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Io360 A1A loose intake flanges

ERJDriver

Well Known Member
Hey all, I noticed one or two cylinders the pipes are loose in the flanges. It’s like the clearance is too deep between the flange, the pipe, and the mating surface of the cylinder. Is there a way to fix this or do I have to buy new pipes/flanges
 
One option might be the great o-ring seal system that SDS sells. It was jointly developed by Ross Farnham (SDS) and Mike Robinson (Toobuilder).

You do have to cut the tubes to install the new clamping flanges, then re-weld the tubes. Vince at Vetterman Exhaust did that for me for a modest fee. Alignment was perfect.

I highly recommend it. It is a forever fix to a potential problem that is sometimes hard to diagnose.
 
Why do you have to cut the flanges? On my O-360-A1A I just removed the intake pipes and slipped the old ring off of the free end and slipped the new one on. Is the IO intake a manifold?
 
Engines using a formed flange and O-ring seal at the sump end as below will require that the tubes be cut and re-welded. On engines which use a hose and clamp connection at the sump end with 1.5 or 1.75 OD induction tubes, no cutting is required.

Some aftermarket tubes have the tubes enlarged to 2" OD at the sump connection. These will also require tube cutting and re-welding.
 

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Same as pa38112 here. Nothing but just replacing the flanges on my O-360-A1A (converted to hollow crank).
An expensive but worth every penny SDS mod on anyone’s engine. And Ross is a pleasure to deal with :)

PS
I do also recommend their rocker covers, leak free heads for sure :cool:
 
Second solution

OK Maybe I think to much, But, I have the same tubes as Ross shows on my I0-360. If I wanted to put the SDS O-Ring system on my RV-6 ( I have them on my RV-6A) I would probably just cut the tubes and put sleeves of hose and some of Ross's CT clamps on them. Why not? I realize there is only an O-Ring holding into the sump. But it should work.
My three cents worth and not a penny more Art
 
Loose intake flanges on 200 hp sump

Doing an inspection on my intake tubes I noticed one had fuel staining around the flange. I removed the offending tube and while supporting the tube carefully slid the flange across ia flat plate with 300 grit wet/dry sandpaper a couple of times which left a beautiful witness mark on the assembly. Sure enough on one side the flange was making contact before the edge of the tube itself. I filed and sanded the flange down until the intake tube made full contact all the way around. Reinstalled the tube and flange and no more leak.
It appears to me that tightening the intake bolts to the head over time pull the edges of the flange down and bow the collars. Simple fix with about an hour of work.
 
Unlike the parallel valve intake hold down flanges which slide off the tube and can be reworked easily, the angle valve units are married to the tubes for life. Once they start to rattle around in the flange clamps, they keep digging deeper and deeper. The "fix" is to surface the mating flange until the recess is shallow enough to make the intake tube a bit proud. The easiest way to do this is to cut the tube and have the flange surfaced or replaced, but at that point you might as well do the SDS o ring mod and be done with it. Yes, you can slide the flange down the tube and go at it with a file, hoping to keep the surface true, but frankly I can cut and reweld a tube in less time than that would take.
 
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