Milwaukee Midget

[tauruck]

When we were that age girls wore stockings>

[Old Scrambler]

........Millennium Technologies, the folks in the video, are in Plymouth, Wisconsin.......

MM..........They know their stuff..............ask for a tour.  My motor builder, Dave Murre.........Murre Salvage............has a shop account with them. If your in Plymouth...........be sure to stop at the brew-pub on Mill Street (downtown) and have a sample.......or three   If its convenient, I could meet you at M-Tech .....or at the brewery

BTW.........I was thinking the active water-jacket on your block should curtail a great deal of your measured expansion.

[Seldom Seen Slim]

Stainless, when you  (and I) were worrying about getting the girls out of their clothes -- pantyhose hadn't been invented.  Girls (at least where I grew up) wore fancy-striped or -patterned denim stockings -- and you weren't all that interested in what they were hiding, anyway - if you were smart.

happy Birthday next week.  Wait 'til you hear about the gift I think I'm getting!! Whoo-hoooo!!

[bones]

Millennium Technologies are probably the most common used cylinder platers in the US and have an extremely good name.

Every modern sports bike has nikasil or some other plating on the cylinder bores -- it is tough. Those 500hp Hayabusas use stock cylinders

Yamaha used to use hard chrome from the 70's in their 2 stroke production road racers-- the Porche was probably hard chrome.

Some of the Vincent guys are now using an aluminium sleve which is Nikasil plated instead of a cast iron sleve and shrunk into the cylinder

I don't think you would have any trouble with the plating, but will the sleve keep it's proper shape?

            cheers    Bones

[fordboy628]

midget,

Molding compound arrived today.

 
Fordboy

[fordboy628]

midget,

This is the basic process for many Japanese and European engine blocks.   This is a short video, but there are several longer ones that pop up, showing the complete process of boring "away" the original surface, and replacing the bores with a sleeve set to increase displacement/whatever.

https://www.youtube.com/watch?v=RrsUWh0Hs8c

Some use Darton (iron) sleeves, some use alloy sleeves with a Nikasil surface.

I think that both methods can be engineered to work properly.    I also think that you should gather some information about the cost of the 2 different sleeve types.   That might make the decision for you.

 
Fordboy

[ggl205]

Broken rings do the Nicasil in from our experience with 2 strokes.
Expensive to redo. Guys found it easier to just buy new barrels.

Iirc there was a certain type of petrol sold in the UK in the 90's that also caused Nikasil to flake off as well? (High sulphur content?) so this may be something to look into if you are considering using this?

I think we may be mixing technologies here. Early Porches air cooled cylinders (both four and six cylinder high performance engines) used an aluminum barrel coated with Nikasil. It was a durable, long lasting coating that could be reused if no damage was present. High Sulphur fuel did not affect Nikasil but was hell on Alusil. Alusil is a high silica concentration aluminum alloy with other hard particles forming in the alloying process. The Porsche 928 V8 used this alloy for blocks and later used it in liners for water cooled flat six engines. Mercedes and BMW also used Alusil but in different ways. Mercury Marine used their version of Alusil called Merkasil for their low cost outboard engines. Mercury tried to prepare Merkasil by boring and brushing only and this did not work well at all. All versions of Alusil need to be prepared correctly or failures will result. Alusil is parent metal so you are not dealing with a coating here.

I almost forgot the Chevy Vega block. This was a bold venture into high tech hypereutectic aluminum alloy. It used roughly 18-20% silica and other hard particles forming during the diecast and cooling phase, not so dissimilar to how Mercedes Benz cast their version of Alusil. The Vega engine suffered many failures but not because of the Alusil. Rebuilders did not know how to prepare this alloy (Sunnen eventually had a workable yet messy solution) and had trouble because they employed cast iron methods to this alloy including using quick seater cast iron ring packs. To fix this, rebuilders pressed in cast iron liners and pretty much solved the problem. But I have seen Porsche 928 V8 blocks with over 150,000 miles and there was hardly any wear in the thrust side of the cylinders at TDC.

Earlier technologies Porsche used for their aluminum engine cylinders was a simple cast iron coating. This coating had a tendency to wear fast or come off the cylinder bore. These problems gave way to Nikasil.

The Jaguar issue with Nikasil was more of a masking and clean prep problem. The coating was applied just after boring and if memory serves me correctly, on the same machine that did the boring. Good idea but not in practice. BTW, Nikasil can be applied to almost any ferrous and non-ferrous metal. I was looking at it for cast iron cylinders years ago. The problem is getting it off if needed.

John  

[Milwaukee Midget]

Thanks for that, John.  Seems that coatings ALWAYS work in race engines, but the minute you try applying the process to mass production, corners get cut and the next thing you know, the "Inbox" at accounting is full of warranty claims, and all those beans they thought they could save get ground up with the coffee the engineers are drinking at 2:00 AM trying to figure out how to hold on to their jobs long enough to keep their pension.

