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Starting Carb Conversion: Flat Tops to Paltechs


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Good to know! There is also Whitehead Performance in Canada, which shows the identical picture to MSA's. But they never answer the phone or email, apparently. 

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On 2/8/2021 at 2:47 PM, Dadsun said:

 

PXL_20210208_224250973.jpg

The one that you have looks like it has the thick flange and is the square port that you want.  The raised edge on the inside will actually create more sealing pressure, it's not necessarily a bad thing, if it's straight and even all the way around each port.

I'd take it to a speed shop and see what they think.  A bit of hammer work and a twist, followed by a surface grind might get it where you want it for not much.  Make sure you get a quote first though, sometimes those guys will keep working til it's done and charge you by the hour.

Or, there's this.

https://datsunspirit.com/shop/hand-made-6-1-true-equal-length-stainless-steel-header-with-merge-collector/

image.png

Edited by Zed Head
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On 2/10/2021 at 9:19 AM, Dadsun said:

 

I've been looking through eBay, but don't trust a lot of what I see.  Does this (see pic) make sense as a "square port style?":

huh-square-port-style-huh.jpg

 

 

Is your picture from eBay or is it from ZCarDepot?  You didn't provide an eBay link.

https://zcardepot.com/collections/exhaust/products/header-exhaust-ceramic-coated-240z-260z-280z-70-76

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There a lot of people making headers for theL6 but none of them are very impressive.  Looks like a person would buy something close then do some grinding and maybe some filling to get them right.  There's a whole separate eBay page for them.

Many of these cheap headers rust out at the intersection of the tubes or are never completely welded up from the beginning.  Plus, look at the cuts on the flange.  Terrible.  Looks like the center ports aren't even centered over the mounting holes.

https://www.ebay.com/b/Exhaust-Manifolds-Headers-for-Datsun-240Z/33632/bn_20176001

https://www.ebay.com/itm/OBX-Racing-3-2-1-Long-Tube-Header-For-1969-1983-Datsun-240-260-280Z-ZX/133176095712?fits=Model%3A240Z|Make%3ADatsun&hash=item1f01e9f3e0:g:ajcAAOSwkydfYS69

image.png

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On 2/12/2021 at 1:17 PM, Zed Head said:

Is your picture from eBay or is it from ZCarDepot?  You didn't provide an eBay link.

https://zcardepot.com/collections/exhaust/products/header-exhaust-ceramic-coated-240z-260z-280z-70-76

My pic was from eBay.  Can't find the listing at the moment, but yes, it's the same pic as the ZCarDepot link.  As for eBay, the only decent listings there seem to be the ones from California Datsun. But, apparently he has a bad rep here.  Is it bad product or bad customer service?

On 2/12/2021 at 12:43 PM, Zed Head said:

Wow! Beauitful. High end for sure. 

I spent some time yesterday trying to grind down the lips around the ports, and further inspecting. Even ground down, the two ports on the ends have eroded flange at the top of the ports... to the point where they will not seal properly no matter how much I tighten them. Time to scrap them.

So, reading through the other responses and clicking some links, looks like I need to avoid ZStory for now.  And Summit has only one option listed and it has the strange round/square port combo in the pics. https://www.summitracing.com/parts/psm-72c1037/make/nissan/model/240z/year/1973

 

My best options right now seem to be:

1. Order MSA 6-to-1 uncoated and pay to have them coated.  -- probably at least $530 out the door

2. Order from MSDS guy. Will follow up with him for details on what they have. The website doesn't tell me much.

 

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That zcardepot is a Pacesetter, same as ebay. 10 years ago the thickness was short, not good. Maybe better now?

I would wait out msa or go with msds. Msa has theirs built then sent to a coating place nearby called Embee. They could have a batch at Embee almost ready?

Screenshot_20210214-135945_Samsung Internet.jpg

Edited by siteunseen
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5 minutes ago, siteunseen said:

I would wait out msa or go with msds. Msa has theirs built then sent to a coating place nearby called Embee. They could have a batch at Embee almost ready?

Yes, Embee is the hold up.  They've apparently had a batch of MSA's 2020 header orders held hostage for a while, so MSA is telling people they are in wait and see mode.  I told MSA to consider Jet-Hot. They've done it a long, long time and are fast turnaround. Took them about 5-6 business days to get mine coated and back out the door. So, that's why I'm thinking just ordering the uncoated from MSA and then sending them off. Just tough to wait around another month or so with a car that is otherwise ready to roll.

Problem is Embee is a drive across town for MSA and Jet-Hot is a shipment to Oklahoma.

Looks like those Pacesetters are sold by ZCarDepot, Summit, and Holley, among others.

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16 minutes ago, Dadsun said:

 As for eBay, the only decent listings there seem to be the ones from California Datsun. But, apparently he has a bad rep here.  Is it bad product or bad customer service?

