Porting questions
Alright so I have some questions about some housings and plates that I purchased. The plates are street ported. I was told it was a Huge street port but it looks to be a regular street port. But they may have been cut too far towards the center and may eat oil control rings. I’m having the plates lapped right now so if I need to post more pics ill do that. Now the other question is the housings. As you can see they are ported. But they where done pretty shitty. Now I’d like to know is if they are savable. Mainly because they are pretty dam good shape other than the port and very small flaking on the bottom edges. Thanks
http://i644.photobucket.com/albums/u...114_134737.jpg http://i644.photobucket.com/albums/u...114_134712.jpg http://i644.photobucket.com/albums/u...114_134705.jpg http://i644.photobucket.com/albums/u...001_171201.jpg http://i644.photobucket.com/albums/u...001_171153.jpg http://i644.photobucket.com/albums/u...001_171138.jpg |
Also I have cleaned up the plates and housings. Some of the pics where takin the day I got them and where dusty and hate stuff hanging off them and what not. They are much cleaner now. Lol
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i dont know much about porting yet, but those ports do look huge, but it looks like those would be salvageable
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Ya they do. From pics that ive seen on the forums there big but not as big as some i have seen. But becouse they where on 13b's IDK if theres much differance there.
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It could be much worse. But, the intake ports don't look too bad. Definetely not as big as they say. :nod:
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it's hard to tell in those pics, but you should be able to see the trace from where the oil control rings ride around the plates... if it's ported into the trace it's likely the engine will smoke... always. The first port looks fine, but the second one looks like they went into the trace, The exhaust ports just need to be shaped up a little. Those are D-ports.. they flow a lot and are great for spinning a turbo, but they tend to be noisier than round ports.
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If you follow the tracing in the first picture it will probably burn oil. But Idk how much it will it could be an acceptable amount.
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If you have doubts about the porting, make an acrylic template of it. There's a pic of one in my album. This will allow you to rotate the e-shaft/rotor to determine true clearances. I made that guide using a porting template. It's more difficult but one can be made using an iron.
Getting the 2 dowel pin holes dead on is the hardest part but good practice for later porting. Once the first dowel pin hole is lined up, use a junk iron or housing for the 2nd one. Rough out the hole with a step/uni bit, carefully finish with a small carbide bur. Spot the acrylic on the iron, scribe the port, remove and rough out the hole. Finish the edges with the acrylic on the iron. Partially assemble the engine, front iron, housing, loaded rotor and e-shaft. As you rotate the e-shaft/rotor, note where the corner seals/plugs ride and the side seals meet the port edges. The oil ring only seals along the very thin, shiny inner edge. A very small part of the outer edge may ride into the port area w/o causing oil blow by. Depending on where everything rides/meets, you may be able to port wider. Check the Engine Building Porting section @ NoPistons.com for further info. On the exhaust port, bevel the edges to 2 mm wide. |
Thanks trochoid. Ill deff check out what you just outlined. Gonna be hard to score a E shaft atm. But ill do what i can. thanks
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If you're having them lapped, I sure hope you're also getting them re-nitrided. Or are they old-school, non-nitrided plates? Can't tell from the pics.
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i think you bought someone's first port job. i can't really tell from the photos about the oil seal tracks, but if you do what Trochoid said, you'll be able to tell for sure. if they were mine and there is no issue with the oil seals, i'd probably reshape the closing edges before assembly.
for the exhausts, do you have the sleeves? you could reshape them. as you said, the housings seem to otherwise be in good shape. however, they look pretty big as it is (earlier open AND later closing), and cleaning them up is likely to make them a tad larger. so in my opinion, i don't know if they would be the best "fit" for the intake ports you have. maybe they would suit a more radical intake port and/or turbo. i hope that makes sense. |
Originally Posted by PercentSevenC
(Post 10436036)
If you're having them lapped, I sure hope you're also getting them re-nitrided. Or are they old-school, non-nitrided plates? Can't tell from the pics.
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Originally Posted by diabolical1
(Post 10436062)
i think you bought someone's first port job. i can't really tell from the photos about the oil seal tracks, but if you do what Trochoid said, you'll be able to tell for sure. if they were mine and there is no issue with the oil seals, i'd probably reshape the closing edges before assembly.
for the exhausts, do you have the sleeves? you could reshape them. as you said, the housings seem to otherwise be in good shape. however, they look pretty big as it is (earlier open AND later closing), and cleaning them up is likely to make them a tad larger. so in my opinion, i don't know if they would be the best "fit" for the intake ports you have. maybe they would suit a more radical intake port and/or turbo. i hope that makes sense. |
I didn't even notice that the sleeves have been removed.... you'll definitely want to get some sleeves in there if you're going to be driving this thing on the street. Otherwise you're going to be fighting the overheating gremlins all the time.
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can you get a pic of these elusiv sleeves? lol
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Originally Posted by 81WideMariah
(Post 10436317)
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I think your ports are too big for sleeves. Get some and check that they're not in the way of flow.
Also don't resurface. If you do, your oil seals will wear very quickly. |
the plates need to be. They are pretty uneven. Why IDK. Theres no gouges in them but they have some uneven wear on them. I though lappin the plates was a good thing to be done?
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Lapping the plates takes off a few thousands of an inch to make the surface flat again. I forget exactly how many thousandths of an inch off hand it will remove but the hardened surface (or nitrated surface) is only a few thousands of an inch also, so.... If the wear is too deep lapping isn't going to help b/c it will have to remove to much of your hardened surface to regain true flatness.
I'd take a guess here without knowing from 1st hand experience, I think Jeff is trying to say that lapping, even if the wear is minimal and you don't cut all the way through the nitrated surface it'll still make for a less polished finish wearing your oil seals quicker. The wear you're seeing is from the path the seals took when the motor was working. When it goes back together it'll follow the same path and all could still very much be well. The factory manual or even the haynes manual tells you exactly how to measure this wear to see if it's still within tolerence to be used again. |
Originally Posted by Verneuil
(Post 10436164)
1. How would you reshape the closing edges?
2. What do you mean about the sleeves? 2. well, now you've seen what they look like in the photo. Jeff20B might have a point though. i think i can still see traces of the original curves that led to the opening edge in the photo below, and i'm tempted to agree that the port may open below the lower lip of the sleeve. however, this is just a guess on my part based on a photo, so if you can get your hands on some sleeves, you can check that, too. |
^ It's not just the lower lip. The upper corners of the sleeve's edge look like they'd also be in the way of flow judging how these aports apear to have been ported.
And for not having the plates lapped/surfaced, how uneven are they? By uneven, do you mean to say warped? If warped, they're junk. What about them is uneven? Is it just a little bit of step wear in the usual area? Has it worn through the nitride layer? Tell me about the step wear. The main area to check is near the spark plug location. Can you catch a fingernail on it? How deep is the wear? There is a limit in the FSM of .003" or .004" Got a dial indicator? Even a feeler gauge can be useful here. If it's just a little bit of step wear, I'd use the plates as is. It's a lot better for the seals on the side of the rotors if the nitrided layer is left intact. |
There wasnt a lip at all. At least to catch ur finger nail on. There was a slight hump i quess you can call it. Id though having them flat would be better for when i put the plates and housing together with new seals and springs. I think its more than .003" of a inch. If they havent lapped them yet ill find out
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Originally Posted by 81WideMariah
(Post 10436294)
I didn't even notice that the sleeves have been removed.... you'll definitely want to get some sleeves in there if you're going to be driving this thing on the street. Otherwise you're going to be fighting the overheating gremlins all the time.
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Ditto ^
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