Edelbrock heads - acceptable tolerances

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gen2hemi

gen2hemi

former ASE knuckle buster
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I am hoping a couple of the experts can share their opinions, findings, and experiences with Edelbrock heads. I am in disagreement with one of the volume sellers of the LA Performer RPM heads over what are acceptable "out of the box tolerances" for these and his immediate response was if you have a problem, call Edelbrock. No problem, except in this case it was stated that "we buy them bare from Edelbrock and machine the pushrod holes". The P/N I was shipped was not the "bare" head P/N, it was a "flat tappet complete" P/N 60779. (They seem unaware that if they take a product and add value by machining it, they create a warranty of merchantability of their own in the eyes of the UCC.) The tolerance issues I had were in 3 areas - what is acceptable "out of the box"
  • seat concentricity
  • MnBr valve guide clearance intake & exhaust
  • deck flatness
I went to change out the Edelbrock springs and retainers to ones that were matched to my cam for seat and over the top pressure and I was pretty surprised with what I found. Manganese bronze valve guides are designed to run tight, I'm familiar from use on H-D V-twins and aircraft. When I took the out of the box springs and retainers off and did a hand clearance check on the valve stems, I couldn't get comfortable with how tight they were. I mean tight. I also checked the deck with my 12" machinists straightedge and wasnt impressed with the daylight I could see but lacked a longer one to get a better measurement. So I took them to the LMS to get gauged and checked on modern race shop measuring equipment. What they found I couldn't run with in any engine; street or race. Out of the box - well you be the judge. If these are selling in quantity and folks aren't screaming, must be good 'nuff. I have to emphasize I was not looking for blueprinting. This is a somewhat philosophic argument once you start measuring and correcting clearances, but "out of the box" has to be held to a standard. Valve seats/seal. First seat that they measured was .008 out of concentric. Avg across 16 > .006. To have any chance at valve seal and smooth running engine needs a real valve job. They told me most all the Edelbrock heads they see are bad in this regard. Valve guides. Precision ball measuring. Intake I flagged was .0008". Average intake .0010". My machinist wants intakes .0012" +/- .0001. Exhausts were all over the place but all tighter than the .0015" +/- .0001 target. I would appreciate an AERA or other best practices reference, but too tight is too hot, and too hot is too short lived.. Deck. This is pretty basic machining and for all the Made in USA and precision manufacturing, ISO 9000, etc Edelbrock touts, the .006" out of flat (dished) on one and .004 on the other (humped) is pretty poor. Not my first experience with Edelbrock tolerances. Plenty over the years. Even the RPM AG intake on this motor was also badly out of tolerance on the parallel planes of the intake surfaces. Over .100" out of parallel in fact. So before I go to Edelbrock or the reseller I am looking for other experiences with these. The seller says of course we sell these blueprinted, that's not what you bought. I said I bought a ready to run product, short of going a fully blueprinted or CNC ported route it still needs to meet some clearances and specs based on best practices and standards. My only expectation was getting the advertised quality, performance, and reliability from the heads.
 
This is why I have said over and over, "There is no such things as an OOTB cylinder head from the factory." Every head has to go to a trusted machinist and be checked and fixed.

And people want to know how come we charge more for an engine than the crate motor facilities. I will not install an OOTB cylinder head on any engine we build.

Nothing gets installed OOTB, every piece is inspected. You would be suprised how almost everything needs some correction, piston rings, rocker arms, valve springs. We get cylinder heads in here from one source where most of the valves would cut up the bronze guides when we pull them (if we didn't dress the ends with a fine file) and they have never been run. Never run, and some of the valve stems are so nicked up during the spring installation we have to replace those valves. Most of the time they will run screwed up, some of them for a long time.

Had a man come in with his Chevy and say, "This thing seems down on power. Check it out will you?"

Tell him, after a leakdown test, "You got intake and exhaust valves leaking." Say's he, "How can that be? It's not missing yet!"

And away he drives. Still down on power but "not missing".
 
I bought used eddy heads on this sight, took them to my machinest to be checked before I installed them, they worked out ok, but I put diffrent springs and seals in them, that was my choice. You never no.
 
All the issues you found are consistent with factory machined Edelbrock product. And Indy. And Brodix. And TFS. And World. They all suck, and none should be run out of the box. It's not warranty - it's reality.
 
Damn that was an essay, I've got a shorter version: If your that concerned, get a good valve job and call it done.
 
PoisonDart74 said:
Damn that was an essay, I've got a shorter version: If your that concerned, get a good valve job and call it done.
Click to expand...

That's generally the fix, yes. It's another $500-600 to get them ready to install for me. Operations include a 5 angle valve job and milling them actually flat.
I'll add although the OP didn't mention a need to test for it - the roughness average (Ra) for the gasket surface is usually boarderline too rough if you're using MLS gaskets so if those are in the cards that has to be addressed when they cut the gasket surfaces.
 
