Question for those who have an Effy C intake manifold

[FrazerJames]

By this weekend I should have the intake manifold off and ready to replace with an Effy C. I’m pretty sure I can do this without removing the exhaust manifold, correct? As far as gasket, can I use a gasket maker?

I’m searching everywhere for a video on how to do this and coming up with nothing. In fact, I’m shocked at how little decent video footage there is of procedures. Does anyone know of a good resource for this?

[Sac79]

It's an Offy, for Offenhauser... And no, the exhaust manifold will have to be removed. Or at least be loose as the same bolts holds both intake and exhaust on. You have EFI manifolds, right? You should probably document your build in one thread or at least expand your signature.

You could probably support the exhaust manifolds by supporting the exhaust while you remove the intake. I wouldn't use gasket maker. Get a gasket combo, https://www.rockauto.com/en/moreinfo.php?pk=2185152&cc=1121432&jsn=580 . Using both gaskets levels the difference between the exhaust and intake and enables the washers to be flush on both surfaces.

Clifford Performance has videos on the installation, but it's more involved since there is a bigger difference in thickness of the manifolds which requires bending the washers, but it will give you an idea.

I also have pics on my thread, sorry no video, but the installation is reasonably straightforward.

[FrazerJames]

Oh geez... Yeah, I don’t know what I was thinking on the “Effy” part...

I don’t have an EFI exhaust manifold, no. I’m using the stock that was in place for the carb system. Does that make a difference?

[1986F150Six]

The Offenhauser intake will work with either EFI exhaust manifolds or the original log style exhaust manifold.

[Sac79]

As David says, both are fine. It's probably better actually, for the intake anyway. It will provide heat to the intake which the EFI doesn't. And you can connect the two before installing them together instead of trying to hold three(or two in your case) things and insert bolts at the same time. Not sure of the thickness of the log manifold compared to the EFI. Have you considered changing to EFI manifolds?

[FrazerJames]

I did consider the EFI manifold, but though I might upgrade later considering all the other things I’m doing.

The thickness difference is the big question for me. I actually did find a video showing the install, but it was with the EFI manifold. That said, this states the same type of gasket is used for stock set ups with the log manifold. https://www.summitracing.com/parts/mah-ms16040x/applications/year/1983/make/ford/model/bronco?prefilter=1

[Sac79]

Yes, same gasket set regardless of the manifold types. Most people who upgrade the intake change to EFI exhaust, hence the lack of videos for the log manifold, but the Offy intake is designed for the log exhaust.

If you're considering the EFI exhaust manifolds, you should probably do that now. They can be had for cheap. New runs about $150 for the pair or you can get them at a salvage for $50. You would need a Y-pipe for around $80 too. It all depends what your objectives are I guess. Increasing the intake capacity and adding EFI while leaving the exhaust restricted doesn't make an awful lot of sense to me, but if performance isn't a priority and you only want a reliable daily/weekend driver then it makes no difference I guess. To be fair, few people would get a 300 for performance, there are exceptions as was seen in your other thread.

[FrazerJames]

Ok, then I’ll grab one of those gaskets. Thanks for walking me through that.

Performance isn’t much of a priority for me as I’m the daily driver type for sure. I’d like the ride to be smooth, quiet and reliable. I’ve been driving that Mercedes 300TD for years now, so I know the on-ramp struggle well.

[1986F150Six]

Sac79 wrote

To be fair, few people would get a 300 for performance, there are exceptions as was seen in your other thread.

Just poking fun; have you heard of The Frenchtown Flyer?

https://www.bing.com/videos/search?q=The+Frenchtown+Flyer+YouTube&docid=608030364000062137&mid=04493C2D15172FB200AA04493C2D15172FB200AA&view=detail&FORM=VIRE

[Sac79]

Not seen any of the dragster videos. The name is familiar though, a member on another forum?

[Sac79]

 There are probably a few similarities between the 300 and that diesel, definitely both of the tortoise not the hare variety...

[FuzzFace2]

I got to ask a question?
Why a good breathing intake manifold to fill the motor with air but then choke it down as it cant get the air out thru that factory log exh manifold?
I would at least go with EFI manifolds if not a header.

I would take the exh manifold off and lay the 2 together on a flat bench to see just how much the bolt washer area difference is. If to much you will need to come up with something to fix it.

I am running the factory stock intake & carb with EFI exh manifolds.
Dave ----

[1986F150Six]

Sac79 wrote

Not seen any of the dragster videos. The name is familiar though, a member on another forum?

Yes. He is a retired Ford Engineer and drag races using 240 and 300 engines. That was his car in the video.

[FrazerJames]

The intake is because I’m going with the Sniper EFI. I’m certainly not opposed to it. I haven’t looked into what modifications I’d have to do with the exh manifold upgrade, but I did see something (and it was referenced earlier) about getting a heat transfer set up? Is there something off the shelf that helps with that?

[1986F150Six]

Using a gasket, which goes between the stock exhaust and intake manifold [just under the carburetor] as a template, one can cut a piece of 3/8" aluminum [or steel] and drill out the three holes for the bolts which hold the two manifolds together. This plate is then drilled and tapped for fittings [usually elbow]. A new gasket needs to be made as the original one, used as a template, is designed to hold in exhaust gasses, not hot coolant. Splice this heating plate into the heater hose going to the heater core. The circulating heated coolant will heat the area directly under the carburetor.

Some have suggested that if EFI exhaust manifolds are used, and the manifolds have bungs for EGR purposes, one could make a similar plate [as described above], but pipe it so that exhaust gasses pass under the carburetor. This is how VW heated the remotely mounted carburetor on the older air cooled engines.

[FrazerJames]

Yeah, that’s where I’m going to have trouble. I’m in the city and don’t have the room, tools or experience to be able to knock that out even as simple as it sounds. Time is of the essence too - there’s no way my wife is going to allow me to take her spot in the garage (or spend any more time in the garage than what I’ve already “negotiated”) for much more time.

[old55pete]

An Industrial machine shop could whip something like that in little or no time at all.

I am also with Dave on the exhaust manifold, you need to give some thought to getting the exhaust un restricted as possable to relise the full potential of that after market EFI. The stock exhaust may make it run worse.

Just a thought.

[myrl883]

Just a thought for you to consider. Ford's research from the 70s and 80s showed that using an exhaust manifold gasket on a 300 leads to cracking and warping of those long exhaust manifolds. Therefore, Ford only ran a paper intake gasket and NO exhaust gasket. That's why the flange thicknesses are different. All you want is a thin film of graphite grease on the face of the exhaust manifold when you mount it to the head.

The cylinder head (on any engine) acts as a heat sink for the exhaust manifold. A gasket insulates the manifold and causes it to run hotter than without a gasket.

[FrazerJames]

Oh man... That’s what I had read somewhere else too. So, I should just grab the intake gasket it sounds like.

myrl883 wrote

Just a thought for you to consider. Ford's research from the 70s and 80s showed that using an exhaust manifold gasket on a 300 leads to cracking and warping of those long exhaust manifolds. Therefore, Ford only ran a paper intake gasket and NO exhaust gasket. That's why the flange thicknesses are different. All you want is a thin film of graphite grease on the face of the exhaust manifold when you mount it to the head.

The cylinder head (on any engine) acts as a heat sink for the exhaust manifold. A gasket insulates the manifold and causes it to run hotter than without a gasket.

[FrazerJames]

Welp, ya’ll talked me into it. Just ordered all the parts for the EFI exhaust. Hopefully I’ll have this all set up in 2 weeks. I’m sure there will be questions...

Thanks for all the advice!!!