A question about corner seals.
09-20-09, 11:28 PM
#1
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A question about corner seals.
So I just pulled apart my motor after finding low compression on the front rotor (30-10-10). I found the culprit to be a broken side seal and it will be replaced with the rest of the seals. But what I found most interesting and the reason why I'm posting this is that I found no corner seal plugs in any of the corner seals on both front and rear rotors. The last time it blew it was rebuilt by rx7store and me and my engine builder have never heard of corner seals being installed without the corner seals plugs. Is this something some engine builders do or what?
09-21-09, 06:57 AM
#5
So I just pulled apart my motor after finding low compression on the front rotor (30-10-10). I found the culprit to be a broken side seal and it will be replaced with the rest of the seals. But what I found most interesting and the reason why I'm posting this is that I found no corner seal plugs in any of the corner seals on both front and rear rotors. The last time it blew it was rebuilt by rx7store and me and my engine builder have never heard of corner seals being installed without the corner seals plugs. Is this something some engine builders do or what?
On some high boost (20+psi) applications we have seen them get "cooked" out, upon tear down there were minute remnents or they were gone completely. This may have more to do with the fuel being used, but that is a different thread topic.
09-21-09, 09:35 AM
#6
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No, it is not something that engine builders do, we certainly would never consider not installing them. There are a couple builders that do leave them out and claim "to be building it old school", this is pure garbage. If it were "old school" they would be using solid corner seals. It is more of an effort to cut corners and save a few cents.
On some high boost (20+psi) applications we have seen them get "cooked" out, upon tear down there were minute remnents or they were gone completely. This may have more to do with the fuel being used, but that is a different thread topic.
On some high boost (20+psi) applications we have seen them get "cooked" out, upon tear down there were minute remnents or they were gone completely. This may have more to do with the fuel being used, but that is a different thread topic.
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09-23-09, 07:29 AM
#9
"Alot of people" leave parts out of their engines? That certainly does not make it the correct way to rebuild an engine. We see all kinds of crappy/budget engine rebuilds, they do not last very long. It ends up costing much more to cut corners, blow the engine, then send it to us for a proper rebuild. Makes more sense to build it correctly the first time.
You would be amazed at some of the things we see when we crack engines open. Everything from mixed turbo and N/A rotors to apex seal springs being used to hold coolant seals in irons that have retention wall failure. Just because someone does something, does not make it right.
You would be amazed at some of the things we see when we crack engines open. Everything from mixed turbo and N/A rotors to apex seal springs being used to hold coolant seals in irons that have retention wall failure. Just because someone does something, does not make it right.
09-23-09, 09:33 AM
#10
Landers used to build without them for years(he uses them now), he probably built 30 engines for me without them without a problem, all still made excellent compression and ran perfect. I use them in all my builds over the last year and half or more. They become so hardened so fast I doubt you see much if any benefit to having them in there, the lack of them certainly will not lead to engine failure.
However, I install them to prevent threads like this where people get worried over what is likely nothing. There is no real way to do a comparison with and without them and get accurate results. For the $20.00 they cost there is not a real reason not to run them, to the OP, you will never notice a difference if they were there or not.
However, I install them to prevent threads like this where people get worried over what is likely nothing. There is no real way to do a comparison with and without them and get accurate results. For the $20.00 they cost there is not a real reason not to run them, to the OP, you will never notice a difference if they were there or not.
Please tell me you took pics of this? I have seen some jacked up stuff, mostly from remans but never anything that crazy.
09-23-09, 10:07 AM
#12
Landers used to build without them for years(he uses them now), he probably built 30 engines for me without them without a problem, all still made excellent compression and ran perfect. I use them in all my builds over the last year and half or more. They become so hardened so fast I doubt you see much if any benefit to having them in there, the lack of them certainly will not lead to engine failure..
Again, just because someone does something and gets away with it, does not make it right.
We took pictures of the entire breakdown and rebuild, as we do with all engines, but not specifically of the apex seal spring holding in the coolant seal. It didn't do the job very well as the engine was here for coolant seal failure.
Last edited by Banzai-Racing; 09-23-09 at 10:11 AM.
09-23-09, 10:13 AM
#13
I can't agree with you on this. It is a very rare to have a side seal fail in the first place, however on the few that have come into our shop with this failure, the corner seal plugs were omitted from the build. This may only a coinsidence, but I am not willing to cut corners to test it. I have pulled my own personal single turbo 13b-rew engine apart every 5k miles for inspection, not once have the plugs been so hard that they could not have been reused.
Again, just because someone does something and gets away with it, does not make it right.
.
Again, just because someone does something and gets away with it, does not make it right.
.
I understand and I agree, but I know of several of those engines that went 30-40k miles before I lost contact with the car/owner that never once had a problem.
09-23-09, 02:06 PM
#14
I've torn down probably 3-4 engines that have had no corner plugs at all in them. There was no presence of them ever being there either (residual rubber). They were all large street ported engines so the reason was to prevent from them from falling out into the intake and being puked out the exhaust port into a nice turbine wheel/wheels. FWIW two of the engines were built by very reputable rotary GURU's.
I completely agree with David on this matter and I've also built two engines without them in place as the port allowed for around 35-40% of corner seal support. I see no compression difference, nor most importantly vacuum difference with the engine running.
When I built my motor in my one FD I only did a conservative street port (port match, casting smoothing, later closing) I did use the plugs as there's no reason to not run them. Unless you have a significantly large street port USE THEM.