IQ52 said:
This is why I have said over and over, "There is no such things as an OOTB cylinder head from the factory." Every head has to go to a trusted machinist and be checked and fixed.

And people want to know how come we charge more for an engine than the crate motor facilities. I will not install an OOTB cylinder head on any engine we build.

Nothing gets installed OOTB, every piece is inspected. You would be suprised how almost everything needs some correction, piston rings, rocker arms, valve springs. We get cylinder heads in here from one source where most of the valves would cut up the bronze guides when we pull them (if we didn't dress the ends with a fine file) and they have never been run. Never run, and some of the valve stems are so nicked up during the spring installation we have to replace those valves. Most of the time they will run screwed up, some of them for a long time.
Click to expand...

Word

p.s. to the thread starter Eddy came out with Gen2 hemi heads just about a week ago. the price is actually a little higher than the Indy aluminum hemi heads i think.
 
No new news to be read here. Regular order of things with aftermarket parts.
 
IQ52 (Jim)
I have had two sets of heads done by him .
I trust and respect what he says .
When you want the truth or the real scoop why not from the people that do this for a living !!
Quality ain't cheep !!
But neither is taking something apart to be redone !!
Easier to do it right the first time !

By the way Jim and Cody's work is top notch !!!
 
I ran a set ootb for a bunch of years on a mild street 408. Got around 1hp/CID- dynoed at 350/400 at the wheels. I never did hook it up good at the track without breaking parts (4spd) but it was MPH'ing around 108-110. For what it was- a clean upgrade to tired iron heads- I was happy.

I just got them back from Shady Dell where they got a clean up deck, his "stage II" porting, and a nice valvejob. I can't wait to feel the difference!
 
You all validated what I suspected. I will sleep better having made the investment to go through these heads completely. Others that believe the OOTB viability of these heads, YMMV..

Agree with the surface finish comment too Moper, the .003 true up cut we made first was primarily to remove this pattern roughness. Then it took a second pass .003 to get below the uneven areas. Even tho I'm not running MLS - going FelPro composite with only 10.5:1 static, the head surfaces are much improved (and jewel-like) now.
 

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moparlover said:
I like my Stage V setup just fine but this is an interesting move by Vic. They clearly had a plan going with a valve-guide-in-port design and larger exhaust valve. I don't see provisions for the "extra" hemi valley head bolts in this picture. Designed to work on RB wedge blocks too?

61169-int.jpg
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If they are close to perfect out of the box, the only charge would be to have a pro check them out. That's a small price to pay for peace of mind. If they aren't right, be prepared to pay the price to make them so. Also a small price to pay. tmm
 
gen2hemi said:
You all validated what I suspected. I will sleep better having made the investment to go through these heads completely. Others that believe the OOTB viability of these heads, YMMV..

Agree with the surface finish comment too Moper, the .003 true up cut we made first was primarily to remove this pattern roughness. Then it took a second pass .003 to get below the uneven areas. Even tho I'm not running MLS - going FelPro composite with only 10.5:1 static, the head surfaces are much improved (and jewel-like) now.
Click to expand...

I have the same heads and intake. What did you get out of them? I'm really praying for the 417hp edelbrock advertise.
 
Aspen79 said:
I have the same heads and intake. What did you get out of them? I'm really praying for the 417hp edelbrock advertise.
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You should make at least that I'm making 420 hp 440 tq on a mild build XE 262 cam , air gap and EDE heads .
 
Aspen79 said:
I have the same heads and intake. What did you get out of them? I'm really praying for the 417hp edelbrock advertise.
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If the engine build is still apart ,at least check valve to valve guide clearance , a lap the valves with compound properly. Personal experience. A good valve job ,would help immensely.
 
Abodybomber said:
If the engine build is still apart ,at least check valve to valve guide clearance , a lap the valves with compound properly. Personal experience. A good valve job ,would help immensely.
Click to expand...

So have you done any serious work to them? I have the mild street cam from edelbrock 7177. They say 415hp. Do u have a stock stroke crank?
 
FYI.

On the engine line that I worked on, we had to keep the tolerance for the valve seat out of roundness to 13 microns (.013 mm - about the diameter of a hair or less). That is how much the seat can be off of a perfect circle. Even with dedicated tooling/machines, we still struggled to keep that tolerance.

You also have to keep the concentricity to the valve guide held tightly as that will also affect the valve seating. Concentricity, then roundness. Concentricity is how well the center of the valve guide is aligned to the center of the seat. Roundness is how far off a perfect circle that the seat is. They both have to be kept to a minimum.
 
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