.065 thickness on cylinder walls > Pour Block and use?

[dozz302]

Hello, what about a 390-block bored to a 428 4.13 bore but some of the cylinders are as thin as .065 at the top or bottom. Blocks oiling system has been really nicely worked for high flow so I would hate to trash it.  If block was poured with block fill all the way or maybe halfway would it live?  Even if some of the thin spots were high on the thrust side? Would the pour add strength to the unfilled area of the cylinder wall since the length of the unsupported cylinder wall had been greatly reduced or shortened? Thanks

[frnkeore]

Could we see the sonic map?

[Rory428]

Sounds risky to me. I have had 428 blocks split cylinder walls, even with block filler (up to the bottom of the water pump holes ), in my drag car before. Also, block filler should be installed and allowed to cure BEFORE the block is bored and honed, as the filler tends to squeeze in the cylinder walls, as the filler hardens, which can distort the cylinders, so that they are not round anymore, and make the piston to wall clearance tighter. Not to mention cooling issues if the water jackets are filled to the top.

[blykins]

Hello, what about a 390-block bored to a 428 4.13 bore but some of the cylinders are as thin as .065 at the top or bottom. Blocks oiling system has been really nicely worked for high flow so I would hate to trash it.  If block was poured with block fill all the way or maybe halfway would it live?  Even if some of the thin spots were high on the thrust side? Would the pour add strength to the unfilled area of the cylinder wall since the length of the unsupported cylinder wall had been greatly reduced or shortened? Thanks

Unfortunately, it's going to be one of those things where you won't know until you try. 

As far as experience goes, I will tell you that I did something similar to a Cleveland engine.   The cylinder wall thicknesses are absolutely horrible on these, even at standard bore.   This block in particular sonic'd at about .070-.080" on a couple of cylinders.    I filled it to the bottoms of the water pump holes with filler.  It went on to make about 620 hp @ 8000 rpm without issue, many times during a cam swap session.   

For a daily driver or weekend street/strip deal, your guess is as good as mine as to how it would hold out long-term.

I will also tell you that the block filler will support the cylinders though, but it will also cause the oil temperatures to run a little hotter.

[Tommy-T]

The motor in my Comet is a D4TE 390 block bored to 4.13. A couple of the cylinders sonic checked .075 in a couple of places so I filled it to the water pump holes with Moroso filler.
I've been driving it around all summer and it's been fine. I did install a Blue Thunder SCJ oil filter adapter and an oil cooler with it's own electric fan.
Give it a shot, but finish hone the cylinders a week or 2 after the filler takes a final set.

[cammerfe]

It is very common in the most modern engines that the water jackets only exist in the heads and down the cylinder walls to below where the ring package sits with the piston at TDC. Of course, the water and the oil flows have both been optimized for the design. But you can re-do to increase water flow and oil cooling. It's your choice, 

KS

[e philpott]

.065 is pretty thin , I was worried about .113 in a non thrust spot on one cylinder and had a half fill on my D2 block with Pro Gram caps that was other wise .225 and thicker on the other cylinders