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What to Check on Aftermarket Heads
#1794371
04/01/15 06:26 PM
04/01/15 06:26 PM
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Joined: Aug 2007
Posts: 1,271
Vista, California
67Satty
OP
pro stock
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OP
pro stock
Joined: Aug 2007
Posts: 1,271
Vista, California
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I see over and over to never just bolt a set of aftermarket aluminum heads on to an engine without having them checked out first.
I would like to learn how to do this myself.
Let's use 440Source Stealth heads as an example of a head that people say you shouldn't try to just bolt on and run right OOTB.
First, the valve springs. Now even their own website says to not use them on any cam with over .510 of lift. I have a cam that is .534 lift but if I call Engle they will say to use valve springs that are rated the exact same as what the Stealth heads come with OOTB. So is there any reason to not use the valve springs the Stealth heads come with as long as the spring rate matches what the cam manufacturer recommends?
Next, the locks and retainers that come on Stealth heads. If they are using Comp Cams locks and retainers now, is there any reason to change these to the 10 degree locks and retainers they are now recommending for any cam over .460 lift? I've read that 7 degree locks have a better bite when used with springs with mild pressures (125/300)? I guess I don't get the point of changing Comp Cam 7 degree locks and retainers for another set of Comp Cams 7 degree locks and retainers or am I missing something?
Valve job: I see people saying the valve job on the Stealth heads is so-so, can I just hand lap the valves in and call it good? Or do they need to be brought into a machine shop and redone? Is there a way to check at home if it is any good?
Valve guide clearance too tight: This is another thing people report on Stealth and Edelbrock heads, is this something I can check by feel? In other words, if the valve stem seems to go freely into the guide and not feel like it's binding when assembling the head, is it good to go?
Anything else someone can check themselves at home? Thanks!
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Re: What to Check on Aftermarket Heads
[Re: RJS]
#1794373
04/01/15 07:07 PM
04/01/15 07:07 PM
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Joined: Jan 2003
Posts: 8,021
Tulsa OK
Bad340fish
master
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master
Joined: Jan 2003
Posts: 8,021
Tulsa OK
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I can only speak for Edelbrocks that I bought new. My machine shop thought the guides were a little tight and the valve job wasn't all that great. He did his valve job on them and honed the guides for me.
68 Barracuda Formula S 340
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Re: What to Check on Aftermarket Heads
[Re: RJS]
#1794374
04/01/15 07:08 PM
04/01/15 07:08 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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I dont know anything about the Stealth heads.. I have looked at Mopar heads from MP.. the valve job was JUNK.. the springs were so far off that you shouldnt run them on anything but a hyd cam... so based on this I would either take them apart and check them myself OR have a shop check them out... why listen to anyone or an website... so it cost a few bucks.. it might save your engine... one valve guide to tight and you eat a engine...... but this is JMO 
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Re: What to Check on Aftermarket Heads
[Re: RJS]
#1794375
04/01/15 07:12 PM
04/01/15 07:12 PM
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Joined: Aug 2007
Posts: 1,271
Vista, California
67Satty
OP
pro stock
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OP
pro stock
Joined: Aug 2007
Posts: 1,271
Vista, California
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Quote:
I'm inches away from buying Stealth Heads and bolting them on also so this is a good topic to hear about. I have a buddy that had worked in a machine shop years back and has been a mechanic his whole life with some pretty stout Mopars. He has bolted these right on numerous engines of the past few years without incident.
The valve lift and 7 degree questions are answered by 440 source right on their site.
Who's cam are you going to use with that lift? Can you share details?
Ron
The answer the valve spring and lock and retainer question right on their site but I suspect the answer is pretty generic and just meant to cover all the basics.
For example, they say any cam over .510 lift needs the other Comp Cams springs they carry. The problem is that you can't find the original Comp Cams part number on their site to see which specific set of Comp Cams springs they really are or what the actual spring pressure is of the upgraded springs they recommend.
From what I've seen people report, the springs that come with the Stealth heads OOTB are rated at about 125/300 which is exactly what Engle recommends for my cam which is a hydraulic with .534 lift and 238 @ .050 duration.
I also remember Jeff at MCH coming on here and saying that the 7 degree locks and retainers they are now coming with are perfectly good and standard industry stuff.
Others have said when they get their heads, the box has a sticker on it saying words to the effect of "now with Comp Cams locks and retainers".
But when I call 440Source, they automatically echo the website and say any cam over .510 needs different springs, locks, and retainers without bothering to ask what spring pressure the cam manufacturer recommends.
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Re: What to Check on Aftermarket Heads
[Re: 67Satty]
#1794376
04/01/15 07:17 PM
04/01/15 07:17 PM
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Joined: Feb 2013
Posts: 760
Canada
CTD5.9
super stock
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super stock
Joined: Feb 2013
Posts: 760
Canada
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Quote:
But when I call 440Source, they automatically echo the website and say any cam over .510 needs different springs, locks, and retainers without bothering to ask what spring pressure the cam manufacturer recommends.
Is there a chance they are just cheap springs and approaching their coil bind at .510?
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Re: What to Check on Aftermarket Heads
[Re: MR_P_BODY]
#1794377
04/01/15 07:17 PM
04/01/15 07:17 PM
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Joined: Aug 2007
Posts: 1,271
Vista, California
67Satty
OP
pro stock
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OP
pro stock
Joined: Aug 2007
Posts: 1,271
Vista, California
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Quote:
I dont know anything about the Stealth heads.. I have
looked at Mopar heads from MP.. the valve job was JUNK..
the springs were so far off that you shouldnt run
them on anything but a hyd cam... so based on this
I would either take them apart and check them myself
OR have a shop check them out... why listen to anyone
or an website... so it cost a few bucks.. it might
save your engine... one valve guide to tight and you
eat a engine...... but this is JMO
So what I'm wondering is if there is a way for someone at home disassemble the head at home and check the valve job quality? If you can hand lap the valves and get a good contact pattern does that mean it's good? Is there another way to check? Is there no way to check the valve job?
