TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC V8 Engine Repair and Modifications
  New Posts New Posts RSS Feed - Would you grind on these header tubes?
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

Would you grind on these header tubes?

 Post Reply Post Reply Page  123>
Author
Message
rang-a-stang View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Sep/25/2018
Location: Camarillo, CA
Status: Offline
Points: 106
Post Options Post Options   Thanks (0) Thanks(0)   Quote rang-a-stang Quote  Post ReplyReply Direct Link To This Post Topic: Would you grind on these header tubes?
    Posted: Mar/21/2020 at 11:58pm
I spent some decent time ensuring the exhaust ports are matched to the exhaust gaskets when I built my 401. I was not able to port match the header flange itself though because the header had too much movement relative to the gasket for me to correctly determine where it should go. But now that they have run for a while you can see how terribly they match the exhaust ports! These are probably killing TONS of flow...right? I guess that's what I get for a set of headers this cheap.

Anyway, would you take a die grinder to these to hog them out a little? I am worried that I will eat through the tube and create leaks. At the same time, some of these exhaust ports are really bad...

79 Cherokee, 401
Back to Top
WesternRed View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Aug/03/2010
Location: Australia
Status: Offline
Points: 4238
Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2020 at 12:06am
Those images are not really showing gasket/port mismatch. Would be better to lay a gasket over the top and see how it lines up and do the same on the heads.
I've finally given up drinking for good...........now I only drink for evil.
Back to Top
PHAT69AMX View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/07/2007
Location: West Virginia
Status: Offline
Points: 4973
Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2020 at 1:01am
On the cheap dogleg headers I had, the surface that seals to the head was the tube to flange attachment weld bead(s) that had been slightly flattened out with a belt sander or whatever.  I had a couple few additional beads welded around the existing ones which I thought were to narrow, and used a large flat file and good work holding to then 're-surface' flat the header to head sealing surfaces which were then considerably wider than before because of the added weld beads...  I guess the point is how wide is the sealing surface on any given header most likely would play into the sealing success rate.

( edit, wrong, carbon witness shows only the gasket hole size and shape, not the cyl head or exhaust )
And looking at your pictures, I would dremel or die grind the header ports to match or blend
the carbon witness marks that indicate the cylinder head port size and shape...

Yes, one must use judgement and prudence when grinding / blending NOT to break through the tube.
Alternatively, one can have a welder run a bead around the Tube and flange on the OUTSIDE as insurance, but watch bolt clearance.
A rat tail file or grinder can also be used on the outside bottom flange edge to chamfer it to ease spark plug socket clearance. 
I see a lot of areas that would greatly benefit from additional weld beads being laid on the mating surface.
The AMC dogleg exhaust port shape just has to give header manufacturers headaches...

( edit, wrong, carbon witness shows only the gasket hole size and shape, not the cyl head or exhaust )
I mean looking at your pictures, everywhere there is carbon, the exhaust
is running dead into a surface rather than an opening, is it not ?...




Edited by PHAT69AMX - Mar/22/2020 at 10:52am
Back to Top
WesternRed View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Aug/03/2010
Location: Australia
Status: Offline
Points: 4238
Post Options Post Options   Thanks (0) Thanks(0)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2020 at 3:04am
Originally posted by PHAT69AMX PHAT69AMX wrote:

I mean looking at your pictures, everywhere there is carbon, the exhaust
is running dead into a surface rather than an opening, is it not ?...

I don't think that is the case, the gasket will only be compressed where it sits on the weld bead on the header flange, so exhaust gasses/carbon can get into the space where the gasket is not clamped. 


I've finally given up drinking for good...........now I only drink for evil.
Back to Top
rsrguy3 View Drop Down
AMC Nut
AMC Nut


Joined: Jun/24/2012
Location: Utah
Status: Offline
Points: 295
Post Options Post Options   Thanks (0) Thanks(0)   Quote rsrguy3 Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2020 at 6:11am
Originally posted by WesternRed WesternRed wrote:

Originally posted by PHAT69AMX PHAT69AMX wrote:

I mean looking at your pictures, everywhere there is carbon, the exhaust
is running dead into a surface rather than an opening, is it not ?...

I don't think that is the case, the gasket will only be compressed where it sits on the weld bead on the header flange, so exhaust gasses/carbon can get into the space where the gasket is not clamped. 



