MK 58A Sport Port 44XS "Giant Killer"

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MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Sat Jan 05, 2019 8:29 pm

Ok here we go. I have hinted about this special build and now, with permission from the designer, will proceed with what I feel is the best 4 cylinder Merc I have tested. This is the motor the factory should have, but never built. I am confident it will outrun a stock 44XS on the race course, but retain a closed exhaust and "Classic Merc" exterior. The design works well on a hydro yes, but has also been proven on a Lund fisherman in full gear-shift trim. The parts pile is well under way. What you see here is a similar batch of carefully selected parts one would use in a MK 55HS in terms of the rods, crankshaft, reed cages,bearing caps. etc. We are also quite fortunate to have a set of ultra low-mile 44 small wrist pin pistons weighing within 0.5 grams! Block is std bore, bead blasted and professionally ported, chamfered and honed via Sunnen machine. The trick here is a port mod that corrects a factory design flaw built into every 44 and some later 40 Mercs done without changing the port timing. The result is a marked enhancement in performance without sacrificing low speed idle behavior. More details to follow...


Chuck
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby Four Sons » Sun Jan 06, 2019 12:52 am

Oh boy, I’m looking forward to this.  I certainly enjoy your well documented projects! As always, thanks for taking the time to share with us.

Pat
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby mark 55 » Sun Jan 06, 2019 9:08 pm

Chuck, you may have mentioned this in the past, but are your blocks simply bead blasted? Or are they painted also? Where do you get them done?
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Sun Jan 06, 2019 10:37 pm

Hi Scott,

The block above was painted white in 1959. It has been chemically stripped and blasted in a media cabinet with medium glass bead. After a very thurough cleaning, it then recieved a light spray of high-temp ceramic clear coat. I wipe down the bores with LPS-2 to prevent corrosion. I have a bench top cabinet in the garage that works great for small items like pistons, rods and crankcase covers. I have friends with larger stand-up cabinets that I use on the blocks and H-tower sections. There are benefits to this process beyond cosmetics. It also gives my machinist a very clean product to work with.

Not all of my builds have gone this route. I found a high-temp ceramic aluminum color from DupliColor that works quite well on the silver painted blocks like the 1958 models. If the finish is in decent shape, I like to keep the bare treated metal look of the 1955-56 motors. The MK55HS build (shown below) was a late 1955 "dark block" that was just cleaned up and wiped down with some WD40 at the very end to enhance the color. Lot's of elbow grease and Q-Tips used on that one!


Hope this helps.


Chuck
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby 58woody » Mon Jan 07, 2019 5:04 am

What steps do you take so the cylinder walls do not get any media damage?
Same goes for the inside of the crank area?
Thx
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby jdub47r » Mon Jan 07, 2019 6:16 am

Here is a ported 44 with a Thunderbolt Ignition, Mercury 500 tuner under Mark58 cowling. It is still a work in progress, but once I get the 1-1/8” KC’s jetted right, I think it will be a really cool “Sleeper”. It has shown some good promise already.

https://m.youtube.com/watch?v=tWhO-NCbz54
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Mon Jan 07, 2019 6:57 pm

One critical area to clean up via the glass bead blasting are the cylinder heads. Be sure to get any bits of carbon cleaned up as beads like to hide there. All this takes place prior to the finish hone and/or boring if needed. Also ,with regard to the pistons, I do mask off the sides with painters tape prior to blasting. Other areas to protect include crank and rod bearing surfaces.

Chuck
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Mon Jan 07, 2019 11:08 pm

Here is another detail some may find of interest. The early 1955 MK55 blocks had no oiler feeds on the side of the block period. The next generation had a feed line running from the center main bearing up to the top bearing cap. OK idea. Then they changed that route to the lower bearing seal, but kept the unfinished boss on top(see photo#2 white Merc500). My thought is to take the oil from where you really don't need it to where the motor might like some! For these performance 44's, I like to route the oiler line from the lower cap to the upper cap and plug the center. I also like to use the newer solid top end cap(no slots). Only problem here is they were not drilled. Solution - drill both the top feed boss and cap as a pair. A little deft work with a Dremel tool will also add the factory style "feed" slot in the top cap.


