minimalist 13B S4 N/A rebuild
10-21-06, 08:25 PM
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minimalist 13B S4 N/A rebuild
Later this week i hope to get a compression tester and get some hard #'s, but i was wanting to know the minimum i would need with good #'s. I was thinking that i should be fine with just the Engine Gasket Set from AtkinsRotary or Mazdatrix, but i didn't know if i would need the front/rear main seals, corner seals/springs, or side seals/springs. Yes? No? I'm an idiot?
The only reason i'm rebuilding the motor is because the previous owner overheated it (i'm guessing that's the case, with only 56k miles on the clock when i bought it), and since i bought the car during the winter i didn't catch any of the signs of a bad coolant seal on the exhaust side (it was barely burning coolant, and only at startup). Stop-leak has ended the coolant burnoff at startup, but i'm still limited in range i'm able to drive because the exhaust is pushing into the coolant system.
The only reason i'm rebuilding the motor is because the previous owner overheated it (i'm guessing that's the case, with only 56k miles on the clock when i bought it), and since i bought the car during the winter i didn't catch any of the signs of a bad coolant seal on the exhaust side (it was barely burning coolant, and only at startup). Stop-leak has ended the coolant burnoff at startup, but i'm still limited in range i'm able to drive because the exhaust is pushing into the coolant system.
10-21-06, 08:48 PM
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replace everything... don't go cheap. get the Atkin's master rebuild or the RA master rebuild, both are great kits.
In fact, I believe Atkin's is doing a group buy deal, may have to check if they're still are:
https://www.rx7club.com/showthread.php?t=581020
In fact, I believe Atkin's is doing a group buy deal, may have to check if they're still are:
https://www.rx7club.com/showthread.php?t=581020
10-21-06, 10:29 PM
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I'm only wanting to go cheap, because i don't want to spend more than i have budget for right now. If i get a new job and can afford a better rebuild a year or two from now, then i probably will just for peace of mind, but for now i just want to be able to drive it to visit my sister up north without having to worry about the coolant being pushed out the overflow bottle.
10-24-06, 06:11 AM
#4
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If you're looking for cheap, get rid of the car.
Seriously.
Overheat is always bad.
Best case, you melted a soft seal.
Worst case, you warped all the housing.
Usually, it's something in between, and you killed at least ONE housing.
Replacing just one housing is either 1) a PITA, or 2) EXPENSIVE.
PITA = looking for a good, used one.
EXPENSIVE = buying one new.
You're asking too vague a question, and we can throw guesses all night long.
What you need to do is TEAR DOWN the engine and spec everything out first.
Cross your fingers and hope none of the big internals parts are bad.
Cause if any of the big stuff is bad, all those nice shiny new parts you just bought just ended being a waste of time - i.e. you still need to replace that rotor housing or side housing.
-Ted
Seriously.
Overheat is always bad.
Best case, you melted a soft seal.
Worst case, you warped all the housing.
Usually, it's something in between, and you killed at least ONE housing.
Replacing just one housing is either 1) a PITA, or 2) EXPENSIVE.
PITA = looking for a good, used one.
EXPENSIVE = buying one new.
You're asking too vague a question, and we can throw guesses all night long.
What you need to do is TEAR DOWN the engine and spec everything out first.
Cross your fingers and hope none of the big internals parts are bad.
Cause if any of the big stuff is bad, all those nice shiny new parts you just bought just ended being a waste of time - i.e. you still need to replace that rotor housing or side housing.
-Ted
10-24-06, 09:50 AM
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I was going to order the kits so that i could just pull the engine, check it out, rebuild it, and drive it again as soon as i could. Worse comes to worse i pull the motor out of my '86 GXL, change it from auto to manual stuff, and drop it in. Then worry about that beater until later.
The original question i was asking, simplified, was if i had good compression numbers that indicated none of the springs were sagging, then should i replace the springs and seals anyway since it's a low milage motor?
The original question i was asking, simplified, was if i had good compression numbers that indicated none of the springs were sagging, then should i replace the springs and seals anyway since it's a low milage motor?
10-24-06, 10:06 AM
#6
Minimum stuff I'd consider are listed exactly below. This is not a kit you can buy, simply call and order these parts:
-apex seals
-86-88 aftermarket gasket kit (comes with coolant orings etc.)
-thermal pellet replacement for front cover
-viton oil oring inserts
-93+ corner seal springs
-front and rear main seals
These parts should cost less than 450 shipped, I think.
Consider that if this is your first rebuild you are likely to screw up some of the other seals and springs which you intend to reuse. This is why a builder like myself can reuse the stuff with success...I have drawers of spares in case I bend or break one, or lose one, because I have torn down lots of cores. You on the other hand only have one set of everything so if you screw anything up you'll have to buy replacements. You also need old side seals to clean the side seal slots in the rotors, as no tool can fit in there. It's for these reasons that most individuals are told to order pretty much everything new, even though that is not my practice when doing a build.
