wthdidusay82's engine build
03-28-13, 01:29 AM
#1
wthdidusay82's engine build
As some of you may remember, he had two engines, one from his turbo II and one from a junkyard. He didnt know if either of them was any good, both were assumed to be high mileage. He wanted to get the car running, and was really debating back and forth as to whether to try and use them as-is, try to rebuild one/both himself, or send them out to be built by a shop.
https://www.rx7club.com/2nd-generati...dvice-1022715/
https://www.rx7club.com/2nd-generati...es-**-1027570/
Well he wound up bringing both of them to me. I thought you guys may enjoy seeing the progress and finding out what he actually had and what would have happened if he hadn't listened to me and the other experienced builders who advised not to trust these used/unknown cores.
We hoped that between the two of them there would be enough parts to build one decent block.
Well, it's a good thing he didn't try to use either of them as is. But he also got pretty lucky compared to what I expected he would have (a bunch of pretty worn high mileage parts).
Turns out that one had been rebuilt at some point by someone. That one had a destroyed front thrust plate, bearings, spacer, etc. from someone letting a thrust bearing slip out of place during a botched front pulley/front cover job. It was weird because it had obviously run for quite a long time before the failure happened, so it wasn't an assembly error from what I could tell. The flywheel was grinding on the rear stat gear/bearing due to the endplay. So, it wouldn't have run (for very long) as-is before it ate every bearing in the engine and destroyed most every component inside. But it had some pretty decent parts inside it as it was. All 3 irons were miraculously still good, and the rotors appeared okay. The rotor housings were near mint and probably only had 20-30k on them I'd guess.
Turns out that the other was a fairly low mile mazda reman. But it could not have run as-is either. It had two spun rotor bearings which makes both rotors junk, one rotor had rubbed on the intermediate iron and destroyed it, and of course the shaft was junk. But the rotor housings were nice and the front and rear iron survived okay. IT also had good front stack parts to replace the damaged stuff from the other core. So between both cores there was enough to make one good block plus some nice leftover parts that I took in trade and helped lower his cost.
Then later I discovered that the surviving e-shaft had some significant wear that I did not want to reuse so it wound up having to be replaced.
https://www.rx7club.com/2nd-generati...dvice-1022715/
https://www.rx7club.com/2nd-generati...es-**-1027570/
Well he wound up bringing both of them to me. I thought you guys may enjoy seeing the progress and finding out what he actually had and what would have happened if he hadn't listened to me and the other experienced builders who advised not to trust these used/unknown cores.
We hoped that between the two of them there would be enough parts to build one decent block.
Well, it's a good thing he didn't try to use either of them as is. But he also got pretty lucky compared to what I expected he would have (a bunch of pretty worn high mileage parts).
Turns out that one had been rebuilt at some point by someone. That one had a destroyed front thrust plate, bearings, spacer, etc. from someone letting a thrust bearing slip out of place during a botched front pulley/front cover job. It was weird because it had obviously run for quite a long time before the failure happened, so it wasn't an assembly error from what I could tell. The flywheel was grinding on the rear stat gear/bearing due to the endplay. So, it wouldn't have run (for very long) as-is before it ate every bearing in the engine and destroyed most every component inside. But it had some pretty decent parts inside it as it was. All 3 irons were miraculously still good, and the rotors appeared okay. The rotor housings were near mint and probably only had 20-30k on them I'd guess.
Turns out that the other was a fairly low mile mazda reman. But it could not have run as-is either. It had two spun rotor bearings which makes both rotors junk, one rotor had rubbed on the intermediate iron and destroyed it, and of course the shaft was junk. But the rotor housings were nice and the front and rear iron survived okay. IT also had good front stack parts to replace the damaged stuff from the other core. So between both cores there was enough to make one good block plus some nice leftover parts that I took in trade and helped lower his cost.
Then later I discovered that the surviving e-shaft had some significant wear that I did not want to reuse so it wound up having to be replaced.
03-28-13, 01:30 AM
#2
Once the rotors were media blasted I could see that whoever rebuilt it last time used a rotor that had significant previous damage, in such a way that the rotor apex slots were WAY too open on the ends. Spec for the apex slot clearance is 2-4 thou standard with a 6 thou max IIRC. Well some of his were 6-8+ at the ends. I guess somebody was salvaging a damaged rotor and filed the ends out too far, but used it anyway. I decided it couldn't be used as is so we replaced it with one from my shelf.
03-28-13, 01:35 AM
#3
I picked out a cleaner used e-shaft from my shelf for him.
