Customs Engine machining question

Hi Guys, It has been a long time since I posted. I need some guidance from any of you familiar with sleeving an engine. Years ago, I bought a blown 400 sbc short block for my 54. It had been bored .030 over and soon after running it had blown up (7 pistons were still clean). The front main had seized from lack of oiling and broken a rod. The bottom of #5 (furtherest from the oil pump) cylinder had a small arc of the lower cylinder wall measuring 1 1/4 inch wide and 3/4 inch tall knocked out by the stump of the rod. My question is whether or not that kind of defect would prevent being able to sleeve it.

 

Maybe post a pic, and someone who’s “been there, done that “ can see it.

Edit: the shop you use will tell you as well.

 

Being a sbc it shouldn't be hard to find a replacement unless it's something special.

Besides the money you spend doing all of that it's probably cheaper buying a used block and starting over. Also you won't have to worry about problems down the road...

..

 

Sleeving is no real issue. Except the bores next to it will be distorted due to press fit of sleeve.
A line bore would be called for to correct the main cap that had the spun bearing.
I would also magnaflux to check for cracks where rod let go.

 

Not a lot of 400 SBC’s around.

 

If I rebuilt an engine and it failed again shortly after, I'd be upset and want to either toss it for superstitious reasons or spend a lot of time to deduce the root cause, and probably still replace it if I couldn't determine it or it was cheaper to just start with another.
Given this is a 400 SBC, I'd look for another before pricing out a sleeve job. They are siamesed bores and fairly thin IIRC.

 

I disagree with the red part. I'd price the repair first, that would give me incentive to pay more for a good block!
Years ago I'd just get it sleeved. But that was when shops charged 25 bucks an hour, or cheaper. When I started fiddling with engines in the 60s my local guy only charge 5-10 bucks a hole labor to sleeve.

 

@KenC So true, price out all options, then decide with full information.

 

If it’s the bottom of the bore well below the ring travel I would be tempted to smooth it out and run it. But pictures would help

 

You might want to look into aftermarket blocks. There's blocks available with 4.125 bore that can stand some healthy overbores. Dart Little M2 blocks are one example. Spendy, but what isn't these days.

 

Around my Area , price per sleeve is around $150 -200 per hole ,
After market Blocks are the way to go,
Especially if going to be blown ,
For many years when I had stock pile of
Gm 400s ( late 80s to early 90s)
I was running 10psi on
10 & 11:-1 on stock gm 400 parts ,
2 & 4 bolt .
I would get between some times less then 1k miles , some 5k to 10k miles
With 50-100 passes witch cast & Trw piston , some times breaking crank , pistons , rods , blocks , & burning across
7&5 4 & 6 of block , # 6 always the lean Cylinder

Many times taken stock & stockish
Engines & throwing 300 or so of
Laughing gas, only needed to make
Most time 1 pass
Engines where plentiful

 

I have a 400 block fresh bore to be honed to .030 over but no main caps you can have for the shipping

 

Take him up on it, as SBCs usually need a line hone anyway.

jack vines

 

It's the only way to go if building 400SBC . Yes it costs more but look at the big picture and the end results. I don't want to sound like an AH nut fir you can't afford to do this the best way possible then don't bother doing to at all. I have been there done that.

Pat

 

So the only way to build a decent motor is to start with all brand new aftermarket parts? I wish someone had told me that before I built all the engines I have.

 

$200-$400 will still buy a 400 block on my Marketplace.

The block you have needs align honed.

If you sleeve it there's a chance of distorting the adjacent cylinder. Maybe you could make it round again with a rigid hone, but it won't be cherry.

I'd be tempted to chamfer where the chunk's broken out and run it. If it's below the ring pack and if it's not going the piston rock at BDC. My luck the broken chunk sent out a crack that goes to water though.

Seems to me like you half-ass it as much as possible and hope for the best or start with a new block.

 

looks like you been drinking the “ koolaid” lots more ways to skin any cat

 

Thanks for all the replies, Guys. I did some more research and as someone pointed out I learned that the adjacent bore is involved in the repair too. Moneywise I am not deep into the block anyway so I will scrap it.

