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5Likes
09-21-2021, 09:17 AM
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Half-Ass Member
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Join Date: Jun 2005
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
Posts: 22,011
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Not Ranked
Quote:
Originally Posted by eschaider
This looks like an 11/32 valve stem in a ⅜ guide.
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That's what I thought. But the out-of-the-box inside diameter of the Edelbrock valve guides, which are designed for 3/8" valve stems, is .365". Even if you did no diamond honing at all, and just blindly dropped an 11/32" stem in there you would spot a wiggle of over .02" as you did it.
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09-21-2021, 11:39 AM
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CC Member
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Join Date: Dec 2001
Location: Louisville,
KY
Cobra Make, Engine: I'm Cobra-less!
Posts: 9,417
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Quote:
Originally Posted by eschaider
+1 on what Brent said. This looks like an 11/32 valve stem in a ⅜ guide. This is very likely not a wear problem as much as it is a parts mismatch problem.
Ed
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That is not what I'm saying at all.
It is indeed a wear problem.
These heads do not come with 3/8" guides because *they are NOT out of the box Edelbrock heads*. These were CNC ported, guides installed, and valves supplied by Craft Racing.
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09-21-2021, 12:51 PM
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CC Member
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Join Date: Aug 2020
Posts: 41
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Quote:
Originally Posted by patrickt
Oliver, is there a stamping on the outside of the valve guide that is visible? For instance, the Edelbrock guides (which it is said you do not have) often have the number 39-1119 on the outside. Of course the inside diameter of that particular Edelbrock guide is already too big for an 11/32" valve. But it would be interesting to know if your guides have an identifying stamp.
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Patrick, I have absolutly no stamps on the guides.
Brent knows what he speaks about : I have 11/32 guides not factory 3/8.
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09-21-2021, 12:53 PM
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CC Member
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Join Date: Aug 2020
Posts: 41
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Quote:
Originally Posted by blykins
That is not what I'm saying at all.
It is indeed a wear problem.
These heads do not come with 3/8" guides because *they are NOT out of the box Edelbrock heads*. These were CNC ported, guides installed, and valves supplied by Craft Racing.
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OK Brent but can you give me #guide reference I would need to order to keep my valves ? guides for 11/32 valves of course.
Thanks, OliveR
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09-21-2021, 01:07 PM
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CC Member
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Join Date: Dec 2001
Location: Louisville,
KY
Cobra Make, Engine: I'm Cobra-less!
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Call Lance at Craft Racing and ask for some guides.
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09-21-2021, 01:27 PM
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Quote:
Originally Posted by blykins
Call Lance at Craft Racing and ask for some guides.
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Sorry Brent but I don't know "Craft Racing".
If you have a web site / phone number / email address for me please ??
Thanks, OliveR
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09-21-2021, 01:38 PM
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CC Member
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Join Date: Dec 2001
Location: Louisville,
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Lance at Craft Racing is taking off where Keith Craft left. They still do the same CNC ported Edelbrock heads and will have parts on the shelf.
https://www.craftperformanceengines.com/
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09-21-2021, 02:35 PM
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CC Member
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Join Date: Feb 2006
Location: Gilroy,
CA
Cobra Make, Engine: SPF 2291, Whipple Blown & Injected 4V ModMotor
Posts: 2,730
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Quote:
Originally Posted by blykins
That is not what I'm saying at all.
It is indeed a wear problem.
These heads do not come with 3/8" guides because *they are NOT out of the box Edelbrock heads*. These were CNC ported, guides installed, and valves supplied by Craft Racing.
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Poor sentence structure on my part, Brent. I was agreeing with what you said, and then observing (my opinion, not yours) that an 11/32" stem in a ⅜" guide could produce a significant wobbling of the valve in the guide — similar to what he was experiencing.
Ed
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Help them do what they would have done if they had known what they could do.
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09-21-2021, 03:03 PM
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Quote:
Originally Posted by blykins
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Thank you very much.
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09-21-2021, 04:18 PM
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Senior Club Cobra Member
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Join Date: Mar 2002
Location: God's country,
ME
Cobra Make, Engine: Original ERA 427sc, Powered by Gessford
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If it was me, I'd replace the valves too.