I wanted to keep all 3 of the irons from the first core together because they all were in nice condition and were a matched set. But he was worried because the rear iron had a little bit of the "ear" for one of the bellhousing bolts broken off. I told him that rotaries don't make much torque and the remaining bellhousing bolts would be more than enough to hold it securely even if that one bolt was left out. But it seemed like it still bothered him, so I repaired the break by welding a nut onto the front of the hole then welding around it to make it stronger. I'm not a great welder but it's a good enough repair.
He wanted to use ALS 2mm apex seals. Here is everything cleaned up and laid out ready to build.
I wanted to keep all 3 of the irons from the first core together because they all were in nice condition and were a matched set. But he was worried because the rear iron had a little bit of the "ear" for one of the bellhousing bolts broken off. I told him that rotaries don't make much torque and the remaining bellhousing bolts would be more than enough to hold it securely even if that one bolt was left out. But it seemed like it still bothered him, so I repaired the break by welding a nut onto the front of the hole then welding around it to make it stronger. I'm not a great welder but it's a good enough repair.
He wanted to use ALS 2mm apex seals. Here is everything cleaned up and laid out ready to build.
03-28-13, 01:38 AM
#4
I had to find another rotor on my shelf that was the proper year/model, would be balanced with the other one, and had no major issues and all clearances correct. The one on the left is the replacement. At some point somebody else has had their hands on it and did some scratching or sanding on it, but all the seal slots were great and it was nearly a perfect match for his other good rotor. They both got new rotor bearings pressed in. That's another reason I wanted to use a nicer e-shaft...this engine had to have all new bearings. If it had been a cheaper build with used bearings then maybe I would have let that original shaft ride.
03-28-13, 01:42 AM
#5
Here's his nice rotor housings and irons.
These rotor housings are near-mint, very uncommon to find s4's in this condition, and will give him above average compression in my estimation.
These irons are in good, normal condition with light step wear in the normal positions. This is completely normal and will have a minimal impact on compression or longevity IMO.
These rotor housings are near-mint, very uncommon to find s4's in this condition, and will give him above average compression in my estimation.
These irons are in good, normal condition with light step wear in the normal positions. This is completely normal and will have a minimal impact on compression or longevity IMO.
03-28-13, 01:46 AM
#6
Rotors with seals and springs installed (all except apex springs and apex triangle end pieces, which get installed during the stack). These are new hand-fit side seals and I put them at about 2-2.5 thou of side-to-corner seal clearance which is at the low end of the scale. I try to put them there (on engines that get new side seals) because over time it will open up as the side and corner seals wear. The tighter you can get them (within spec), the better compression you can have...similar to a piston ring gap.
Side seal clearance...
Nice straight/tight apex slots...
Side seal clearance...
Nice straight/tight apex slots...
03-28-13, 01:54 AM
#7
Assembly...
Right about now you're asking, "why is there sealant on the rotor housing mating surface?". I do that for most all builds I do with used rotor housings. There is always some pitting on the sides of the rotor housings where the coolant seals mate up. Sometimes more than others, but always some. Those pits could theoretically form a tiny bypass around an otherwise perfect coolant seal, and make for a small coolant/compression leak that would mimic a coolant seal failure. So I put a thin layer of sealant there (so thin that you can almost see through it) as a 'dressing" which will fill in most of these pits. I've built literally hundreds of engines this way and although it's not quite "by the book" it's been proven not to hurt anything.
The stuff on the rotor tips is vaseline. Once the rotor is set inside the housing, I insert the short and long apex springs, which press the apex seals out against the housing. Then I insert the apex end triangle piece, and use vaseline to help hold it in place until the next iron is placed on top of it. If one of those triangle pieces pops out of there (under spring pressure) it will fly across the room and you will NEVER find it again. Then you'll have to stop the build for a few days until you can get a replacement...IF you can get a replacement that is. Vaseline on both sides of the triangle helps keep it in place.
Right about now you're asking, "why is there sealant on the rotor housing mating surface?". I do that for most all builds I do with used rotor housings. There is always some pitting on the sides of the rotor housings where the coolant seals mate up. Sometimes more than others, but always some. Those pits could theoretically form a tiny bypass around an otherwise perfect coolant seal, and make for a small coolant/compression leak that would mimic a coolant seal failure. So I put a thin layer of sealant there (so thin that you can almost see through it) as a 'dressing" which will fill in most of these pits. I've built literally hundreds of engines this way and although it's not quite "by the book" it's been proven not to hurt anything.
