Brodix heads massive guide wear - Chevelle Tech
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post #1 of 35 (permalink) Old May 29th, 20, 10:45 PM Thread Starter
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Matt
 
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Brodix heads massive guide wear

I have a small block Chevy with 225cc Brodix Dragonslayer heads. The engine is about 3 years old, has about 2000 street miles and maybe 15 passes on it.

A few weeks ago it started to smoke under acceleration so I decided to investigate. I pulled the heads and discovered that the valve guides are the worst I've ever encountered on any engine. I can move the valves side-to-side almost a 1/4 inch! All of the valves guides are bad, with the exhaust guides being the worst. I'm amazed it ran an 11.70 several months ago. And I'm thankful it didn't drop a valve!

I double checked the rocker geometry and the pushrod length is spot-on. The tips of the rockers are centered on the valves as they should be.

All valves and pushrods were checked for straightness. No issues there.

The cam is a mild hyd roller with 240 duration and .550 lift. I run Scorpion 1.6 rockers which puts the lift close to .600

The lifters are special high rpm lifters by Morel. They all look like new.

The tops of the pistons look fine with no indication of valves hitting them. Valve float doesn't seem to be an issue. I've tested the engine to 7k RPM and it does it with no issues. Engine typically sees 6500 shift and crosses the stripe at about 6700.

I run Brad Penn 20w/50 racing oil. The heads were setup professionally and are equipped with PAC-1220x beehive springs and titanium retainers.

Hopefully I didn't leave out any important details, but this has me very baffled at the moment. Why did the guides wear out like sticks of butter. The geometry is perfect, no signs of float etc.

Any ideas guys?
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post #2 of 35 (permalink) Old May 29th, 20, 11:38 PM
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Gene
 
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Re: Brodix heads massive guide wear

The question has to be asked, where they tight when the heads were installed, or did someone ASSUME they were?

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post #3 of 35 (permalink) Old May 30th, 20, 12:53 AM
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Re: Brodix heads massive guide wear

Quote:
Originally Posted by toomanymodz View Post
The tips of the rockers are centered on the valves as they should be.
But did you check the width of the sweep? I believe that the sweep patterns should be no wider than about .065" being shown on the valve stem tips. I'm no expert on this, but the professional engine builders say that a narrow sweep is better than a centered one. Ofcourse the goal is to also have the sweep pattern occupying the center third of the valve tip.

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post #4 of 35 (permalink) Old May 30th, 20, 5:02 AM
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Re: Brodix heads massive guide wear

I'll second that question....exactly how did your set-up the valvetrain geometry??

The only way to do it right is in the sticky at the top of this section, the method shown in the video from Straub Technologies.

Being centered on the tip is the LEAST important aspect of setting up the valvetrain. Just using the pushrod length to get a centered tip usually results in a wide sweep pattern, and that will kill guides quickly.
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post #5 of 35 (permalink) Old May 30th, 20, 7:31 AM
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Re: Brodix heads massive guide wear

That thing has to be a mosquito killing machine with valves that loose.

The sweep of the tip has to be all over the place.

What does Brodix say? They should be your second call, right after the one to the guy that assembled them.

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post #6 of 35 (permalink) Old May 30th, 20, 9:02 AM
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Re: Brodix heads massive guide wear

For years now I've said this and it hasn't been well received: A valve job starts with a round strait valve guide with the correct finish and clearance to the valve stem, with out this being right you can not cut a valve seat that is concentric and provides a good contact patch between the valve and the seat. When the valve bounces off the uneven seat it fatigues the head of the valve, example: bending a thin piece of sheet metal between your hands, the contact patch is not there and WILL NOT transfer the heat from the head of the valve through the valve seat, hence the destruction of the valve guide. Brodix heads are the worst of the worst when it comes to guide and valve job work from the manufacture.

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post #7 of 35 (permalink) Old May 30th, 20, 9:49 AM
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Quote:
Originally Posted by VORTECPRO View Post
..
Brodix heads are the worst of the worst when it comes to guide and valve job work from the manufacture.
I sure hope mine are an exception
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post #8 of 35 (permalink) Old May 30th, 20, 10:20 AM Thread Starter
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Re: Brodix heads massive guide wear

I have an adjustable pushrod and mock/measuring rocker arm. I also mark the valve tip and turn the engine over by hand to mark a pattern on the tip. All is good.

I haven't called Brodix yet but plan to. I may also take these to a local machine shop for analysis assuming Brodix doesn't want to see them first. And I may just replace these heads with a set of AFR heads and be done with it.

