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PostPosted: Mon Jun 08, 2020 3:48 pm 
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3 Deuce Weber

Joined: Sun Apr 12, 2020 6:13 pm
Posts: 68
Car Model: 67 Valiant, 73 Duster
Quote:
Do you find evidence of a vacuum leak at the higher RPMs the engine will run at? Sputter/poof sound effects at the exhaust? An intake leak big enough to prevent idling should be big enough to make itself evident at the speeds the engine will run at.


Yes there is much Proofing and sputtering at 1500RPM. Less at 2000.

Loosened everything and re torqued in the proper sequence. Little improvement.

I realize it is meaningless, but from the naked eye it looks like a perfect seal—it’s not like it highly visible where the issue is. If I was to guess it would be near the center. Just a guess.

Ordered the Remflex gasket like I should have to begin with.
Will likely enlarge the inboard intake hole as well to allow for more wiggle.

I guess the question is should this be enough to fix the leak or should I be investigating taking it to a machine shop for further modifications? I’d like to not do the job a third time...

I realize Dorman is really one of the best options for folks like me trying to keep things as original as possible, but it is more of a pain than the OE. I’ve found it’s not a direct replacement at least on my application.

Thanks


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PostPosted: Mon Jun 08, 2020 6:44 pm 
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Rodrju wrote:
Quote:
Do you find evidence of a vacuum leak at the higher RPMs the engine will run at? Sputter/poof sound effects at the exhaust? An intake leak big enough to prevent idling should be big enough to make itself evident at the speeds the engine will run at.


Yes there is much Proofing and sputtering at 1500RPM.


Okeh. That suggests a do-over of the manifold install will clear up the problem.

Quote:
I realize it is meaningless, but from the naked eye it looks like a perfect seal


Vacuum leaks at gasket junctions are seldom visible. Did you try the carburetor cleaner spray trick?

Quote:
Will likely enlarge the inboard intake hole as well to allow for more wiggle.


Don't overdo it. You don't need much wiggle here.

Quote:
I guess the question is should this be enough to fix the leak or should I be investigating taking it to a machine shop for further modifications?


If you have a good, reliable, dead-straight straightedge you can place it along the mount face of the intake manifold once you've removed it and see if you see light between the straightedge and each runner, but the intakes don't usually warp. What can happen is bits of old gasket get stuck/baked onto one surface or the other and spoil the ability of the new gasket to seal.

Quote:
I realize Dorman is really one of the best options for folks like me trying to keep things as original as possible, but it is more of a pain than the OE.


That is true. There's an unfortunate gap between "best available" and "as good as original".

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PostPosted: Tue Jun 09, 2020 5:50 pm 
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Turbo EFI

Joined: Sat Feb 18, 2006 2:19 pm
Posts: 1601
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viewtopic.php?f=19&t=10045&p=51562&hilit=manifold#p51562 Want to make sure about this. Older manifold 5/16 stud drilled out to 3/8 hole for new stud of 3/8,so 0 clearance no movement no wiggle room. The newer intake hole for that stud 1/2 inch . That 27/64 bit 0.421 will give about .056 clearance with 3/8 stud,go to 7/16 0.437 that will give 0.625 clearance.


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PostPosted: Wed Jun 10, 2020 9:58 pm 
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3 Deuce Weber

Joined: Sun Apr 12, 2020 6:13 pm
Posts: 68
Car Model: 67 Valiant, 73 Duster
Gaskets came from Amazon today...completely destroyed.
How they could have been placed in a box and shipped that way is beyond me? They were destroyed PRIOR to packaging and shipping.

So we will wait some more for a new set...hopefully intact.

Will try the carb cleaner trick to try and pinpoint where the leak is more evident before I dismantle...then make that inboard hole slightly larger.


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PostPosted: Thu Jun 11, 2020 6:17 am 
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Joined: Tue Oct 29, 2002 8:27 pm
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Location: Salem, OR
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Quote:
Gaskets came from Amazon today...completely destroyed.


Next time. Order them directly from Remflex they tend to package them in
stout material to keep things from bending during transit. Amazon times their
employees to fill the order faster so items tossed in boxes on the fly tend to
be handled without care or regard for fragility....FYI.

http://catalog.remflex.com/


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PostPosted: Mon Jun 22, 2020 9:19 pm 
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3 Deuce Weber

Joined: Sun Apr 12, 2020 6:13 pm
Posts: 68
Car Model: 67 Valiant, 73 Duster
Hello:

Quote:
Next time. Order them directly from Remflex they tend to package them in
stout material to keep things from bending during transit.