The stuff on the rotor tips is vaseline. Once the rotor is set inside the housing, I insert the short and long apex springs, which press the apex seals out against the housing. Then I insert the apex end triangle piece, and use vaseline to help hold it in place until the next iron is placed on top of it. If one of those triangle pieces pops out of there (under spring pressure) it will fly across the room and you will NEVER find it again. Then you'll have to stop the build for a few days until you can get a replacement...IF you can get a replacement that is. Vaseline on both sides of the triangle helps keep it in place.
Trending Topics
03-28-13, 02:06 AM
#9
Freshly resurfaced flywheel!
First endplay check. Found 2-2.5 thou, right in the middle of the 1.5-3.5 you're supposed to have. So we're good to go with assembly. IF it were out of spec then I'd go back down to the spacer and go with a different thickness to increase or decrease endplay.
That pesky front cover o-ring is held in place with vaseline and the correct gasket. Most rebuild kits come with the 89-91 gasket that uses the big hole for the double o-ring set found in s5 engines. Even if you order a rebuild kit for an 86-88 car, you still get the (wrong) 89-91 front cover gasket, and this is a source of screwup for many DIY'ers.
Second endplay check after assembly just to be sure. Endplay is not always absolute and sometimes you have to play with the torque/tightness of the front bolt to get it where you want it.
Coolant system pressure test to 20psi. In a working engine the cooling system is normally pressurized to a max of 13psi. So if it holds 18-20 for half an hour or more then you know it's good and the coolant seals have been installed correctly and there are no problems with the coolant jackets anywhere.
I let it sit this way for a little while and then take the test stuff off later. But it's basically ready to go now.
First endplay check. Found 2-2.5 thou, right in the middle of the 1.5-3.5 you're supposed to have. So we're good to go with assembly. IF it were out of spec then I'd go back down to the spacer and go with a different thickness to increase or decrease endplay.
That pesky front cover o-ring is held in place with vaseline and the correct gasket. Most rebuild kits come with the 89-91 gasket that uses the big hole for the double o-ring set found in s5 engines. Even if you order a rebuild kit for an 86-88 car, you still get the (wrong) 89-91 front cover gasket, and this is a source of screwup for many DIY'ers.
Second endplay check after assembly just to be sure. Endplay is not always absolute and sometimes you have to play with the torque/tightness of the front bolt to get it where you want it.
Coolant system pressure test to 20psi. In a working engine the cooling system is normally pressurized to a max of 13psi. So if it holds 18-20 for half an hour or more then you know it's good and the coolant seals have been installed correctly and there are no problems with the coolant jackets anywhere.
I let it sit this way for a little while and then take the test stuff off later. But it's basically ready to go now.
03-28-13, 02:13 AM
#10
A lot of the point of me making this thread is to show some of you other guys who are in a similar position as this guy that you NEVER know what you have with these things and it is a HUGE risk to try and use an unknown condition used core or JDM engine. You may get lucky and get an engine that can run as-is for years. But the odds are that there are one or more problems and you could wind up with an engine that lives for months, weeks, or is DOA upon install. And in fact you could take an engine with an issue and make it a lot worse (doing more damage to expensive components) in the attempt to use it as-is.
There is a reason that experienced enthusiasts and builders tell people not to trust used/unknown rotaries. Some people would say that builders such as myself who give this advice are doing so because it is self serving, to generate more business. In fact we are the most qualified to speak on the matter because we take so many cores apart and we see all the issues that they normally have, and we know not to trust them until they've been gone through or you can quite possibly be wasting not only your time but materials and money.
Also consider that even a rebuilt engine such as this will not be perfect and even with this, it is hard enough to get all the rest of the car and accessories around the engine block working properly so the car can run fairly well. Now consider all the issues that an old/original/unknown engine block might have if you try to run it, and all the difficulties you'd encounter trying to get THAT car running normally. It would be next to impossible! Does this sound at all familiar to any of you having issues with starting, idle, etc. who are using a tired original engine?
There is a reason that experienced enthusiasts and builders tell people not to trust used/unknown rotaries. Some people would say that builders such as myself who give this advice are doing so because it is self serving, to generate more business. In fact we are the most qualified to speak on the matter because we take so many cores apart and we see all the issues that they normally have, and we know not to trust them until they've been gone through or you can quite possibly be wasting not only your time but materials and money.
Also consider that even a rebuilt engine such as this will not be perfect and even with this, it is hard enough to get all the rest of the car and accessories around the engine block working properly so the car can run fairly well. Now consider all the issues that an old/original/unknown engine block might have if you try to run it, and all the difficulties you'd encounter trying to get THAT car running normally. It would be next to impossible! Does this sound at all familiar to any of you having issues with starting, idle, etc. who are using a tired original engine?
03-28-13, 09:55 AM
#12
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,826
Received 2,595 Likes
on
1,843 Posts
nice build, its a great starting point.