 

Any serious 400" SBC build would need square decking, line honing and cylinders bored. Your problem is you'd hoped to reuse the seven good .030" pistons. That might not be possible in a sleeved block, as sleeving distorts the adjacent cylinders. It would still be possible to use the existing pistons in another block.

jack vines

jack vines

 

No.I knew all along it would need to go 0.040 over

 

Your getting pretty close to the head bolt holes and as I recall they like to crack out in that area if you try to sleave them not to mention your sleaving a Simeased cylinder in a block that has already had the crap beat out of it. Going .040 on these is also getting thin ( I have one .060 over ;( ) Yes a lot of guys do it but there is more going on than if you break through once bored .

If I was doing a high HP Blown 400 SBC Id half fill the block and try to keep it at .030 max on a stock block . you night be ale to go .040 or even .060 BUT the cylinder rigidity is not great, and this can compromise ring seal .
I have seen more than a few bored 400's that when torn down have interesting cylinder wear in the middle to top of the cylinders . I used to do a few iron block 406 spring car engines and IMO boring with a half filled block and a torque plate was almost a must. Yes they run with out half filling the block but those thin cylinders are likely flexing and you're not making the most HP you can especially at 13-1 and high RPM.

Unless your racing it id skip the 400 and just do the tried and true 383 on a 350 block, turn the crank you have to fit the 350 size mains. Id honestly like to know on a street driven blower engine the real HP difference between the two given the same boost, cam heads and such.

I may do a different 400 ( actually a 427 ) on a after market block for my 57 Vette.
a stock 400 block if you can find one with out steam hole cracks to the bolt holes and can be cleaned up with a .030 bore is around $400 on up unless you just stumble onto one ( I have been looking for a good block ofr about 5 years thats cheap) then factor in stripping it down , cleaning it , boring it , decking it , line boring it and maybe even doing a splayed 4 bolt main cap conversion on it doing a half fill ( If you desire your likely over $1000-$1500 into a block hoping the machinist does not find a issue half way through before you can start putting parts if its a engine you plan on using a good crank rods and forged pistons on and have no idea how many times its been over heated by the previous owner and its still got a thin factory type deck with bolt holes into the water passages and they don't flow coolant as well as a after market block and likely do not oil as well .
IMO the extra grand or so for a after market block that you can get options like a raised cam bore and bearing sizes like a 350 mains instead of 400 mains and clearance for even more stroke is likely money well spent on any thing making serious high HP , taking boost or nitrous especially if you want bigger than a 406 .

It was different when a block was $50 and machine work was $300 and we all ran a factory cast $75 400 crank and stock rods and iron heads and it was no big loss is it let go . When your putting a set of $2000 heads over a set of $600 forged pistons on after market rods and crank the extra block cost is the cheap part and it also lets you go bigger and keep the gaskets in place . MY opinion .

Market place had a 4 bolt main stock bore ( might have honed out ) 400 block last week for $500.I was still tempted to buy it .

 

I’d just find a 396.

 

^^^^^^^
Low to Mid Budget builds
377 over 383

400-408 over 396 dollar for dollar
& lighter

377 rpms 7,000 -7,500
vs
400 6,200 - 6,800

Throw in like 5-6k
Crank
Rods
Piston
Heads
Killer engine
Then next up grade , with out mid plate
Stock gm 350 case & m22 breakage,
350 up grade , bell , 4L60 1st/ Reverse drum & HD 3rd drum/ sprag
3,000 pd car that hooks

 

#5 is the farthest from the oil pump ?
And it’s on the #1 main ?

Tommy

 

By the time you have ALL the necessary machine shop work done to verify the block isn't cracked and could actually be sleeved, you would be better off saving your money till you can buy an aftermarket block as a starting point. It won't need hardly any machine work, so that helps offset its cost. Don't get in a hurry if money is tight, just wait a while and save the extra money.......in the end you will have a much more reliable engine.

 

Because the 400 in Siamese cylinder with no water gap between cylinders the pressing a sleave in can distort the adjacent cylinders

 

I still think ask a shop “will this be a problem, or”?

 

It is.... in "Ford speak"

 

So is this going to be a super charged race engine like some of the responses refer to, or just a plain old driver?
If the latter, I'd do what 57 Fargo suggested in post 9.

 

Still haven’t seen a picture so it’s all guessing at this point