California Datsun used to be Datsun Parts Limited.  The guy that owns the business is named Al.  He has a membership on this site as URGELIS.  You can search the name on this site, and the former company name on the internet to learn more about him.  His old business had a bad reputation for selling defective parts then refusing to make things right.  

Notice that he does not really address the major concerns with the headers.  The port shape and the flange thickness.  He does not show photos of either either, just s single photo of the view that doesn't tell much, with a universal shaped gasket. 

Get on to Rock Auto and compare things like distributors with the same parts on his site.  Compare prices.

https://www.californiadatsun.com/headers/datsun-nissan-z-240z-280z-n42-p90-e88-header.html

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I exchanged emails with Marty (MSDS). His header flange he's been making forever has a 0.5" thickness, which is less than my intake manifold thickness I'm measuring (which is about 0.6"). So, now I'm wondering if I have an unusually thick intake manifold flange? What's the standard?  Maybe mine is standard and MSDS is not thick enough... but Marty has been making it a long time.  :confused: :dunno:

I'm thinking MSA is the way to go. 

 

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11 minutes ago, Dadsun said:

I exchanged emails with Marty (MSDS). His header flange he's been making forever has a 0.5" thickness, which is less than my intake manifold thickness I'm measuring (which is about 0.6"). So, now I'm wondering if I have an unusually thick intake manifold flange? What's the standard?  Maybe mine is standard and MSDS is not thick enough... but Marty has been making it a long time.  :confused: :dunno:

I'm thinking MSA is the way to go. 

 

That's only 0.1", not a lot.  I think that the thin flanges are typically 3/8" (.375").

MSA should be able to tell you the thickness of theirs.  It's a big selling point.  They work best if you call them.  Old school guys.

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5 hours ago, AK260 said:

Spotted this earlier - looks tasty but no real history I’m aware of, hopefully someone in the US can comment ....

That one on eBay shown as coming from Top End is the MSDSinc.com product (aka Marty mentioned earlier in this thread).

Go to Marty's site instead if you want that one. You'll save $60-70 buying directly from him. He has a good reputation on here. I wound up going MSA's product over his but only because they have the exhaust-to-tail connection ready to go. Marty's part number related to that eBay item is HO-241, I think.

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  • 1 month later...
Posted (edited)

Ok, I'm back. Got the MSA header, then had Jet-Hot coat it, and also have the MSA performance exhaust system to tie it into. 

The thing I'm most giddy about today is successfully getting off all of the old mount studs. Spent time here and there over the last few weeks with PB Blaster, hammer taps, and good old vice grips. 

So, I'm ready to reassemble. 

My previous efforts here have used the bolts at the intake manifold, not all studs. Any tricks to assembling? I'm thinking I should start only with the studs shown to get the header and bottom of intake manifold in place and a little snug before adding the top studs. 

Edit: ok, I learned the hard way... Set all the studs then get after it. Looks like a good seal across the header. Will crank tomorrow. 

PXL_20210402_191520505.jpg

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Edited by Dadsun
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Posted (edited)

Need some insight...

So, the header and new exhaust are in. No leaks as far as I can detect!

Sounds pretty good although I still have some carb tuning to get back to. 

But, I have an issue with the accelerator/throttle linkage. It is tight and requires me to push down fairly hard to get it moving. Which results in a big rev and jerking. I think it's that the two springs connected to the heat shield are too tight. 

See yellow arrow on pic. Any suggestions?

And how do the carbs stay in idle if there is no heat shield and springs?

Also, that connecting rod between the carbs linkage and the top idle screw seems at a less than optimal angle when trying to generate movement downward on the linkage. It'd be better if it were longer, but then the idle would be very high unless I made adjustments elsewhere. 

Any help appreciated.

 

PXL_20210406_211516895.jpg

PXL_20210406_211547270~2.jpg

Edited by Dadsun
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I see that the rod coming off the bell crank is pretty well extended on its adjustment threads. This is increasing the mechanical advantage and adding to the "jerk". You can adjust that rod shorter and soften the response a bit. Softer return springs at the heat shield will also improve the problem, just not so soft that the carbs will not shut down when you lift from the accelerator pedal.

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11 hours ago, Mark Maras said:

Does the linkage operate smooth without the springs?

No, it stays open.  Revs up high immediately. Not good. 

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 I'd start by disconnecting the two linkage rods with the plastic ball ends and operate the three linkage assemblies from the gas pedal up to the carbs independently. Hopefully you'll be able to isolate the problem. As an alternative, if you haven't lubed all the pivot points yet, you could start at the pedal and start oiling all the pivot points one at a time until you find one that may be binding.

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I'd like to thank you guys for the discussion on this.  I have a similar issue (difficult to control engine speed just off idle).  Lubricating all the linkage points helped, but making the adjustment JFA mentioned also made improvement.  I don't think I even knew that ball was adjustable.  I shortened it as much as possible, the height of the throttle pedal was raised slightly, but low RPM does seem easier to control.

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