02-24-2021, 03:56 PM | #113 | |
Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016
Location: US
Posts: 1,196
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Also do you know if TSP does anything with the guides or seats? Do they replace them with new stock ones? Or do they just visually check them and if they look ok proceed with porting? I have asked them and they won't tell me any details. |
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02-24-2021, 04:35 PM | #114 |
Drives: 6th gen Join Date: Aug 2013
Location: US
Posts: 3,664
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I remember it as katech specifically calling out lt4 heads
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‘22 2SS 1LE M6 Summit White - RF, Flexfuel, LT2 intake, 95mm tb, ATI udp, VT ramair, full 28” dragpack - 11.68@122
‘16 1SS M6 LT2 intake + boltons on DR 11.0@126+ (Sold) |
02-24-2021, 06:22 PM | #115 | |
Drives: 2016 Camaro 2SS Join Date: Apr 2018
Location: Central Texas
Posts: 1,011
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02-24-2021, 06:57 PM | #116 |
Drives: 2016 Camaro 2SS Join Date: Apr 2018
Location: Central Texas
Posts: 1,011
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It just says competition 5 angle valve job and porting they really don't specify what the whole process is.
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02-24-2021, 08:28 PM | #117 | |
Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016
Location: US
Posts: 1,196
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I wonder what the difference is between the intake and exhaust seats? I wonder if the LT4 uses different seats than the LT1? I wonder how much the factory does in finish machining to the seats after they are out of the die or mold if they are cast? I wonder if you just can't expect to machine stock seats? Maybe it induces cracking? Either way, if my preload was off, even though TSP said I should be ok? (maybe ok for 10k miles haha) the valves would wear on the seat and more and more of the slack would be taken up until I have more slack and lash in the valvetrain and therefore more impacts to the seat? If you go back and look at the pictures, I don't know what you could call the damage to the other intake seats, pitting? knicking? If you look close at some of them its very weird its almost looks like someone took a very small pick trying to pry the seat out of the aluminum bore. And on top of that in some places the edge of the aluminum bore that holds the seat is also damaged? How would that happen? |
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02-24-2021, 09:59 PM | #118 |
Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016
Location: US
Posts: 1,196
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I got the passengers side head off, overall a lot less intake seat damage, #8 actually had no visible damage that I can tell:
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02-24-2021, 11:03 PM | #119 | |
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Drives: A Tricked Out Mountain Bike Join Date: Jun 2019
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I was speaking in general (air/fuel i.e. meth vs. air and fuel). I should of just said air since were talking DI motors and save any confusion. Thanks for clearing it up!
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02-25-2021, 02:57 PM | #120 |
Drives: Hyper Blue 2016 2SS 6M Join Date: Sep 2017
Location: North Ga
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I'm not certain but I would bet the seats are fully machined ductile iron. Typically replacement seats are basically just little short cylinders. The o.d. is controlled to within a half-mil or so. The i.d. is machined after installation in the head using the guide as a pilot.
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2016 Hyper Blue 2SS/6m/MRC/NPP/Silver Rally stripes/ZL1 wheels & brakes/GForce DS and axles/ZLE Cradle Bushings/FE4 ARB front & rear/SEMA Grill/Rotofab dry/95mm TB/Magnuson 2300/Full LT4 fuel system/JMS boost-a-pump/E85 Sensor/Ported CID heads from LME/Cammotion PD cam/Thompson Motorsports forged shortblock/catted Kooks 1 7/8 headers /JRE remote tuned |
02-25-2021, 06:12 PM | #121 |
Drives: SS 6 speed of course Join Date: Jan 2016
Location: Hilo, HI
Posts: 4,316
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modern powder seats are super strong. IMO this is all caused by valve bounce.
The exhaust valve seat is subject to a lot of heat which can cause burned valves / seats The intake is heavy and hollow, the heavy causes valve bounce (especially with boost), the hollow means it is easy to get out of kilter or just plain break. I was worried about the OEM valve, truthfully I'm not worried at all about the seat given a blue printed and maintained valvetrain and reasonable expectations for application. sub .600 cam slow controlled ramps, change springs at 50K, I think 100K miles at 90% reliability. Building a full boost car for the Texas Mile, IMO nothing that leaves the facory is adequate, OK maybe the block.