My thoughts exactly. The only way to know for sure is to weld more bead on the inside, surface,  fit, run, remove and recheck. In any case, what are your power requirements?  Why does this matter?  
I'm not sure your  going to get perfect fitment without pulling the head and custom precision fitting  new thick flanges to the ex ports. I'm assuming your doing this on a budget,  can you find a pair of thick flanges and re-use your tubes, how long can the car be down? 


Edited by rsrguy3 - Mar/22/2020 at 6:17am
javguy
Back to Top
BassBoat View Drop Down
AMC Addicted
AMC Addicted


Joined: Aug/29/2008
Status: Offline
Points: 1236
Post Options Post Options   Thanks (1) Thanks(1)   Quote BassBoat Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2020 at 7:12am
I ground the flanges, as you would predict, ground through the tube.  Had my friend weld up from the outside.  Held up OK.

Back to Top
PHAT69AMX View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/07/2007
Location: West Virginia
Status: Offline
Points: 4973
Post Options Post Options   Thanks (0) Thanks(0)   Quote PHAT69AMX Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2020 at 10:49am
Okay, can see what you all are saying, the carbon witness marks show
only the opening in the gasket, not the opening in the cylinder head or the exhaust header.
My incorrect statement(s) suggest a gasket with Zero Thickness, which uh... ain't happenin'... 
Back to Top
rang-a-stang View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Sep/25/2018
Location: Camarillo, CA
Status: Offline
Points: 106
Post Options Post Options   Thanks (0) Thanks(0)   Quote rang-a-stang Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2020 at 1:46pm
Here is my head after gasket matching

Here it is now (after about 1000 miles and header removed, most of the REMFLEX gasket scraped off:

Here are my headers with the new REMFLEX gasket laid over them:


These are Hedmans. I think I don't remember the part number:


79 Cherokee, 401
Back to Top
rang-a-stang View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Sep/25/2018
Location: Camarillo, CA
Status: Offline
Points: 106
Post Options Post Options   Thanks (0) Thanks(0)   Quote rang-a-stang Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2020 at 3:07pm
Originally posted by rsrguy3 rsrguy3 wrote:

.... The only way to know for sure is to weld more bead on the inside, surface,  fit, run, remove and recheck. In any case, what are your power requirements?  Why does this matter?  
I'm not sure your  going to get perfect fitment without pulling the head and custom precision fitting  new thick flanges to the ex ports. I'm assuming your doing this on a budget,  can you find a pair of thick flanges and re-use your tubes, how long can the car be down? 
I'm not really looking for perfect but on at least #8, almost the entire dogleg is blocked. Some ports, like #2, there is a good 20% blockage all the way around. I would like it better than what they are. 

I am budget conscience with this build but will spend money when I need to. Another set of headers would be $300'ish, plus exhaust work to get the Y-Pipe to match. This Jeep can be down for a couple weeks if need be but hopefully not. I know Bulltear has a nice header flange but they are $109/side. 

I am a terrible welder and have a terrible HF welder. Maybe I can pay a buddy to run a bead around the outside then at least bevel the inside? 

I sent a tech email to Hedman today. I guess they are in Whittier (not that far from me) so hopefully they can offer some advice or warranty work? 
79 Cherokee, 401
Back to Top
jcisworthy View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jul/23/2009
Location: North Carolina
Status: Offline
Points: 1995
Post Options Post Options   Thanks (0) Thanks(0)   Quote jcisworthy Quote  Post ReplyReply Direct Link To This Post Posted: Mar/22/2020 at 3:40pm
It is up to you but it is better to weld around the flange first if you do.  

I have seen exhaust ports flow the same or more air on the bench when holding a pipe in hand over the exit and raising it up. The port does not fall off until about .200" or so when raising the pipe. 

I was told by a expert in the industry that he once raised a pipe until the flow fell off then welded tabs extending into the header pipe the height flow fell off and the engine picked up 25 hp. I never tired it but it could help with pulsing and it does not hurt flow on a bench up to around .200" raising the pipe, with an AMC dog leg anyway. 

As far as flow goes it I would say it is not hurting anything. As far as power goes there is only one way to find out. 
Specializing in engine building and cylinder head porting

rbjracing.com
Phone Number 518-915-3203
Back to Top
 Post Reply Post Reply Page  123>
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.125 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or