Doug Thourly Headers

[William]

I've got a chance to have my header replaced for 250 dollars, plus parts, and the guy doing the work recommends a Doug Thourly header.

Anything beats the current set up: flames shooting out the side...

[Paradiddle]

I've been told that nothing is better then the second generation stock headers. Robert had a good source that I purchased from Olympic 4x4. This is the replacement I had installed.

Here is Roberts post:

"Get the new style stocker from Olympic 4x4 - they are under $200. With the accordian joint, they are much improved as far as resistance to cracking. Aftermarket headers typically compromise clearance from what I have seen, particularly the Borla - stay away from that one."


Jeff

[TObject]

http://cgi.ebay.com/ebaymotors/ws/eB...tem=8001081354

[Jeff Weston]

Originally posted by TObject
http://cgi.ebay.com/ebaymotors/ws/eB...tem=8001081354

Wow, that is cheap! FWIW, the Borla in my dad's Jeep did develop a small crack by the collector. My "accordian style" replacement from the dealer on my '99 has held up for 5 years and about 80K miles.

[Paradiddle]

I do run Thorle y headers on my motorhome - they've performed far better then the stock ones that always crack - just as an FYI to Thorley quality.

[norcaljr]

I have been running a banks header for almost 2 years now and it looks new. I have heard nothing but good things about banks from other friends who have run their stuff.

[William]

I have the accordian style now, and it is what died. The dealer won't play with replacing it, as it only has a 12k mile promise.. and I'm past that.

[Robert J. Yates]

If you have less than 70K in Milage William - the emissions warranty will cover the replacement. That is how I got mine replaced and with the new style header, I have had no more pro lems. Course, re-routing and raising the exhaust helped a bit too

Thorley's are on my Suburban and forthe most part, I've been happy with them. If I was doing my Jeep again however, I'd get a stock header and have it ceramic coated and call it good.

[William]

Unfortunately I'm at 110k miles. Wish it were less, that's for sure.

I'm gonna see if I can get my hands on a stock header and put the Thorely's on hold. They're price at 400, but the install is going to be only 250.

I've got a list of things to get repaired.. and if I could save a dime on this it could go towards the other stuff.

Thanks.

[1BLKJP]

Originally posted by Robert J. Yates
If you have less than 70K in Milage William - the emissions warranty will cover the replacement. That is how I got mine replaced and with the new style header, I have had no more pro lems. Course, re-routing and raising the exhaust helped a bit too

Thorley's are on my Suburban and forthe most part, I've been happy with them. If I was doing my Jeep again however, I'd get a stock header and have it ceramic coated and call it good.

Robert,

Will the stock steel of the manifold hold up to the temperatures produced on the inside of the tube from being ceramic coated? I have always thought of doing this, but couldn't ever find any information as to my concern.

[Robert J. Yates]

Well....
I have a new ( installed last December) set of Thorleys on my 'burb which are coated. I used to have a set of non-coated Thorleys on it which were made out of the exact same size tubing. My 'burb now runs 20 or so degrees cooler so the only thing I can think of making the difference is the coated vs non-coated. What that might mean towards longevity though is anyones' guess. My take is that ceramic coating is a plus.

[William]

Originally posted by Robert J. Yates
My take is that ceramic coating is a plus.

Thanks for this insight: I'll have this done. Do you think a wrapped header is as good?

[Robert J. Yates]

Originally posted by William
Thanks for this insight: I'll have this done. Do you think a wrapped header is as good?

No - the ceramic coating is bonded to the metal and is supposedly more thermal efficient. If you are buying aftermarket - ie. Banks, Thorley, Borla ect., you should be able to buy the header with the coating.

[Daless2]

Hi William,

I have "Thorley Headers" on my 97 4 L TJ and find them to be made very well.

Mine are the relatively new ?Tri-Y? design that came out about 3 years ago. They are also NOT Ceramic Coated, but rather chrome plated.

Been holding up well.

