[Z06] *Broken LS7 SS exhaust valve...
07-26-2016, 10:20 PM
#22
Drifting
Thread Starter
[QUOTE=Unreal;1592712899] Where is the last cap on the intake valve?
[/QUOTE
They are a one piece Del West tumble polished titanium intake valves with no lash caps.
[/QUOTE
They are a one piece Del West tumble polished titanium intake valves with no lash caps.
07-26-2016, 11:35 PM
#23
Burning Brakes
07-27-2016, 12:36 AM
#24
Race Director
07-27-2016, 07:39 AM
#25
Safety Car
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I think one of the possible scenarios being discussed here is that the builder, for whatever reason, installed the OEM intake lash caps on some/all of the S/S exhaust valves. If so, this would have caused a MAJOR FUBAR on exhaust valve rocker geometry. This definitely could have caused the busted exhaust valve tip failure. The one question (in my mind) is if the OEM Ti intake valve stem tip diameter is the same as aftermarket S/S exhaust valves. At least that would give us an indication if the Ti intake lash caps could be physically swapped to the exhaust valve. Hopefully the OP will check and possibly post some pics of the rest of the exhaust valves.
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SSMOKE (07-28-2016)
07-27-2016, 08:00 AM
#26
Race Director
[QUOTE=RWE 427;1592713840]The Del West valves are the stock ones and need lash caps. When the heads come back from being redone you need to install them. I think from the pics it does look like a lash cap with a piece of the valve broken off in it.
07-27-2016, 08:31 AM
#27
Drifting
Thread Starter
The heads were assembled by WCCH and shipped to Lethal for installation, so I'm sure they were done correctly. This isn't the typical failure of the exhaust valve as mentioned above.
Still interesting conversation,which is why I posted the info.
Keeping an ear and eye on heads after being fixed is still important even if your Corvette isn't tracked or raced
Last edited by RWE 427; 07-27-2016 at 08:43 AM. Reason: added bolding for the take away of this thread!
07-27-2016, 08:36 AM
#28
Race Director
The heads were assembled by WCCH and shipped to Lethal for installation, so I'm sure they were done correctly. This isn't the typical failure of the exhaust valve as mentioned above. Still interesting conversation,which is why I posted the info.
Keeping an ear and eye on heads after being fixed is still important even if your Corvette isn't tracked or raced
Keeping an ear and eye on heads after being fixed is still important even if your Corvette isn't tracked or raced
07-27-2016, 08:44 AM
#29
Drifting
Thread Starter
07-27-2016, 09:04 AM
#31
Technically, this particular valve isn't "broken" in the practical sense. The hardened tip insert broke.
It is not that uncommon to separate a hardened tip insert when you do not use a roller tipped rocker. It's just the nature of the beast. Increase lift with the OEM rockers, you compound the problem (friction).
Not all solid stemmed valves use tip inserts. Some are hardened. I prefer to use lash caps on valves with tip inserts, and do not use anything but a roller tip when lifts get high enough to warrant.
It is not that uncommon to separate a hardened tip insert when you do not use a roller tipped rocker. It's just the nature of the beast. Increase lift with the OEM rockers, you compound the problem (friction).
Not all solid stemmed valves use tip inserts. Some are hardened. I prefer to use lash caps on valves with tip inserts, and do not use anything but a roller tip when lifts get high enough to warrant.
07-27-2016, 08:16 PM
#33
Burning Brakes
[QUOTE=AzDave47;1592714471]I know they'll do whatever, but I said typically. Still not clear if these are stock intake valves or not.... There definitely isnt a lash cap on the intake, which is why I'm asking.
07-27-2016, 08:50 PM
#34
Race Director
[QUOTE=rio95;1592720768]OP said they are Del West, but you are right, it requires clarification as Del West makes the OEM intakes and also makes a higher quality aftermarket Ti intake valve for the LS7. They may even manufacture the Katech TiMo intakes (requires no lash cap) I have as a third production item.
07-27-2016, 09:06 PM
#35
Race Director
Technically, this particular valve isn't "broken" in the practical sense. The hardened tip insert broke.
It is not that uncommon to separate a hardened tip insert when you do not use a roller tipped rocker. It's just the nature of the beast. Increase lift with the OEM rockers, you compound the problem (friction).
Not all solid stemmed valves use tip inserts. Some are hardened. I prefer to use lash caps on valves with tip inserts, and do not use anything but a roller tip when lifts get high enough to warrant.
It is not that uncommon to separate a hardened tip insert when you do not use a roller tipped rocker. It's just the nature of the beast. Increase lift with the OEM rockers, you compound the problem (friction).
Not all solid stemmed valves use tip inserts. Some are hardened. I prefer to use lash caps on valves with tip inserts, and do not use anything but a roller tip when lifts get high enough to warrant.
Specs are here so you don't have to look them up- http://store.katechengines.com/torqu...haft-p223.aspx
07-27-2016, 10:54 PM
#36
Drifting
Thread Starter
[QUOTE=rio95;1592720768]
Yes they make an titanium intake valve with hardened tips that need no lash caps. The exhaust valve failure was a REV solid exhaust valve. Just goes to show that you should keep an eye on rebuilt "fixed" heads no matter if you track it or not,.
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aceinthesky (05-06-2019)
07-28-2016, 09:21 AM
#37
Early next year I plan to install a mild cam like the Katech Torquer 116 or something similar. Would you use roller tips for that application?
Specs are here so you don't have to look them up- http://store.katechengines.com/torqu...haft-p223.aspx
Specs are here so you don't have to look them up- http://store.katechengines.com/torqu...haft-p223.aspx
Regardless, .650" lift is pushing your luck. From what I've seen with these heads, OEM rockers.... at about .620", the wipe starts running toward the edge of the stem tip.
07-28-2016, 09:31 AM
#38
Race Director
Maybe I missed it. if so sorry but what rockers would you recommend with having a roller tip that will bolt in place of the factory ones.
07-28-2016, 09:40 AM
#39
That's not a simple question to answer. As far as I'm concerned, there are only two choices for a bolt on roller rocker. The YT's and T&D's. I'd take the T&D's over the YT's any day of the week. I do not like aluminum rockers. Call me prejudice, I don't care. Don't use them on any of my engines. With either choice, you need to make sure you have enough spring to use them. The other option is complete rail set ups, but they are not bolt on and require machine work.
07-28-2016, 09:50 AM
#40
Race Director
That's not a simple question to answer. As far as I'm concerned, there are only two choices for a bolt on roller rocker. The YT's and T&D's. I'd take the T&D's over the YT's any day of the week. I do not like aluminum rockers. Call me prejudice, I don't care. Don't use them on any of my engines. With either choice, you need to make sure you have enough spring to use them. The other option is complete rail set ups, but they are not bolt on and require machine work.