Replacing intake - couple of Q's

[Ol'Blue]

Motor is out of a '77 and has Elelbrock 3721 intake with EGR and water passage across the back. Changing to Edelbrock 2121 non EGR for earlier model.

Is it ok to run this manifold without the water passage across the back?

I read that the best gasket is the Fel-pro 1250-S3 that has the steel core, true?

And is it best to ditch the end gaskets and use RTV?

And proper torque sequence and values are key, any other advice?

 

[blubuckaroo]

Even the older 2121 manifold came with the rear crossover coolant port at one time. The new ones have no coolant crossover in the rear. It's not needed.

The 1250 S3 is the gasket you'll want. The 1250 will leave you crying.

Use a caterpillar of RTV rather than the end gaskets that come in the set.

Lightly coat just the coolant port seal surfaces in the head and intake with high temp RTV.

4 long bolts with the heads removed work great as a guide so you set the manifold on straight.

Torque for that aluminum manifold is 18 ft lbs. Retorque it after a few heat cycles.

 

[Ol'Blue]

Even the older 2121 manifold came with the rear crossover coolant port at one time. The new ones have no coolant crossover in the rear. It's not needed.

The 1250 S3 is the gasket you'll want. The 1250 will leave you crying.

Use a caterpillar of RTV rather than the end gaskets that come in the set.

Lightly coat just the coolant port seal surfaces in the head and intake with high temp RTV.

4 long bolts with the heads removed work great as a guide so you set the manifold on straight.

Torque for that aluminum manifold is 18 ft lbs. Retorque it after a few heat cycles.

Perfect thanks Blubuckaroo!

 

[williamjbonney]

Great information, I will add that I used the right stuff for the china walls and that stuff work beyond my expectations. I also installed the ARP stud kit for the intake, well worth the money.

 

[Ol'Blue]

Tha gasket doesn't have an openings for the exhaust gases to pass through the intake manifold. Do I leave these closed up or should I cut openings?

 

[blubuckaroo]

Tha gasket doesn't have an openings for the exhaust gases to pass through the intake manifold. Do I leave these closed up or should I cut openings?

There is sure to be a debate on this but...
After eliminating mine, I haven't missed the heat riser crossover. I believe that's the reason I don't have problems with the fuel in the carb boiling anymore. Mine, like most aftermarket heads, have the ports to the exhaust rail undrilled when you get them. I can't remember seeing anyone drill them to enable the heat riser.

 

[Ol'Blue]

There is sure to be a debate on this but...
After eliminating mine, I haven't missed the heat riser crossover. I believe that's the reason I don't have problems with the fuel in the carb boiling anymore. Mine, like most aftermarket heads, have the ports to the exhaust rail undrilled when you get them. I can't remember seeing anyone drill them to enable the heat riser.

My thoughts as well as I think having it would contribute to vapor lock. And the gasket material will hole up and not blow through?

 

[Ol'Blue]

Well I'm not too happy with the gasket fit. There is a gap at the front or back near the water jackets if the gasket is slide front to back. See pic near screw driver. Centered perfect and it covers but only by 1/16". I centered it and filled the area around jacket with RTV. I torqued all the bolts and had good consistent sealer squish out. Fingers crossed.

 

[savage]

I've always have used the High Performance Intake Gaskets #7220 by Edelbrock. I know same people don't like them, but I've had good luck with them.

 

[El Kabong]

The 4 long studs trick has been the best help for me. The intake slides down straight without moving gaskets or sealant out of place.

 

[Broncobowsher]

I thought the 4 studs was how the factory did it in the first place?

I will agree with the above. Didn't know the latest flavor of intake gasket. RTV on the china rails. Studs.

The exhaust crossover helps when cold. The heat vaporizes the gas dribbled down the carb into the engine. Performance intakes don't have it. Production intakes do. Being southern California, I would consider blocking it off but would not put too much trouble into it. The blocked gaskets will be good enough. If it leaks a little, no big deal. If you were someplace cold and drove when cold, I would keep it open.

 

[El Kabong]

I have found a few with & more without. I don't know if people take them out or if they came stock without. Bottom line is that it is far easier with them. Buy them if you need to.

 

[Ol'Blue]

Yep, I made the four long studs and it helped hold the gasket in place and guide the manifold down in place, but still not sure why I have the gap.

Thanks all, especially blubuckaroo for all the tips and help. Going to call Felpro on Monday and see if this is expected or if I have different heads then I thought or something else is off.

 

[mattt]

Is this the small water passage early heads vs. later version head & corresponding gasket of a later gen head? There have been other threads about that problem with using late model, big water port gaskets on early motors with the smaller water passages. I don't know the particulars, but there was a thread here about it in the last 6 months.

 

[Ol'Blue]

Is this the small water passage early heads vs. later version head & corresponding gasket of a later gen head? There have been other threads about that problem with using late model, big water port gaskets on early motors with the smaller water passages. I don't know the particulars, but there was a thread here about it in the last 6 months.

The heads are from a 77.

 

[nvrstuk]

Intake gaskets...

Many high performance SBF builders are now using Cometic intake gaskets. I did and the quality is amazing and the price is the same as the "R" series Felpro.
You tell Cometic what you want, which aftermarket gasket port sizes you want and bingo...an excellent gasket that won't fail/walk/distort/shrivel up like many others. At least go with one that has steel core or fibers. So many port shapes, I can't tell you which is best in your application.

I've got pics of Felpro failures (first time ever after many builds) and they are identical pics of many other SBF build gasket failures. Many threads on this on other sites.. maybe their gasket composition is different now? Maybe "China-made"...??? I have no idea...

As you probably already know, do not put any silicone around the water ports thinking that you are helping the gasket seal around the water port. The ONLY place for silicone/RTV are at the ends of the valley.

Good luck

 

[Ol'Blue]

I spoke to Federal Mogul today and e-mailed them pictures of the poor gasket coverage of the 1250-S3. They said Ford has several coolant port sizes and that the standard Fel-Pro 1250 has smaller coolant ports and would fit. They are looking into changing the coolant port size and/or creating a new part for the 1250-S3 for heads with the smaller ports.

They are shipping me the standard 1250 gaskets at no cost but not sure if I will use them. I may run the 1250-S3 for now and see how long they will last then go to the Edelbrocks or Cometics as suggested.

 

[mattt]

I personally would never use the 1250 gasket. Do a google search on Fel Pro 1250 gasket failures and you'll see why...that gasket does not hold up at all, long term.


You need to read this thread....click the link in post #3 and that will take you to a very good thread that details the issue you are up against. The meat and bones on the small water port vs. big water port issue starts on page 3 of the second linked thread.

http://classicbroncos.com/forums/showthread.php?t=256195&highlight=intake+gasket

 

[Ol'Blue]

I personally would never use the 1250 gasket. Do a google search on Fel Pro 1250 gasket failures and you'll see why...that gasket does not hold up at all, long term.


You need to read this thread....click the link in post #3 and that will take you to a very good thread that details the issue you are up against. The meat and bones on the small water port vs. big water port issue starts on page 3 of the second linked thread.

http://classicbroncos.com/forums/showthread.php?t=256195&highlight=intake+gasket

Thanks Mattt, great info. You would think that replacing an intake gasket should be pretty much a slam dunk. It sucks learning the hard way.

 

[Action]

I have had good luck with edlebrock intake gaskets.
Jack