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Forged short block, large duration sub .600 lift Cam Motion cam, 7200 RPM fuel cut, Pray Ported Heads, 3.85 pulley D1X, stage II intercooler, DSX secondary low side, DSX E85 sensor, Lingenfelter big bore 2.0 pump, ported front cats, 60608 Borla, LT4 injectors, ZL1 1LE driveshaft and Katech ported TB, ported MSD intake, BTR valvetrain, ARP studs, ProFlow valves, PS4 tires.
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02-25-2021, 06:14 PM | #122 |
Drives: SS 6 speed of course Join Date: Jan 2016
Location: Hilo, HI
Posts: 4,316
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why does one seat have a scratch and the other has a few dings from the grinder collet? A scratch is a perfect place for the seat to start burning away.
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Forged short block, large duration sub .600 lift Cam Motion cam, 7200 RPM fuel cut, Pray Ported Heads, 3.85 pulley D1X, stage II intercooler, DSX secondary low side, DSX E85 sensor, Lingenfelter big bore 2.0 pump, ported front cats, 60608 Borla, LT4 injectors, ZL1 1LE driveshaft and Katech ported TB, ported MSD intake, BTR valvetrain, ARP studs, ProFlow valves, PS4 tires.
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02-25-2021, 06:31 PM | #123 |
Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016
Location: US
Posts: 1,196
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I looked back at my notes and found something interesting, i was going from memory but I thought I had excess lash (not enough preload) but it was actually the opposite. I was having trouble getting a lash measurement with the adjustable pushrod and called TSP. They said they sent me the wrong tool apparently and my best guess was around .048 but of course that's dependent on what you consider your base line zero lash. I'm reality i think it was more than that and TSP told me to run it like that with those pushrods.
So would having more preload than recommended cause extra wear and impact on the seats? I guess they could bottom out to eventually. As for the seat material, i was wondering why the damage is limited to the intake? More valve mass? Seat area? Different metallurgy between the intake and exhaust? |
02-25-2021, 07:27 PM | #124 | |
Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016
Location: US
Posts: 1,196
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I guess a valve seat shows up as iron haha The 86k change was when I put my cam in, iron went from average to 55ppm. |
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02-25-2021, 07:28 PM | #125 | |
Drives: SS 6 speed of course Join Date: Jan 2016
Location: Hilo, HI
Posts: 4,316
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IMO NO vendor can recommend a pushrod length unless you have adjustable rockers. All pushrods have to be individually spec and even more so with the R limited pump lifters. Now OEM LS7 lifters have a lot of movement so all else the same (never is), stock length pushrods should work. Alls I can say is that I reused ZERO pushrods from first to second cam change. I just don't remember if they had to be all shorter or longer. I must have purchased 50 to 60 pushrods for my motor over two cams. Maybe I got every length made now. LOL, so one again IMO, no way a vendor can tell you what pushrod will "work" in a large cam engine. GM hot cam and LS7 lifters = OK, but that is a factory ramp cam and factory lifters and factory pushrods on factory springs. There is a whole lot of forgiveness in the setup. I think max rev is either 6600 and .577 lift. https://www.jegs.com/p/Chevrolet-Per...4897/10002/-1# That is easy peasy compared to .640 lift and 7200 RPM.
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Forged short block, large duration sub .600 lift Cam Motion cam, 7200 RPM fuel cut, Pray Ported Heads, 3.85 pulley D1X, stage II intercooler, DSX secondary low side, DSX E85 sensor, Lingenfelter big bore 2.0 pump, ported front cats, 60608 Borla, LT4 injectors, ZL1 1LE driveshaft and Katech ported TB, ported MSD intake, BTR valvetrain, ARP studs, ProFlow valves, PS4 tires.
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02-25-2021, 07:36 PM | #126 | |
Drives: 17 2SS, 8L90, Cam, Heads, E85 Join Date: Dec 2016
Location: US
Posts: 1,196
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