You should ALWAYS replace apex seals when the motor is apart, unless they have less than 25k or so on them. They are THE wear item in the engine, they are what "makes it go". They only cost a little over $200 for a set. IF you cant afford that, you have no business owning the car as stated above. Also, it is difficult to reuse the stock 3pc seals for most first timers, making it an even worse idea to try.
-apex seals
-86-88 aftermarket gasket kit (comes with coolant orings etc.)
-thermal pellet replacement for front cover
-viton oil oring inserts
-93+ corner seal springs
-front and rear main seals
These parts should cost less than 450 shipped, I think.
Consider that if this is your first rebuild you are likely to screw up some of the other seals and springs which you intend to reuse. This is why a builder like myself can reuse the stuff with success...I have drawers of spares in case I bend or break one, or lose one, because I have torn down lots of cores. You on the other hand only have one set of everything so if you screw anything up you'll have to buy replacements. You also need old side seals to clean the side seal slots in the rotors, as no tool can fit in there. It's for these reasons that most individuals are told to order pretty much everything new, even though that is not my practice when doing a build.
You should ALWAYS replace apex seals when the motor is apart, unless they have less than 25k or so on them. They are THE wear item in the engine, they are what "makes it go". They only cost a little over $200 for a set. IF you cant afford that, you have no business owning the car as stated above. Also, it is difficult to reuse the stock 3pc seals for most first timers, making it an even worse idea to try.
10-24-06, 12:58 PM
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I was just trying to keep the rebuild as affordable as possible, which for me is ~$500-700, and i didn't want to order a bunch of things i didn't really need. In that respect, which are the most commonly broken seals during teardown that i would need to replace?
Thanks for the help so far, guys, now i atleast have a better general idea of the total cost sans anything disastrous happening.
Thanks for the help so far, guys, now i atleast have a better general idea of the total cost sans anything disastrous happening.
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10-24-06, 01:15 PM
#8
Apex springs are usually reuseable, especially considering the expense. If the tips are worn to a fine point I sometimes replace them with other, less worn used ones. You can also bend them slightly to put more spring pressure back in them...don't go overboard, add maybe 1/16" arch to them overall. Use a knife to scrape off any carbon buildup.
Apex seals obviously get replaced, as do coolant seals, upper dowelpin orings, and tension bolt washers. Use the old apex seal bottom piece to clean out the apex seal slot in the rotor. I used to tap the tip with a hammer, at an angle, to break up the carbon.
Corner seals are almost always reuseable and wear very little. IF you let a motor sit for a long time they can be hard to get out and can be damaged that way. Otherwise just pop the hardened rubber plug out of the middle, clean them off, and reuse. Dont replace the rubber plug...they don't perform any necessary function and arent worth the $20 to replace.
The stock FC cornerseal springs are crappy, so get 93+ style new ones which cost maybe $35. IT is possible to reuse the stock FC springs though, just bend them with pliers to put more spring back into them.
Side seals are generally reuseable and wear very little. IN fact it is to your advantage to reuse them most of the time...they are pre-clearanced from the factory. Whereas new ones are cut long intentionally, and must be hand clearanced with a grinder/belt sander/file...a job which is hard to get right your first time and takes a while. Many people screw up by replacing side seals and geting the clearance wrong, versus just reusing the old ones which would have served them better. Sometimes they stick in their slots and are hard to get out...and you tear them up by bending them and pulling on them. It just depends.
However...as mentioned above you need a way to clean the side seal grooves out, meaning you need a junk side seal to do it with (you WILL destroy this one, possibly 3 or 4). Even if you plan to reuse stockers, you may want to buy 2 or 3 new ones to clean the grooves. Or you might buy 12 new ones and use your 12 old ones to clean.
Side seal springs are almost always reuseable, but sometimes motors are so carboned up that the carbon built up on top of the spring won't let it come out of the groove, and the spring gets all bent up when you try to get it out of the carbon. You can bend these back pretty straight, though.
The metal oil rings are reuseable, but sometimes you might break one upon reinstall, especially with viton oil orings which are stiffer than stock. Springs are reuseable too. The rubber inserts must be replaced with either new stockers or preferrably viton.
Thats about as simple as I can make it. You wont know more until you tear it down. I would wait until then to order parts.
Apex seals obviously get replaced, as do coolant seals, upper dowelpin orings, and tension bolt washers. Use the old apex seal bottom piece to clean out the apex seal slot in the rotor. I used to tap the tip with a hammer, at an angle, to break up the carbon.
