how does this valve stem wear pattern look?
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,672
Likes: 8
From: Sumter South Carolina
how does this valve stem wear pattern look?
Well engine has been run for total of about an hour. The wear patterns look thin but off center. What do you all think? Engine is solid roller with about .630 gross lift. Planning on spinning it to 7k, Afr 220, 1.6 Harland and sharp rr, hardened thick wall pushrods which were pretty pricey and I would rather not buy them again.
. 
Bonus: here is the nick the piston stop made. I will just lightly sand it I guess.
. 
Bonus: here is the nick the piston stop made. I will just lightly sand it I guess.
Last edited by rithsleeper; Feb 14, 2015 at 02:12 PM.
Le Mans Master
Joined: Feb 2005
Posts: 6,477
Likes: 565
From: Clearwater Florida
....... It will be fine ... For peace of mind you can measure the half moons and the stem itself with calipers and verify that you're pattern is in the middle of the stem at some point ... preferably midway to full open ... Same with the nicks on the piston , they won't hurt anything but while you're there you might as well polish them up a bit ...........
Last edited by C409; Feb 14, 2015 at 05:14 PM.
Melting Slicks
Joined: Jan 2009
Posts: 3,482
Likes: 196
From: folsom california
can you get an adjustable push rod for setting overall length needed to center the pattern in the middle of the valve stem, and then order custom length(s) to match ?
Melting Slicks
Joined: Jan 2009
Posts: 3,482
Likes: 196
From: folsom california
With the solid roller, what kind of valve lash do you run?
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,672
Likes: 8
From: Sumter South Carolina
A new set of these push rods are over $200 since the springs are so big.
I run .025 lash.
Yes they are the Afr 8000
Last edited by rithsleeper; Feb 14, 2015 at 11:23 PM.
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
Go with a different manufacturer if you need to. You should be able to obtain a perfect pattern with the correct length. Custom order them if you need to. Your pattern starts at the center and moves towards the outside. You don't want to run with the geometry thus far off.
Last edited by 383vett; Feb 14, 2015 at 11:57 PM.
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Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
Go with a different manufacturer if you need to. You should be able to obtain a perfect pattern with the correct length. Custom order them if you need to. Your pattern starts at the center and moves towards the outside. You don't want to run with the geometry thus far off.
with 383vett, if your going to be turning high rpms, it's even more important to have the rocker tip centered... You can always put the pushrods you have now up for sale to get some money back...My pattern was very close to what you have now after installing the 1.6 Crane Gold rockers, moving one pushrod size got my pattern more centered...To check your pattern after changing pushrods,use a permanent black marker on the valve tip,put the rocker back on , run the engine a minite , then remove the rocker to check the pattern..The closer you can get the roller to the center , the less wear on the valve guides..My pattern is not perfect , but close enough, and I'm turning much lower rpms then you are.....WW
Last edited by WW7; Feb 15, 2015 at 11:27 AM.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
.When I changed to the Crane Gold rockers, the witness mark opened up ( wider) to what you see above in post #9 , but at least it is centered........WW
Last edited by WW7; Feb 20, 2015 at 10:31 PM.
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,672
Likes: 8
From: Sumter South Carolina
On my original problem I had with the clearancing the large retainer lash caps were a thought and I even bought some then called Afr and they said don't do it. Get the right rocker so I did Harland and sharp.
I don't get how shimming the rocker stud would do anything...? The rocker doesn't bottom out in the first place, so it would just leave more threads up top but still have the same angle... Or maybe I'm visualizing it wrong.
Shorter push rods.... My ones I have now are 7.950 so I guess I will try a 7.900 since my measurement was in between the two.... Some of the patterns are very close to the center so if the 7.900 puts the wear pattern too close to the intake side I can mix and match depending on the valve. Some of the rockers are angled because of clearance to pushrod to the head... Afr said this was because large runner volume in the 220cc head....
I don't get how shimming the rocker stud would do anything...? The rocker doesn't bottom out in the first place, so it would just leave more threads up top but still have the same angle... Or maybe I'm visualizing it wrong.
Shorter push rods.... My ones I have now are 7.950 so I guess I will try a 7.900 since my measurement was in between the two.... Some of the patterns are very close to the center so if the 7.900 puts the wear pattern too close to the intake side I can mix and match depending on the valve. Some of the rockers are angled because of clearance to pushrod to the head... Afr said this was because large runner volume in the 220cc head....
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
7.900 are common length.
Just going off Summit prices.
.080 wall are between $100 for TFS and $130 for Manley.
.120 wall are $192.00 from Manley.
If I had to choose between the pattern being slightly towards the exhaust side or slightly towards the intake side.... as long as the roller is starting out on the intake side, rolling outwards to the centerline and back to the intake side.... you'll have more lift at the valve if its slightly towards the intake side.
Will
Just going off Summit prices.
.080 wall are between $100 for TFS and $130 for Manley.
.120 wall are $192.00 from Manley.
If I had to choose between the pattern being slightly towards the exhaust side or slightly towards the intake side.... as long as the roller is starting out on the intake side, rolling outwards to the centerline and back to the intake side.... you'll have more lift at the valve if its slightly towards the intake side.
Will
Last edited by rklessdriver; Feb 16, 2015 at 12:48 PM.
Thread Starter
Drifting
Joined: Dec 2007
Posts: 1,672
Likes: 8
From: Sumter South Carolina
Afr said I need to use .120 wall rods and so did comp cams (they just want more money). I'll bite the bullet and get the smaller rod.
My pattern width is much larger than any walkthrough or guide to setting a pushrod length. Is that because of my high lift? Does anyone have a smaller pattern and have close to .700 gross lift?
My pattern width is much larger than any walkthrough or guide to setting a pushrod length. Is that because of my high lift? Does anyone have a smaller pattern and have close to .700 gross lift?
Racer
Joined: Dec 2007
Posts: 416
Likes: 3
I'd get an adjustable pushrod, install a weaker spring, mark the valve tip, adjust it until the pattern is centered, send the pushrod out to have the right ones made.
I don't understand why anyone would put so much money in an engine build, get so close, then want to leave something "close enough".
I don't understand why anyone would put so much money in an engine build, get so close, then want to leave something "close enough".