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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Thank you for the instructions 1972. I've driven it about 500 miles since the swap. I agree with you MTP, especially since Kohle is so thorough to have written in the box "must install lash caps" several times. Given the ease to pull a valve cover, I'll do it when I have some time during this week and post some pictures.
Thank you for the instructions 1972. I've driven it about 500 miles since the swap. I agree with you MTP, especially since Kohle is so thorough to have written in the box "must install lash caps" several times. Given the ease to pull a valve cover, I'll do it when I have some time during this week and post some pictures.
Definitely get in there to have a look for peace of mind...but yes, Kohle cant make "install lash caps" any more clear.
This is what happens after a couple hundred miles without lash caps. Look at the intake valve stems. They're disintegrated...completely pulverized by the rocker arm to the point one fell into a cylinder, and the others weren't that far behind.
I just pulled my passenger side valve cover off and took video and a picture (below). The lash caps look like they were installed properly on the intake valves. Your thoughts? If there is anything else I should check before putting the cover back on, let me know. 1972: the rocker bolts were at least 22 ft lbs.
That looks a little more difficult to access. Is that strut tower brace stock? I see you also live in Indiana. You should bring that 1972 to the Corvette Indy all Corvette show in August in Carmel. http://www.corvetteindy.com/penske-v...-show-819.html. Thanks again for the help on the covers. It was a pretty easy removal with the instructions you and Jay posted.
I added the strut tower brace. I've replaced the rocker arms on that car, but I think to remove the heads, I drop the engine out.
Thanks for the car show info. Your car looks good-to-go. I know exactly how you felt about needing to know for sure everything was okay. Way too much at stake here.
Looks like I had 6 intake valves that were out of spec
Are those wiggle test measurements? Because if they are not, then all 16 were out of spec. GM spec is anything over 0.0037" clearance between valve and guide is over acceptable tolerance
Are those wiggle test measurements? Because if they are not, then all 16 were out of spec. GM spec is anything over 0.0037" clearance between valve and guide is over acceptable tolerance
Those appear to be his raw measurements, so anything over .008 would be considered out of spec...which aligns with his comments on 6/8 intakes being over that.
Those appear to be his raw measurements, so anything over .008 would be considered out of spec...which aligns with his comments on 6/8 intakes being over that.
Can you please define raw measurements? All I've ever seen was GM spec of anything over 0.0037" on diametrical difference was out of spec.
Can you please define raw measurements? All I've ever seen was GM spec of anything over 0.0037" on diametrical difference was out of spec.
Raw wiggle is the full movement (both directions). Rule of thumb to convert that raw number is as Kohle describes below (from another thread)...
Originally Posted by American Heritage
We have found that the wiggle test readings are roughly half of the actual mic and bore measurements.
Use this formula:
Wiggle test measurement on dial indicator divided by two then minus .0005". That will get you very close to the actual dial bore and mic measurements.
So looking at his Cyl #8 raw measurement of .009/2 -.0005 = .004 (fail)
Looks like these are "raw" measurements. Good thing you decided to do something about it.
Yup, these were raw measurements. I'm super lucky I decided to take the plunge and just get it fixed. Could've ended up in a very bad situation. I even saw the bad intake valves in person during pickup at AHP and they were definitely in bad shape.
Last edited by SpeedwaySD; 03-08-2018 at 02:06 AM.
From my 07 Z06, all was quiet, car was dead stock (27K miles) when I bought it, I plan on tracking so this was step one, sent to AHP:
1 int: .0011" 1 exh: .007"
3 int: .008" 3 exh: .006"
5 int: .0085" 5 exh: .006"
7 int: .009 7 exh: .0065"
Got it milled, went with the moldstar 90 guides, upgraded springs and the 115 cam, So much better to take the car without wondering if today is the day
02-12-2018, 10:37 AM
This engine had 30K miles.
