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Message |
raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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 Posted: Thu Sep 20, 2018 6:14 pm Post subject: Re: Intake manifold gasket? |
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| Wildthings wrote: |
| raygreenwood wrote: |
| thewalrus wrote: |
The thicker gaskets are for F.I.? That seems weird because I removed this gasket from between the carbs and the top of intake tubes:
This is 3/16" thick and has VW markings on it. The engine had never been removed before also. |
It seems weird but its but. The thick spacer. On the EFI gaskets...made of phenolic plastic ( bakelite).....is not there for heat insulation. There is "0" need for a heat insulator on the efi runners because the injector does not contact the runner anywhere. Its fully suspended by its rubber o-rings.
Its a spacer. Its designed to hold the runners at the correct height for the center manifold as well as insure that the spray cone from the injector is spaced correctly from the valve and centered correctly in the port.
As BD mentioned....yes.....you can put the gaskets on dry.....but only dry between the outside of the gasket and the head. The gasket itself works far better when adhered to the phenolic spacer with a thin layer of adhesive/sealant. Ray |
Colder air equals more power, the gaskets are there to insulate the runners from the heads. If what you claim is true, the VW engineers would have made the manifolds a bit difference in shape and saved a dime or two per car by eliminating the expense of the phenolic insulator. |
Obviously you have never measured. Even on the hotteat days....without a spacer...and I have run it without to test ( and it was a pain to fit)....there is not even 1° F rise in intake air temp created by heat from the manifold...and.....without the spacer the injector pattern sprays on the port wall.
I think you are giving the VW engineers too much credit. If they thought that far ahead they would have used bakelite heat spacers on the twin carb version that commonly boils its float bowels in hot climates.
Ray |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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| Posted: Thu Sep 20, 2018 6:50 pm Post subject: Re: Intake manifold gasket? |
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| raygreenwood wrote: |
| Wildthings wrote: |
| raygreenwood wrote: |
| thewalrus wrote: |
The thicker gaskets are for F.I.? That seems weird because I removed this gasket from between the carbs and the top of intake tubes:
This is 3/16" thick and has VW markings on it. The engine had never been removed before also. |
It seems weird but its but. The thick spacer. On the EFI gaskets...made of phenolic plastic ( bakelite).....is not there for heat insulation. There is "0" need for a heat insulator on the efi runners because the injector does not contact the runner anywhere. Its fully suspended by its rubber o-rings.
Its a spacer. Its designed to hold the runners at the correct height for the center manifold as well as insure that the spray cone from the injector is spaced correctly from the valve and centered correctly in the port.
As BD mentioned....yes.....you can put the gaskets on dry.....but only dry between the outside of the gasket and the head. The gasket itself works far better when adhered to the phenolic spacer with a thin layer of adhesive/sealant. Ray |
Colder air equals more power, the gaskets are there to insulate the runners from the heads. If what you claim is true, the VW engineers would have made the manifolds a bit difference in shape and saved a dime or two per car by eliminating the expense of the phenolic insulator. |
Obviously you have never measured. Even on the hotteat days....without a spacer...and I have run it without to test ( and it was a pain to fit)....there is not even 1° F rise in intake air temp created by heat from the manifold...and.....without the spacer the injector pattern sprays on the port wall.
I think you are giving the VW engineers too much credit. If they thought that far ahead they would have used bakelite heat spacers on the twin carb version that commonly boils its float bowels in hot climates.
Ray |
I think the VW engineers are quite capable of designing a manifold that could have been used without the insulators. They just didn't add the insulators for no reason. As for running carbs, you can run any combination of gaskets and spacers that works for your climate and driving style. You can even change them seasonally if you want to go to the effort to get the best performance and gas mileage. |
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udidwht
Samba Member
Joined: March 06, 2005
Posts: 3779
Location: Seattle, WA./ HB, Ca./ Shizuoka, Japan
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| Posted: Fri Sep 21, 2018 12:45 am Post subject: Re: Intake manifold gasket? |
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| raygreenwood wrote: |
| Wildthings wrote: |
| raygreenwood wrote: |
| thewalrus wrote: |
The thicker gaskets are for F.I.? That seems weird because I removed this gasket from between the carbs and the top of intake tubes:
This is 3/16" thick and has VW markings on it. The engine had never been removed before also. |
It seems weird but its but. The thick spacer. On the EFI gaskets...made of phenolic plastic ( bakelite).....is not there for heat insulation. There is "0" need for a heat insulator on the efi runners because the injector does not contact the runner anywhere. Its fully suspended by its rubber o-rings.
Its a spacer. Its designed to hold the runners at the correct height for the center manifold as well as insure that the spray cone from the injector is spaced correctly from the valve and centered correctly in the port.
As BD mentioned....yes.....you can put the gaskets on dry.....but only dry between the outside of the gasket and the head. The gasket itself works far better when adhered to the phenolic spacer with a thin layer of adhesive/sealant. Ray |
Colder air equals more power, the gaskets are there to insulate the runners from the heads. If what you claim is true, the VW engineers would have made the manifolds a bit difference in shape and saved a dime or two per car by eliminating the expense of the phenolic insulator. |
Obviously you have never measured. Even on the hotteat days....without a spacer...and I have run it without to test ( and it was a pain to fit)....there is not even 1° F rise in intake air temp created by heat from the manifold...and.....without the spacer the injector pattern sprays on the port wall.
I think you are giving the VW engineers too much credit. If they thought that far ahead they would have used bakelite heat spacers on the twin carb version that commonly boils its float bowels in hot climates.
Ray |
VW used them between the intake and carb on the 72-74 variants.
When I had the stock set up (decades ago) they would on hot summer days still percolate. LOL!
_________________
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96mm Biral AA P/C's~7.8:1CR
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