "sonic" checked if your shop has the equipment. I think .030 & .060 over pistons are still readily available for the G block. These guys show forged pistons in 030,040,& 060 sizes. I've never bought anything them, but they say their parts are made here! I'm sure others here on the site can chime in. They seem to have lots of nice stuff for Oldsmobiles.

 

Was that Mark's thread? Cutlassefi. You may want to contact him on the newer Mopar pistons. Compression may be lower.

 

Bronze. Don't ask me how I know this.

 

Did the same thing for my 69 442. I used a J intake and a 251 carb as well.

 

Go as much as it will safely go and allow a little margin incase in the future, if it needs an overbore again. Guys have gone way overbore on these motors. Dale Robinson mentioned the 307's he built could have probably gone .200" overbore on the one he pushed over 400 hp out of. Makes sense with Olds 4.4" bore spacing, a 3.8-3.9" bore can easily have much thicker cylinders than a 4.351" 403 block. Get it sonic tested and find out where you stand. Good luck, you may need it.

 

Went out this afternoon to try to finish tearing down the engine. Got the cam and lifters out, pulled the mains and got 6 of the 8 rods loose. There are 2 that I can't get to the nuts (cyl 5 & 8) and since the crank doesn't spin were going to just hope we can get the crank loose to be able to get them out. I'm sure there's a better way, but until I find it that's what we're doing.

 

The '68/'69 400 blocks had very thick cylinder walls and most could easily take boring out to 4 inches. I personally know of one young guy that in 1969 bought a set of .060" oversize TRW forged pistons for a 400 Olds, sent them and his block to the machine shop. When he went back to pick up the block the machinest chided him for having to bore the block so much. Turns out he had bought pistons for an early 400 Olds and the bore on his late 400 ended up at 4.060". I sold him a set of 7'" early 400 rods and he had the appropriate amount cut off the top of his new pistons and everything balanced. Ended up with about 440 CID and it was a monster. Never had any problems with it. Erosion inside the water jackets on these older blocks could be a problem now so a sonic check is a must if going that large.

 

Well, left the office today with a verbal commitment to buy the car, and am scheduled to pick it up Saturday.

Now that I'm paying for machine work for sure, I'll start asking the more detailed questions..ha.

Granted, the crank is still stuck..so I probably should figure that one out. Anyone have any suggestions?

 

Acetone/ATF 50/50 mix poured into the bottom of those cylinders maybe after you put a blowtorch around the underside of the piston to heat it up.

It looks like they are at the top of the bore. Maybe you could tap them with a sledge a few times. I guess you could break the pistons as a next step.

 

So am I not the only one with this idea? Nice.

Mothball that 400 for later. 455 it. 455 it. 455 it. Paint it bronze.

 

See that just sounds like too much work to still end up with what you already know. That motor will take mad money time etc. ANYTIME an engine sits outside is Never good. Original motor. Hold onto it. Make it Your car. Enjoy it!!

 

do it right in the current build - it will never be done right in the future

 

Since the pistons are junk, there is no need to baby them. Get out the air hammer, break the pistons into pieces.

I have had reasonable luck getting mildly stuck pistons freed up by a combination of heat and soaking in oil. Get a block of hard wood and a hammer, smack the piston at the top of the bore, and the bottom of the bore. The idea is to try and get the piston rocking in the bore.

 

I've got a couple that seem to be allowing fluid through the top of the piston, that being said I'm still not really sure how to soak the pistons that are at the top of the stroke. The crank is being held in by those 2 rods, and (assuming) rust. We're going to flip it and soak one side at a time now instead of trying to fill the cylinder and work the fluid around with a pick.

The amount of fluid in the cylinders though has seemed to clean the walls up though, so I'm being cautiously optimistic..ha

 

Put the engine upside down on the stand, pour in from bottom side.

 

...not sure why I never thought of that..haha.

 

What hurst68olds said. You're going through all of this effort because it sounds like you actually care to make the car right rather than simply get it running. If you don't invest in getting that original 400 rebuilt now, chances are it'll sit in the corner of a garage for the next 20 years. Do you really think anybody'll care to mess with it then?
Keep at it, you're making great progress.

 

that's exactly it. I've built a car to thrash on, this one I want to keep as correct as I can.

I'd love aluminum heads, cam for days, EFI, disk brakes all the way around, the list goes on..but it's an original car. The most I'd possibly do is a Holley (Summit) carb and maybe a bit more cam strictly for sound.

 

Might as well get started sourcing pistons now. When I was building my G-block, the only 0.030 ones available were cast aluminum from Egge. Hopefully for you, things have changed by now.

 

I heard (earlier on this thread actually) that small block Mopar pistons work well. Once I know for sure what I'll be looking at (size wise) I'll track all that down for sure.