I downloaded Sketchup this week - a little wonky, but it lets you turn your work into jpegs, so here's a preliminary iteration of the proposed cylinder liner - material yet to be determined.

It is sans flange flats -

[Interested Observer]

OK, now, again, I’m a bit confused--but good to see the advancement to diagrammatic presentation..

The 5mm rib at the top was unexpected.  From the description in reply #5433, it sounded like the plan was to extend that large OD down to the level of the original shoulder, having re-faced the block shoulder to the larger diameter, creating a wider seat for the larger OD liner to sit on.  Otherwise, what is the point of the larger OD, just interface with the bolt bosses?   
Perhaps a cross-section drawing of the block/liner (and head and gasket?) interfaces would be useful for discussion.  I was going to do that for myself in order to sort out the load paths and dimensional stack-ups but haven’t gotten around to it. 
Also, it appears that there is some sort of seal at that shoulder to separate the coolant from the lubricant.  Is that so, and how about some elaboration on that issue?  As if you don’t have anything else to do!

[Milwaukee Midget]

IO, to your points -

Yes, it's my thought that anything we can do to better stiffen up the block/liner combination would be in our best interest, thus the 5 mm rib at the top.  It will require flats, as we're 88mm on center with the bores.

Granted, we have considerable surface mating on the bottom of the liner - 79 mm deep into the crankcase - but if there is any shimmy of the head where it mates to the block and the top of the liners, having the block and liners tied together at both the top and the bottom would minimize the possibility of the block, the liner and the head creating sheer in 3 directions, and help limit it to only 2.

Additionally, there's not a lot of meat between the bores in the block, so any interference fit is going to have to be achieved cautiously.  The casting is ~4mm between the bores, so diameter "C" may need to be adjusted down to be no larger than necessary to achieve an interference fit in a clean-up of the block bore.

As to sealing the liner so oil and water do not mix, it's likely some sort of epoxy will be necessary - but if we're able to use aluminum liners, we minimize the different rates of expansion, and as deep as the bore goes into the block, maybe an interference fit might be sufficient?  I'm not sure.

As if you don’t have anything else to do!

Let me get a better handle on this program before I start delving into cross sectional diagrams and exploded views.  It took me 3 hours to get the cylinder right!

I DO have a lot of things to do - but I'd rather do this! 

[Milwaukee Midget]

One other thing, I.O. -  By making section "B" 87 mm, we can still circulate some coolant around the entire top half of the liner.  As thick as it is, I'm thinking of cooling grooves through this section as well.

[fordboy628]

Thanks for that, John.  Seems that coatings ALWAYS work in race engines, but the minute you try applying the process to mass production, corners get cut and the next thing you know, the "Inbox" at accounting is full of warranty claims, and all those beans they thought they could save get ground up with the coffee the engineers are drinking at 2:00 AM trying to figure out how to hold on to their jobs long enough to keep their pension.

I downloaded Sketchup this week - a little wonky, but it lets you turn your work into jpegs, so here's a preliminary iteration of the proposed cylinder liner - material yet to be determined.

It is sans flange flats -

midget,

Just a reminder:

As we discussed with the Darton engineer at the PRI show, the "B" Ø must exceed the "C" Ø by 6mm or .25", whichever is more convenient.   I agree with Darton's assessment that the barrel "footing area" is too small (thin) to properly support the load applied, a shortcoming of the original design.    The minimum "footing area" that Darton recommended was .125" per side.   (Or 3mm [.118"] per side)    This is approximately double the stock dimension.   Take a good look at the barrel seats in the block to see how "indented" they were from the load on the barrels . . . . . .    Loss of pre-load there, is going to result in a loss of "clamp load" at the gasket interface, not a good thing.

At those dimensions I quoted, a "siamese flat" will need to be machined on the mating faces of each barrel, to fit in the 88mm bore center spacing, OR, the cylinders could be "contoured" ala a "French curve", in addition the required clearance flats @ the top and the bottom of the barrels.   "Coolant grooves" should be included in the design, Darton should use their greater experience to define size and placement.

Once again:  "Packaging is everything."

Run wild with Sketchup . . . . . . .        My idea of a "French curve:



C'est si bon!    NO flats there . . . . . .

 
WishIspokeFrenchboy

[4-barrel Mike]

As above, but 2014:



Mike

[Rex Schimmer]

As I just know that Chris is on the verge of winning the Power Ball lotto, so based upon the potential of unlimited funds that will then be available, have you ever thought about making a 3/4 inch (19mm) thick dry deck plate that would separate the head from the block but most importantly provide a place where you could make some good 1/4 wide counter bores that you could then shrink the new aluminum sleeves into, plus it would strengthen the block and eliminate the somewhat minimalist head from having to do some structural work that it appears less than able to do.

Rex 

[WOODY@DDLLC]

As above, but 2014:

Mike

Mike, please Google: resize picture!! PLEASE!