Two types of manifold heat riser gaskets?

[Maxoceanblue]

I do like the idea of having one side smaller than the other as outlined above. They could be moved a little I guess. I think the universal fit explanation is the correct one though.
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1964 Beetle Sedan/1600cc DP 12v converted

[Eric&Barb]

[Eric&Barb]

[APPLEGREENVW]

Will using one small and one big hole heat riser gaskets on aftermarket exhaust systems, help heat up the stock intake like a stock muffler would?

https://www2.cip1.com/searchresults.asp?Search=3487

https://www2.cip1.com/ProductDetails.asp?ProductCode=C13%2D3100
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Parts for sale https://www.thesamba.com/vw/classifieds/search.php?username=APPLEGREENVW

02/76 Beetle sedan

[Eric&Barb]

Only if they are designed for such movement of exhaust thru the intake manifold heat riser tube. Those you posted links to are not designed for that. So unless you drill, cut, bend and weld in tubing to get suction on one side, those will not work.
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[Eric&Barb]

Read and get to understand:

https://www.thesamba.com/vw/forum/viewtopic.php?t=709093&highlight=heat+riser
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[APPLEGREENVW]

[Eric&Barb]

No problem!
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[viiking]

Here's what I said some time ago re heat risers and the correct orientation of gaskets....

I've worked with large heat exchangers in chemical plants and the principle is the same regarding direction of flow and heat exchange.

The outlet pipe of the cooling or heating medium is usually restricted to ensure that the cooling or heating medium (steam, water, air) completely fills the heat exchanger. This maximises the contact area between the cooling/heating medium and the product being cooled or heated.

Taking this to the VW heater riser example, I would assume for maximum efficiency that there should be a restriction on the opposite side of the exhaust gas inlet to the heat riser (left or right depending on what side the inlet is). The exhaust gas is the heating medium, whereas the air/fuel in the intake manifold is the medium being heated. This restriction can be either done by differing pipe diameters or as someone has indicated, a smaller orifice sized gasket. I must admit I have never realised that the gaskets are different.

Over the entire heat riser pipe, there HAS to be a reasonable temperature difference between one side and the other. If there is NOT, then no heat has been exchanged and the heat riser is not working efficiently. The heat in this case could simply be taking the route of least resistance and just flowing through without giving up its heat. Or it could be blocked of course.

Take the example of a water filled radiator. When the radiator is working, the water returning to the motor is much cooler than the water entering the radiator after it has been cooled by the air rushing through the radiator. The air gets hotter, the water gets cooler. In a VW, the air/fuel gets hotter and the exhaust gas (going through the heat riser) gets cooler.

So in short, one side should be cooler. If a smaller gasket has to be installed (not sure if it does however) then it should be on the opposite side to the exhaust inlet.

This is of course very oversimplified and does not take into account heat transferred by conduction, convection along the muffler etc. But I'm not sure it is as significant as the heat exchange effect I've discussed.

Sorry for the physics lecture!

This is from this discussion

https://www.thesamba.com/vw/forum/viewtopic.php?t=...p;start=20
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1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[APPLEGREENVW]

[Eric&Barb]

[viiking]

[FL-Frank]

The gasket kits I have come with only the large size gaskets. WW has the smaller size available to buy separately for $2.50 each. Is there anywhere else that sells the smaller sized gasket seperately?
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“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[Eric&Barb]

Have you ever tried the Classifieds on this very website?? Hover your mouse cursor over the "Classifieds" button and left click on the "Search". Try "Heat Riser Gasket".

You can also look up part like that in the original VW dealer parts manuals here:

http://www.oacdp.org/

Do check out the type 2 parts manual there and the type 1 is available thru the "Upcoming" button at the upper right of that web page.

Here is how you can read and use part numbers for future WWW searches for such:

When you do WWW searches with the nine digit part numbers, put VW and a space before the part number. Remove the two spaces in the part number, and leave off any letter suffix at the end of the part number. So you will get a "VW XXXXXXXXX" to search with. Also "VW XXX-XXX-XXX" will work for other websites.

Keep in mind about every nine digit VW part number:

1. That the very first digit is what model of VW the part was originally designed for. Lots of type 1 parts on the type 2s, some type 2 and 3 parts were used in the type 1. Other parts are only used on that type of VW and no other.

2. 2nd and 3rd digits are the model the part was originally designed for. Some parts are ONLY for that model. Others were later fitted to all VW models.

3. 4th digit tells you which section/chapter of the parts manual the part is found in.

5. The 5th thru 9th digits are the actual part number.

6. Letter suffix means it is an improved part over the last part without letter suffix, or as each letter ( A, B, C, D, etc.) is used the later letter means some change has been made. Sometimes each later part can be used directly in the same area, some can not without replacing other parts around it.

7. If you know a part is RH or LH ONLY, you can tell by the last digit of the part number which side it goes on. an even digit then the part is RH, odd digit and the part is LH. Easiest way to remember this is that a LH drive VW has to have at least the driver, so one person, which is an odd digit. A VW with one driver and one passenger is two people, so an even digit.
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[FL-Frank]

I was able to purchase a few of the smaller diameter gaskets from a member advertising in the classifieds here.

Previously, I had the larger diameter gasket installed on both sides. The manifold is a newly refurbished piece with completely unobstructed heat riser tubes, 30 Pict 1 carb, original oil bath air cleaner, complete and functional thermostat and choke, recently installed NOS Liestritz muffler.

With a larger diameter gasket installed on both sides, fully warmed up temps taken at the heat riser to manifold connection while idling were 336 degrees F on the right side, and 196 degrees F on the left side.

After replacing the larger diameter gasket on the left side with the correct smaller diameter gasket, I was amazed to find the temps at the heat riser to manifold connection have dropped down to 251 degrees F on the right, and 159 on the left.
_________________
“Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD

[Eric&Barb]

Interesting change that made! Thanks for the update.
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[viiking]

[FL-Frank]

[Ferrety66]

[Ferrety66]