Slant Six Forum :: Dutra Duels ????'s

I just looked up the Dutra Duals installation stuff on Doug Dutra's page and did that. I just hacksawed the front three off where he suggested, drilled and tapped holes, made a plate and sealed it off with high temp silicone sealer. I did use stainless steel screws in hopes that they would gall in the iron manifold and not try to back out with vibration. I do realize that "hope" is the best I can "hope" for. I tightened the hell out of the screws and used silicone sealer on the threads, for whatever that might be worth. Remember that a good torque limit is one quarter turn before the screw breaks off. Tricky, however.

made a plate and sealed it off with high temp silicone sealer.

When I installed the manifolds I found that the new Remflex gasket is a thick sonofagun.

My intake nuts only go on about half the thickness of the nuts.

It appears to me (I let some water out) that the threads in the head must be fine threads (5/16-24). Does that sound right?

It also appear that all the studs might go into water.

You had mentioned somewhere that someone had some correct studs to replace the originals. Wondering if they're the kind with a fat threadless spot in the middle so they can be set in there nice and tight and not back out

Author:	Augie Dog [ Mon May 28, 2012 10:30 am ]
Post subject:	Dutra Duels ????'s
Is any one using the Dutra Duels? I have an 87 D-100 and would like to put duel exhaust but not headers. What do I need to do to accomplish this? Are the Dutra Duals worth the investment?

Author:	60jerry [ Mon May 28, 2012 3:15 pm ]
Post subject:	Dutra Duals
Funny you should mention Dutra Duals. Just this afternoon I installed my new Dutra front manifold and the stock rear portion that I cut and sealed myself. Gonna be driving it to the muffler shop with open manifolds. Should be an interesting drive. Anyhow, whether or not it's worth the expense and effort depends on what you're after. There would be (I'm hoping) a slight increase in fuel econcomy with a more free-flowing exhaust. More torque, maybe. Better sound, ya betcha. Now it is often recommended by the gurus on this site that Dutra Duals into one large exhaust system is the best, but in my case I'm doing this simply to achieve that old school split six sound. Any economy or power benefits are all gravy to me. I'd suspect that there will be power and economy benefits on your truck. Watch your thread and you will most likely hear from those who are really in the know about all the benefits and any possible drawbacks--possibly just the expense. Jerry in Denver

Author:	63gtcv [ Mon May 28, 2012 3:45 pm ]
Post subject:
You might get some of that flexy pipe and run it to the ground before driving. Wouldn't want to start an engine bay fire.

Author:	Augie Dog [ Mon May 28, 2012 4:15 pm ]
Post subject:
Front Dutra? Can you buy just a front? Not sure how these work. How did you cut the manifold and seal it? I have read some info on this set up but not sure if I need both manifolds or in your case you used just one. I did read the starter can get in the way. How did you overcome that?

Author:	THOR [ Mon May 28, 2012 4:20 pm ]
Post subject:
Augie, Please do a search for "Dutra Duals"... there have been numerous threads, and conversations regarding Dutra Duals, headers, benefits, disadvantages... etc. ~THOR~

Slant Six Forum https://slantsix.org/forum/

Dutra Duels ????'s https://slantsix.org/forum/viewtopic.php?t=48919	Page 1 of 2

Author:	Augie Dog [ Mon May 28, 2012 4:27 pm ]
Post subject:
Thanks Thor for your suggestion! In this search is there info on how to purchase the Dutras? I have been on his site and can not find purchasing info.

Author:	60jerry [ Mon May 28, 2012 5:18 pm ]
Post subject:	Augie
I just looked up the Dutra Duals installation stuff on Doug Dutra's page and did that. I just hacksawed the front three off where he suggested, drilled and tapped holes, made a plate and sealed it off with high temp silicone sealer. I did use stainless steel screws in hopes that they would gall in the iron manifold and not try to back out with vibration. I do realize that "hope" is the best I can "hope" for. I tightened the hell out of the screws and used silicone sealer on the threads, for whatever that might be worth. Remember that a good torque limit is one quarter turn before the screw breaks off. Tricky, however.

Author:	60jerry [ Mon May 28, 2012 5:21 pm ]
Post subject:	63gtcv
After starting the engine and listening to the incrredible noise, I was wondering just how much heat I would be directing onto various parts of the underhood area. I might just make a couple of bends and direct the exhaust flow straight down to the ground. It's about ten miles in city traffic to get to the muffler shop.