Corner seals are almost always reuseable and wear very little. IF you let a motor sit for a long time they can be hard to get out and can be damaged that way. Otherwise just pop the hardened rubber plug out of the middle, clean them off, and reuse. Dont replace the rubber plug...they don't perform any necessary function and arent worth the $20 to replace.
The stock FC cornerseal springs are crappy, so get 93+ style new ones which cost maybe $35. IT is possible to reuse the stock FC springs though, just bend them with pliers to put more spring back into them.
Side seals are generally reuseable and wear very little. IN fact it is to your advantage to reuse them most of the time...they are pre-clearanced from the factory. Whereas new ones are cut long intentionally, and must be hand clearanced with a grinder/belt sander/file...a job which is hard to get right your first time and takes a while. Many people screw up by replacing side seals and geting the clearance wrong, versus just reusing the old ones which would have served them better. Sometimes they stick in their slots and are hard to get out...and you tear them up by bending them and pulling on them. It just depends.
However...as mentioned above you need a way to clean the side seal grooves out, meaning you need a junk side seal to do it with (you WILL destroy this one, possibly 3 or 4). Even if you plan to reuse stockers, you may want to buy 2 or 3 new ones to clean the grooves. Or you might buy 12 new ones and use your 12 old ones to clean.
Side seal springs are almost always reuseable, but sometimes motors are so carboned up that the carbon built up on top of the spring won't let it come out of the groove, and the spring gets all bent up when you try to get it out of the carbon. You can bend these back pretty straight, though.
The metal oil rings are reuseable, but sometimes you might break one upon reinstall, especially with viton oil orings which are stiffer than stock. Springs are reuseable too. The rubber inserts must be replaced with either new stockers or preferrably viton.
Thats about as simple as I can make it. You wont know more until you tear it down. I would wait until then to order parts.
10-24-06, 10:44 PM
#9
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I'm doing a rebuild for a customer now, and a minimal rebuild is going to come out to about $750 for just the parts.
All are Mazda OEM with the exception of the inner water jacket o-rings, which I use McMaster-Carr replacements.
Most gaskets don't need to be replaced.
Use silicone RTV to help seal the two mating surfaces.
Almost all the "hard" seals can be reused, with the exception of the apex seals.
Almost all the springs can be reused.
So my estimate is close to what Rotary Resurrection's estimate is...
-Ted
All are Mazda OEM with the exception of the inner water jacket o-rings, which I use McMaster-Carr replacements.
Most gaskets don't need to be replaced.
Use silicone RTV to help seal the two mating surfaces.
Almost all the "hard" seals can be reused, with the exception of the apex seals.
Almost all the springs can be reused.
So my estimate is close to what Rotary Resurrection's estimate is...
-Ted
10-24-06, 11:01 PM
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Any specific reason why you use McMaster-Carr inner water jacket o-rings? I'm also assuming that the 'reused' gaskets and seals you're refering to are if you're careful in opening the engine up?
10-25-06, 02:25 AM
#12
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10-25-06, 06:44 AM
#14
Originally Posted by RotaryResurrection
Apex springs are usually reuseable, especially considering the expense. If the tips are worn to a fine point I sometimes replace them with other, less worn used ones. You can also bend them slightly to put more spring pressure back in them...don't go overboard, add maybe 1/16" arch to them overall. Use a knife to scrape off any carbon buildup.
Apex seals obviously get replaced, as do coolant seals, upper dowelpin orings, and tension bolt washers. Use the old apex seal bottom piece to clean out the apex seal slot in the rotor. I used to tap the tip with a hammer, at an angle, to break up the carbon.
Corner seals are almost always reuseable and wear very little. IF you let a motor sit for a long time they can be hard to get out and can be damaged that way. Otherwise just pop the hardened rubber plug out of the middle, clean them off, and reuse. Dont replace the rubber plug...they don't perform any necessary function and arent worth the $20 to replace.
The stock FC cornerseal springs are crappy, so get 93+ style new ones which cost maybe $35. IT is possible to reuse the stock FC springs though, just bend them with pliers to put more spring back into them.
Side seals are generally reuseable and wear very little. IN fact it is to your advantage to reuse them most of the time...they are pre-clearanced from the factory. Whereas new ones are cut long intentionally, and must be hand clearanced with a grinder/belt sander/file...a job which is hard to get right your first time and takes a while. Many people screw up by replacing side seals and geting the clearance wrong, versus just reusing the old ones which would have served them better. Sometimes they stick in their slots and are hard to get out...and you tear them up by bending them and pulling on them. It just depends.
However...as mentioned above you need a way to clean the side seal grooves out, meaning you need a junk side seal to do it with (you WILL destroy this one, possibly 3 or 4). Even if you plan to reuse stockers, you may want to buy 2 or 3 new ones to clean the grooves. Or you might buy 12 new ones and use your 12 old ones to clean.