I don?t know if this makes a difference or not but where actually two companies making Thorley headers a few years ago, ?Thorley Headers?, and ?Doug Thorley Headers?.

Apparently Doug and his Bride got a divorce, and the Bride got ?Doug Thorley Headers? as a part of the settlement. Doug then went out and started a business called Thorley Headers to compete. I don?t know if this is still the case, two separate businesses or not, but mine came from the new business, and are the new ?Tri-Y? design (As of about 3 years ago.)

I don?t know how good they are as compared to any other headers but I can say they were a perfect fit. No persuasion was necessary to get them to fit, all bolt holes where perfectly aligned and the install was a breeze.

There are two other things worth mentioning.

The header flange, where it bolts to the cylinder head was substantial. I am estimating at least 5/8 of an inch thick.

The other is the chrome plating, which after two good years of use and one year of just sitting around still looks as good as new. I have no ?blueing? of any kind that I can see and I was under there just yesterday! (Yea for me!)

Hope this little bit helps,

Frank

[William]

The upside: I have a header installed now. The jeep is again, silent.

The down side, I probably have a bad vavle, I'm still dumping fuel into the exhaust: the pipes glow red when the engine picks up speed and I get a sputter/near stall.

I thought it'd be the plug, but I don't think it is, and judging from my (stupid) time driving with it broken, it probably sucked the valve while driving with the broken exhaust.

Sucks, but it's life. So, now the Jeep needs a valve job.

[Paradiddle]

Put one of those fancy aluminum high performance heads on it so we can all know if it's worth the obscene amount of money they want for them!

[Dan-H]

I learned a trick (technique?) for diagnosing burnt valves.

do a compression check to find the lowest cyl.

bring that cyl up to TDC on a compression stroke,

find a fitting that threads into the spark plug hole that you can put compressed air to.

listen to where the leak is coming from. exhaust, crank case or intake, and you'll have a clue where the problem may lie.

I think the proper diagnosis is called a cylinder leak down test.

[Robert J. Yates]

Originally posted by Paradiddle
Put one of those fancy aluminum high performance heads on it so we can all know if it's worth the obscene amount of money they want for them!

Judging from the result on Bruces' CJ, its worth the money in some situations. A TJ will see far less improvement - around 29hp as opposed to the close to 50 a CJ might see. OTH, there is a good possibility that a TJ might see improved milage and better cooling as the aluminum head will dissipate heat much better thanthe cast iron version. I've been considering this upgrade along with a ceramic coated header.

[Stu Olson]

I'll 2nd Dan's suggestion to check your compression before telling a shop you need a valve job.

And just a suggestion.....if you are convinced that too much gas is getting to that cylinder, perhaps it is a bad injector? Easy method by which to determine that is to swap it with another cylinder. If the problem moves, the injector is bad. If the problem stays as it was, the injector was not it (assuming the control wiring to the injector is working correctly).

[William]

I could try that, in fact I will.

He did a compression check for me and claimed there was no problem with compression. This doesn't make much sense, but he's going to do a leak down test.

After that, perhaps I'll break down (ha ha, guess I already "broke down") and go to the dealer and have them run the computer check.

[scorpio_vette]

don't quote me on this, but i think you could unplug the fuel injector that you think is faulty. if the pipe stops glowing then you can continue testing that injector and make sure your getting decent spark to it. it could be getting the correct fuel but not enough spark. but don't quote me on that.

it would safe you the time of having to swap them back and forth.

just curious. which pipes are glowing. the manifold pipes, down pipe, catback?

[William]

Originally posted by scorpio_vette
don't quote me on this, but i think you could unplug the fuel injector that you think is faulty. if the pipe stops glowing then you can continue testing that injector and make sure your getting decent spark to it. it could be getting the correct fuel but not enough spark. but don't quote me on that.

it would safe you the time of having to swap them back and forth.

just curious. which pipes are glowing. the manifold pipes, down pipe, catback?

Manifold pipe and it's one specifc catch at one of the "Y" 's.