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View Full Version : INJECTED HEADERS = BROKEN EX. VALVES?



TTYTWSTR19
06-25-2001, 06:35 AM
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
06-25-2001, 07:48 AM
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
06-25-2001, 08:21 AM
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
06-25-2001, 08:56 AM
Lightning mfg. has water jacketed headers, but for thru-transom applications only

Brewer
06-25-2001, 10:04 AM
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
06-25-2001, 11:39 AM
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
06-25-2001, 11:56 AM
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
06-25-2001, 04:58 PM
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
06-25-2001, 07:46 PM
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
06-25-2001, 07:54 PM
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.

mister460
06-25-2001, 09:27 PM
Twister, I'm guessing that you went up in elevation. In that case your engine would actually run richer. But if you were going down, 1000 feet wouldn't be enough to lean it out to a dangerous level. Probably wouldn't even notice much difference in perf. Everyone else is right though, iconel valves are pretty sweet. Expensive but they last. Just remember never to use bronze valve guides. They wear valves out very quickly unless you have valves with nitrided stems. But to be safe I'd run just enough water to keep the Sheriffs off your tail. I'd also double check everything else before I dropped 700 bucks for a set of valves. Do you have the heads off right now?

TTYTWSTR19
06-26-2001, 03:06 AM
MISTER460,
UPON DISASSEMBLY OF THE MOTOR, I FOUND THAT THE EXHAUST VALVE BANGED THE HECK OUT OF THE HEAD, CHOSE A PRETTY QUICK PATH THRU ITS CYLINDER'S KIETH BLACK PISTON, AND DEPOSITED ITSELF NEATLY IN THE OILPAN WITH THE GRENADED PISTON. THE CYLINDER WALL IS CRACKED.
GAME OVER.
THE NEW MOTOR I AM BUILDING WILL HAVE INCO VALVES - I AM THINKING ABOUT PLUGGING THE INLETS FOR THE H20 INJECTION BY THE HEAD AND RELOCATING THEM UP PAST THE COLLECTOR TO GIVE THE ILLUSION OF WET EXHAUST.?
JON

superdave013
06-26-2001, 07:08 AM
TTYTWATR19, That's what i did too. Your headers also have holes on the bottom for water to come out before it gets in the heads. You might want to drill them out a little bigger. I drilled mine out allot bigger. I sitll say I would rather run them dry with mufflers. Good luck.