Has anyone ever block filled a sbb 350?

It would seem my strategy to support the entire thrust side from about an inch from top to the very bottom so the piston won't be able to distort the cylinder because the fill behind the thrust side won't allow that to happen, should work very well. There will still be about 3" of fill surrounding all of the cylinders starting from 1" below the deck's surface with fill all the way down to the bottom on both thrust sides.(passenger side of both cylinder banks if anyone was wondering, so on the driver side bank that would mean to fill from top to bottom on the cam side of that bank and on the passenger side bank that would mean filling on the freeze plug side of that bank)

Even without supporting the in between sides with fill the piston in the cylinder shouldn't be able to push itself apart if its pushing on a solid surface(the thrust side) while its travelling up and down. We should end up with the passenger side filled close to the centerline of the cylinder, with the driver's side a little bit less than the centerline because of how the water pump ports are a bit off center.

IIRC even after boring .105" over I think the thinnest wall was still .120" thick. With boring to 4" bore on this block I would move the centerline of the 2 back cylinders(with plenty of thickness on the other side to compensate) that were the thinnest towards the rear of the block forwards a bit to compensate. But seeing we're only going .105" instead of .200", we don't need to do that.



Derek

 

Here are a few pictures I wanted to load with the above post but my confuser was not cooperating ;

So this is the passenger side water pump inlet.


This one the driver side W/P inlet.


This is a full frontal picture of a naked sbb 350. :Brow:




Derek

 

Anything other than complete filling of the water jacket is going to create a stress riser in the cylinder wall at the surface of the filler. There can't be many ways around that. From reports that filling results in enough force being generated to decrease the bore by about 0.001" indicates this stress riser is also pre-stressed, and since combustion pressure is outward force that would just add to the pre-stress. Then you have head bolt stress in the same general area. We've seen in the Rover engine that generates horizontal cracks at about the bottom of the thread boss below the deck. Pretty close to where your block fill would be with a 1" gap.

Jim W, were the cracks you observed horizontal or vertical?

Jim

 

would a wise man fill the block with a torque plate installed then? just a thought.

 

Yes, we will with the torque plate installed.

Jim, I have seen both, seems to me that horizontal is more common. One I recall distinctly was a half fill, broke right on top of the fill. Also heard that story from several others. That steered me away from half fills. I have no issue with just an inch in the bottom, that helps stabilize the bottom end and absorbs harmonics.

Bottom line, block filler is not a substitute for finding the best block you can.

 

Typically a 1" from the deck's surface with a cast iron block is almost as strong as it would be filling it to the top. 1" from the deck's surface would be about an 1/2" area below the actual deck's thickness for coolant to flow. With 3/16" of an inch variance in the thicknesses, meaning in spots the deck's thickness can be thicker or thinner by 3/16" in areas and vice a versa. Oh yeah, 1" from the top of the deck ISN'T considered a half fill either. Although the method I'm using JW thinks the crack would happen below where the fill would be if this was a thin block and why he is referring this as a half fill.(which will actually be more like a 3/4 fill)

Yes, torque plate fill as described by Dan in a much earlier post wax filled to displace the 1/2" below the deck's inner thickness.

And again, the fill is for redundancy and for a bit of outer block stiffening to help to minimize outer block flexing like Sean described blowing the head gaskets at the #3 cylinder on 2 occasions on the chassis dyno which I believe was caused by the motor mount distorting the block in that area. Hopefully Andy will use an engine plate of some sort though so that isn't even an issue? But if he uses motor mounts then perhaps the fill will give him that little extra he needs to not distort the block enough to blow a head gasket in the same spot?

Still in the research stage, I'll post pics of the process we end up using, in the mean time if anyone else has anything else to add please do, thanks in advance. And a big thanks to everyone else who has contributed to this thread so far. :TU:






Derek

 

Yes, and a wise man did it exactly that way when Dan said he filled his sbb 350 blocks, with a torque plate bolted on. :Brow:








Derek

 

The reason for filling the block in my situation was cylinder failure. Was having issues with#2 cylinder cracking after 75 runs on 030 over in the stocker setup. After filling no more problems. As a side benefit the car would run in*11 sec range by getting better ring seal. Better consistency do to more stable cylinder temp from*run to run.*It takes a long time to heat up the hard block.
Still using one block that is 068 over with out issues.