03-28-13, 10:13 AM
#13
I about dropped my jaw when he took the junkyard block apart and said. "These are some of the nicest series 4 housings I've seen"
You know when your builder says something like that and he's built 100's of engines that you're definitely going to have a nice engine.
You know when your builder says something like that and he's built 100's of engines that you're definitely going to have a nice engine.
03-28-13, 10:33 AM
#15
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,826
Received 2,595 Likes
on
1,843 Posts
03-28-13, 10:48 AM
#16
Those are some legitimately nice housings.
I'd like to hear your method for clearancing the side seals. I have done it with a dremel tool clamped to a flat table so I can slide the seal up to the flat face of a cutoff disc. Then de-burr with a fine file. But everyone does it differently.
I always do a surface prep of the irons with a palm sander and kerosene, but it's not strictly necessary.
I'd like to hear your method for clearancing the side seals. I have done it with a dremel tool clamped to a flat table so I can slide the seal up to the flat face of a cutoff disc. Then de-burr with a fine file. But everyone does it differently.
I always do a surface prep of the irons with a palm sander and kerosene, but it's not strictly necessary.
03-28-13, 11:48 AM
#20
And how the hell do take pictures when you're smearing vasoline, oil, and sealant all over the camera?!?!?!
I don't touch the vaseline. I have it in a "flavor injector" turkey baster, and just inject a bead in the coolant seal grooves, and little dabs here and there as needed.
I shoot the oil onto the bearings with a handheld oil can, and in the rear rotor and stat gear I do smear it around with my finger then wipe it off with a towel.
03-28-13, 11:59 AM
#21
Those are some legitimately nice housings.
I'd like to hear your method for clearancing the side seals. I have done it with a dremel tool clamped to a flat table so I can slide the seal up to the flat face of a cutoff disc. Then de-burr with a fine file. But everyone does it differently.
I'd like to hear your method for clearancing the side seals. I have done it with a dremel tool clamped to a flat table so I can slide the seal up to the flat face of a cutoff disc. Then de-burr with a fine file. But everyone does it differently.
I always do a surface prep of the irons with a palm sander and kerosene, but it's not strictly necessary.
03-28-13, 12:00 PM
#22
I've always said that just about any retard can assemble an engine from all new parts. I mean seriously, they probably have old japanese women doing it in a plant in japan right now. It takes more effort and experience to judge used parts and make something out of them. In reality it should cost the customer more to reuse parts than to replace them, because of all the extra work it is for the builder to clean, inspect, and sometimes doctor the used parts.
03-28-13, 12:24 PM
#23
Last car was an NA and that was a fun experience for me. I've been wanting a Turbo rotary for years, I've never even driven a Turbo car never mind a Turbo rotary.
Should be alot of fun to drive after break in, might take me awhile to get it running since this is my first Turbo 13b and I want it done right and I'm solely doing the work myself.
Plan is to keep it simple and delete all the emissions, ac,possibly the omp as well. I'm on the fence on the omp, part of me wants to keep it, part of me wants to run strictly premix. I'll keep the power steering and bac. Also delete the cold start etc.
03-28-13, 12:39 PM
#24
Just looking forward to getting it and putting it in and all.
Last car was an NA and that was a fun experience for me. I've been wanting a Turbo rotary for years, I've never even driven a Turbo car never mind a Turbo rotary.
Should be alot of fun to drive after break in, might take me awhile to get it running since this is my first Turbo 13b and I want it done right and I'm solely doing the work myself.
Plan is to keep it simple and delete all the emissions, ac,possibly the omp as well. I'm on the fence on the omp, part of me wants to keep it, part of me wants to run strictly premix. I'll keep the power steering and bac. Also delete the cold start etc.
Last car was an NA and that was a fun experience for me. I've been wanting a Turbo rotary for years, I've never even driven a Turbo car never mind a Turbo rotary.
Should be alot of fun to drive after break in, might take me awhile to get it running since this is my first Turbo 13b and I want it done right and I'm solely doing the work myself.
Plan is to keep it simple and delete all the emissions, ac,possibly the omp as well. I'm on the fence on the omp, part of me wants to keep it, part of me wants to run strictly premix. I'll keep the power steering and bac. Also delete the cold start etc.
It would be drop in and plug up ready. Doesn't that sound appealing?
03-28-13, 12:58 PM
#25
I do appreciate the offer, probably wouldn't fit in the trunk of the car I'm bringing with it installed anyways. Lol. Using a car this time to save money on gas since I'm only hauling one engine not two.
Out of curiosity, in case there is a chance I can get it. How much would you charge for them without being installed?