Mazda re-man engine teardown pics & scratched side housing
#1
Mazda (used) re-man engine teardown pics & scratched side housing
Hello all,
I just got my engine re-built after it started leaking coolant into the rear combustion chamber. The core was a Mazda re-man with only 36k miles on it. Never really ran right since being installed by a dealer, history of detonation/pinging in warm temperatures, symptoms of a vacuum leak somewhere in the LIM, and some problems with heat before new Koyo radiator was installed. Never severely overheated though, only hit 230 F a few times.
Rebuilder sent some pics that I wanted to share here.
1st is the apparent source of the coolant leak - rotor housing cracked around spark plug hole. Apparently both housings were cracked in that location, though only the rear one was leaking.
Next up is the rear side housing (iron) with what appears to be deep scratches. They were too deep for re-surfacing and the part had to be scrapped, which was an unwelcome surprise for my wallet. I am at a loss as to what may have caused this. None of my apex/side seals were broken. Rebuilder thinks it may have been assembled with this defect at Mazda. Anyone have any thoughts about this?
Finally some gross rotors with carbon buildup.
Also my OMP lines were apparently brittle from heat/age (car has 136k miles) and 3 of them cracked. Getting those replaced was also painful - those suckers are $40 each, apparently.
This rebuild has turned out to be at the upper end of what I was expecting, and definitely more than I was hoping for - this core was pretty trashed. I'm in for new housings, a replacement used side housing, as well as all new bearings because the old ones were showing copper, in addition to the usual seals/springs.
I just got my engine re-built after it started leaking coolant into the rear combustion chamber. The core was a Mazda re-man with only 36k miles on it. Never really ran right since being installed by a dealer, history of detonation/pinging in warm temperatures, symptoms of a vacuum leak somewhere in the LIM, and some problems with heat before new Koyo radiator was installed. Never severely overheated though, only hit 230 F a few times.
Rebuilder sent some pics that I wanted to share here.
1st is the apparent source of the coolant leak - rotor housing cracked around spark plug hole. Apparently both housings were cracked in that location, though only the rear one was leaking.
Next up is the rear side housing (iron) with what appears to be deep scratches. They were too deep for re-surfacing and the part had to be scrapped, which was an unwelcome surprise for my wallet. I am at a loss as to what may have caused this. None of my apex/side seals were broken. Rebuilder thinks it may have been assembled with this defect at Mazda. Anyone have any thoughts about this?
Finally some gross rotors with carbon buildup.
Also my OMP lines were apparently brittle from heat/age (car has 136k miles) and 3 of them cracked. Getting those replaced was also painful - those suckers are $40 each, apparently.
This rebuild has turned out to be at the upper end of what I was expecting, and definitely more than I was hoping for - this core was pretty trashed. I'm in for new housings, a replacement used side housing, as well as all new bearings because the old ones were showing copper, in addition to the usual seals/springs.
Last edited by Jastreb; 08-01-2017 at 08:04 PM.
#3
Water Foul
I think we need to reset expectations around here for the cost of a rebuild. People keep throwing around numbers in the $2500 range, but almost never costs that little. $3500 is probably a more sensible floor cost.
The following 2 users liked this post by Steve Dallas:
gwilliams6 (08-04-2017),
NotAPreppie (08-02-2017)
#5
SARX Legend
iTrader: (46)
Yes, $2500.00 is a pipe dream for a reliable rebuild. The carbon on the rotors looks about normal but what is interesting is that the rotor coating that the S2's have does not appear to be there so it looks like Mazda uses S1 rotors in their S2 rebuilds. Which makes sense since they are rebuilt at the same plant.
the other wear is bad though too just by what I can see.
the other wear is bad though too just by what I can see.
#8
No respecter of malarkey
iTrader: (25)
Well if you can afford it, new rotor housings should always be used if you want it to last. Those cracks are common on the Rene housings. Run colder plugs if you can.
won't even post what my last engine cost, still too painful to think about ....
.
won't even post what my last engine cost, still too painful to think about ....
.
Last edited by TeamRX8; 08-02-2017 at 05:32 PM.
#9
Smoking turbo yay
Looks like a S2, as there are 6 OMP lines.
Sucks that you can't simply buy these rotors with the coating, and looks like not all rebuilds use them. Hopefully, when the time comes, I can reuse mine...
Sucks that you can't simply buy these rotors with the coating, and looks like not all rebuilds use them. Hopefully, when the time comes, I can reuse mine...
#12
Yes, based on my pre-rebuild research, $2500 is the absolute minimum, if re-using housings and main bearings. This does not include installation/removal of the engine. With new housings, this becomes a $4k rebuild + installation, and it seems that $1k in unforeseen costs should be budgeted in as well. Of course with the amount of miles on my car, I sprang for professional oil cooler cleaning and flushing the oil lines, new heater hoses and belts. It adds up quickly, but I figured better to do it right if I'm going to go through the expense and trouble in the first place.
Actually that was me jumping to conclusions. Lucky7 Racing is doing the rebuild, and in a conversation months ago it was mentioned that coolant leaking into combustion chamber could be caused by a cracked housing. When I saw the pic I automatically assumed that it where the leak was, but after doing a bit of searching, that would have to be a pretty massive crack to go all the way to the cooling jacket. So it is probably unrelated to the blown coolant seal. I wonder though if the pinging caused the cracks. Either way, I would not have re-used those housings. Still mystified by the scratched rear iron though...