Chuck
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby 1500J » Tue Jan 08, 2019 5:20 am

What is the port design flaw?  When you get time.  Thanks  Conrad
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby zul8tr » Tue Jan 08, 2019 1:34 pm

ctpdsr wrote:Here is another detail some may find of interest. The early 1955 MK55 blocks had no oiler feeds on the side of the block period. The next generation had a feed line running from the center main bearing up to the top bearing cap. OK idea. Then they changed that route to the lower bearing seal, but kept the unfinished boss on top(see photo#2 white Merc500). My thought is to take the oil from where you really don't need it to where the motor might like some! For these performance 44's, I like to route the oiler line from the lower cap to the upper cap and plug the center. I also like to use the newer solid top end cap(no slots). Only problem here is they were not drilled. Solution - drill both the top feed boss and cap as a pair. A little deft work with a Dremel tool will also add the factory style "feed" slot in the top cap.


Chuck


Chuck

As you note Merc did some interesting things with the top bearing oilier system, I like your mod to the oilier system.

Another Ex: on the first series of the 25ss in 1973 the oilier system was used and had a bottom fitting with 1 way check ball for residual oil only up. That fitting was connected via rubber tube to the bottom facing down of a T fitting with the T branch into the top cylinder airflow stream upstream of the intake ports of the top cylinder. The top of the T had a hose to a fitting at the top of the block just below the top cap on the intake side of the block. This top fitting had a selected orifice size (different sizes in different years from 73 to early 80's? and a change in location of top fitting to front of crankcase).

The operation: oil is pulse pushed up from bottom cylinder bearing thru the only up check ball, at T during fuel mix flow into top cylinder the high velocity fuel mix has a low (-) pressure at the T probe that pulls in oil from lower bearing and the low pressure allows oil into Top cap thru the bearings and out thru top fitting back to the T. When top cylinder crankcase pressure is reversed and under higher (+) pressure the pressure at the top fitting is about the same as at the T probe and no oil flow, thus a pulse oil flow at the top cap bearings.  The side effect was additional oil to the top cylinder combustion chamber to be added to the inflow fuel oil mix. Never noticed any plug color difference top or bottom cylinder.  

I think a single hose from bottom check ball fitting to the top fitting (no T fitting) would also do an adequate pulsing oil job to oil the top bearings. Maybe the engineers knew something that required the T that is lost in history like other mod things at Mercury :?:  

https://www.bing.com/videos/search?q=ve ... ORM=VRDGAR

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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby 1500J » Tue Jan 08, 2019 4:29 pm

Ive had one of those top hoses come off a later Inline 6.  It made a mess  under the cowling in a fairly short order.    They push more fuel/oil up to the top bearing than I realized.
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby zul8tr » Tue Jan 08, 2019 5:12 pm

That's probably why the orifice in the top fitting.
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Tue Jan 08, 2019 5:48 pm

Oh, I should have mentioned - the brass fittings are OEM with the check valve version on the bottom. Always test those as they tend to get messed up over time.


Chuck
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Wed Jan 09, 2019 1:09 am

I want to emphasize the precise nature of the porting done here. We are not changing the port timing or touching the intakes period. I am getting ready to ship a 1958 MK 58 block to my machinist that has been cleaned. If you look close, you can see the difference "before & after" vs. the MK58A. The performance boost is real while maintaining a smooth idle and low speed operation. Go any further, and you will limit the usability to performance applications only. Go too far and you will succeed in making a pooch out of a decent stock motor. I saw way too much of the later during my racing days.


Chuck
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby TNT Teen » Wed Jan 09, 2019 1:21 am

I was wondering if you were referring to it as "sport port" because it was Jerry's design, or just a coincidence. I have a Mk 25E block I've been debating doing this port to.
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby Yellowjacket » Wed Jan 09, 2019 1:34 am

In post #8 there are three shots of intake ports.  One, the middle one appears to have the ports raised up into the roof of the transfer port.  

How much are these ports raised up and how does this compare with APBA 44 cube stock spec port timing that the 44xs has???

And if this is opened up a lot more tha a 44xs you sure would expect that it would make a lot more power than the xs..  

The real point being that if you did the same thing to a late model 500 block what kind of power would that make?
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby 1500J » Wed Jan 09, 2019 2:08 am

Thanks for the good photos.   I peaked past your intakes photos earlier and guessed you squared them.  I assume it was not worth the time for Mercury to add the extra machining steps to accomplish this on a production motor.

