Author Topic: Fun with Nitrous, how to torch cut a valve under load...  (Read 38160 times)

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Offline TRNorBRN6001

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Fun with Nitrous, how to torch cut a valve under load...
« on: November 06, 2008, 10:59:43 PM »
I have a little winter project to finish up on. Thought you all might enjoy some pics.











Think it'll buff out!  :-D  :-D  :-D

Offline sabat

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #1 on: November 06, 2008, 11:26:28 PM »
Couple new valves, some lapping compound and it'll be good as new Gary :D

If it was a stock head, you might be able to get a replacement on ebay for less than you'd spend fixing it.  I bought a bare head for $100 shipped, another complete head w/o cams for $200 shipped.

Offline TRNorBRN6001

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #2 on: November 07, 2008, 08:58:27 AM »
Yep, it's a Carpenter head. It's a little erroded (oxydized) by the exhaust seats. Don't know if they will build that up a little, sink the seats or just tell me my head is junk. I have access to a stock head, worst case scenerio. I still really don't know exactly what happened. The exhaust valve damage on all but the missing one was after the fact. I never found the missing valve, might have vaporized or shot out the exhaust. I was running on C16, very,very,very rich, and 12 deg of timming out......................with a 120 shot that put out about 100 actual HP. The motor normally runs 210HP on pump and upper teens low twenties with oxy fuel and timming. It was set up real rich and 0 deg advance for right at 200HP.

Nitrous is down right evil, but very addictive!

Gary

Offline Stainless1

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #3 on: November 07, 2008, 09:31:42 AM »
What is very rich? 5:1 ?  It actually looks lean, like a 7:1, sometimes 4:1 can destroy like lean.... how is the fuel flow and N20 flow over time?  If all that is good, I would go to plugs, what were you running.  Retracted gaps? minimizing the hot spots like electrodes is very important over time, not essential for drag racing but in LSR is way important. 
The missing valve mystery may be solved by looking at the stem, when N20 trims one off, it looks like a clean torch cut, the others I'd probably ask to see the plugs, including the survivor. 
Fixing the head will probably cheaper than making a new one, but let a trained professional make that evaluation.  Show us the plugs and pistons for fun...  :-o
« Last Edit: November 07, 2008, 09:38:27 AM by Stainless1 »
Stainless
Red Hat 228.039, 2001, 65ci, Bockscar Lakester #1000 with a little N2O

Offline RansomT

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #4 on: November 07, 2008, 09:53:28 AM »
Yep, it's a Carpenter head. It's a little erroded (oxydized) by the exhaust seats. Don't know if they will build that up a little, sink the seats or just tell me my head is junk. I have access to a stock head, worst case scenerio. I still really don't know exactly what happened. The exhaust valve damage on all but the missing one was after the fact. I never found the missing valve, might have vaporized or shot out the exhaust. I was running on C16, very,very,very rich, and 12 deg of timming out......................with a 120 shot that put out about 100 actual HP. The motor normally runs 210HP on pump and upper teens low twenties with oxy fuel and timming. It was set up real rich and 0 deg advance for right at 200HP.

Nitrous is down right evil, but very addictive!

Gary

What type of fuel system?  Those stock pumps/lines just can't keep up sometimes over a mile long run ...

Offline Seldom Seen Slim

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #5 on: November 07, 2008, 10:02:08 AM »
There's nothing wrong with that head -- it's just been changed into the Briggs and Stratton "Easy-start" model where the exhaust valves stay open a little to reduce the tug needed for Mom to start the mower.  See, Gary, we understand your methods -- it's easy to get along with an older battery and starter this way.
Jon E. Wennerberg
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Offline TRNorBRN6001

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #6 on: November 07, 2008, 10:43:42 AM »
Yep, sure does make it easier to turn over. No more 24 volt system needed!

I was running an after market Muzzy fuel pump (Walbro GS....) It is suppose to be rated to 400 HP and Muzzy stealth system which is a "wet" type nitrous application. The cylinders and everything looked pig fat, so it did not seem like it leaned up. I have read articles by Dough Meyer on Fuel pump types and pressure and it does not seem that the pump would be over taxed. I sprayed 4th, 5th, and 6th. It is on a progressive system as well start 25HP to 100% in 2 seconds. 4th hit real strong and brought the front tire up a little, 5th hit good but did not feel as strong (might have started to loose one cylinder by then), 6th felt like I lost 2 cylinders from the get go and the RPMs started to drop (I shut it off ASAP) and coasted.

Head also had a full ceramic coat. If the exhaust side would not have tagged the pistons, they would be in perfect condition. Cylinder block in good condition, but the head gasket was blown across all 4. Maybe EFIR did not take timming out?

Any ideas, questions, comments would be greatly appreciated.

Thanks you all,
          Gary
 

Offline TRNorBRN6001

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #7 on: November 07, 2008, 11:01:34 AM »
Thanks Stainless, I'll post up pics of the pistons and plugs when I get home. I can not remember exactly on A/F ratio, I'll have to look it up, but I would say somewhere around 10.8:1 -11:1 on spray.

Thanks again,

Gary

Offline sabat

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #8 on: November 07, 2008, 12:35:54 PM »
Bummer, Carpenter is proud of those heads  :|

What was your pill spread?

Offline TRNorBRN6001

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #9 on: November 07, 2008, 01:22:30 PM »
Pill spread? 2 Vicodine, 1 flexoril, 3 skelactin every 2 hours taken with a couple shots of crown! Just kidding, don't know what that means.


Yep, Carpenter is very proud, but he is known for good numbers. I'd probably be a jerk though and bust the dremel out on the stock head!

Offline Seldom Seen Slim

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #10 on: November 07, 2008, 01:28:13 PM »
"2 Vicodine, 1 flexoril, 3 skelactin every 2 hours taken with a couple shots of crown!"

Ah, yes -- the old saying is once again proven -- "Better living through chemistry!"
Jon E. Wennerberg
 a/k/a Seldom Seen Slim
 Skandia, Michigan
 (that's way up north)
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Offline wolcottjl

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #11 on: November 07, 2008, 02:10:47 PM »
Ah, yes -- the old saying is once again proven -- "Better living through chemistry!"

That's what my Family Doctor says about my Cardiologist.  As she puts it "His philosophy is better living through chemistry versus dropping the weight and living a healthier lifestyle".  I am trying both!   Better odds.  :)
Joel Wolcott
Moving to 2 wheels in 2010

Offline sabat

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #12 on: November 07, 2008, 02:35:42 PM »
LOL. What I actually meant was "what size nitrous and fuel jets are you running to get to 120hp?" Some folks call them pills, and the difference between nitrous and fuel jets - the "pill spread". 120hp might be 42N/46F, others 42N/38F and so on. Running an NX Piranha nozzle, my old bike made about 100hp with a 38N/34F, 6psi fuel pressure, and -8 timing.

Offline TRNorBRN6001

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #13 on: November 07, 2008, 05:29:51 PM »
N28/F32 Funnel type, I believe, jet for steel line (Muzzy Stealth Kit). ~7 or so PSI.

Thank you much Dean, it is Dean correct?



Gary Dow

Offline sabat

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Fun with Nitrous, how to torch cut a valve under load...
« Reply #14 on: November 07, 2008, 05:52:06 PM »
If that's what Muzzys specifies, I'm sure it's fine. I was gonna suggest you flow check these particular pills, but from the pics it looks like 3 of 4 cylinders got too hot, seems unlikely too have so many pills so far off. Maybe like you say the EFIR flaked, I know they are unreliable. Crud in your fuel, clogged fuel filter, crappy nitrous fuel pump, argh.