I think in a street application the top of cylinders would get too hot. I never tried it on street application. The water area at the top might work.

I also fill the block with the standard bore reassemble and race it at the brackets to get a good set on the fill then take out for the over bore. This seasons the hard block with some heat cycles before I do an over bore.

Dan
*

 

I like the heat cycle idea, I think we'll be doing that by installing the wax in a hot block, then let it cool before its filled, then it will need to be heated again to remove the wax. We can probably let it set outside and freeze for a few days(after the fill is totally setup) before the wax is removed to mimic a couple of seasons of hot and cold cycles. Yose guys down in the warm states would have to have a freezer big enough for a block to do this. :Brow:

Might even have to remove the first wax before the 2nd wax is installed to keep from making to much of a mess out of the block oven. o No: Not sure until we do it.






Derek

 

I put a lot of thought and research into block filling the 350 and decided it was not something I wanted to do for a street car... Max effort race, yes.

Any pics of the girdle you made?

 

With all the thought and research you did, what did you come up with?

I think there is a pic in the other thread of the girdle, when I get around to working on that part again I will post pictures of it before and after its installed. :TU: Soon, next year.

I think the way I have the fill planned so far is going to work great! The fill will end about 4 1/2" from the top of the deck , the stroke is only 3.975", so 4.5" - 3.975" = .525" more than the stroke that will easily cover the rings on bottom dead center. With the thrust side all the way down to the bottom that will support the piston skirt when its on its least amount of pressure area in the combustion process, probably not even needed but I like the idea of a pillar on one side.



Derek

 

What I realized from the research:

1. Filling the block fully obviously wouldn't work on the street
2. Filling the block partially is very likely to lead to cracking of the block

So I decided not to do any filling....

It's been a long g time but I do vaguely remember swing pics of the girdle. Will try to find them.

 

Dan said when he started partially filling his 350 blocks he stopped having block cracking problems. o No:




Derek

 

Sounds like an opinion to personal preference and not wanting to go through a learning curve of R&D, testing, and subjecting an investment of parts to disposability for the cause....which is quite reasonable

 

Each to thier own... Was the cracking of the block a fluke in the first place or would it be normal for a block to crack when submitted to about 390 hp which is roughly what Dans engines are? I would be curious to know the overbore of the engine that cracked.

I have no doubt that a half fill of the block would be fine in the 400 hp range but what about at 800?

For me it's all or nothing it's a fully filled block or nothing but that's just my opinion and we all have one...

If I were building a max effort racing only Buick 350 it would burn E-85, 11:1, feature the block girdle, full fill, 370 cube, alum heads, MPFI, twin turbo but personally I want something that can be driven on the street and not overheat... And I can do that with 355 cubes, mild flat tappet cam, iron or alum heads... And the girdle and billet crank I added are just extra insurance for when the stock parts may or may not give up down the road...

After hearing about Casper 1 breaking a stock crank at about 380 HP after a bunch of runs it made me realize that it's not just the max HP that breaks stuff it's the repeated acumulation of stress over time.... Was the stock crank flawed to begins with? Maybe but it passed the magniflux test...

As you know Derek it is sometimes a disappointment when you invest time and money into a crank, block etc, and have it turn out to be useless like you found with the magnifluxing of the block the first time. It's still great that you caught it but it's a drag.

My point is that I'm sure there are a huge number of people driving or racing with blocks and heads that are cracked and many of them will never have an issue with them or even even realize they are cracked.

 

^^ Good post.

I suppose the inspection also depends on whether it was wet or dry mag on the crank.
Wet or dye might not show a sub-surface crack until too late.
Dry mag is strongly not recommended by some due to difficulty of demagnetizing the crank completely. Imagine the potential troubles there...
Xray might be a better choice but not very common. Maybe make friends with a mobile tech (nurse)
At the end of the day it's tough to determine previous abuse or fatigue life left.
Some circle track guys running cast cranks have found a service life depending on their specific use and rotate them out before failure.
Cryogenics has proven to do wonders for cast iron fatigue life.
Looking back to the prep work, machining, and other processes to Grumpy Jenkins' stock sbc cranks might offer some ideas, even if forged and...sbc.

