INJECTED HEADERS = BROKEN EX. VALVES?

[TTYTWSTR19]

HAS ANYONE HAD PROBLEMS SNAPPING STAINLESS EXHAUST VALVES AS A RESULT OF RUNNING H20 INJECTED HEADERS? - THAT WAS A SUGGESTED DIAGNOSIS OF MY CATASTROPHIC MOTOR FAILURE.
HOW MUCH HOTTER DO DRY OVER THE TRANSOM HEADERS REALLY RUN VS. INJECTED? ARE THERE ANY BENI'S OF ONE VS. THE OTHER?
THANKS FOR THE INFO,
JON

[Jetmugg]

Jon:
Yes, it can happen, but several things need to be wrong in order to hydraulic your engine. First, your cam has to be very large, and have a lot of overlap before sucking water in gets to be a problem. Secondly, and much more common, is a problem with the plumbing of the lines going to the headers. There should be absolutely no water going to the headers until 1500-2000 rpms. Check the spring in your "T" valve, and check the water flow to make sure it's coming in at the right time. Also, some guys use water restricters in the injection lines to further limit the water flow.
Dry headers should be considered a drag-race only option. They get extremely hot, and are extremely loud. Most places they are illegal as well, and are definitely cop-callers. If your water injected headers are set up properly, you should not have a problem.
SteveM.

[TTYTWSTR19]

STEVE,
I MAY BE MISTAKEN, BUT I DON'T THINK THE MOTOR HYDRAULICED. I THINK MY MOTOR BUILDER WAS REFERING TO THE RAPID COOLDOWN DUE TO WATER IN THE CLOSE PROXIMATEY OF THE VALVETRAIN WHEN YOU SHUT THE MOTOR OFF - WHILE THE H20 IS EVAPORATING AND COMING OUT THE WEEP HOLES.
ARE THERE SUCH BEAST AS JACKETED OVER THE TRANSON HEADERS? NEVER SEEN ANY.
JON

[lakecrazy]

Lightning mfg. has water jacketed headers, but for thru-transom applications only

[Brewer]

My last motor broke a Manley SS Exhaust valve and I am running water injected Bassetts, however I don't know if this was the cause. I do know that it was expensive to fix, and now have the water injection set to "mist" out the back while under way. So far no problems, except for the occasional burn that happens as a result of contact w/ those headers. I did run O/T dry headers, very hot (and loud), and even after wrapping w/ thermal tape, still too hot. I do like those jacketed thru-transom headers and would like to try them, but they are expensive. Anybody running those?

[mister460]

I'm pretty sure that running injected headers would not cause a valve to break. First off, make sure your timing is properly advanced or else you will overheat exhaust valves VERY fast. And that means quick failure whether it be gas cutting(burnt) or a tulipped or busted stem, especially if you're using undercut stems. See, retarded timing will cause too late combustion and the flame will still be burning as it exits the chamber. Second, too much advance can cause detonation not audible and that can shank a valve too. Third, make sure you're not burning too lean. We all know what a lean-burn motor does!! Expensive noises! And while you've got the heads off, polish the inside surface of your combustion chambers. You'll be able to run more advance safely, a little lower octane gas, and you'll actually use a tad less gas and broaden your torque band. You get quite a lot for a few minutes with a die grinder and sandpaper roll on each chamber! Well, sorry to ramble on but I just wanted to put in my sixteen dollars and twenty six cents!!! Also, nitrous, meth, and a blower makes eveything work real nice!!!

[TTYTWSTR19]

M'460,
DO YOU THINK AN ELEVATION CHANGE OF 600-1000 FEET WOULD CAUSE A 600 HP. BBC TO LEAN OUT ENOUGH TO SNAP THE HEAD OFF AN EXHAUST VALVE?
- THE FAILURE HAPPENED AT LAKE WINNIPESAUKEE, I NORMALLY BOAT ON LAKE CHAMPLAIN (IN VT).
JON

[Boater Bill]

Inconel exhaust valves are insurance against valve breakage. Reg and S/S valves exposed to "wet" exhaust cycles will become become "brittle". They are expensive insurance though, mine cost $40 a pop. Another thing you can do to minimize water in injected systems is resticting flow as per the above post and/or install a valve that you can turn off the water to the headers when idling.

[jaqquuuz]

Twister im running a set of thru-transom headers from rewarder and I have to say it was one of my better investments.I got the ceramic coated ones and I had to make some changes. Went to 4 in. pipes with stainless flappers ( no more rubber to replace ) and I also had to run a dump-out the back. Instead of one T fitting I now use 2. I liked the T I got from Jim but I choose to use Bassets T instead it seem to have a much stronger spring. Its nice and quiet when you idle but when the gas goes down you know you have a set of headers out the back.

[superdave013]

I have had the same problem. I didn't break any but replaced them before they did. I even ran the slighest amount of water and injected it into the collector (dry at idle). Still was getting it in the heads! My cam was a huge roller with .810" lilft but still. So after a few sets of valves I just ran them dry. Water or not you will still get burnt if you touch them. I would rather run a muffler than water in my headers. Now I am building a cruiser and it will have fully jacketed headers and a new set of Inconel valves.