Doug Thorley Headers Fitment. Show me your ball Flanges.

Updated:


Issue:

Passenger to Y pipe.

I cannot change the angle that the Y pipe fits up to the passenger header.

Ignore for a moment the header fixed flange and the bolts. Pay attention to the flare and the floating flange. This is the angle that the Y fits up.

Loose


Loose


How it looks tightened up.




This is pretty much with what I end up with any way I do it. I can try to tighten the bolts evenly or try to make the flange even around the flare. It changes the outcome a little but either way it’s not going on straight.

After speaking to Thorley they insist that it’s within tolerance. So at this point I just have to install it all and do the best I can to make that passenger flange even.

Not really mad at this point just more disappointed and frustrated that the issue they were sent in with was not addressed. and it’s probably going to one of those things Ill think about from time to time that’s just bothers you.

some of the areas I complained about have explanations and are sound or I was able to work out.





I deleted that first post and replaced with the email I sent Doug Thorley. It’s a good explanation of my experience.

Jamie did end up calling me after this.

I ordered this set of headers on 5/3 for a 2004 3.4l Tacoma and the following weekend during install I noticed that they just were not lining up.


The issues I was having was that, once tightened down, the crossover is touching or extremely close to the passenger cylinder head and the flanges on the passenger side don’t seem to line up enough for a seal. You can look at the passenger side once tightened and see light creeping through.


I ended up sending some pictures to Customer service and they responded with asking me to send them in and sent me a label on 5/10. I sent them out a few days later after I tried to fit them one more time.


On 5/25 I received an email that the headers were “going to get fixed”.


On 6/15 I received the headers. And the next day on lunch break I eagerly go to install them. What I’ve noticed is, frustrating. Ive noticed that the areas that were giving me the issue are no different than before.


I called customer service to ask to speak to someone about the fitment issue. I was told the design engineer, Jamie. would call me about it. I still have not received that call.


In the following days I called, left a message, and emailed a number of times. Never got an answer, never got a reply.


This is perplexing because the handful of times I’ve emailed and called prior to this I had no issues at all getting assistance. Ive been wondering if I’m being ignored on purpose. But why?


Maybe it’s the position of Doug Thorley that when the headers were put on a fixture they fit within spec. Well I’ve also considered this. But then I ask myself why the very first response to the email I sent was not to trouble shoot, or offer suggestions, but urging me to send them in? Along with the email that mentioned they “were going to be fixed” I was/am pretty convinced that there really was a fitment issue.


This is confirmed every time I try and go fit them. It takes all of lining that y pipe/crossover up with the passenger side header to hear and feel the contact with the cylinder head to convince me it’s just not going to work without something being forced.


It’s well known that the 5vz header job is probably the most time consuming anyone could take on. This is why I’m not too confident with the idea of forcing something to work. The very last thing I want to do is go back and remove the headers due to fatigue failure that forcing could create.


The next issue I would like to bring up is that the driver side header, which wasn’t even giving me any issues, was replaced. And for what reason? I don’t know.


The new header is an EGR style with the flange welded shut and, for some inexplicable reason, spray painted over the new welds and also over the carb EO plate tacked to the primary. It’s already begun to rust in those areas and probably won’t last long in the extreme environment that an exhaust system lives in. This is all in direct contradiction to an email I received on 6/4 that mentioned the header was gong out for ceramic coating.


I don’t think it’s too much to ask that I receive a set of headers as advertised. So the idea that a “warranty repair”, which I don’t necessarily agree with it being classified as, should leave me with a product that isn’t something Doug Thorley would put in every box is disappointing.


Is it the position of Doug Thorley that spray paint is an acceptable substitute for the advertised Ceramic Coating on their headers? How would something like this even leave the building?


Ive dumped hours into this project. Soaking everything down with penetrating oil for several days in a row. Slowly backing the rusted nuts and studs out, tightening, then backing off as to avoid seizing or stripping anything. Spending close to $200 on titanium studs/nuts and other hardware. I’m pretty invested in this project.


All in all I’m not happy, And I don’t even want an apology…..I just want the set of headers I purchased that are as advertised. That’s it. That should be a reasonable request.


To wrap this all up I do believe I would feel very different if someone had just spoken with me to hear my concerns. Maybe I only need 1/16” of a gap between the cylinder head and crossover, maybe even the crossover touching the cylinder head isn’t an issue, maybe forcing the passenger flange won’t fatigue anything, maybe the small hole in the flange letting light though will close up with a heat cycle, maybe what I perceive as spray paint isn’t actually spray paint. These questions were never answered because nobody would reach out after several attempts on my part.


