[lust4speed]

Wondering if a pinhole wouldn't be rather difficult to detect with magnafluxing? Cracks show up easily but not sure if there would be a recognizable pattern with a round dot. I farm the magging out so no experience with it.

Way back in my life I worked for a pump manufacturer. Pinholes were a pretty common experience in the castings and these were new pieces so wall thickness wasn't part of the problem. All it takes is a void (glorified little air pocket) close to the finished surface or casting debris. Either of these will lead to an eventual failure but difficult to find beforehand.

[Baron Von Zeppelin]

Just wondering / curious if the pinhole in cylinder was from INTERIOR rust corrosion .

No matter what anyone's comment looks like in print , be assured we are all pulling for you and wish you success on this car.
The engine saga has sure been a wild ride.

Maybe you will find a briefcase full of cash someday as a karma payback.

[64speed]

The block is now .30 over. My machinist said he has had this happen once before on a Ford. I don’t think it shows up on magnaflux.

[Gach]

Yep they rust from inside out. Unfortunately you can’t see inside. Tough because you never know. SUCKS!

[hurryinhoosier62]

Originally Posted by 64speed

The block is now .30 over. My machinist said he has had this happen once before on a Ford. I don’t think it shows up on magnaflux.

Correct; pin holes rarely show up during a magnaflux inspection. The best way to fix them is to sleeve the cylinder in question and re-bore.

[64speed]

The block was delivered clean as a pin, wrapped in plastic and didn’t appear rustier than any other block I’ve ever seen that weren’t immediate pullouts. If this one goes south I will park the damn car and save for an Indian adventures. I screwed myself in that my first 455 block was free and I put a lot of money in a rotating assembly for that block. Now I am stuck with that rotating assembly. Much easier/cheaper to find 400 than a 455

[Gach]

Blocks corrode internally; they also suffer from coolant erosion and cavitation. So the block on the outside may look super clean, like brand new. If you ever look inside with the freeze plugs out. You’ll see what I mean. Some times you can see allot of rust. Usually when you get the block the freeze plugs are in it.

[Gach]

Is it a 400 block or 455 block ?

[Gach]

Here’s something you need to think about, if that one cylinder has pin hole after boring and pin hole developed because of corrosion/rust. How good is the rest of the block, I mean putting in one Sleeve to solve the problem is no guarantee down the road same issues won’t pop up in another cylinder when you least expect it. Some of these blocks are 50 years old. My decision will be save your money and buy IA block.

[Baron Von Zeppelin]

That was my line of thinking too , Gach.
If one popped , others may follow.
I guess sonic testing might give clues.
And pulling all the freeze plugs just to get a visual idea compared to the appearance of the bad cylinder might give ballpark/horseshoe insight.

Sometimes its probably best to just grin and bear it. idunno

He uses 455 block / large main journals

[64speed]

I am gonna give it a chance and see how it does with the one sleeve. I want to enjoy the car ASAP! Even though I’m not done with the interior it is a great driver. I will start putting money aside in the event of failure. I know y’all think I’m stupid but I have confidence in my builder.

[grivera]

Maybe 3rd time will be a charm, maybe not. Another 455 block would be a good investment since they are still available, albeit harder to find than 10 years ago. I think it's a bit premature to buy an aftermarket block considering the intended use of the car and the price would delay the project big time.

[64speed]

I am always looking for Pontiac blocks. The aftermarket block would take me two years to save for. I’ve depleted my big money. At this point I’m gonna run it. I don’t plan to scream the **** out of it on a daily basis so hopefully I will be alright. Something has to hold these projects up. I dodged the pain bullet so this is my cross to bear.

[Baron Von Zeppelin]

Try running an 8psi radiator cap versus 15psi on the next revival.
And maybe a late model type overflow expansion tank.

It might be a (thin) extra layer of prevention if there is another interior pit that is near the borderline.

[PAUL K]

I don't think the repaired block will be an issue. We ran across an identical situation years ago with a 800+ HP Ford engine. The cylinder had been in service for decades and survived a dyno session. It started leaking immediately when installed in the vehicle.... The block was repaired with a sleeve and many years later it's still in service with zero issues.

Stuff like this happens when you are using fifty year old parts. The deal with the Ford was not detectable with a Sonic check.... I recall a lot of porosity issues with new aftermarket Pontiac blocks years ago. So spending $3500 for a "just incase" may not guarantee an issue free build.

[JSchmitz]

Casting flaws are not uncommon. I've turned cast iron parts and run into mysterious trash in the casting. A void in the casting may have been uncovered when it was bored.

Good luck with your next attempt! I hope it runs for decades next time!

[ZeGermanHam]

Don't beat yourself up too much over the scratch. Stuff like that happens to all of us eventually.

[HWYSTR455]

I had a long handled pruning shear fall off a shelf a door slammed from wind, it's a 4.5" scratch down to the metal on the quarter panel. Uhg.

I tossed some touch up paint on it, totally visible, but nothing I can do about it at the moment. Technically, the whole quarter needs to be repainted.

Chit happens.

Had it at a car show when I 1st got it driving, and if I had $5 for everyone that came up and said 'You know you have a scratch back here?' I could have paid for the repair. Like duh, it has touch up paint on it, think it's self-healing or something!?!

.

[HWYSTR455]

Magnaflux won't pick up a thin area on a block, have to sonic check it. Which, I thought was SOP for any used block, but guess some don't.

Things go bad when you're in a hurry, I too advise to have the block checked before moving forward, regardless if you lose drive-time.

Now the question is, is the shop you're using competent enough to do a sleeve? Search it here and you make a determination. Many are not competent enough.



.

[Greg Reid]

Originally Posted by ZeGermanHam

Don't beat yourself up too much over the scratch. Stuff like that happens to all of us eventually.

That's the right way to look at it.
Every scratch and ding on my car happened in my garage. All were put there by me, myself and I. The worst one happened because I overloaded a wall mounted cabinet with paint cans and one night it pulled off of the wall and landed directly on the rear edge of my trunk lid.
I've actually started to enjoy driving my car even more now that I don't worry about every little rock chip.