Googled and yahoo'ed for almost 2 weeks but nothing useful found. So try my luck here.

I have 2 side housing and an intermediate having similar problem with the pic below.


The housings' corner seal contact area looks like being compressed more than worn out. The deepest is around 1mm (0.04").

My questions are:

1. What is the max can be cut away from the housing?
2. Can I weld it back (normal weld, hardfacing or etc) then lap and get nitrated?
3. After lapping process, if I found housing being cut a little bit too much, let's say 0.05", can I get a dry film treatment for gain back a little bit of the thickness?


Thanks for helping. It is too bad that I live too far from The State. Sending a Cobb AP cost me almost US$50 of shipping. Else I would just send all housing for repaired.

 

Street or race use?

 

the wear is about the maximum thickness of the nitrite layer. the only way to properly fix it is to mill the housing flat and re-nitrite it.

some shops can do it cheaper than others but ideally you'd be looking at new plates compared to the cost of shipping to and from those shops and the cost of lapping/milling and re-nitriting.

milling is $70-100, nitriting is about $100 per iron, add in shipping and you may as well toss in another $100 for a brand new iron.

 

^^ yep

well dunno, he does not live in the states so getting an iron might cost more than milling + re-nitriting. if shop like that is available locally.

 

i'd have to imagine they probably still have mazda dealers somewhere nearby. nitriting and rotary iron milling is pretty specialized service. i'd look into both as close as possible though to save on the shipping costs.

 

Thanks all for the reply. Labor over here is cheap. Example, lapping 1 piece of housing is about US$20-30, with proper lapping machine, not grinding. I found a shop that do nitrating but not sure about the cost but sure won't be expensive like US$100. 3 pieces of new housings cost about US$2000 so it is a bit too much for me.

I use my car only for street not track. But I admit that I rev the car hard most of the time. Planning to fabricate a top mount with Tomei M8270 turbo so need to revive my previous low compression engine as spare, just in case tuner blow my current block.

I guess most probably I'll send the housing to the shop and cut the groove deeper then weld it back and lap it flat then nitrating. I expect the total cost to get it done at my place will not more than US$250 for 3. So hope everything will be ok. If my plan will create a disaster, please correct me before too late. Thanks.

 

let me know how welding the cast iron works out...

your only real option is to cut them down to the wear line which will shorten the block slightly, not sure if this is an issue with the renesis as not many have put that much wear on their motors yet. was not an issue with earlier engines as they could only really be cut one time due to the coolant seal groove depth.

 

karack the water seal groove are in the rotor housings on the renny like the old 12As and 13Bs. so yes they can be ground and renitrided. This is what the OP needs to do. I have successfully welded a spot on a side iron before and its not for the weak hearted. I do not recommend doing this on the surface of the plate. You can toss it in the trash before you weld because this is where it will be going if you attempt to weld on it.

Get the plates lapped and treated, end of story.

 

i meant with tighter tolerances to the intake and exhaust, bolt patterns might not match and cause issues.

 

Looks like welding is not an option. So I'll go ahead just lap and nitrate. The only thing I concern is the thickness of the intermediate housing vs the eccentric shaft profile. I just can't calculate the the shaft play after the housing being lapped. If too tight after installation or rotor not in center position then may create another issue which may create a problem that haunting me all the time. For header and lower intake manifold, I can always bore the bolt holes from the manifolds slightly towards the rotor housing. The center bolts will stop the manifolds from moving left-right. The 2 pipes that spins, from the lower intake manifold may give some problem but I guess it can be solved.

How good if the housing surface can be replaced by a piece of plate.

 

My last hope, spray metal. Will find a piece of nasty housing for the test.