I completely agree with David on this matter and I've also built two engines without them in place as the port allowed for around 35-40% of corner seal support. I see no compression difference, nor most importantly vacuum difference with the engine running.
When I built my motor in my one FD I only did a conservative street port (port match, casting smoothing, later closing) I did use the plugs as there's no reason to not run them. Unless you have a significantly large street port USE THEM.
09-23-09, 02:36 PM
#15
I don't care what "guru" built the engine. There are right ways and wrong ways to do everything. If the porting is so aggressive that there is a fear of the plugs falling out, then solid corner seals should be used. For that matter one piece apex seals should be strongly considered. Sorry, but just deleting them from the build is the wrong way to do it.
How do you know there was no difference in compression or vacuum? What are you comparing it to? An engine built to the same specs with the seal plugs installed or with solid seals?
In the hundreds of engines that I have personally assembled I have never installed a standard corner seal without a plug.
Read post #3 which explains the science behind the plug.
How do you know there was no difference in compression or vacuum? What are you comparing it to? An engine built to the same specs with the seal plugs installed or with solid seals?
In the hundreds of engines that I have personally assembled I have never installed a standard corner seal without a plug.
Read post #3 which explains the science behind the plug.
09-23-09, 06:27 PM
#18
In the picture it looks like the corner seal is flush with the rotor, which would mean that it is not functioning correctly. If the corner seals were difficult to remove from the rotors, this is a direct result of exhaust gases being allowed in and causing carbon deposits. On a 100K miles engines the corner seals come right out.
What does the porting look like on the intermediate plate? Is there any evidence of the side seal getting "hung up"? As arghx had asked, what does the clearancing look like on the other side seals? Are there any excessive carbon deposits under the side seal springs? Without much more info and details on the engine it is hard to determine what caused the failure.
09-23-09, 06:50 PM
#19
I understood the science behind the plug. Gas seal leakage has to be related toward compression and vacuum that's where I was basing my reason toward compression numbers. My comparison was related toward other members compression and vacuum numbers that most likely used the corner plugs. My numbers were equal or better so the gas leakage must have been minimal. I'm not arguing that it doesn't happen I'm sure there is some leakage.
As for the apex seals, why not just rotate the seal like you're suppose to and put the corner piece toward the primary ports??? No reason why you have to run a one piece seal.
You've built more engines than I ever will, I'm not arguing with you at all. Like I said, if you're running a mild port or smaller there's no reason to not run them. I just would rather not have the chance of them entering my engine. When I was rotating the assembly around with my porting template on-top of the rotor housing you could seem next to nothing holding the plug in place. Mixing in some heat to soften it up and rotational force I figured that I would rather not have them in.
As for the apex seals, why not just rotate the seal like you're suppose to and put the corner piece toward the primary ports??? No reason why you have to run a one piece seal.
You've built more engines than I ever will, I'm not arguing with you at all. Like I said, if you're running a mild port or smaller there's no reason to not run them. I just would rather not have the chance of them entering my engine. When I was rotating the assembly around with my porting template on-top of the rotor housing you could seem next to nothing holding the plug in place. Mixing in some heat to soften it up and rotational force I figured that I would rather not have them in.
09-23-09, 11:02 PM
#20
I can't agree with you on this. It is a very rare to have a side seal fail in the first place, however on the few that have come into our shop with this failure, the corner seal plugs were omitted from the build. This may only a coinsidence, but I am not willing to cut corners to test it. I have pulled my own personal single turbo 13b-rew engine apart every 5k miles for inspection, not once have the plugs been so hard that they could not have been reused.
Perhaps it was not coincidence. Corner seal plugs have to be left out when you do an early opening street port and many people ("gurus" included) do not scissor or bevel correctly when doing an early opening side port and it ends up severely wearing or even breaking side seals.
I went through this on my 1st motor when I bought it from a rotary "guru".
Even my mild streetport is early opening and though I like to use 3mm seals and solid corners I just omit the rubber corner seal piece if using 2mm seals (Atkins solids are sketchy quality).
Perhaps it was not coincidence. Corner seal plugs have to be left out when you do an early opening street port and many people ("gurus" included) do not scissor or bevel correctly when doing an early opening side port and it ends up severely wearing or even breaking side seals.
I went through this on my 1st motor when I bought it from a rotary "guru".
Even my mild streetport is early opening and though I like to use 3mm seals and solid corners I just omit the rubber corner seal piece if using 2mm seals (Atkins solids are sketchy quality).
09-24-09, 07:21 AM
#22
You are correct bad porting can cause side seal failure. However, this engine had no porting, no corner seal plugs and shattered side seals http://www.banzai-racing.com/farmer_breakdown.htm
I agree that the port in in Ball Joint's picture looks very poorly done, what does the primary look like?
I agree that the port in in Ball Joint's picture looks very poorly done, what does the primary look like?
09-24-09, 09:22 AM
#23
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Right now the motor is at my builders house and as soon as I go back over there I'll take plenty of pictures for you guys to look at. So check back, because I definitely want your guys opinions.
09-24-09, 09:24 AM
#24
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Ihor and I have never seen the need to remove the corner seal plugs from any build.
When it comes to engine internals, 'oem' and 'by the book' tend to be the best choice (with a few exceptions) for applications up to double stock horsepower.
When it comes to engine internals, 'oem' and 'by the book' tend to be the best choice (with a few exceptions) for applications up to double stock horsepower.
09-27-09, 09:17 AM
#25
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Ok guys here are the pictures of the ports, they are in order from back to front. I checked the side seal clearance on the rest of the side seals and they were within spec.