I will never order these gaskets from Amazon again---second set also came damaged. Was able to make one set out of two set shipped. Not worth the hassle.

Upon removal, I placed the attached intake/Dorman exhaust combo on the relatively flat table saw top and found what appears to be an obvious gap.

Image
Image

Fearing the worst, I called two local machine shops to see about milling--neither wanted to mess with it.

With regards to the Dorman manifold, Dan said it best:
Quote:
There's an unfortunate gap between "best available" and "as good as original".

Its much more of a hassle than the stock, but It is fortunate that is still available.

Decided to roll and dice and install using the Remflex and so far we seem GOOD! Given the gap, it speaks volumes about the ability of those gaskets to seal.

Paid close attention to the installation sequence and torques as suggested by folks on this forum.

I've driven it two times...Idles smoother than previous, with no obvious exhaust leak (sound and smell not evident under the hood).
Still needs more time, testing and driving to call this a complete success.

Also need to make some cold start adjustments to the carb and I may need to revisit the choke with the new Dorman manifold. I used the old existing spring loaded choke, despite the new manifold pocket is slightly different in that is is more open. This will need looked at more. It the electric conversion still the route to go...?

So far, the Remflex appears the problem solver...

Off topic, for those with a good eye, you will notice this engine is Hemi Orange. Everyone will say Mopar never made an Orange slant six. But I cannot figure how this engine became orange. This is an original CA car with 54k (from records going back to the 80s). I have not owned it for very long. But it is completely stock and very original--not restored. It still wares its faded original paint and I replaced the original convertible top. While parts of the engine have been obviously resprayed, the places where it would be difficult to change color are in-fact orange. It would seem someone went to a LOT of effort to make it orange (pulled the engine) OR Mopar decided it was orange day when they built this one. Even removing some layers of paint do not indicate the Chrysler Red I would expect to see. Its not faded. Its orange. No indication the engine had been rebuilt or removed from the car. So....?

And for the moment it does not seem to have a vacuum leak OR exhaust leak, thanks to Remflex

Thank you all for your input and responses


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PostPosted: Mon Jun 22, 2020 9:42 pm 
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Supercharged
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Joined: Thu Jan 27, 2005 8:32 pm
Posts: 7834
Location: Portland-ish
Car Model: Fiat 500e
Remember the very first reply to your post?

Joshie225 wrote:
I sounds as though the exhaust manifold flange may be thicker than the intake manifold flange putting more clamping force on the exhaust manifold. The intake manifold needs to be thicker at the flange and receive more clamping force than the exhaust manifold. You should be able to see this if it's bad enough. Yes, I have had this happen to me. The quick fix is to find or make small shims (small flat washers may do) to go between the bridge washers and the intake manifold.

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PostPosted: Tue Jun 23, 2020 4:47 am 
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3 Deuce Weber

Joined: Sun Apr 12, 2020 6:13 pm
Posts: 68
Car Model: 67 Valiant, 73 Duster
Josh-

Yep. You were right on.

Also forgot to mention, I drilled the center intake hole out to 13/32 to provide a little more wiggle.

Thanks for your help.


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PostPosted: Tue Jun 23, 2020 4:12 pm 
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Rodrju wrote:
Also need to make some cold start adjustments to the carb and I may need to revisit the choke with the new Dorman manifold.


There's no "may" about it—this is a necessary step.

Quote:
I used the old existing spring loaded choke, despite the new manifold pocket is slightly different in that is is more open.


Right, which means the car's going to waste a lot of fuel until you address the choke. Yes, the № 1231 electric choke kit is still the right thing to put in.

Quote:
for those with a good eye, you will notice this engine is Hemi Orange.


No, it's not.

Quote:
Everyone will say Mopar never made an Orange slant six.


Yes, they did—in South Africa.

Quote:
I cannot figure how this engine became orange.


The red engine paint used in the timeframe your car was made was very prone to fading with age and heat, and it tended to fade strongly towards orange.

Quote:
Its not faded.


Yeah, it is. This is how some batches of that paint fade.

Quote:
And for the moment it does not seem to have a vacuum leak OR exhaust leak, thanks to Remflex


Yay!

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Too many people who were born on third base actually believe they've hit a triple.

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