Standard design technique in sealing for EMI in electronic boxes that fly.


Aluminum girdle on iron block: please consider designing in for creep movement based on CTE ; Girdle expansion can put tension on an iron block.

The idea of bringing oil to the mains from the bottom seems like a great idea. The NorthStar Cadillac brings all the main oil to those bearings from the bottom. They machine a rather complicated separator plate much like an auto trans that bolts to their mid-plate directing oil all over the place including feeding the mains from the bottom. In a High HP application while combustion is trying to push the crank out of the block, having a feed at the bottom seems like the way to go. Until your Billet Cage was available, doing this was pretty impractical. With that big hunk of aluminum, you have many options available. It is likely that our old reliable MD 54 pump will run out of volume at 7.5 GPM to supply the new oiling plan at the pressures we will need. Titan, external wet, or dry sump may be the only way to go.

In the aircraft engine business, we use jack screws extensively, because most everything has to be a press-fit. A few rules to go by:

1) enough screw locations that they don't bend the part when they're used. The screws should be located close to the interference-fit location to minimize bending (but see note 3 below).

2) the surface that they bear against needs a small spotface (.020 deep is sufficient) so that the metal that is raised by the end of the screw won't hold the joint apart at reassembly.

3) don't put the screw location too close to a precision machined feature. The action of the screw pushing down on a surface will also cause it to balloon out by a few thousandths, nearby.

Hope this helps,
Eric

... i agree Mike, i would suggest dry sump for this option, but i'm sure the Titan would be capable too, we have a couple of Titans here and will be testing one for this application ...

My own investigations in doing this on a Pontiac revealed a stockfit pump with stock ish oilscheme would be fine for many apps. The oil pan can be a whole separate new piece or a cut down piece you may already have...it would only need a flat flange fabricated.

One plus not mentioned is aluminum helps absorb harmonics...something to consider in high rpm applications.

I saw Cody's Olds piece last night. Nice!!!

Very nice,have to be careful you don't price it too high for the factory block guys,otherwise they may just as well buy an aftermarket block. I think it's likely that more factory blocks will need this girdle than aftermarket blocks will.

Mike, Do the Northstar people actually introduce the oil to the bearing surface at the "Cap" bottom? Or do they just have oil at the bottom of the bearing shell diameter (6:00) BUT
actually have another passage that introduces the oil to the bearing/crankshaft interface at the more typical 3:00-4:00 entry point?

It seems like if you introduced the oil at the 6:00 point you would be "late" on the oil film wedge taking effect.

Tom Vaught

Tom, I am really not sure what clock position the oil actually enters the main bearing area. The bearings are 3/4 groove like the FM Pontiac bearings. The next time we have one apart I will take a closer look at it. The interesting part of that engine that relates to the "Billet Cage" is almost none of the oiling system is in the part of the engine we would call the "Block". The oil pump sends the pressurized oil into this plate, girdle, cage first to oil the mains then up to the valvetrain etc.

I give Bill and others a lot of credit for trying to come up with a "Billet-Cage" crank/block support system (we use a similar system on our 4 cylinder engines to tie all of the mains together but it does not tie into the rails of the block. (More of a Girdle design). Steve B probably has run a version of the "Billet-Cage" crank/block support system longer that anyone.

One other comment: Anytime we drill/cast in an oil passage in a block design we weaken the design somewhat. Eliminating the block oil feed drilling(s) would improve the strength of the block more than you would think.

Tom Vaught

Yes Tom this is Steve B's concept but not multi-piece. Actually nothing revolutionary more evolution is a better term I'd guess.

I think this concept could be done in ductile iron IF lightened properly with correct shape scallops and possibly lightening holes strategically placed in the casting. (otherwise it would be a serious weight penalty. Even this billet aluminum has got some weight to it. (Duplicated as is in iron it would be heavier than a sewer cover.). Combine with precision casting and final cnc and fitting its not going to be cheaper than billet steel caps but ductile iron properties might be a better match to an iron block. IA and MR1 come to mind as well as the "crazies" like me working with an already stout stock block. (Aftermarket block with standard equipped caps probably cost similar so practicality of doing it to a stock block comes into play.)

Oiling... Oil through the cage is certainly something to investigate.

Its also possible to modify existing Pontiac oil scheme to priority main if one wants to do some drilling/plumbing... plug 8 existing driver side lifter feeds and plumb 8 new feeds from passenger galley to newly drilled driver side lifter feeds.(I'll be sure to post details/pics when I do mine) All lifter feed would then be metered at entrance to passenger galley reducing lifter feed area @ by half as all 16 lifters would then oil from same source helping balance feed as well.

Blocking lifter feed at driver galley forces oil to mains first. It already goes to #5 first. #1,2,3,4, are fed by the DS galley anyway but all lifter feed would now occur after the mains got fed.