Mostly unrelated but similar, Mercury did this with a few production 1500’s in the 1974 time frame.  Then they stopped doing it.

Conrad.
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Wed Jan 09, 2019 5:03 am

Some really good questions.

The "Sport Port" IS Jerry's  design. I'll add his comments regarding the development process soon. When I looked at the photo of the intake ports, I knew there might be a comment or two. Note the disclosure earlier that the intakes are 100% stock. That being said, the variance from the factory resulted in some of the surfaces showing a higher "clean up" grove vs. ports on the low end of the scale. My camera simply highlighted this condition. Port mods were limited to the exhaust side period. While the blocks shown here are early 44's, every 44 and some of the later 40's shared the factory defect that makes this transformation so effective.

Oh - if you were referring to the photo in the post regarding historical oiler feeds, there was a 55H-1 block shot included with a really early dark MK55S. The former does provide a view of what the factory raised intake ports looked like.

Chuck
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby Locomotion » Wed Jan 09, 2019 4:07 pm

Does losing some (I know it's very little) of the material in the port web lead to any issues with heat?
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Wed Jan 09, 2019 7:00 pm

Yes sir. That's why there was very little removed there. This area gets hot & metal will tend to bend inward towards the heat source. I have seen some blocks with silly thin webs. Not a good plan.


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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby zul8tr » Wed Jan 09, 2019 7:11 pm

ctpdsr wrote:Some really good questions.

The "Sport Port" IS Jerry's  design. I'll add his comments regarding the development process soon. When I looked at the photo of the intake ports, I knew there might be a comment or two. Note the disclosure earlier that the intakes are 100% stock. That being said, the variance from the factory resulted in some of the surfaces showing a higher "clean up" grove vs. ports on the low end of the scale. My camera simply highlighted this condition. Port mods were limited to the exhaust side period. While the blocks shown here are early 44's, every 44 and some of the later 40's shared the factory defect that makes this transformation so effective.

Oh - if you were referring to the photo in the post regarding historical oiler feeds, there was a 55H-1 block shot included with a really early dark MK55S. The former does provide a view of what the factory raised intake ports looked like.

Chuck


Chuck

"While the blocks shown here are early 44's, every 44 and some of the later 40's shared the factory defect that makes this transformation so effective."

What is the factory defect?

The pistons you have in the 1st post do they have the pin offset, if yes  how much toward the intake?

Do you know why they went to large pin pistons and rods?
Setups I have weighed large pin are heavier.

Pete
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Wed Jan 09, 2019 8:04 pm

40 and 44 Porting, Urban Myths.doc
(29.5 KiB) Downloaded 33 times


I hope this attachment file got through OK. There is a lot of information here. The bottom line is to note the change in manufacturing process that occurred in 1958-59.

The pistons you see are later small wrist pin versions. These are slightly heavier than the early 44 pistons found in MK58/MK78 motors, but still much lighter vs. larger pin models. I am not sure why they made the change, but will ask a smart guy.

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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby zul8tr » Wed Jan 09, 2019 9:45 pm

ctpdsr wrote:
40 and 44 Porting, Urban Myths.doc


I hope this attachment file got through OK. There is a lot of information here. The bottom line is to note the change in manufacturing process that occurred in 1958-59.

The pistons you see are later small wrist pin versions. These are slightly heavier than the early 44 pistons found in MK58/MK78 motors, but still much lighter vs. larger pin models. I am not sure why they made the change, but will ask a smart guy.

Chuck
B501435B-A6C0-4111-8F5F-6702417B1738.jpeg


Chuck

What a bunch of machining confusion at the factory. Racers did quite a bit of measuring and looking to determine all this.
Of course Jerry explains it well and probably did a lot of the looking and measuring.

Do those pistons have off set pins?

The answer for small to large pin will be interesting

Pete
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby 1500J » Thu Jan 10, 2019 12:15 am

Thanks for posting .  Ive never read Jerry's write up before.  Very interesting.

Stock porting is just how the factory decided to port it at the most reasonable rate that got the HP rating they needed.   Not necessarily a flaw so to speak that causes a failure over time.


You could look back at the evolution of all 2 stroke motors and call earlier versions flawed.