 

Thanks, I just thought I would sleep better at night with a billet crank rated for 1400 HP... And King really did a bang up job on this part wow it was a huge process to R&D the design and make it and the various stages of cry treatment and machine work was impressive... They even drove to Ethans house and picked up the core crank for me... Very much worth the $.

Bill Mah did not have any fill in his block that made the 1021 HP, there must have been a reason for that.... Maybe it was to prove they could do it without the girdle or fill... Same reason they used the stock intake manifold as well.

 

In the purple, you would have to ask Dan that, not me.

In the green, not sure what the breaking point for an half filled block would be, my plans are more of a 3/4 fill. But still if you're calling what Dan did a half fill, then you're very mistaken on what HE did as well. Like what I outlined in post #51 that you deleted from my quote in your reply about the way he filled his block was still more than the stroke that his engine has!

The half fill failures are the blocks that get filled from the bottom and stopping half way up creating a "crack" point in the higher pressure combustion area. The way Dan did it was from the top down covering the entire stroke(which is genius by the way) and still having coolant on the bottom of the bore to cool the oil! I will be taking that to the next step and leaving some cooling on top and still supporting the thrust side as well, all the while having the ENTIRE where the piston goes up and down on its stroke filled! Where will a cylinder crack if the entire cylinder where the explosion happens is supported with fill?(answer: probably nowhere)

Did Dan stumble on to the holly grail of sbb block filling out of necessity? I think he did. The only way to improve what he did is to have the little extra cooling just below the deck using the wax to displace fill.

I was at my wits end trying to figure out how to get any fill in one of these sbb 350 blocks the way the water pump inlets are! I may of eventually figured out to flip the dam thing upside down, but Dan opened my eyes before that happened! Dam gravity, the way it works and my experience filling brand X blocks that could easily be filled deck side up, wasn't really any help!(Tony) But we have a good game plan now, its either going to work or its not! :grin:

100% supported thrust side of cylinder + 100%(would be 130% if there was fill all the way to the top) of the stroke 100% filled = a VERY strong block with very good ring seal with no fill transition point where there will be any cylinder pressure except the 1/2" of space at the top which will still be VERY strong because of its short length.

In the red, your definition of an engine that can be driven on the street is probably different than mine. Filled quite a few brand X engines that run an oil cooler to run on the street because of the fill being 1" below the deck's surface. With the upside down fill and 1" below the deck's surface Andy will probably not have any oil overheating issues at all like Dan said with his experience with coolant still at the bottom of the bores, but we'll see. Worse case scenario he has to add an oil cooler. As for what effort this build will be is up to Andy on how much power he wants to boost it too. I can't guaranty if the crank will stay in one piece at 20 psi, I'm just trying to make everything else as strong as I can make it before Andy gets it if he wants to try that much.


In the blue, yeah, I seen that post and it did seem that you were a bit upset that his crank failed. I agree that the many passes probably took its toll but IIRC he was running the very heavy cap screw rods with heavy speed-pro pistons pushing the limits of the RPMs with every pass. Surprised he didn't break a rod when the crank broke! A lighter rotating and reciprocating assembly should help the longevity of the crank, boost or no boost.

In the bold, the worse part about finding out the first block was cracked was trying to find another one! LOL Very little $$(like $10 because I did the work so the only charge was for the propane) into that block at that time, the best time to find those things out!

In the regular text color(or colour for our Canadian friends) Usually when an engine cracks in the cylinder a simple compression test tells the tail of low to no compression in that cylinder. Also coolant can leak in that cylinder as well making one believe a head gasket failure has happened until the head is removed and the truth is revealed. Point is if there is a crack in an cylinder the owner of the car that is being raced will know there is something wrong when their ET is way down from where it was before the crack. :shock:



Derek

 

I have been wondering about this mythical engine and what happened to it? Is it still in service? Is it still being raced? Or did the block buy the farm?

Or are they still just refreshing it every season and still racing it? o No: What happened to this white whale?





Derek

 

FYI, I poured some gasoline onto some cured expandable foam.
When it did nothing I Googled that and found that nearly nothing dissolves it once cured.
Styrofoam instantly melts though.

[Edit; Acetone and any other thought of chemical has been tried and failed, according to Google. Uncured, probably.]