Tom I also agree on oil drillings weakening things (espeacially if not well placed). Fwiw I noticed a distinct sharp "step" (in a 69 400 block ) in the feed drilling between mains and the lifter galley when I was looking at the priority feed mods required. I need to check my 59. If that is present on stock blocks it certainly needs to be smoothed.(possibly taper reamed) It could be a source of stress cracks.

I think this is just a preview of some of the things that will be incorporated into their billet block in some form.

Personally I think that you could get more strength with Nodular Iron Cross-Bolted Caps attached to the "Billet-cage" (main cap strength) and still have more strength vs a pure aluminum "Billet-cage" configuration.

You would also remove the Jack Screws requirement in the one piece design.

The dual material design would keep the caps from "waving in the wind", would allow smaller "side fasteners" that bolt to the Nodular Iron Caps and eliminate the outer main web drilling of the splayed or 4-bolt cap design.

Tom Vaught

Looks like Powerstroke parts.

Nice machinework!

Just curious, could you be a little more specific about your theory of the caps "waving in the wind" ?

If I was a better machinist I would have made an ali clamshell to fit over the machined down main caps on my '59 block and then crossbolted them.
I do like twinturbo's design though cost would be a big factor if I was going to buy one. Up to 1500-2000HP I would expect an IA11 block to be man enough for the job,if the girdle is aimed at those making more power than this then how many over 2000HP Pontiacs do you know of? Now, if the girdle was aimed at factory block racers and it would strengthen and extend the life of a factory block up to say 1200HP,then I think you would sell loads of them,as long as the price worked out significantly cheaper than buying an aftermarket block.

Not a Theory, really. More of a fact

Think Empire State Building where at the top of the building the observatory can be moving around (with just wind blowing on it) vs rock solid at the bottom of the building.

Same deal happens with the main caps on a block, (we saw this on some of our engine testing using high speed cameras).

So we now have fasteners tie into the caps and into the rails of the block.

Here is a link to how we try to limit the travel of the caps (to keep them from "waving"). http://www.google.com/imgres?imgurl=...QEwBA&dur=1367

In the photo you can clearly see how the designers are trying to secure the cap not only at the bottom of the cap but also at the top of the cap, as well as at the normal 2-bolt main fastener points.

If the cap moves you have "fretting". Fretting is basically metal transfer at the surface of the block and cap.
Securing the caps more securely eliminates a lot of the potential for fretting at the block surface as well as maintain a more consistent hydrodynamic wedge between the bearing and the crankshaft. Hope that helps.

Tom Vaught

... the loads you are describing being emposed on the Empire State building are totally unrelated to the Billet-Cage Tom, the loads described there are coming from the top of the building and the sides ?? ...

... in a running engine the loads are underneath, not above ... so i dont think taking something made of this high quality material, and it being one solid piece, would be stronger if you were to make it 7 seperate pieces and made of 2 different materials ??? ...

... and the pic you posted is also totally unrelated, as this is a skirted main block, in order for us to achieve that, we'd have manufacture our own block based on this design ...

... we are developing a one piece main support, to be fitted to an already existing block casting, and therefor making it even stronger than it already is ... meaning, anyone with this type of standard main cap block design will be able to upgrade to the Billet-Cage, also the machining time alone of a multi-piece design would be very cost prohibitive as there would be many different "Set Up's" requiring even more tooling & fixturing, and therefor more cutting time, something like this is not an easy thing to do, making it one piece solves a lot of serious obstacles ...

... making the block you described in your picture would not need this upgrade, but it would require the purchase of this new block, which is what we are trying not to do ...

... we will be making them for both factory blocks and aftermarket blocks, be it aluminum or iron, but yes we are working to keep the price points as low as we can for this reason you described ...

I think that you missed the basics of the stuff I posted Bill.

1) Why do you have a full girdle unless you are locking all of the caps together Top and Bottom?

2) The Bottom of the Cap touches the Block. The Top of the Cap is below the normal oil pan gasket surface. The top of the cap moves during normal engine operation. That is a fact.

3) The picture I provided in my post shows one method to keep the top of the main caps from moving as much as well as supporting the caps with a skirted block.

4) We do not have a skirted block, in your design, but we would have a main web structure that could act like a skirted block structure.

5) Making the structure so that the main caps were separate from the structure would eliminate the jack screw requirement. Are you going to add that jack screw feature to your design? The structure will distort with removal otherwise. Read Eric's and Mike's posts.

Just trying to help you look at the big picture vs machining out a web structure that distorts the first time you remove it. Then where is your support or strength?

Tom Vaught

Basically this cage makes a Pontiac type block similar to a skirted block.(could be done to SBC or BBC) Having the caps be one with the rail extension( bolt on skirt) makes it stronger as there is nothing bolted from the "skirt" to the cap its all one piece. Across the mains it can still be bolted just like splayed caps. The material is very strong.

Steve B's system works well on his Blown fuel 389. This is an evolution of his setup, one solid piece and stronger because there are no joints and fastening points to/at the main/rail . OEM's are using similar concepts not multi piece. We dont have a skirted block like some Fords and Mopars have.