Is there a way to check that the valve guides aren't too tight? If the valve stems go in nice and easy and turn without binding is that a good indication or does it have to always be measured to know?
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Re: What to Check on Aftermarket Heads
[Re: 67Satty]
#1794378
04/01/15 11:19 PM
04/01/15 11:19 PM
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Joined: Jan 2003
Posts: 21,065
Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,065
Niles , Ohio
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My Stealths were one of the first sets.I changed spring locks and retainers.i run a .588 solid cam and the springs that came were a bit weak I hear Eddys are also.I ran comp everything.My machinsit checked them and just said the valves need a cleanup on the backcut and he is a perfectionist.He also open them up when he was doing the work.I hear the new locks etc are better than the first ones.I sold all mine to a guy and he runs them today on a milder cam.Never had a problem.Rocky
Chrysler Firepower
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Re: What to Check on Aftermarket Heads
[Re: therocks]
#1794379
04/01/15 11:48 PM
04/01/15 11:48 PM
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Joined: Oct 2011
Posts: 515
geezer acres rest home
dakotawilly
mopar
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mopar
Joined: Oct 2011
Posts: 515
geezer acres rest home
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simple answer,check everything you buy.period.if you dont have the required tools to do it,just take them to a reputable shop,spend a few coins and sleep well at night.its a crapshoot out of the box,may be fine may not.the thing is,if you are going that far,why settle for something you are unsure about? sort of like marrying a russian bride over the internet.you just may end up with helga the female ironworker from chernoble....
SFI 25.5 depends,no leak,even at 213 mph....
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Re: What to Check on Aftermarket Heads
[Re: 67Satty]
#1794381
04/02/15 01:43 AM
04/02/15 01:43 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
I would like to learn how to do it myself, so I guess what I'm asking is, what are the required tools other than a valve spring compressor? When a machinist checks them out, what specifically are they checking and can it be done at home with the right tools?
I called 440Source today and got some answers to some of my questions.
Locks and retainers: 7 degree locks and retainers that come on them OOTB now made by Comp Cams, but he felt that my cam still needed the 10 degree upgrade.
Springs: 105/300 spring pressure, he said it was more a matter of them not being as durable in the long run with my cam than the spring pressure being too weak for why he recommended that I upgrade the springs.
Comp Cam spring upgrade they offer: 130/330 spring pressure (which would be just right for my cam). Comp Cams part number 924-16.
With 330 open pressure I'd stick with 7* stuff... high
spring pressure will pull the lock down through the
retainers.. but you dont have it
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Re: What to Check on Aftermarket Heads
[Re: BradH]
#1794388
04/02/15 02:54 PM
04/02/15 02:54 PM
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Joined: Aug 2007
Posts: 1,271
Vista, California
67Satty
OP
pro stock
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OP
pro stock
Joined: Aug 2007
Posts: 1,271
Vista, California
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Quote:
I'll try to make this quick:
1. Valve guides being tight... take it to a local shop and ask them to check the clearance while you watch. Even if a clean stem & guide move freely, there may still be insufficient clearance.
There will actually be a little bit of wobble when the clearance is around .002". Once you've felt them set up properly, it's easier to feel when they're too tight... and my last couple sets of Edelbrocks were definitely too tight.
2. Valve job... many aftermarket heads simply don't have a great valve job. In some cases the equipment used doesn't result in a concentric seat, and/or it can be that the out-of-the-box (OOB) valve job doesn't take advantage of more performance-oriented angles & widths.
Edelbrock's OOB valve jobs on Performer RPM & Victor heads are far from ideal in that they have really wide seats and simple angle combinations compared to what a well prepped set of performance heads will have. That results in lost performance that simply lapping the valves in isn't going to recover.
I hope this helps.
That helps thanks!
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Re: What to Check on Aftermarket Heads
[Re: CTD5.9]
#1794389
04/02/15 03:35 PM
04/02/15 03:35 PM
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Joined: Jun 2004
Posts: 741
Carson City, NV
440sourcedotcom
super stock
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super stock
Joined: Jun 2004
Posts: 741
Carson City, NV
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Quote:
Is there a chance they are just cheap springs and approaching their coil bind at .510?
Coil bind height is listed on our cylinder head specifications page at 1.130". Because the springs use an installed height of 1.875", if you do the math, (1.875-1.130= .745), the springs can be compressed up to .745" before coil bind becomes an issue. This does not mean that they can be used with a .745 lift cam, that's a separate issue related to spring pressures. However, it does tell you that coil bind will not be an issue until you get to .745" lift, which is WELL beyond any application you would ever use a single spring with.
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Re: What to Check on Aftermarket Heads
[Re: 440sourcedotcom]
#1794390
04/02/15 05:04 PM
04/02/15 05:04 PM
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Joined: Jan 2003
Posts: 4,296
Chicago, IL
TonyS451
master
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master
Joined: Jan 2003
Posts: 4,296
Chicago, IL
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I purchased a set of CNC Indy EZ 295's and for the price, one would think you could bolt them on and go. Not so fast, says Dwayne Porter. He touched up the valve job and did a little hand blending and found about another 20cfm. I felt very good about having them looked over by a pro.
That being said, I think the fact that many of the bolt-on heads need to be checked first, is a shame. Takes away from the convenience of buying something bolt on in the first place. Maybe there needs to be stricter inspection practices before those items leave the factories.
2 kids and a dog
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