| Author |
 Topic Search  Topic Options
|
HudCo 
Orange Level
Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 3431
|
 Post Options
 Thanks(0)
 Quote  Reply
 Topic: new ap 46 piston made
Posted: 09 Jul 2024 at 5:45pm |
|
|
 |
|
Sponsored Links
|
|
|
Ol case mike
Bronze Level
Joined: 24 Dec 2022
Location: Michigan
Points: 7
|
Post Options
Thanks(0)
Quote Reply
Posted: 09 Jul 2024 at 5:48pm |
|
Do those need 170 cut off the tops still
|
|
HudCo
Orange Level
Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 3431
|
Post Options
Thanks(0)
Quote Reply
Posted: 09 Jul 2024 at 5:50pm |
|
four brand new ap 46 just waiting on the d17 crank so we can decide on compression ratio i had the pin hieght and the bowls the same as my sample piston we will see how much to mill
|
|
HudCo
Orange Level
Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 3431
|
Post Options
Thanks(0)
Quote Reply
Posted: 09 Jul 2024 at 5:54pm |
|
|
|
DrAllis
Orange Level Access
Joined: 12 Sep 2009
Points: 19921
|
Post Options
Thanks(0)
Quote Reply
Posted: 09 Jul 2024 at 5:55pm |
|
NOW WE"RE GETTING SOMETHING DONE !!!! Remember to mark the flywheel for 20 and 22 degree BTDC because that is where you need to be.
Edited by DrAllis - 09 Jul 2024 at 5:57pm
|
|
Thymansrepairandcust
Bronze Level
Joined: 23 Jun 2024
Location: Cameron, WI
Points: 8
|
Post Options
Thanks(0)
Quote Reply
Posted: 09 Jul 2024 at 5:55pm |
|
Im interested in a set of these if they are available. And will come back to see if they do need milling or not for a d17
|
|
steve fischer
Orange Level
Joined: 11 Jul 2011
Location: sleepy eye mn
Points: 955
|
Post Options
Thanks(0)
Quote Reply
Posted: 09 Jul 2024 at 6:40pm |
|
Is that the sample I sent you
|
|
HudCo
Orange Level
Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 3431
|
Post Options
Thanks(0)
Quote Reply
Posted: 09 Jul 2024 at 9:45pm |
|
yes sir steve i still thank you i am keeping it on file in case you need it agian
|
|
HudCo
Orange Level
Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 3431
|
Post Options
Thanks(0)
Quote Reply
Posted: 09 Jul 2024 at 9:48pm |
|
how much compression am i going to be with out milling the top ? i cant waite to get the crank back so i see what volume i have at tdc
|
|
DrAllis
Orange Level Access
Joined: 12 Sep 2009
Points: 19921
|
Post Options
Thanks(0)
Quote Reply
Posted: 10 Jul 2024 at 8:07am |
|
When I used SP-46 pistons I had to remove .170" from the outer top lip because the piston would hit the cylinder head !!! I had 240 psi of cranking compression and always felt it was around 11 to 1 ratio. 110 octane fuel was easily good enough along with retarded ignition timing of 20 to 22 degrees BTDC at full throttle.
Edited by DrAllis - 10 Jul 2024 at 8:48am
|
|
WF owner
Orange Level
Joined: 12 May 2013
Location: Bombay NY
Points: 4482
|
Post Options
Thanks(0)
Quote Reply
Posted: 11 Jul 2024 at 3:11pm |
|
Just a question, but if they are custom building the pistons, couldn't they shave .170 from the top or move the wrist pin up .170 during the build?
|
|
DrAllis
Orange Level Access
Joined: 12 Sep 2009
Points: 19921
|
Post Options
Thanks(0)
Quote Reply
Posted: 11 Jul 2024 at 3:27pm |
|
Sure. They have to be told exactly what you want and they will make it like that.
|
|
NEVER green
Orange Level Access
Joined: 28 Feb 2013
Location: MN.