Side seal springs are almost always reuseable, but sometimes motors are so carboned up that the carbon built up on top of the spring won't let it come out of the groove, and the spring gets all bent up when you try to get it out of the carbon. You can bend these back pretty straight, though.
The metal oil rings are reuseable, but sometimes you might break one upon reinstall, especially with viton oil orings which are stiffer than stock. Springs are reuseable too. The rubber inserts must be replaced with either new stockers or preferrably viton.
Thats about as simple as I can make it. You wont know more until you tear it down. I would wait until then to order parts.
Apex seals obviously get replaced, as do coolant seals, upper dowelpin orings, and tension bolt washers. Use the old apex seal bottom piece to clean out the apex seal slot in the rotor. I used to tap the tip with a hammer, at an angle, to break up the carbon.
Corner seals are almost always reuseable and wear very little. IF you let a motor sit for a long time they can be hard to get out and can be damaged that way. Otherwise just pop the hardened rubber plug out of the middle, clean them off, and reuse. Dont replace the rubber plug...they don't perform any necessary function and arent worth the $20 to replace.
The stock FC cornerseal springs are crappy, so get 93+ style new ones which cost maybe $35. IT is possible to reuse the stock FC springs though, just bend them with pliers to put more spring back into them.
Side seals are generally reuseable and wear very little. IN fact it is to your advantage to reuse them most of the time...they are pre-clearanced from the factory. Whereas new ones are cut long intentionally, and must be hand clearanced with a grinder/belt sander/file...a job which is hard to get right your first time and takes a while. Many people screw up by replacing side seals and geting the clearance wrong, versus just reusing the old ones which would have served them better. Sometimes they stick in their slots and are hard to get out...and you tear them up by bending them and pulling on them. It just depends.
However...as mentioned above you need a way to clean the side seal grooves out, meaning you need a junk side seal to do it with (you WILL destroy this one, possibly 3 or 4). Even if you plan to reuse stockers, you may want to buy 2 or 3 new ones to clean the grooves. Or you might buy 12 new ones and use your 12 old ones to clean.
Side seal springs are almost always reuseable, but sometimes motors are so carboned up that the carbon built up on top of the spring won't let it come out of the groove, and the spring gets all bent up when you try to get it out of the carbon. You can bend these back pretty straight, though.
The metal oil rings are reuseable, but sometimes you might break one upon reinstall, especially with viton oil orings which are stiffer than stock. Springs are reuseable too. The rubber inserts must be replaced with either new stockers or preferrably viton.
Thats about as simple as I can make it. You wont know more until you tear it down. I would wait until then to order parts.
10-26-06, 10:34 AM
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Originally Posted by RETed
I remember those now. Wasn't there something you had to do differently with those than the standard o-rings? Or am i thinking of the silicon o-rings that were supposed to survive higher temps?
10-26-06, 08:23 PM
#19
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good info. how about a rebuild guide for a moderate powered TII.....can you use re-use side seals and such for them? besides the apex seal's...what can be used if they are in spec's?
Last edited by 88rxn/a; 10-26-06 at 08:27 PM.
10-26-06, 08:25 PM
#20
That is a great post by Rotary Resurrection. What confuses me is the mention of using Viton oil o-rings. If you read Blake's posts (Pineapple racing) he states that the viton rings don't hold up well....I think he said around 10k miles or so. Who has the most reliable seals...OEM???
10-27-06, 01:41 AM
#21
Originally Posted by scrip7
That is a great post by Rotary Resurrection. What confuses me is the mention of using Viton oil o-rings. If you read Blake's posts (Pineapple racing) he states that the viton rings don't hold up well....I think he said around 10k miles or so. Who has the most reliable seals...OEM???
I've used viton in all my builds since about 2002. Some have exceeded 60k miles and are still fine. I've torn down rebuilds with viton in them and they come out looking like brand new.
I tear down LOTS of oem cores and the soft mazda oil inserts start to flatten and fail very quickly, in as little as 25k miles.
10-27-06, 02:37 AM
#22
dozens of rebuilds this year and not a single issue with the viton oil seals, i have been using them for a few years and some of them have over 50k on them now.
wish i could say the same for OEM oil control seals, a number of times i have seen the outer ring completely MIA on all 4 seals and the inners severely flattened and crumble when removing them.
wish i could say the same for OEM oil control seals, a number of times i have seen the outer ring completely MIA on all 4 seals and the inners severely flattened and crumble when removing them.
10-27-06, 09:19 AM
#23
Thanks for the info guys. I have a tII torn apart right now that has flattened inner seals (orange) and crumbling outer seals (black). The outer seals seem to take the most punishment since they are more exposed to combustion gases and high temps from leaky side seals.
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