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Quote:

Originally Posted by getrdunn (Post 4663422)

Where did your water mix and what cam? Sorry if you mentioned in earlier post.

The cam is a COMP Cam XM284HR nothing to extreme 284in 290ex 112 lsa see attached pic of risers, I made my own for a few reasons (1) I could use a 3.5" inner tube instead of the stock 3" (2) make it to what I wanted with O2 bungs (3) I just like doing stuff like this and the winters are long and cold in Canada lol.
https://cimg8.ibsrv.net/gimg/www.off...9bf0555897.jpg
The first riser see pic below still reverted so I added 4" to the inner with a bell end (no punt intended lol) and this stopped all reversion it could idle all day long.
https://cimg9.ibsrv.net/gimg/www.off...61084d38e9.jpg

Quote:

Originally Posted by getrdunn (Post 4663422)

Where did your water mix and what cam? Sorry if you mentioned in earlier post.

I posted a picture of my cam spec sheet towards the beginning of this post and pictures of my risers. the water exits at the end of the riser. where it mounts to the transom.

Quote:

Originally Posted by Camalot (Post 4663412)

These are the risers I made to stop my reversion the inner ends just as it turns before where it fits the transom. From what I found out before I got it to work is height is your friend!
https://cimg7.ibsrv.net/gimg/www.off...eb9ec3ffd3.jpg
https://cimg8.ibsrv.net/gimg/www.off...9eff2f119e.jpg

very nice work!!!

Quote:

Originally Posted by BUP (Post 4663047)

many things can promote water reversion. Alot of times it can be the waterline height - that height needs to meet a min distance from the bottom portion of the riser. to the waterline. One has to test that end with the boat in the water and how the boat is going to be loaded plus with a FULL tank of gas -- plus all the batteries, stereo equipment and so forth.

Next is idle settings - if too high at shut down - and the engine diesels -- that will cause reversion.

Ign. Timing can play into it as well for idle / rpm speeds / along with misfires if that is taking place as well.

exhaust manifolds and risers too cold -- creates condensation that runs down the internal walls into the exhaust ports.

and of course there is more along with the cam / valve overlap

AS MENTIONED riser height is so important.as well.

if all possible one is better off using riser extension blocks for the exhaust manifold / riser combo

also dry to the tip will really help.

Quote:

Originally Posted by BUP (Post 4663539)

riser extension blocks https://cimg8.ibsrv.net/gimg/www.off...8234121e38.jpg

What manifold is that used on? Gil??

Quote:

Originally Posted by BUP (Post 4663539)

riser extension blocks https://cimg8.ibsrv.net/gimg/www.off...8234121e38.jpg

wish I could use a extension block but my manifold/risers don't bolt together like that they are flanged with clamps

Quote:

Originally Posted by chopperkell (Post 4663542)

wish I could use a extension block but my manifold/risers don't bolt together like that they are flanged with clamps

Just saying -- My post and most of them are for whomever that maybe is the mass not just one person. I understand you have Stainless marine and low profile risers with a different manifold to riser mount.

triple post have no idea WHY ???

triple post delete have no idea WHY