Best,

C
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Thu Jan 10, 2019 1:08 am

I agree 1500,
Perhaps a poor choice of words. My larger point is that the production method change did have a negative effect on performance that is fairly easy and economical to fix without creating an adverse effect to other areas of operation. How many of our readers knew about this change prior to this post? Just curious. Also keep in mind the porting is just one piece of the puzzle here. This build contains all the special elements we found worked well in the 40 cid MK55HS Merc Challenge Motors that had to pass stock inspection. What we really have here at the end of the day is the MK58H that Mercury never built with the added benefit of the very mild port mods. These mods were inspired by the research done by several smart D-Stock racers trying to sort the best combination of legal parts available to them 50+ years ago.


Pete,
You are correct. Jerry was one of the D-Stock Hydro Racers that figured a bunch of this stuff out, but there were others that were doing the same. Just think about the competition they had at local races in Wisconsin in the 1970's. Jerry Wienandt, Dee Berghauer, Dewey Berghauer, Sam Hemp, Hank Menzies. By the time I got involved in 1983, the motors were all figured out, but the boat technology was in hyper-space. Sitting in the B&H Hydro shop watching Sam Hemp work was like looking in on a mad scientist. Then you had John Puestow put a side fin on a D-Stock Runabout! All this tech changed racing strategy to "floating" around the course at high speed vs. plowing your way around the buoy line. But I digress...
Oh - I think the piston wrist pin offsets came with the change to large wrist pin pistons & rods. Idea was to cut down on the "slap" for quieter operation. I have very limited experience working with these.

Thanks guys!

Chuck
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby 1500J » Thu Jan 10, 2019 1:50 am

How many of our readers knew about this change prior to this post?


I don't think I did.  If I saw it I was not paying attention.   Most of my L4's that I have fully torn down have been 1960-1964 44's.     I wonder if my older L6's are ported the same way with a double pass?  I should bore scope my MK 75 .  I have a 1960 700 apart now I can look at that easy tonight.

Does the "Sport Port" raise the RPM power band?  Or is the power band similar, just stronger?

Thanks.  Very interesting read.

Conrad
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby zul8tr » Thu Jan 10, 2019 11:51 am

ctpdsr wrote:I agree 1500,
Perhaps a poor choice of words. My larger point is that the production method change did have a negative effect on performance that is fairly easy and economical to fix without creating an adverse effect to other areas of operation. How many of our readers knew about this change prior to this post? Just curious. Also keep in mind the porting is just one piece of the puzzle here. This build contains all the special elements we found worked well in the 40 cid MK55HS Merc Challenge Motors that had to pass stock inspection. What we really have here at the end of the day is the MK58H that Mercury never built with the added benefit of the very mild port mods. These mods were inspired by the research done by several smart D-Stock racers trying to sort the best combination of legal parts available to them 50+ years ago.


Pete,
You are correct. Jerry was one of the D-Stock Hydro Racers that figured a bunch of this stuff out, but there were others that were doing the same. Just think about the competition they had at local races in Wisconsin in the 1970's. Jerry Wienandt, Dee Berghauer, Dewey Berghauer, Sam Hemp, Hank Menzies. By the time I got involved in 1983, the motors were all figured out, but the boat technology was in hyper-space. Sitting in the B&H Hydro shop watching Sam Hemp work was like looking in on a mad scientist. Then you had John Puestow put a side fin on a D-Stock Runabout! All this tech changed racing strategy to "floating" around the course at high speed vs. plowing your way around the buoy line. But I digress...
Oh - I think the piston wrist pin offsets came with the change to large wrist pin pistons & rods. Idea was to cut down on the "slap" for quieter operation. I have very limited experience working with these.

Thanks guys!

Chuck


Chuck

" I think the piston wrist pin offsets came with the change to large wrist pin pistons & rods. Idea was to cut down on the "slap" for quieter operation. I have very limited experience working with these."

