installing exhaust manifolds

[mattdh]

got the maniffolds back from the coater today. looking for help on the insatll process. do i need to put any anti-seize in between the block,gasket,or manifold? can i use lock washer instead of the locking tabs-or not a good idea? can i use a stainless steel bolts here or is that not a good idea either? just to let you know(if you are curious) they are my factory manifolds and if any one wants i will post pics after the install.

[javelinadave]

Are the faces (part that bolts up against the block) powder coated???

[kellymoe]

What kind off coating? Jet Hot?

[norros]

Matt,

YES, please post pics...
And I am curious too as to whether the 'faces' are powder coated ... ?

Thanks

Nicholas Orros

[mattdh]

yes the faces are coated-its a high temp ceramic coat like jet hot.the guy that did them,i heard he did jet hot for awhile then switched-i will have to ask him if thats true and if, so why?

[evilfij]

You want the "updated" hardware.

It came on 97 and up or so. They are longer bolts with spacers. Ask your favorite parts place for them

Locktabs are a PITA and lock washers will come loose.

You also want the metal shim style gaskets. I put high temp anti seize on the threads of the bolts. I am wishy washy on whether to recommend this or not.

Ron

[OCD90]

Slightly off-point, but are there any "shorty" headers that offer better performance while attaching to existing exhaust? The stockers look so small and restrictive...that seems to be the chokepoint...or maybe the intake as well.

If not, what's popular for a header? I've seen plenty on exhaust recently...but not headers/manifolds...

I can just hear my engine wheezing trying to breathe better...help me...help it.

[Doug]

I think you can get headers for Defender V8s from the usual UK places. Pretty much, one size fits all. Get a LR mag and look thru the ads. I decided against them because of the huge noise factor.

[mattdh]

doug are you goin with factory 3.9 maniflods off your old 3.9 on your new 5.0?

[Doug]

Yup. They are installed. The port sizes matched pretty close. If I find that they are too restrictive, I'll start researching a change. But I think it's going to be a matter of getting air IN, rather than OUT. ;) Anyway, my goal is not to acquire all 340 hp out of this monster. I'll be happy to get 270 to 280 hp -- should be adequate for climbing the 395 into the High Sierras at 80mph, and beating hummers off the line on the Sunset Strip. I'm totally confident low rpm torque will be maxed with the existing manifold.

Comments welcome. Engine should be cranked for the first time within a week.

[kellymoe]

I was considering headers for my truck but the more I look into it I am leaning against it. Cost is one issue, quality is the major issue, most header flanges are pretty slim and with time they will start leaking. Heat is another issue but can be cured with Jet Hot. Noise is also a big factor. I have decided to match port the existing manifolds and have them Jet Hot coated.

[JohnC]

Torrance, a friend of mine is installing Headman Headers on his 94 D90 with Summit Racing cats.

My partner had the same combo on his 91 RR and he did notice an improvement in performance.

You can get the Headman for $119 (uncoated) and $319 (ceramic coated). I had gotten a quote from Jet Hot for $299 to get them coated.

You can also get the Janspeed from the UK but they are pretty expensive. I don't have the price sheet in front of me but I could get you a price next week.

Just my 2 cents.

John C.

[evilfij]

Do they headmen bolt up or do you need a new y-pipe?

Ron

[OCD90]

I'd lean towards something like that. Headers don't inherently lead to loud exhaust...it's the muffler/ resonator and pipe size that has more to do with that. You can get a lot more flow through without necessarily leading to a lot (if any) more noise...

I would be interested in knowing if it's a bolt-in...but my entire exhaust is pretty shot anyway, so it's not really a factor...

Thanks! I look forward to reading more.

[loykd]

Matt, are those stock manifolds? I thought I read that the stock manifolds didn't take to coatings because the welds couldn't stand the heat. Do I remember wrong?

Jet-Hot cites on their website improvements in efficiency and power increases. Does it really, or just more advertising hype?

[mattdh]

hi ken!! i hope thats not true about the heat?i have not ran the engine. and i wont know about the power increase because i put a 4.6 block in it --- so the increase could be the coatings-- ha ha ha..sorry for the delay on paying you, i will drop a check int the mail thurs or fri i promise unless you have a paypal account

[loykd]

Matt, Oh, so that's all I need to do to get a performance increase? Install a 4.6? I'll swap out tonite! haha

Anyone else with experience on coatings? I remember some guys talking about this in another thread, but didn't see any comments after the install. (Nor did we ever see any pics of your beauty, Matt, but that's a different subject. :grin) Someone mentioned "street rod" experiences.

[JohnC]

We got my friend's D90 back from the shop after installing the Headman Headers and there IS a noticeable performance increase, and it sounds good (throaty).

I'll try to get some pics tonite.

[loykd]

Thanks John. I saw your post earlier on that. Any info on the Janspeeds? (I sent you an email btw)

[rover4x4]

sweet photos..

[OCD90]

Photos? I don't see any on the thread...I'd like to though...

[JohnC]

I think Phillip is busting my chops 'cause I haven't taken any yet.... I'll have them asap.

[rover4x4]

<--not busting chops

[Marx-110]

I inquired about the Headman Headers and was told they are only for right hand drive vehicles? I looks like people have used them on their 90's, anyone know the deal here?

[Bowtracer]

The stock mans are cast! no welds!

[artm]

I recall reading somewhere that coatings allow "too much" heat to reach the cats thereby shortening their life. ???

The point of headers is to benefit from their better geometry. I don't see how that can ever be matched by coating stock (restrictive) manifolds.

[kellymoe]

Simon,
The headmans state they are for rhd vehicles but I have heard of several people fitting them to lhd's. I think there is a guy at www.neversummeroffroad.com who put them on his rig and can tell you what he had to do. I don't think it is that big a deal. After speaking to the guy who built my exhaust I think I will go with stock manifolds, match port and coat the inside only. There is a procsess done localy where they push a abrassive mud through the manifold to smooth the pathways and then have it internaly coated with Jet-Hot or similar proscess. I am a little wary of the Headman Hedders, there flanges are very wimpy and tend to warp. Keeping costs down is also a major motivation with sticking to the stock manifold, my pocketbook is just not that large.

[loykd]

JohnC mentioned something about Janspeed headers, I recall, but don't remember seeing anything more about them.

[Marx-110]

Kevin, I think I am going to stick to the stock. I don't thik I want to monkey with modification, I think I will look to upgrade the rest of the exhaust in the future when it comes time. The NRP system looks good, really expensive but good. Thanks again!