Engine Rebuild - which route to take

[TitaniumTT]

So here's the backstory with this motor. It was an SMP motor that was assembled with RE housings, RE sleeves, new corner, side and apex seals but S6 front thrust bearings in an S5 stat gear. The motor ran for 25 minutes before it seized. I bought the motor and tore it down. Replaced the front bearings including the stat gear, e-shaft and the housings. I used a near MINT set of S5 N/A housings that I ported. The motor ran for ~1000 miles before it overheated during an emmisions test (idiots and a different story all together) The engine was never the same.

When I had 50 miles on the engine I did a comp check with a piston style gauge and got 105 in the front, and 110 in the rear. Three perfect even bounces. The day of the overheat but after the fact I got 90 psi in the front and 100 in the rear with one LOW bounce using the same gauge. That's when I started the insurance claim for the new engine.

So a few days ago I was @ KDR to have a comp test done for the insurance company (the shop that overheated it owes me a motor basically) and we got three perfect bounces @ high 112's in the front, two @ low 113's and one at 88 in the rear. It seems that a side seal is jammed. So what to do?

I have an o-ring kit that I won @ the DGRR raffle but need corner, side, and apex seals, maybe.

I could
A) crack the rear iron off and replace the one stuck side seal and the two corner seals associated with it. (~$120 in parts)

B) Dissasemble the entire engine and replace all the corner and side seals (+~$200)

C) Dissasemble the entire engine and replace all the corner, side, and Apex seals with the RA Super Seals and springs (+~$550)

What to do? The motor as she sits has about 4k in mileage on her. I believe the housings are in the same shape that they were in when the engine was first assembled. I could re-use the apex seals I'm sure but I want this engine to sustain alot of abuse. Shooting for 380 RWHP, 15 PSI and 8k rpm...... I'm so torn and want to order parts in the next day or two.

Thoughts, opinions?

-B

[classicauto]

I voted for the least replacement, simply because if everything else specs out OK - you shouldn't need to replace them. And as you know grinding side seals isn't a wicked fun job.

However, there's really no telling until its apart, right? There may be abnormal wear on something like an apex seal where it runs in the rotor slot that makes you want to toss in a new one......soooo.....I guess you'll find out

[TitaniumTT]

Lol.... That's exactly what I'm trying to avoid is waiting on parts. I need to order everything at once otherwise I have no hope of making the next event. If I tear it down and inspect an the orde parts, I'm done. Which is one reason I'm leaning
towards just replacing everything

[Caim]

In the motors that i build that did not have detramental damage to them... i go the route of getting the following.

Oil controle rings unless you have the viton ones they last a while ha. Oil controle rings last a long time.

As far as side seals i would buy about 3 or 4 of them so that way if you brake one or two of them when you are taking them out you have them. All side seals are good for about 300k miles. We measured the average wear on them and the minimal they could be and that is what we came up with.

New apex seals are needed and go with all new apex springs and side seal springs as well. As the side seal springs can be a pain and bend when you take them out. And yeah.

New gaskets are needed as i am sure you know, but that is as far as i go with the rotors. It works for me every time unless something really bad happened to the motor.

[classicauto]

Originally Posted by TitaniumTT

Lol.... That's exactly what I'm trying to avoid is waiting on parts. I need to order everything at once otherwise I have no hope of making the next event. If I tear it down and inspect an the orde parts, I'm done. Which is one reason I'm leaning
towards just replacing everything

ahhh, I gotcha.

I don't know how to say this without sounding sadistic, but if you have stuff left over, it'll likely get used down the road!

[RETed]

Originally Posted by Caim

Oil controle rings unless you have the viton ones they last a while ha. Oil controle rings last a long time.

Unless we're talking about very low mileage on them, I change them out.
Oil control o-rings tend to "square out" and this causes more blow-by.
The oil control o-rings are the primary soft seal to minimize blow-by (and oil burning) from engine oil circulating in the engine.
The proper cross-sectional shape of the o-ring is ROUND, not square.
The green silicone ones from Mazda tend to hold their shape up until 50k miles - I replace them when they start heading towards 100k miles or more.
I don't use the aftermarket Viton ones cause they are not properly sized and cause their own headaches by not seating properly.
Really...the cost of these oil control o-rings are very minimal versus almost anything else in there.

As far as side seals i would buy about 3 or 4 of them so that way if you brake one or two of them when you are taking them out you have them. All side seals are good for about 300k miles. We measured the average wear on them and the minimal they could be and that is what we came up with.

Side seals should be fine to reuse on a motor that has no damage or abuse on it.
In fact, it's recommended due to the fact that they are all clearanced for each slot.
Newbies will find it difficult to clearance BRAND NEW side seals properly - you f*ck up the side seal and you blow $10+ for each seal you kill!
Too tight a clearance and the side seal seizes in the slot - increased blow-by.
Too much clearance and you get too much blow-by.
Screwing this up either way causes a motor to burn a lot of oil.
A motor that was overheated or drop of oil pressure will most likely kill all it's side seals - but a motor like this will most likely not be able to be reused in a rebuild.

New apex seals are needed and go with all new apex springs and side seal springs as well. As the side seal springs can be a pain and bend when you take them out. And yeah.

I've never had a side seal spring bend out of shape.
Even when the side seal spring is EMBEDDED in it's slot due to lots of carbon...
Of course, I don't FORCE the side seal spring out by twisting and torquing it if it's truly rusted into the side seal slot.
This is why I either soak the rotor down with WD-40 or equivalent or dunk them in a part wash soak.
If the side seal spring is rusted into the slot, the rotor is junk anyways - side seals should not be able to be removed in this case.


-Ted

[2gslse]

I would just buy everything new if the shop/ins co is paying for it. but if you are doing it yourself I would buy option 3 with the apex seals but I would use OEM apex seals.

[TitaniumTT]

Well, I opted for option C. Ordered my RA Super Seals today, and will be calling MazdaComp in the morning to order all new corner and side seals and springs. Reason being, I want this motor to last and I don't want to have ANY doubts about beating the piss out of her on the auto-x/HPDE events that I plan to participate in this year.

I was also thinking, when the motor was first started she was pulling 14" of vac. After the break-in she was pulling ~18" of vac. After the overheat 10" and after 2k miles back up to 14". I believe that a few of the other seals were slightly damaged as well causing the low vac so I decided to replace all of them. I'll get some pics up of the damage, if any, in the next week or so. I hope to be stacking this motor by next w/e.

[TitaniumTT]

Originally Posted by classicauto

ahhh, I gotcha.

I don't know how to say this without sounding sadistic, but if you have stuff left over, it'll likely get used down the road!

Yeah, we know this all to well