Seems reasonable and I have read about the piston slap theory and that make sense. However I have a pair of early standard bore Merc 22 ci small pin pistons with 1/8" offset, so the mystery continues  :?:  To explore offset I developed a detailed spreadsheet that calcs for each degree in 360 crank rotation from TDC the: piston position, velocity and acceleration. It compares no offset to offset pin. Interesting changes with velocity and acceleration with and without pin offset.  For ex. with my 1973 25ss that has large pin pistons with 1/8" offset pins, has less acceleration with offset from TDC to about 75 degrees ATDC  on power stroke, thus less force loading on exhaust side of cylinder, so probably less piston slap. Merc engineers probably knew this and tried it and listened and said it works  icon_thumbup.gif   Also pin offset changes the intake and exhaust port open and close degrees compared to no offset.

But why large pin pistons and rods that are heavier   :?:

Pete
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Thu Jan 10, 2019 5:35 pm

The piston castings in general got heavier over time. The early MK58/MK78 pistons were about 20g lighter vs. the later Merc400/Merc700 versions. With regard to the porting, my guess is similar machining occurred on the 22 and 66 cube versions. Question for a 25SS guy. I remember some racers getting caught using early Merc200 Service blocks on 25SS rigs. Was the temptation there to take advantage of double cut ports? My knowledge and experience is limited to the 4 cylinder stuff. The change there occurred with the "Siamese" port cover models in 1958-1959.


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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby zul8tr » Thu Jan 10, 2019 6:11 pm

Chuck

My years (1970's) with the 25ss class and talking with Harry Pinner and Marshall Eldridge who were inspectors on occasion I do not recall that being mentioned in Region 5. I spent many hours with Harry and Marshall at their shops and at the Boat Racing Club of Palm Beach County.  Maybe in other regions that could have occurred  :?:
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Thu Jan 10, 2019 10:05 pm

Just for grins, I took an inventory of the finished pistons in my drawer and checked weight ranges.

The early style (MK58-MK78) small pin denoted by the ridge in the interior casting have a weight range between 243-251g. (**Piston and Pin - no spacers). The later style (Merc400) small pin in the center of the photo range 256-267g. I only have a few large pin examples floating around from an early 70's Merc500 donor. This guy tipped the scales at 282g. I honestly don't remember what donor 44 the perfectly matched set for this build came from. My guess is a MK58A or Merc400, but they all came from the same motor. I wonder if this was a rebuild or just dumb luck that they all weighed out virtually the same. I typically see a 3-5g range high to low from the factory and this is just fine for a service motor. If you notice, I get very picky for a performance application.

Also keep in mind we are trying to get away with fairly low mile standard bore blocks, reconditioned rods and pistons and new OEM rings (available for 44's but not 40"s...). If a block needs boring & oversize pistons, you have no choice but to go with large hole rods & new aftermarket large hole pistons. There may be a few sets of new OEM small pin +.015" 44 pistons out there, but not in my parts cabinet!


Chuck
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby 1500J » Thu Jan 10, 2019 11:36 pm

I didn't realize just how much bigger the pin got.
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby zul8tr » Fri Jan 11, 2019 2:13 pm

For comparison here are weights from my 2 cylinder engines for pistons + pin + rings +retainers, not an exact comparison to above with just piston + pin but gives an indication of weight changes.

1) Older Merc 200 22ci service engine std bore 3 ring small pin pistons:                     282.8 g and 288.2 g diff = 5.4 g fair   
2) 1973 25ss 22ci std bore right from Mercury w/ 3 ring large pin pistons:                  303.5 g and 303.2 g diff = 0.3 g very good quality control
3) Same as 2) w/ 15 over bore in 2012 w/ Mercury 44 ci 2 ring large pin pistons:        309.8 g and 310.1 g diff = 0.3g very good quality control

Small pin defiantly lighter  3) is cast and I think 1) and 2) are forged
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"If all the economists were laid end to end, they'd never reach a conclusion," George Bernard Shaw
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Re: MK 58A Sport Port 44XS "Giant Killer"

Postby ctpdsr » Fri Jan 11, 2019 10:44 pm

One last comment on stock factory tolerances. Check out the 44 blocks below. One is our MK58A feature build, the other a MK58 cleaned up and ready to ship to my machinist in MN. The intake ports are untouched from the factory, but it is obvious that one set is slightly higher. I don't remember the inspection limits for D-Stock, but there was enough of a difference right out of the factory that guys would seek out examples that would measure out to either extreme(low or high) depending on the desired setup. OK - time to dress some piston spacers and a center main bearing!


Chuck
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