Author:	SlantSixDan [ Mon May 28, 2012 5:58 pm ]
Post subject:
Howdy, Jerry, good to see you on here. Yep, don't run with just the bare DDs dumping into the engine bay -- it's half a dozen different kinds of dangerous. Either tow the car to the exhaust shop (got AAA?) or rig up a quick and nasty pipe setup to dump somewhere safer. Dutra Duals page is here. I am a big fan of the DDs rather than headers.

Author:	emsvitil [ Mon May 28, 2012 6:46 pm ]
Post subject:	Re: Augie
Quote: I just looked up the Dutra Duals installation stuff on Doug Dutra's page and did that. I just hacksawed the front three off where he suggested, drilled and tapped holes, made a plate and sealed it off with high temp silicone sealer. I did use stainless steel screws in hopes that they would gall in the iron manifold and not try to back out with vibration. I do realize that "hope" is the best I can "hope" for. I tightened the hell out of the screws and used silicone sealer on the threads, for whatever that might be worth. Remember that a good torque limit is one quarter turn before the screw breaks off. Tricky, however. WAIT What........ You sealed the plate with silicone......... I don't think that's going to last very long........

Author:	60jerry [ Mon May 28, 2012 7:16 pm ]
Post subject:	emsvitil
I was a bit brief with my post. I made a quarter-inch plate, cut a high-temp gasket, and then sealed it all up with lotsa high temp silicone sealer like the muffler guys sometimes use on the donuts between exhaust manifolds and head pipes. I suspect that the high temp gasket material will be my best insurance, but Doug Dutra did suggest using the silicone sealer too--in somewhat large amounts, so that it makes a nice pile inside the manifold. Can't hurt. Oh, and I did take some exhaust tubing and made a temporary front section that dumps to the ground. I cut off the original exhaust pipe about two feet back and reinstalled it, so I should be able to make the drive OK. It's still really loud, but with those short pipes I can get that nice split manifold sojund at about 2000RPM. Just like high school days.

Author:	SlantSixDan [ Mon May 28, 2012 7:19 pm ]
Post subject:	Re: Augie
Quote: made a plate and sealed it off with high temp silicone sealer. Wait, what? That's not gonna work for more than ten minutes or so. The blockoff has to be done with 100% metal. Weld or braze. There isn't a silicone sealant that'll withstand anything like the temperatures the manifolds reach.

Author:	emsvitil [ Mon May 28, 2012 7:21 pm ]
Post subject:
Print off a mapquest (or equivalent) directions and map of the muffler shop so if you do get pulled over you can show the officer where you were going........... (might let you off that way)

Author:	60jerry [ Mon May 28, 2012 7:26 pm ]
Post subject:	Hey Dan
When I installed the manifolds I found that the new Remflex gasket is a thick sonofagun. My intake nuts only go on about half the thickness of the nuts. It appears to me (I let some water out) that the threads in the head must be fine threads (5/16-24). Does that sound right? It also appear that all the studs might go into water. '66 Dart 225. You had mentioned somewhere that someone had some correct studs to replace the originals. Wondering if they're the kind with a fat threadless spot in the middle so they can be set in there nice and tight and not back out when the nuts are removed. It looks like I'll be pulling this apart again sometime when I get tired of thinking about those nuts not being completely filled with stud. I'll keep tweaking on the nuts everyday hoping to crush the gasket down a little at a time. That activity gives me heartburn too. Longer studs seem the correct thing to do.

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Author:	SlantSixDan [ Mon May 28, 2012 7:31 pm ]
Post subject:	Re: Hey Dan
Quote: When I installed the manifolds I found that the new Remflex gasket is a thick sonofagun. It is indeed. Quote: My intake nuts only go on about half the thickness of the nuts. Notta lotta fun. Quote: It appears to me (I let some water out) that the threads in the head must be fine threads (5/16-24). Does that sound right? 5/16-18 into the head, 5/16-24 into the nut. Quote: It also appear that all the studs might go into water. Yup. Quote: You had mentioned somewhere that someone had some correct studs to replace the originals. Wondering if they're the kind with a fat threadless spot in the middle so they can be set in there nice and tight and not back out Yup and yup. See thread here. You've got mail, BTW.