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"If you can't be a good example, then you'll just have to be a horrible warning."
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09-21-2021, 06:11 PM
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Half-Ass Member
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Join Date: Jun 2005
Cobra Make, Engine: ERA #732, 428FE (447 CID), TKO600, Solid Flat Tappet Cam, Tons of Aluminum
Posts: 22,011
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Quote:
Originally Posted by Chaplin
If it was me, I'd replace the valves too.
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With that much clearance, he could just hone it up a bit and go with 3/8" stems. A half hour of lapping and badda boom badda bing we're done.
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09-21-2021, 07:26 PM
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Or why not hone for a K-line guide insert to bring back 11/32, and run a tight clearance, since they claim to have better life.
I am still dubious about the Edelbrock guides.
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Gold Certified Holden Technician
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09-22-2021, 05:47 AM
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CC Member
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Join Date: Apr 2009
Location: Little Rock area,
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Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
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Keith Craft seemed to do a fair amount of international sales when they built my engine so unless they have changed under Lance, it should not be a stretch for them to get parts to you.
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09-25-2021, 02:38 AM
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Well I've done a partial test which should required a full engine reassembly but here is what I did:
I've resinstalled rockers assembly on one of my head without valve springs. As there is a "line" on each valve showing where valve stop when full opening I make pictures of rocker when valve is closed and when valve is open (stopping rocker when "line" on valve reachs the top of the valve seal).
OK this test should be done with head installed on block, pushrods, etc... BUT does my test doesn't show a rocker pivot issue / pushrod lenght issue ? which could have caused my valve wear premature failure ?
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09-25-2021, 02:39 AM
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valve full lift
Last edited by CLV8; 09-25-2021 at 02:44 AM..
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09-26-2021, 03:48 PM
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Join Date: Feb 2006
Location: Gilroy,
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Cobra Make, Engine: SPF 2291, Whipple Blown & Injected 4V ModMotor
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A rocker, roller or otherwise, will not remain centered on the valve stem. The reason is the roller or (rocker wear pad) traces out an arc that is determined by the distance from the center of the roller to the center of the pivot on the rocker shaft.
If you use the valve lift to establish the length of a chord describing the valve motion in the guide you can position the rocker to center the motion of the roller across the middle of the valve stem, favor the portion of the valve stem closest to the exhaust side of the head or favor the portion of the valve stem closest to the intake side of the head.
My personal preference, when building pushrod engines, is to center the motion of the roller across the middle of the valve stem. When you go to either of the exhaust or intake positioning models you place unnecessary side loading on the valve stem and the guide, resulting in premature wear of the guide.
Ed
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Help them do what they would have done if they had known what they could do.
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09-26-2021, 11:52 PM
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The roller should start from the rocker shaft side of valve stem centre, roll ACROSS centre at half lift, then be at back to the start point at full lift.
Yours appears to start at centre, and by full lift is coming to far away from centre at full lift.
So your valve stem height needs to be increased, longer valves, a lash cap, or lower the rockers. Lash cap is by far the easiest way.
Your roller moves too far, especially since this happens at the highest load at max valve lift.
Gary
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Gary
Gold Certified Holden Technician
Last edited by Gaz64; 09-27-2021 at 09:47 PM..
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09-27-2021, 02:57 AM
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Join Date: Dec 2001
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It’s because on the “full lift” picture he has “input” way more lift than what he has. He is trying to go to whatever mark that is on the valve and that’s not accurate. When the valve lock groove is almost touching the valve seal, that should be an indicator that somethings not right with the experiment. If you try to open the valve an inch, you’re gonna see something like that.
There is nothing wrong at all with that first picture. T&D rockers are some of the easiest to set up and I’m probably the most anal about setting up valvetrain geometry.
In addition, pushrod length has nothing to do at all with geometry on a shaft mounted rocker.
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09-27-2021, 07:23 AM
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CC Member
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Join Date: Apr 2009
Location: Little Rock area,
AR
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
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I was thinking that looks like a lot of camshaft lift.
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09-27-2021, 10:47 AM
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Join Date: Jul 2005
Location: Bartlett,
Ill
Cobra Make, Engine: Everett-Morrison LS1
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what caused those marks on the valve stem just below the keeper lock grove??
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