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1988RedT2
1988RedT2 MegaDork
8/5/22 11:29 a.m.

Okay, back on the Nova.  Got a Pypes full system to install.  Headers for this car are notorious for fitment headaches, and this one is no exception.  As it sits, Hedman Elite headers with the supplied gaskets are installed.  Both sides are touching--drivers side on the steering box and steering arm, passenger side on the shock tower.  I've already shimmed the solid engine mounts to get a little more clearance.

When I say touching, I mean by the slightest of margins.  I was able to slip a sheet of paper between the steering box and the headers, but after fully tightening the bolts, no go.

So, am I insane to consider running these without gaskets?  RTV?  I need to pick up at least a few thousandths.  angry

 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/5/22 11:39 a.m.

We run our turbo to manifold joints without gaskets. Works fine until someone knows better and they put a gasket in, then they get leaks :) It's all about the quality of the machined surface. RTV won't work, don't even go there.

But in this case, I'd dent the headers. It won't make any difference in performance, and I'll bet those headers will grow enough when hot that your gasketless mounting will be to no avail.

HotNotch
HotNotch New Reader
8/5/22 11:51 a.m.

Not a SBC, but I've ran headers on several SBF over the last 10 years with no gaskets, with only the high temp copper RTV.  No issues.  Both on aluminum and iron headed versions

 

84FSP
84FSP UberDork
8/5/22 11:58 a.m.

Not exactly the answer to your question but...  There have been a couple of good tests on dynos where the dents were shown to have zero loss in HP/Tq.  It may hurt your eyes by I had to "clearance" my freshly cerakoted headers to make them fit on my V.   Likely solves both problems!

03Panther
03Panther UberDork
8/5/22 12:22 p.m.

Like others, does not answer the original question... I never tried. Was happy with dead soft aluminum gaskets. 
I pony'd up for the coated headman elites for my Malibu G body wagon. Not even close to fitting!!! Called customer service, and was treated great. Tech guy had me send him pictures, and agreed they needed to buy them back, a they would cover the return shipping. Fwd my info to warranty dept. Guy that called me left a voice mail... rude and obnoxious, sounded like a city guy from, well, y'all know the type. Said " I don't know why I was asked to contact you, Headman doesn't even have a listing for any station wagons (uh, what?) so it's not our problem you bought the wrong headers, and they don't fit"

I never bothered to call him, cause it would not have gone well. 
Anyway, to point: Dents we're not gonna fix mine... I put a 3' pipe in the collector. Bent the header closer to block. Fit great, other than what it did to my high dollar coating!!!

Appleseed
Appleseed MegaDork
8/5/22 12:28 p.m.

If the header company recommends it, run em. If they don't,  or have no recommendations, why not? If they leak, you have a solution 

Noddaz
Noddaz GRM+ Memberand PowerDork
8/5/22 1:32 p.m.

Can you mill down the header flange a few thousandths?  It needs to be flat to seal against the head.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
8/5/22 1:48 p.m.

A 10lb sledge fixes clearance issues.  It is a very rare set of headers that does not need some extra hammer attention.

If you are that tight, engine motion is going to self clearance anyway, may as well do it yourself.

 

Besides, nothing is more fun than taking a brand new $1000 set of headers and beating the heck out of them.

obsolete
obsolete GRM+ Memberand HalfDork
8/5/22 2:53 p.m.

You can make nice, clean, almost-looks-like-it's-supposed-to-be-there header clearance dents by heating the spot on the header with a torch, then laying a piece of thick-walled pipe across that spot and hammering on the pipe, not the header.

But yeah, a thin coating of copper RTV on manifold-to-head flanges works fine in my experience too.

L5wolvesf
L5wolvesf HalfDork
8/5/22 2:57 p.m.
Noddaz said:

Can you mill down the header flange a few thousandths?  It needs to be flat to seal against the head.

THIS is the best way to do it.

AxeHealey
AxeHealey GRM+ Memberand Dork
8/5/22 4:19 p.m.

Engine Masters tested the whole denting the header thing and if memory serves there was almost no, if none at all, drop in power until the runner was like totally smashed closed.

1988RedT2
1988RedT2 MegaDork
8/5/22 4:33 p.m.

Well, apologies to Keith, but I picked up a tube of Permatex Optimum Red.  Suggested uses are manifolds, headers, and turbochargers.  We shall see.  The Hedman Elite has a heavy flange, but I'd like to avoid the trouble of machining.  The internet seems to have no shortage of people who have run RTV for years without issue.

1988RedT2
1988RedT2 MegaDork
8/5/22 4:38 p.m.
AxeHealey said:

Engine Masters tested the whole denting the header thing and if memory serves there was almost no, if none at all, drop in power until the runner was like totally smashed closed.