Points: 6887
|
Post Options
Thanks(0)
Quote Reply
Posted: 12 Jul 2024 at 9:21am |
If they were mine I would like the ring pack higher, I guess with the bowl so big - wide there is not enough material.
|
|
2-8050 1-7080 6080 D-19 modelE & A 7040 R50
|
|
DrAllis
Orange Level Access
Joined: 12 Sep 2009
Points: 19921
|
Post Options
Thanks(0)
Quote Reply
Posted: 12 Jul 2024 at 10:30am |
|
I would have preferred the top ring height match the old pistons location to keep the compression exactly the same. I know it will be a very slight difference.
|
|
WF owner
Orange Level
Joined: 12 May 2013
Location: Bombay NY
Points: 4482
|
Post Options
Thanks(0)
Quote Reply
Posted: 12 Jul 2024 at 2:20pm |
I remember talking to Don Bradley several years ago and he was totally against using flat-top pistons. He claimed Power Crater pistons would always dyno better than flat-tops, despite the fact that the flat-tops had more compression. I don't think we talked about M&W pistons. Is that why you aren't using flat-top pistons?
|
|
DrAllis
Orange Level Access
Joined: 12 Sep 2009
Points: 19921
|
Post Options
Thanks(0)
Quote Reply
Posted: 12 Jul 2024 at 2:55pm |
|
I've never used flat tops because I always felt Power Crater was better. When I had Ross make me custom pistons I was able to spec the bowl diameters (top and bottom) and bowl depth (cc's) and compression distance (pin to piston top) to exactly what I wanted. So, why not go with the Power Crater design ?? I also have never had the time or money (maybe the other way around) to build an engine with 8.25 to 1 compression flat tops and then tear it apart and install 8.25 to 1 Power Craters from a 175 tractor. I would assume all things being equal (4 inch bore and same compression, same cam, head and carburetor) the Power Craters would show some slight advantage. I would also be willing to bet if the flat tops were at 9.0 to 1 instead of 8.25 to 1, that might be the winner in making the most HP. We will never know. My pulling engine is 4 5/8" plus bore and cranking compression tests at 300 psi with Ross custom made Power Crater pistons.
Edited by DrAllis - 12 Jul 2024 at 2:57pm
|
|
HudCo
Orange Level
Joined: 29 Jan 2013
Location: Plymouth Utah
Points: 3431
|
Post Options
Thanks(0)
Quote Reply
Posted: 12 Jul 2024 at 7:29pm |
|
i told them i wanted the bowls and pin hieght exactly the same on purpose so i can shave what i want , and start with somthing that allready works, i left the ring grooves to them they recomended lighten ing them up and shortening the the skirts some maybe the next go around i will have the recipe changed it took a long time to get done and they were not cheap
|
|
DrAllis
Orange Level Access
Joined: 12 Sep 2009
Points: 19921
|
Post Options
Thanks(0)
Quote Reply
Posted: 12 Jul 2024 at 7:53pm |
|
I've always said that using an SP-46 M&W piston that .170" had to be removed from the top of the piston. This was not a way to get the compression where I wanted it. It was necessary to keep the piston from smacking the head !!! The cranking compression will be approximately 240 psi when doing this. Remember, the connecting rods have their limits !! My pulling engine uses stronger rods than the ones you will use, so I can tolerate 300 psi of cranking compression.
|
|
steve(ill)
Orange Level Access
Joined: 11 Sep 2009
Location: illinois
Points: 79276
|
Post Options
Thanks(0)
Quote Reply
Posted: 12 Jul 2024 at 8:52pm |
|
was the "sample piston" already in an engine ?? If so, and i obviously did not hit the head, then the .170 or so has already been removed and designed into the NEW pistons ?
|
|
Like them all, but love the "B"s.
|
|
DrAllis
Orange Level Access
Joined: 12 Sep 2009
Points: 19921
|
Post Options
Thanks(0)
Quote Reply
Posted: 12 Jul 2024 at 9:56pm |
|
The sample piston was used in a WC/WD with a 4 inch stroke crank. Not a 4 1/2" stroke crank.
|
|