One thing I discovered in the past is that the rocker arms themselves can make a huge difference in geometry. I once built a big block and assembled it with Harland Sharp rockers. The engine needed custom-length pushrods at that point. A buddy came over with some Crane Gold rockers and we installed a pair. The geometry was perfect with those rockers.

I'll spend some more time doing some sweep analysis and use whatever provides the smallest sweep that is centered. I've never used Scorpion rockers before (usually run Crower stainless), so I hope they aren't the issue.

1966 Chevelle, mild SBC stroker, factory 10 bolt, 3.08 gears, column shift, Performer RPM intake. 11.70's at 116 mph through 2 1/2 exhaust.
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post #9 of 35 (permalink) Old May 30th, 20, 10:39 AM Thread Starter
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Re: Brodix heads massive guide wear

Quote:
Originally Posted by Ericnova72 View Post
I'll second that question....exactly how did your set-up the valvetrain geometry??

The only way to do it right is in the sticky at the top of this section, the method shown in the video from Straub Technologies.

Being centered on the tip is the LEAST important aspect of setting up the valvetrain. Just using the pushrod length to get a centered tip usually results in a wide sweep pattern, and that will kill guides quickly.
I just watched that video and found it very informative. I usually just visually watch the tip sweep. I setup the rocker tip so that it sits on the 'intake' side of the valve stem, and at half-lift it is centered, and at full lift it's over on the 'exhaust' side of the valve stem. Using the 90 degree technique may produce the same result but maybe not. I plan on checking using that technique next. Thanks for sharing.

1966 Chevelle, mild SBC stroker, factory 10 bolt, 3.08 gears, column shift, Performer RPM intake. 11.70's at 116 mph through 2 1/2 exhaust.
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post #10 of 35 (permalink) Old May 30th, 20, 11:54 AM
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Re: Brodix heads massive guide wear

Quote:
Originally Posted by toomanymodz View Post
I just watched that video and found it very informative. I usually just visually watch the tip sweep. I setup the rocker tip so that it sits on the 'intake' side of the valve stem, and at half-lift it is centered, and at full lift it's over on the 'exhaust' side of the valve stem.
That's not right it sounds like the CC method. 1/2 lift should be the closest to Ex. & full lift sweep back towards In. Doesn't have to be centered just not running off the edge of the valve.

Jim

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post #11 of 35 (permalink) Old May 30th, 20, 12:19 PM
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Re: Brodix heads massive guide wear

You are going to be badly surprised when you check things over with the Mid-lift method.

The method you used of starting inboard and ending outboard is a guide killer. I'm still amazed that in this day and age of widespread instant information that some cam companies still have that crap posted in their catalogs and on their websites. Doesn't help any that for years car magazine writers have parroted that same bad info.

You re going to find your pushrod is at least .100" too short, and probably more from that wrong method..
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post #12 of 35 (permalink) Old May 30th, 20, 12:26 PM
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Re: Brodix heads massive guide wear

Quote:
Originally Posted by toomanymodz View Post
I usually just visually watch the tip sweep. I setup the rocker tip so that it sits on the 'intake' side of the valve stem, and at half-lift it is centered, and at full lift it's over on the 'exhaust' side of the valve stem..
This is completely wrong, absolute worst thing you can do is have a roller tip rocker sweeping across the valve tip like that.
It will take the guides out every time.

Calling "A" the intake or valley side of the tip (upper side)
And "B" to the outer or exhaust side...............
You want your sweep to go from "A" on the seat
To "B" at half lift
And back to "A" at full lift
Forget about centered most rockers do not come close to centered on aftermarket heads when the geometry is correct
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post #13 of 35 (permalink) Old May 30th, 20, 12:57 PM Thread Starter
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Re: Brodix heads massive guide wear

I wonder why they even make 'mock' rocker arms if they are so worthless. You're correct that the sweep goes back towards the center of the valve tip. I forgot to mention that. I'm very curious how far off the pushrod length is once I check using the angle technique. I'll report back.

1966 Chevelle, mild SBC stroker, factory 10 bolt, 3.08 gears, column shift, Performer RPM intake. 11.70's at 116 mph through 2 1/2 exhaust.
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post #14 of 35 (permalink) Old May 30th, 20, 1:45 PM
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Re: Brodix heads massive guide wear

What length pushrods did you have?

Jim

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post #15 of 35 (permalink) Old May 30th, 20, 2:13 PM
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Re: Brodix heads massive guide wear

I'm fully with ericnova, geometry is not correct, loading the stem adversely. Seen it a lot before, all sorts of whacko info on doing it incorrectly on the net.
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