All I want is a set of headers as advertised, with a warranty, and some customer service if need be. I don’t think that’s too much to ask.

 

Meant to say passenger side in the beginning*

 

I don’t think a few bends will get it to fit up. It seems like the passenger female side needs to be longer.

I can hook up the driver side of the Y and sort of hover the passenger side flanges about an inch away and it seems to line up much better.

If I try to mate them up then it “swings”over and I get misalignment and contact with the back corner of the cylinder head to the crossover.

I have not spoken to Thorley about this because they won’t call me back and I can’t get them on the phone. But if I had to guess I’m going to be blamed for the fitment if I ever get a hold of anyone.

 

Do you have all the extraneous crap removed or out of the way?

It only takes 1 small item to FUBAR a fit up.

 

If it won’t bolt up tightly enough outside of the truck to seal out daylight, how will it ever seal up when it’s in the vehicle?

Questionable manufacturing to blame?

 

Nothing is in the way.

I never said I put them together off the vehicle.

If you’ve ever put together a set of headers off the vehicle it’s not helpful. The flanges at the Y could line up and be straight as an arrow but you would never know if the ports and head flanges are aligned and at the correct angles. Eyeballing this won’t work.

 

Words like "cinch up" and "balls" in the same sentence make me wince.......

 

not sure if the following is going to help or not... I can see that they have been coated, damn, will reliveing the crossover where it contacts the head with a large diameter pipe / socket and hammer help? Wanting the flare on the P/S header to downpipe to fit perfectly might not be possible. I know that replacing the stock exhaust on a 96/97 3.4 was impossible with the motor in the chassis for 98 on it was possible with a little jack / motor mount looseneing work. I also learned that if I took off the brake vacuum booster, none of the ones I worked on had ABS, allowed for LOTS of room on the D/S. Didnt have to take the brake lines off the master, just slowly move the master forward for booster clearance.

I am wondering if they will sent you a set of raw steel headers so that you can so the mods, make sure they fit, then get them coated.

 

As a thought......

Have you tried loosening the anchor points on the rest of the exhaust system? Sometimes a shift in mating components will make the fitment.

 

Good instinct, although I think he's past that. If i understand him correctly, none of the rest of the system is hooked up currently. He mentions being able to see daylight when he looks into the tail end of the crossover/collector pipe.

 

Bump.

updated title and original post.

 

The DT headers seem to be botched from the beginning tbh. They are shorties and long tube headers and with that design, it makes you wonder about the quality of the connections. From what I can see, it’s not you. It’s DT, at some point you will need more forceful words to get them to fix their stuff

 

Obviously no good… thats bs…. Don’t try to make them fit otherwise you’ll never get your money back

 

I have never installed but I can can get pics of mine if you want?

 

You’re more than welcome to. The areas of concern is the crossover like the pictures above and the Passenger header to Y pipe. A picture of that flange looking through the passenger wheel wheel and from above in the bay would be helpful.

Thanks!

 

Ouch. This a TAF fit if you're only able to slip a piece of paper through the crossover and head. For every 5 people who mention great things about DT, there's probably 3 who have nothing but negative things to say.

Well, at least the 2 I know personally want to leave DT a -5 star, lol. Both truck leak like crazy, you can actually hear the exhaust leak when parked in the garage. 1 guy took it off so many time that he became an expert and learned to live with the issue and p0420. The other guy, after the third attempt, put his factory manifold back on and sold it.

 

This is going to be fun.

 

After reading this thread and then reviewing our conversation, I can finally understand what it is that you are referring to. Here are some close-up phone pics I took a few minutes ago.

Looking down on the passenger end of the crossover. It is very dificult to see from this angle, but there is definitely a gap.




This view is from the passenger side looking across the crossover pipe, between the firewall the back of the engine. These two show what appears to be at least an 1/8" gap.




The y-pipe flange as seen from above.

 

This is what my passenger side looks like when bolted up. this is as straight as I could get it.

Yours does looks more aligned. That’s more what I figure it should look like.

 

I have a dumb question. Do those flanges use a gasket? I am unfamiliar with them. I personally would try to get a sheet of 3/16 or 1/4 soft, malleable copper allow and add a gasket. It will form to the flange configuration. Don’t try lead flashing…. It melts at 620 and you will poison the neighborhood. Try Grainger or McMaster-Carr