To_slow

Here is a 20b side plates i did for a customer. Just to give you guys an idea what they look like. If you want to build a good motor this is a must. Especially if you put all that time and money in new seals and internal parts. Its the same as buying new rotor housings. But at 30% of the cost off new plates.. The plates have oil put on them, in the pic.

drewrey2004

how much do you charge for the lapping of the plates

it looks really good

To_slow

Here are some info on the resurfacing and re-nitrading prices.



Some of you guys called up for pricing on this.



Here is a break down on the prices.



13b irons machined re-nitrading with new freazer plugs and oil galleries plugs 590.00$



20b irons machined re-nitrated with new freezer plugs and oil galleries plugs 800.00$



Thanks

To_slow

One thing i forgot to mention.



Some shops that offer the lapping and grinding of the surface will miss lead you in saying that after lapping 1.5 thow off the surface of the face there is still hardness to the plate. Not true at all.



If you take a used plate gage check if for hardness prior to resurfacing and gage check it after the plate had been resurfaced 1.5 to 2 thou down you will get different readings. Meaning after lapping or grinding the plate it is very soft. I can actually tell when grinding right at 1 -1.5 thow deep the grinding wheel cuts very easily into the plate. Meaning very soft metal after removal of the material.



I do not have the readings on hand but i will make a short video off it soon.



Hope that helps

TimmyFD

hey whats up chip, just spoke to you an hour ago. im going to hurry up and get the porting done and send them to you. but im having a hard time getting the front studs out. any suggestions?

To_slow

Hello Tim, your plates are done enjoy.



Before pics exactly how i received the plates....



The final result









All stock brass oil galley plugs have been replaced with new npt earls plugs 4 total, new freeze plugs and re zinc plated the dip stick tube with the rear coolant pipe..



You can also see on the front plate i do not cut down the front stationary gear pin. My machine is set up to lapp with out having to cut the pin down..

Maxt

Here's a question, is it a singe stage nitriding or multiple step? yes its a trick question..

To_slow

Single-Stage and Double-Stage Nitriding. Either a single- or a double-stage process may be employed when nitriding with anhydrous ammonia. In the single-stage process, a temperature in the range of about 495 to 525°C is used and the dissociation rate ranges from 15 to 30%. This process produces a brittle nitrogen-rich layer known as the white nitride layer at the surface of the nitrided case.



The double-stage process, known also as the Floe process, has the advantage of reducing the thickness of the white nitrided layer.



The first stage of the double-stage process is, except for time, a duplication of the single-stage process. The second stage may proceed at the nitriding temperature employed for the first stage or the temperature may be increased to from 550 to 565°C; however, at either temperature, the rate of dissociation in the second stage is increased to 65 to 80% (preferably 75 to 80%). Generally, an external ammonia dissociator is necessary for obtaining the required higher second-stage dissociation.



The principal purpose of double-stage nitriding is to reduce the depth of the white layer produced on the surface of the case. Except for a reduction in the amount of ammonia consumed per hour, there is no advantage in using the double-stage process unless the amount of white layer produced in single-stage nitriding cannot be tolerated on the finished part or unless the amount of finishing required after nitriding is substantially reduced.



To summarize, the use of a higher temperature during the second stage:



Lowers the case hardness

Increases the case depth

May lower the core hardness depending on the prior tempering temperature and the total nitriding cycle time

May lower the apparent effective case depth because of the loss of core hardness depending on how effective case depth is defined.



I only do a single Single-Stage.



Thank you for asking that quastion.

Maxt

The reason I ask that, is that in a couple of books written about rotary engine history and in an tour of mazdas engine plant, all sources state that if the nitriding is done in a wholesale uniform manner across the entire surface, the iron warps quickly when heat cycled. The factory nitriding is done in 3 different steps, with different stages, thats why a new iron is not uniform in colour and hardness. Also the nitriding process is manipulated to suit the materials the iron face will see in that area, example the oil control ring is a differnt material than the iron corner and side seals, . With people now attempting to do resurfacing and then nitriding,it does not look like those past observations are being adhered to at all, while the factory does to this day even on the new 16x?

To_slow

You make a good point regarding the oil control ring area on the side housings.



If you look in the pics below, you will se a new 20b center plate purchased from Mazda at 2500.oo a pop several months ago. Meaning these plates are there newest batch of 20b center plate to be made from Mazda



You can clearly see it, one even Nitrating process.



It all comes down to, if you want Mazda nitrating buy Mazda new plates.



[urn="http://img409.imageshack.us/my.php?image=parts007jk2.jpg"][/url]