Should I update manifolds

[old islander]

Manifold update?

I have a 1978 898 5.0 in a sea ray 197. My starboard side manifold has a crack between the two center cylinders. Knowing these are the original manifolds and risers on the boat I believe it is time for replacement of the whole works. Pricing out new "log" style manifolds and risers I have come across a few kits to update to the newer more modern center type manifolds and risers. The cost is very close on both of them. Is there any advantage to go with the newer style, or should I leave well enough alone and just replace the logs? Anyone have any thoughts on this?

 

[jimmy wise]

i think i have the starboard log for mine. i hope they answer im in the same boat

 

[old islander]

Hi All, tried this in the non repair forum and got no response so I will try it here. I have an 898 5.0 1978 vintage. My exhaust manifolds and risers are badly rotted with rust and need replacement. This 898 has the old "log" style manifolds. In shopping for them I have found a few kits that convert the manifolds to the newer center style manifolds and risers. The kits come with everything to hook up to my existing y pipe as well as new mounts for the starter solenoid and fuel filter. My question is, is their any advantage to updating to the newer type of manifold, or is the old log system the better way to go. I have heard of gains in HP with the new set up due to better flow and design. Also, they say they cool better then the old logs. Anyone make this swap? I would think the HP gain would be slight at best, but the newer style manifold is half the cost of the logs, so I see a $$$ gain there. Anyone have any thoughts or experience with this swap?

 

[Bondo]

I have a 1978 898 5.0 in a sea ray 197. My starboard side manifold has a crack between the two center cylinders. Knowing these are the original manifolds and risers on the boat I believe it is time for replacement of the whole works. Pricing out new "log" style manifolds and risers I have come across a few kits to update to the newer more modern center type manifolds and risers. The cost is very close on both of them. Is there any advantage to go with the newer style, or should I leave well enough alone and just replace the logs? Anyone have any thoughts on this?

Ayuh,..... While I think center-risers are atad more efficent, up datin' an older boat is a flip of the coin,....

You won't See any difference in performance, 'n you'll be doin' abunch of Adaptin' to switch,...

Bottom line of yer question,.....
I'd put back on, what's there,....

 

[alldodge]

Hi All, tried this in the non repair forum and got no response so I will try it here. I have an 898 5.0 1978 vintage. My exhaust manifolds and risers are badly rotted with rust and need replacement. This 898 has the old "log" style manifolds. In shopping for them I have found a few kits that convert the manifolds to the newer center style manifolds and risers. The kits come with everything to hook up to my existing y pipe as well as new mounts for the starter solenoid and fuel filter. My question is, is their any advantage to updating to the newer type of manifold, or is the old log system the better way to go. I have heard of gains in HP with the new set up due to better flow and design. Also, they say they cool better then the old logs. Anyone make this swap? I would think the HP gain would be slight at best, but the newer style manifold is half the cost of the logs, so I see a $$$ gain there. Anyone have any thoughts or experience with this swap?

IMO I would not use the old style unless there was no other way. HP increase will not be enough to notice

 

[old islander]

Thanks Bondo, as allways, your the Man.

 

[buzzm19]

I have just replaced and updated from log exhaust to center riser. I have a wellcraft novall 26ft and twin 260's and my job was not a piece of cake. First off none of your accessories will bolt to the exhaust logs (no bolt holes). I had to make my own conversion alt brackets water seperator brackets starter sol (I have two on each motor) had to make new oil dip sticks and re-route them, I had to get the risers with a 15 degree down slope and 80degree elbows to go into my y pipes. the next is a new thermostat housing.because the re-route of the water hoses are different ( I have seen mod's with the old but didn't like it). and chances are it probably needs replace anyway. If you have a friend or someone that has a center riser set up take a close look, I looked on the computer a lot and under images and printed pictures. I have my own mechanic shop and the boat inside and I will tell you there is a lot of time and fabrication necessary, I don't know if there is a complete conversion kit available and if so its probably pretty expensive. Remember these boats we're talking about are 35 years old and a lot of change over in the manifolds occured in 1982. My full conversion on both motors cost me around 1600.00. I made all the fabrication. I hope this info helps as I am happy with my boat. Buz