Pistons

[Guest]

During this years racing we damaged our best D MOD engine which was already .030 oversize. We were able to clean it up but it really want to go the next oversize. Well I can't find any Merc .040 oversize pistons for a 40 cubic inch engine. I have a set of .040 over Weisco pistons for our 44 and thought it would be great to get Wiseco to make D piston.

Currently I have sent a Merc piston to them to get a reading on the possibility of making .020 and .040 oversize pistons. I should know in a couple weeks what the status is. Early discussions indicate they would be produced in 2 ring configuration to match existing manufacturing process. If all works out well Aeroliner Boat will become a Wiseco piston dealer and we will be able to supply a forged piston for all that need them.

If possible I would like to know if others might want pistons and we will include them in our initial order.

Thanks,
Alan

[Larry M]

During this years racing we damaged our best D MOD engine which was already .030 oversize. We were able to clean it up but it really want to go the next oversize. Well I can't find any Merc .040 oversize pistons for a 40 cubic inch engine. I have a set of .040 over Weisco pistons for our 44 and thought it would be great to get Wiseco to make D piston.

Currently I have sent a Merc piston to them to get a reading on the possibility of making .020 and .040 oversize pistons. I should know in a couple weeks what the status is. Early discussions indicate they would be produced in 2 ring configuration to match existing manufacturing process. If all works out well Aeroliner Boat will become a Wiseco piston dealer and we will be able to supply a forged piston for all that need them.

If possible I would like to know if others might want pistons and we will include them in our initial order.

Thanks,
Alan

Alan you might think about +.050 over. There is a few +.030 pistons floating around and a +.040 would only give you .005 on a side to clean up if a +.030 wouldn't work. The NBRA rules on the 40CI motor will allow up to +.070 over. I'm not a big fan of Wiseco but I think they will work with you.

Larry Mac

[Guest]

Pistons

Hi Larry,
I did mention a .050 over piston and we will see if we can get a range of them. It would be good to keep the already ported blocks with the exhaust systems fitted and be able to salvage the investment in the block. I am hoping that they will produce the items. The next step will be for them to provide an engineer drawing and we can work from there. My phone calls with them have been very good and I provide data on our NBRA racing. Hopefully we can do this.

Alan

[STEVE FRENCH]

Might give a call to Dave Scott.

He has put a ton of time into this and may be able to help/team up with your efforts........ehh?

http://www.scottcraftboats.com/aim2/content/contact.htm

100N/Steve French

[crankbearing]

Wiseco Canada has all the measurements on file for D pistons and including a brand new .015 over I sent them, they will be made from the 44 piston mold with a .300" smaller and shorter wrist pin than stock. When I did the 44 small wrist pin pistons I had them move the locating pins as well. If you can sell em for 100 a piston you will be doing good. .020 and .040 were my intentions. The 44 Slugs were awesome and took a std wiseco ring, yes two ring design much better design anyhow, if you talk to Harvey in Canada and mention my name he should have it all, I may need to sign off on the bto to have him supply you the info. I may still have the original BTO in my in-box at the shop as well with the numbers already on paper.

[Guest]

Pistons

Hi Dave,
Thanks for you info. I have a set of your .040 over 44 pistons and they are outstanding. I checked the weight of a Merc 44 piston that was .015 over and they came in at 7 grams more for the Wiseco's. Great news. I would assume that the Merc piston .040 would weigh about the same.
Alan

[crankbearing]

No problem, good luck.

[Art K]

Alan, the intent of the +070 rule was to allow the use of a 44 piston that had been machined to fit. Not sure if anyone has ever done this. Also the pistons must have 3 rings. Pg, 40 under notes section, item F. & there are dimensions on the pistons used also.
Art K

[Larry M]

Alan, the intent of the +070 rule was to allow the use of a 44 piston that had been machined to fit. Not sure if anyone has ever done this. Also the pistons must have 3 rings. Pg, 40 under notes section, item F. & there are dimensions on the pistons used also.
Art K

Not exactly, Phil McDaniels wanted the rule change because he said he was going to have +.070 pistons made for the 40ci. So we passed the rule and they were never made. I have turned 44 pistons down but they are really thin on the skirt and I had [problems with the deflector hitting the dome of the piston at the side. After a lot of work I tried then and it didn't run good at all. I think cutting on the deflector messed it up. I never tried it again.

Larry Mac

[ZUL8TR]

Hi Dave,
Thanks for you info. I have a set of your .040 over 44 pistons and they are outstanding. I checked the weight of a Merc 44 piston that was .015 over and they came in at 7 grams more for the Wiseco's. Great news. I would assume that the Merc piston .040 would weigh about the same.
Alan

Just for checking against the Merc 44 pistions you weighed my 2 ring 44 +0.015 pistons weigh in at 240.5 and 240.6 grams each that I used in my 22 ci 25ss rebuild, also extremly close in dimensions. What were your weights?

[David_L6]

Alan, the intent of the +070 rule was to allow the use of a 44 piston that had been machined to fit. Not sure if anyone has ever done this. Also the pistons must have 3 rings. Pg, 40 under notes section, item F. & there are dimensions on the pistons used also.
Art K

Art, in this case wouldn't it be a good idea to put it to a driver's vote to allow (or not - up to the drivers) 2 ring pistons to help keep some of those old motors alive? What's the main thing that keeps someone from building a D Mod Merc (40")? My guess would be lack of new pistons and rings. I know that's what put me out of that class. I was already scrounging to find pistons for my C Merc. I didn't want to do that for D also so I ended up racing C and E and sold what little D stuff I had.

[Art K]

Alan,your plan for replacement pistons for the 40ci merc has merit. But under the current rules would not be legal. I think you should present your plan at the Nat meeting to see if you can make the change. It would require a vote of the Tech committee. If passed their it goes to the general meeting. If passed their it goes on the ballot. Not an easy process since you are going to have to secure the votes of the Tohatsu drivers to get it passed.. I think I would put on hold on any plans until then.
Art K Tech VP

[LarryR]

Alan Wiseco may require a minimum order for 100 pistons at something like $100 each to make your oversize D pistons. I think that was the deal with the 44 pistons. Perhaps it was 100 .020 and 100 .040 over. Don't know for sure. In either case, you'll need a lot of friends.

I once looked into having Torrington make a batch of mark78 main bearing outer races. No problem they said, that'll be $55 each for a minimum of 1000 pieces. End of conversation.

[blueskyracer]

To me it seems only logical to allow a 2 ring piston in the 40 class since it has been done for the 44 class.. Keep the competition between two different engines alive makes the class more interesting..

[LarryR]

Agree. that wouldn't have made any sense in the 60s, but it certainly would now.