Change OMC Small Block Round Log Style Exhaust Manifold to Riser Exhaust Manifold

[strikemike]

Can i change OMC Small Block Round Log Style Exhaust Manifolds to Riser Exhaust Manifolds? I have to replace my old Round Log Style Exhaust Manifolds and in the Next Step i want to build a Thru hull Exhaust. Thats why i need the Riser Exhaust Manifolds.

 

[Bondo]

Ayuh,.... Is this a Stringer drive,..??

The center-riser manifolds will bolt to the motor, but I imagine yer openin' a nasty can of worms gettin' 'em plumbed up right,....

 

[Boomyal]

Ayuh,.... Is this a Stringer drive,..??

The center-riser manifolds will bolt to the motor, but I imagine yer openin' a nasty can of worms gettin' 'em plumbed up right,....

Now Bondo, where is that infamous creative talent of yours? I can't state the sizes but it would be a relative snap. The center risor outlet is horizontal. The Stringer intermediate inlets are near vertical. There is plenty of room to make a nice, easy 90° bend, with appropriate hose material and size, to hook them together.
Reducing couplers may be necessary to match the intermediate inlet and center risor outlet ports.

Earlier stringers used a reducing coupler on one side as one intermediate port was smaller than the other. Later Stringer drives (I think starting 1978) had identical size intermediate inlet ports.

 

[strikemike]

yes, it is a 1973 Stringer. so what does it mean to me and my plan to replace my old Round Log Style Exhaust Manifolds?

 

[Boomyal]

yes, it is a 1973 Stringer. so what does it mean to me and my plan to replace my old Round Log Style Exhaust Manifolds?

I assume that you have a FORD small block V8. Your '73 will have a reducer between the log manifold elbow and the inlet to the intermediate on one side. The other will be the same diameter from the elbow to the intermediate housing inlet. Like I said, I do not remember the exact hose diameters.

You need to contact a knowledgeable vendor. They should have all the answers to get you to where you need to go.

 

[Bondo]

Now Bondo, where is that infamous creative talent of yours? I can't state the sizes but it would be a relative snap. The center risor outlet is horizontal. The Stringer intermediate inlets are near vertical. There is plenty of room to make a nice, easy 90° bend, with appropriate hose material and size, to hook them together.
Reducing couplers may be necessary to match the intermediate inlet and center risor outlet ports.

Earlier stringers used a reducing coupler on one side as one intermediate port was smaller than the other. Later Stringer drives (I think starting 1978) had identical size intermediate inlet ports.

Ayuh,..... I wouldn't give up Boomer, even on a Stringer,..... I'm more concerned 'bout replumbin' the water,.....
On a Merc, ya really gotta change the t-stat housin' to match the manifolds,...

strikemike wants to go to Thru-hulls,.... I suggest Straight out, off the risers,....
but I donno what parts of a stringer might be in the way,....

 

[strikemike]

No Title

It Is a 307 GM Block. No Ford. First Step ist to change the very old Manifolds. Second step ist the Through Hull Exhaust.

I have to replace the exhaust manifold on grounds of age in any case. I would like then just update to the current exhaust manifold. THEN I would like to convert via CaptiansCall to Thru Hull. It is important that the exhaust manifold be replaced and I would like to see no "one-way street" build. That's why I wanted to convert to the Center Reiser. Sorry for the Google Translation.

 

[jerryjerry05]

Cobe Marine in Pasadena, Md.
Call him, he'll be able to help and can ship you all the stuff you need.

 

[Bondo]

It Is a 307 GM Block. No Ford. First Step ist to change the very old Manifolds. Second step ist the Through Hull Exhaust.

I have to replace the exhaust manifold on grounds of age in any case. I would like then just update to the current exhaust manifold. THEN I would like to convert via CaptiansCall to Thru Hull. It is important that the exhaust manifold be replaced and I would like to see no "one-way street" build. That's why I wanted to convert to the Center Reiser. Sorry for the Google Translation.

Ayuh,.... For the amount of re-engineerin' needed, it oughta be All done in 1 shot,....

 

[Howard Sterndrive]

I have been running Merc dry joint center riser manifolds on a 1980's OMC 3.8 V6 motor with the OMC tstat housing for 5 years or so now. I have had no issues. I just ran the same water lines into the manifolds that went into the old OMC manifolds.


not sure why you'd want open exhaust noise, but going out the hull with mufflers might be easier to plumb up to aftermarket manifolds and it would keep some heat away from your outdrive.

 

[Redrig]

I recently converted to center risers on my ford , I know its not exaclty what you are doing . But I did a write up , with some part numbers for the eblows , hose size , ect .

It may be of help to you to get an idea of what the process is.

http://forums.iboats.com/forum/engi...outdrives/659072-omc-manifold-conversion-ford