In the spirit of full disclosure, there is, hanging on my garage "Wall of Shame," a pair of cheap store-brand (I won't say which store) headers that I hammered half shut trying to fit them on this very car several years back.  After I passed what I felt was 50% of the opening, I gave up.  I don't like to think about just how long this project has been a project. crying

The Hedman's are so much, much closer to fitting.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
8/5/22 5:44 p.m.

If it is so close that the gasket thickness makes or breaks you when everything is static, you WILL smash the headers into stuff.  Yeah, solid engine mounts, but the chassis is flexible and so is the engine to a degree.  You'll end up needing to hammer the tubes no matter what.

1988RedT2
1988RedT2 MegaDork
8/5/22 6:40 p.m.

In reply to Pete. (l33t FS) :

Yeah, I'm sure you're right.  I can't imagine whoever thought that it was a good idea to put a V8 in these cars. wink

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
8/5/22 7:14 p.m.

In reply to 1988RedT2 :

I had a lot of "fun" putting a tall deck BBC in a '70 Nova, that was originally a 396 car!  Ended up needing raised solid mounts and I also had to heavily notch the trans crossmember for header outlet clearance, even after sectioning the mount area down an inch or so.

 

The fun part was the owner was too nervous to drive his now 604ci Nova across the street to his trailer, so we drove it there for him...

NickD
NickD MegaDork
8/5/22 7:17 p.m.
AxeHealey said:

Engine Masters tested the whole denting the header thing and if memory serves there was almost no, if none at all, drop in power until the runner was like totally smashed closed.

Yeah, I believe the first couple dings actually picked up a couple numbers. They smashed them nearly half-closed and the numbers were within where they could almost be blamed on pull-to-pull variance. And they were only 1.75" primaries on a 550hp 383, so it wasn't like they were massively oversized to begin with. Engine Masters is a great show. I love the amount of "I didn't see that coming" that it elicits from guys who have been in the business.

And if dinging the headers does kill too much power, you can always make it back up with The Salad Bowl

NOT A TA
NOT A TA UltraDork
8/5/22 9:44 p.m.

What year Nova?

1988RedT2
1988RedT2 MegaDork
8/5/22 10:00 p.m.
NOT A TA said:

What year Nova?

1966 Chevy II, 2-door hardtop.

kb58
kb58 SuperDork
8/5/22 10:03 p.m.

I recall Carroll Smith saying that they ran either none or milled a small groove in one surface, then tapped copper wire into it, which compressed when bolted together.

GTwannaB
GTwannaB GRM+ Memberand Dork
8/5/22 11:29 p.m.

Ok experience from the high school days, but the header flanges against the head will definitely warp a bit to a lot with heat. Even with gaskets they may leak. Without gaskets it will be a bit of a mess within a few weeks. Maybe forgot the header and just go manifold?

1988RedT2
1988RedT2 MegaDork
8/6/22 9:13 a.m.

Well, the Hedman Elite have a 3/8" thick flange, and this car will be a Sunday driver.  If I can get them installed without contact, I'm going to call it good.  What happens after that, happens.  laugh

NOT A TA
NOT A TA UltraDork
8/6/22 11:05 a.m.

In reply to 1988RedT2 :

Get the measurements for the sub frame and measure it. Perhaps it has sag or been hit and might need tweaking with a porta power or on a frame table to widen the distance between the rails. that would give you more clearance where you need it.

I've run stock manifolds without gaskets after machining but not headers. I'm in agreement with everyone else who said dent the header if you need the clearance and have done it myself.

I had a stock '66 & a '67. The '67 had big headers with crankcase evac etc. forget what brand. I'm in the near lane.

[URL=https://hosting.photobucket.com/albums/ff292/NOTATA/67%20Duece%20Coupe/.highres/DSCN1757.jpg?width=1920&height=1080&fit=bounds][/URL]

1988RedT2
1988RedT2 MegaDork
8/6/22 11:11 a.m.

In reply to NOT A TA :

Nice!  When did you sell it?

NOT A TA
NOT A TA UltraDork
8/6/22 11:49 a.m.

In reply to 1988RedT2 :

Actually I traded it for an '86 Carrera and the labor to paint an '81 Malibu I'd already done the body work on but didn't have time to paint because I was moving from CT to FL in '09.   I had about 15 cars at the time and was selling some, trailering some to FL, and driving some to FL. By trading I could drive the Porsche to FL instead of having to trailer the Nova.  Pic when the new owner came to my shop for the trade.

[URL=https://hosting.photobucket.com/albums/ff292/NOTATA/86%20Porsche%20Widebody/.highres/86PorscheWidebodyConv012.jpg?width=1920&height=1080&fit=bounds][/URL]

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