[gtofreek]

Here is a big picture of the serrations someone cut into the cap sides.

[Tom Vaught]

And the point of these serrations was...............................?

Always trying to learn

Tom V.

[gtofreek]

I suppose they did it so the caps would fit tighter in the register. I see them ripping the registers up when the engine gets run, and heated up. If it was a good idea, all aluminum blocks would be that way.

[dataway]

Back in the day didn't they sometimes knurl valve guides to snug them up?

[JSPONT]

I would figure they thought it would stop cap walk. When you push cast crank then take the cap off you can see they move. Maybe they were thinking this would help?? Not saying this had a cast crank just a thought.

[STEELCITYFIREBIRD]

I've seen the fixture for putting that knurl on main caps. We had it at the shop I worked in...... (20 some years ago).
It might be an old school process and/or considered crude by today's processes available, but I saw it used to fit missing caps or fix loose caps on some rare and obscure cast blocks that would of been scrap otherwise. It was a lost cost solution.

I agree it has no place in an engine of this caliber.

[Will]

Originally Posted by dataway

Back in the day didn't they sometimes knurl valve guides to snug them up?

Sure did, but that's a bit different. The guides would be knurled to raise the material at the "peaks" in between the indentations, effectively closing up the clearance. Then a hone or reamer gets run through the guide to get it to the exact size needed. Since the valve stem is only riding on the raised areas and the low areas fill up with oil, the load bearing capacity goes down. Knurling was a low-cost/budget way to restore guides but isn't a good long-term solution.

A valve sliding up and down inside a guide isn't quite the same thing as a main cap that's holding a spinning crankshaft in place in a main saddle that's also flexing.

I had a friend who had pistons in a Chevy 396 knurled too. The shop honed the cylinders and put new rings in and that left the cylinders a little oversize and he was cheap and didn't want to buy new pistons or pay for an overbore. That always made me cringe - knurling a piston would induce all kinds of little stress risers in it which could lead to cracks and again, only the high spots in between the indentations are taking up clearance and providing a load bearing surface, but he beat on that engine for a couple years and it never gave him any problems...

[SS-TA]

I was at Paul's shop last week and he showed me the block along with describing all the issues. What amazed me is that anyone would spend so much money on this block and then take it to someone to repair who was a hack (presumably the original owner). Great work Paul.

[Blackened]

Fantastic thread Paul, it really shows some of the details and processes that are frequently talked about on forums but rarely shown.

Gives new insight into just what a quality machinist does differently than your average shop down the road and why it is so important to find a qualified one as is frequently stressed in build threads.
I know one place I would be willing to ship an engine to vs. sending elsewhere.
Great info for us novices to have a better understanding of what is being talked about when some of the more esoteric engine-building terms are being used.

Btw, you and Jeff ever work here? https://youtu.be/MpVIT-yccGU

[gtofreek]

Thanks Guys!

[gtofreek]

Originally Posted by Blackened

Fantastic thread Paul, it really shows some of the details and processes that are frequently talked about on forums but rarely shown.

Gives new insight into just what a quality machinist does differently than your average shop down the road and why it is so important to find a qualified one as is frequently stressed in build threads.
I know one place I would be willing to ship an engine to vs. sending elsewhere.
Great info for us novices to have a better understanding of what is being talked about when some of the more esoteric engine-building terms are being used.

Btw, you and Jeff ever work here? https://youtu.be/MpVIT-yccGU

Work there? Hell, we built the Arkenstone!

[gtofreek]

Originally Posted by SS-TA

I was at Paul's shop last week and he showed me the block along with describing all the issues. What amazed me is that anyone would spend so much money on this block and then take it to someone to repair who was a hack (presumably the original owner). Great work Paul.

Good to see you here SS-TA!

[Tom Vaught]

Originally Posted by gtofreek

I suppose they did it so the caps would fit tighter in the register. I see them ripping the registers up when the engine gets run, and heated up. If it was a good idea, all aluminum blocks would be that way.

When the Engine is under high power mode the main caps try to pull inward and upward.
The pontiac dowel pins have helped a lot with that issue (when the dimensions were right)
"Pontiac Engineers did stuff for reasons".

So when you have a "Chebby style registered block" with splayed caps the outer splayed fasteners are supposed to draw the cap up to the register and not allow the main cap to "Pull In" when under high load. The register is simply there to have a surface to pull against. So you want a nice flat wide surface for the fastener to clamp against.

When the "people' cut the serrations in the caps they basically created a bunch of "chisels" that are cutting into the register of the block. Aluminum being very soft vs steel you basically no longer have a surface to exert a clamp load against with the aluminum block. The main cap outer fasteners are doing nothing.

No concept whatever on how a splayed cap works against a block register.

Tom V.

[gtofreek]

It's been a while since I updated this. Finally got it done, and on the dyno. Will make pulls tomorrow. Meanwhile here are some more pics of the progress of building it. Here is the block on a stand so I can check it for stroker clearance.



Needs to be ground on some.

[gtofreek]

Time to start building. Here is a rod and piston ready to go in.



Thrust bearing.



Crank and cam in.

[gtofreek]

Time to check out oil pump, and deburr it. I also make sure the mating surfaces are true and flat, and check clearances







Of course, like on so many of these pumps, the bolts don't bolt down flat against the oil pump.



So off to the mill it goes to get cut square.

[gtofreek]

All done on the mill.





Tuned up the cam thrust plate, as it wasn't very flat. Took a fair amount of sanding on the granite slab to get it flat.

[gtofreek]

Short block together.





Cometic head gaskets.



Heads on.



Well, seems Harland Sharp just can't cut the mustard at this lift, which is around .630". Back of the rocker arm hits the poly lock at full lift. OOPS!

[gtofreek]

Crower to the rescue! I had a set of Crower 1.60 rockers here for another engine so I used one to check to see if they would clear, and they cleared by a mile, so customer had a set of 1.65's drop shipped to us. I'm kind of glad the Aluminum rockers hit because I really don't like running aluminum rockers with solid roller cams.



Figured out pushrod length, and ordered some thickwall pushrods from Smith Brothers.







Because of the tight lash cam[it only calls for .014" lash], and the aluminum block and heads, I had to set the cold lash at 0. I'm figuring it will grow around .014". So I will lash it when it heats up on the dyno.

[gtofreek]

Time to button this thing up, and get done with it.