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Guest
·While trying to figure out why I was down about 50ish rwHp and cylinders are filling with oil. Found this... It explains the loss of power but not the oil consumption and 20-25% leakdown in every cylinder.
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Cure for your winter time blues - More CARNAGE!
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Guest
·The comp rocker arm trunion upgrade bearings are worn out. They grind pretty bad. I think they caused drag wearing out the cam lobes.
Found the source of the oil in cylinders. This is some sweet ring clocking. WTF???
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Found the source of the oil in cylinders. This is some sweet ring clocking. WTF???
G
Guest
·244/254, .612/.622 113lsa. PRC .650 lift dual valve springs. I run amsoil 20/50 with high zinc.
Open pressure is 412 on exhaust. The more I investigated, the more I think the 5/16" pushrods flexed flexed/floated at high rpms. The lifter rollers and cam lobe damage point to that. Looks like its time for some 11/32" Manton's.
The heads are PRC LS3's that were assembled by them. I never double checked the installation of the components. Looking at them tonight it seams that the springs have different install heights. At least some of the valve stems sit higher above the springs.
Open pressure is 412 on exhaust. The more I investigated, the more I think the 5/16" pushrods flexed flexed/floated at high rpms. The lifter rollers and cam lobe damage point to that. Looks like its time for some 11/32" Manton's.
The heads are PRC LS3's that were assembled by them. I never double checked the installation of the components. Looking at them tonight it seams that the springs have different install heights. At least some of the valve stems sit higher above the springs.
G
Guest
·Any recommendations for better lifters and rockers would be appreciated.
I am running Morel lifters based on their reputation which comes largely from their popularity in marine engines that run high rpm for sustained periods.
Yella Terra shaft mounts are popular but are limited in terms of open spring pressure - around 400 pounds if I recall correctly. I went with the Jesel Sportsman but they are not cheap - around a thousand. Comp 1500s are good and I have heard good things from CTSV-154 about the Crane Golds.
Yella Terra shaft mounts are popular but are limited in terms of open spring pressure - around 400 pounds if I recall correctly. I went with the Jesel Sportsman but they are not cheap - around a thousand. Comp 1500s are good and I have heard good things from CTSV-154 about the Crane Golds.
Joined
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2,046 Posts
When I called Texas Speed to set up my 418 CID LS3 build, they recommended the Lunati Street Link-Bar lifters as the first step above the LS7 lifters. The next step beyond that is definitely Morel, as Darkman said.
If you really want to go past the Comp Cams upgrade (which I think you should still be fine with), consider Scorpion rockers (LS3 part here), which are apparently well-liked by the Corvette community.
If you really want to go past the Comp Cams upgrade (which I think you should still be fine with), consider Scorpion rockers (LS3 part here), which are apparently well-liked by the Corvette community.
Morels are great. I have messed with them alot on Gen1 sbc's along. Not sure about Gen III stuff but I have run the Isky lifters and they are awesome but I am not sure what they offer for Gen III stuff
Also Manton is a great company! I swapped to them recently for my drag cars and they are awesome!
Also Manton is a great company! I swapped to them recently for my drag cars and they are awesome!
Hmm, that cam isn't overly aggressive (aggressive lobe?).
The Manton's will be a nice upgrade and as for lifters the morels are definitely top notch, I've also run the comp link bars and luntatis with no issue (link bars are the way to go).
YT ls3 rockers do have a limit on spring pressures, try to find a rocker that has more bearing/bushing surface area than the stock rockers. I have seen many comp trunion upgraded rockers with a lot of wear on the bottoms (load area) of the trunions, on motors that are frequently run at high RPM and load (usually on higher lift/stronger spring motors than yours). The trunion upgrades have their place and provide nice security and piece of mind over the factory uncaptured needle bearings, but like everything, they have there limits. I know there are some decent rockers out there, just can't make any recommendations from first hand experience other than an all out Jesel shaft set up that we run on any of the Big high revving builds, but they are very pricy and require machining the head (overkill, even for you, lol).
The intake valve tips should all be the same height as eachother and exhaust the same as eachother, but intakes may be different than exhausts. If intakes or exhausts are different from eachother (inside the batch) then I would dis-assemble and check everything. Intake valves and seats should all be the same length and location in head. If I recall correctly, on the last set of PRC heads I used, my intake and exhaust pushrods differed by .050".
The Manton's will be a nice upgrade and as for lifters the morels are definitely top notch, I've also run the comp link bars and luntatis with no issue (link bars are the way to go).
YT ls3 rockers do have a limit on spring pressures, try to find a rocker that has more bearing/bushing surface area than the stock rockers. I have seen many comp trunion upgraded rockers with a lot of wear on the bottoms (load area) of the trunions, on motors that are frequently run at high RPM and load (usually on higher lift/stronger spring motors than yours). The trunion upgrades have their place and provide nice security and piece of mind over the factory uncaptured needle bearings, but like everything, they have there limits. I know there are some decent rockers out there, just can't make any recommendations from first hand experience other than an all out Jesel shaft set up that we run on any of the Big high revving builds, but they are very pricy and require machining the head (overkill, even for you, lol).
The intake valve tips should all be the same height as eachother and exhaust the same as eachother, but intakes may be different than exhausts. If intakes or exhausts are different from eachother (inside the batch) then I would dis-assemble and check everything. Intake valves and seats should all be the same length and location in head. If I recall correctly, on the last set of PRC heads I used, my intake and exhaust pushrods differed by .050".
G
Guest
·I can't believe you just quoted anything that Texas Speed said. I effing HATE them right now. I hope your shortblock turns out better than mine. My invoice didn't match the build sheet they provided me and neither matched the actual build. Maybe yours will have full compression and not burn 1 qt of oil every 500 miles after 4 months of running.