Oh **** I missed that comment, Yeah that is not a coolant leak area.
Who is rebuilding your engine?
Who is rebuilding your engine?
The following users liked this post:
9krpmrx8 (08-03-2017)
#14
Regarding the S2 engine tear down shown here, I am guessing something foreign entered the intake at some point. The cracking at the spark plug holes are normal and they do pertain to temperature and warpage. They can be inspected and. modified and re-used if you know what you're doing and it's not too bad.
By the way, there are no different rotors for S1 vs S2 if you order new or get a reman engine. They all use N3Z1-11-B10C and N3Z1-11-B50C.
Paul.
By the way, there are no different rotors for S1 vs S2 if you order new or get a reman engine. They all use N3Z1-11-B10C and N3Z1-11-B50C.
Paul.
The following users liked this post:
gwilliams6 (08-04-2017)
#15
No, they didn't send me any, and I was out of the country at the time of the tear down. I'm picking up the car tomorrow, so I'll see if they still have them around.
But I never ran it without the filter, unless this was done by a mechanic/dealer while I wasn't looking, or during the rear iron's previous life...
So there's some residual value in those housings? If I can recover even a few hundred $$, that's still better than nothing!
Regarding the S2 engine tear down shown here, I am guessing something foreign entered the intake at some point.
The cracking at the spark plug holes are normal and they do pertain to temperature and warpage. They can be inspected and. modified and re-used if you know what you're doing and it's not too bad.
#17
The Michigan "WANKEL"
Yes, $2500.00 is a pipe dream for a reliable rebuild. The carbon on the rotors looks about normal but what is interesting is that the rotor coating that the S2's have does not appear to be there so it looks like Mazda uses S1 rotors in their S2 rebuilds. Which makes sense since they are rebuilt at the same plant.
the other wear is bad though too just by what I can see.
the other wear is bad though too just by what I can see.
#18
SARX Legend
iTrader: (46)
Not all of the Series II have the coating. They started doing that shortly after Series II production. I remember the original post about this, with the date when they started. Sadly, mine was built prior to that date. I'd have to dig up that original post, I believe by ASH.
Well this is a reman, not an original engine so you would assume they would have the most recent part. But as Paul stated the rotors are the same and he rebuilds a ton so who knows.
#19
Registered
iTrader: (2)
when was the reman put together? I had heard that they are getting better, but not sure when they actually started getting better. Mine is nearing the end of the warranty, debating between having it rebuilt (prior to dying) or getting a reman (compression is a tad low, but seems to drive and pull just fine)...
#20
I know they aren't the same engine but on the FD the carbon wings on the housings are from hotter section in the housing there, we fixed this on the FD by increasing flow around the spark plug holes. you can also run a little colder plug there. so what happens is this part of the engine heats up and the apex seals rock over this hump (the heat raises this part of the housing), eventually the apex seal cracks as it rubs over this spot and rocks and can ruin rotor slots.
Cooling in this area is essential and keeping the engine cool is a priority.
the grooves on the iron, we typically see this with too tight of side seal clearance to corner seals, when heated the side seal expands and pushes on the corner seal out of the rotor which puts pressure on the plates causing the grooves.
Cooling in this area is essential and keeping the engine cool is a priority.
the grooves on the iron, we typically see this with too tight of side seal clearance to corner seals, when heated the side seal expands and pushes on the corner seal out of the rotor which puts pressure on the plates causing the grooves.
#22
when was the reman put together? I had heard that they are getting better, but not sure when they actually started getting better. Mine is nearing the end of the warranty, debating between having it rebuilt (prior to dying) or getting a reman (compression is a tad low, but seems to drive and pull just fine)...
I know they aren't the same engine but on the FD the carbon wings on the housings are from hotter section in the housing there, we fixed this on the FD by increasing flow around the spark plug holes. you can also run a little colder plug there. so what happens is this part of the engine heats up and the apex seals rock over this hump (the heat raises this part of the housing), eventually the apex seal cracks as it rubs over this spot and rocks and can ruin rotor slots.
Cooling in this area is essential and keeping the engine cool is a priority.
the grooves on the iron, we typically see this with too tight of side seal clearance to corner seals, when heated the side seal expands and pushes on the corner seal out of the rotor which puts pressure on the plates causing the grooves.
Cooling in this area is essential and keeping the engine cool is a priority.
the grooves on the iron, we typically see this with too tight of side seal clearance to corner seals, when heated the side seal expands and pushes on the corner seal out of the rotor which puts pressure on the plates causing the grooves.
I understand about the grooves/step wear - so it looks like the seals weren't clearanced properly? However the scratches look debris related, but this was the only engine hard part showing this kind of damage, which leads to the belief it might have been assembled like this.
#23
SARX Legend
iTrader: (46)
I am sure it was rebuilt not too long before that, my buddy works at a dealer and they often have decent wait times on remans so I doubt they have them sitting around. When I got my last one it took my dealer (highest volume Mazda dealer in Texas) over a month to get it.