Can I trust a local machine shop to lap these for me or do I have to have them sent out to like Mazdatrix or some place like that?

 

if they indeed do lapping it is fine. Sometimes they only machine the housing and that is not good enough. be aware though that you must tell them you can only lap so far. the mazdatrix website tells you what the maximum and recommended values are.

 

Lapping is a relatively simple process, so any decent machine shop should be abe to do a good job.

There are several fittings that need to be removed from the housings so they will lay flat on the lapping machine's table. These include the dowel pins and a few small pipes. To remove the hollow dowel pins just fill them with grease and use a close fitting bolt (like a piston in a cylinder) to push them out by tapping the bolt wth a hammer. The solid locating pins for the stationary gears are a little more troublesome. The housing may need to be heated to pull them out. If you have your housings nitrided be sure to remove the injector diffusers as the process will melt them (voice of experience here).

The most critical part of this whole process is the nitriding process that is used to toughen the metal. It only penetrates about 2 or 3 thousandths deep and lapping may remove this. Without the nitride hardening there the wear on the housings will be extremely rapid. The machine shop will probably know of a company that will re-nitride the housings for you.

It cost me about 170 bucks for the lapping (not including shipping) and 150 for the nitriding. I used a company called LAPCO in North Carolina for the lapping and a company here in Arkansas for the nitriding. The LAPCO folks have done many Mazda housings and they are very good at what they do.

My housings looked new when all this was done. At 10K miles since overhaul my engine has factory spec compression and is easy to start. It has not flooded at all since the rebuild.

 

When i called Mazdatrix they said that you have to wait a month before you get your side housings. I wouldnt take it to a machine shop though. Most of them dont have the right grinding stones to lap our housings. I called about 20 machine shops around LA and non of them will do a rotary engine. Try POWERHOUSE Engineering. They do it cheaper than Mazdatrix.

 

These are the addresses for the nitriding and lapping companies I used. As I said earlier, LAPCO has done many Mazda housings.

LAPCO
5440 Hwy. 55 East
Lake Wiley, South Carolina 29710I

I do not have their phone number but they are listed of course. If you calll them ask for Bobby.

I sent them a check for 225.30. This included the cost of the machine work plus about 70 bucks for return shipping.

The nitriding company is nation wide, and they have several plants in other states. Look them up on the internet. Their name is as follows;
Moore, McMillen Industries
This particular plant is at 2609 N 12th. Ave
Paragould, AR 72450

They have a minimum fee of 150 bucks, and this is what it cost me.

The whole affair took less than three weeks, including the shipping time.

 

Thanks for all the info!