You think I should still be fine with the Comp Cams trunion upgrade? Absolutely not. If you could feel how bad some of these things are you'd be singing a different tune. I think once you get into the higher lift cams and higher rpms you just need something stronger.
Joined
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2,046 Posts
Most people love their Texas Speed shortblocks. If this was a problem from the start, I hope you called them up. Otherwise, I'm not sure what your options are now.
Neither of our cams are particularly high lift. You're a little taller than me at .622" (I'm at .612"), but compared to something like the MS4 cam (.649" lift), they're tiny.
You seem to be bucking the trend here with the knock on the trunion upgrade. The only complaints I've found are people that have worn valve stems because of the roller-less GM rocker construction.
Edit: out of curiosity, how did that TSP shortblock differ from what you asked for, and how did you find out?
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Guest
·For one thing, the bearings were different than what both sets of paperwork said. I haven't removed my rings from the pistons yet and checked the gap to see if they are close to what the build sheet says and I haven't measured the bore diameters.
Looking down the cylinder walls, there are verticle places about 1/2" wide where the rings sealed better than the rest of each bore. These surfaces are pretty much in alignment with the cooling jackets. I'm sure when I measure I will find that the cylinders are not perfectly round. I specifically told TSP that I was using head bolts and not head studs, it's looks like they attached the torque plate with studs instead of bolts causing slightly different cylinder distortion than the ARP bolts I used to attach the heads. As a reference, my stock LS2 bores were as smooth as the verticle marks on the TSP bores and had better looking cross hatching and ring sealing.
Be very aware of what ancilliary parts they recommend. For instance, they recommended 'Comp stock replacement lifters'. "These are what we use in our builds" is a VERY common sales pitch they all use there. The ones they recommended and sold me are the long (stock) travel 850-16's. I really wish I would have caught that and got what I used with my cammed LS2, the 875-16's. The 875's are the reduced travel ones that comp carries, not the complete race short travel ones, 15850-16.
My sales rep was 'Johnny on the spot" until I received my parts. It took several tries to get him to send me the build sheet (looking back now I think he just found any old sheet and sent it to me). After I started having crankcase pressure and oil consumption issues I tried calling him multiple times and emailing him. I got no reply and since it was 4 months after I installed and started running the motor I figured that I knew what their response would be.....there is no warranty, blah, blah, blah.
I have always been on the Comp trunion upgrade bandwagon and I've installed them on every head and cam setup I've ever done for myself and anyone else. I'm going to see if the ones I removed from my LS2 have any resistance/grinding. Yes, I still have used parts in my basement from three years ago that I never plan on using. I have read elsewhere that the Comp trunions have a tendency to wear out one the wear side with higher spring pressures. The max recommended by the Comp rep I spoke with is 450 pounds so I should have been fine.
Looking down the cylinder walls, there are verticle places about 1/2" wide where the rings sealed better than the rest of each bore. These surfaces are pretty much in alignment with the cooling jackets. I'm sure when I measure I will find that the cylinders are not perfectly round. I specifically told TSP that I was using head bolts and not head studs, it's looks like they attached the torque plate with studs instead of bolts causing slightly different cylinder distortion than the ARP bolts I used to attach the heads. As a reference, my stock LS2 bores were as smooth as the verticle marks on the TSP bores and had better looking cross hatching and ring sealing.
Be very aware of what ancilliary parts they recommend. For instance, they recommended 'Comp stock replacement lifters'. "These are what we use in our builds" is a VERY common sales pitch they all use there. The ones they recommended and sold me are the long (stock) travel 850-16's. I really wish I would have caught that and got what I used with my cammed LS2, the 875-16's. The 875's are the reduced travel ones that comp carries, not the complete race short travel ones, 15850-16.
My sales rep was 'Johnny on the spot" until I received my parts. It took several tries to get him to send me the build sheet (looking back now I think he just found any old sheet and sent it to me). After I started having crankcase pressure and oil consumption issues I tried calling him multiple times and emailing him. I got no reply and since it was 4 months after I installed and started running the motor I figured that I knew what their response would be.....there is no warranty, blah, blah, blah.
I have always been on the Comp trunion upgrade bandwagon and I've installed them on every head and cam setup I've ever done for myself and anyone else. I'm going to see if the ones I removed from my LS2 have any resistance/grinding. Yes, I still have used parts in my basement from three years ago that I never plan on using. I have read elsewhere that the Comp trunions have a tendency to wear out one the wear side with higher spring pressures. The max recommended by the Comp rep I spoke with is 450 pounds so I should have been fine.
My research suggests that the maximum parameters to run the stock rockers reliably are is 0.600 lift and 400 pounds of open spring pressure. The stock LS1/LS2/LS3/LS6 valvetrain is designed for 0.550 lift and at any lift above that the rockers start to scrub the valve tips which in turn introduces some degree of flex into the valvetrain operation. It is generally accepted practice to push the envelope to 0.600 without seriously degrading reliable operation. But, make no mistake the benchmark for reliabilty is 0.550 and not 0.600. Additonally, lift is not the only variable since the shape of the camshaft (ramp rates) can also introduce flex into the valvetrain. If the cam requires more than 400 pounds of open spring pressure whether because of its lift or its ramp rates the stock rocker is operating beyond its intended design.
G
Guest
·Well, Texas Speed also recommended stock rockers. "This is what we use in our builds".
Must be right - Go for it.
G
Guest
·Look where that got me. I think I've decided on a set of scorpion rockers, morel 5206 lifters, Manton's 11/16" pushrods, a bigger cam and changing out the valve springs to a set recommended by Comp for my new cam.
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