Odd Problem

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digginfool
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Odd Problem

Post by digginfool » Thu Feb 25, 2016 3:43 pm

I'm having an odd problem with header bolts. Using Stage locking header bolts and they keep breaking. They snap off inside the block but I always find both ends in the bottom of the boat. Always the same cylinder. I thought initially that perhaps we had over-tightened them but now I have one broken for the third time. Any ideas? This is on my LSA.
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DDSBC
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Re: Odd Problem

Post by DDSBC » Thu Feb 25, 2016 3:50 pm

I know exactly what your problem is Greg. Your boat is cursed!!!! :lol:
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Re: Odd Problem

Post by digginfool » Thu Feb 25, 2016 4:13 pm

DDSBC wrote:I know exactly what your problem is Greg. Your boat is cursed!!!! :lol:
You may be right, Micah! :lol: :lol: If I had taken all the money I've put into this boat and bought new instead, I would have a boat like Killin' Time. Wayne would be jealous of me! :lol: Honestly, shortly after I bought the boat and started having problems, I was told to sell it while the selling was good and just get a new boat. Wish I had followed that advice.
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Re: Odd Problem

Post by Dirtman » Thu Feb 25, 2016 4:21 pm

Greg are you finding the head of the bolt and also the threaded portion in the boat? Is it always the same bolt on the same cylinder? if its always the same bolt on the same cylinder check and see if the threads are nice and tight not partially stripped or slightly oversized. Could be that the bolt is not holding the torque (if thats the right way to phrase it) and slightly loosening and the vibration is causing it to break. Have never used the header bolts you are using so not sure if they can back off any at all or not.
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Re: Odd Problem

Post by rdb » Thu Feb 25, 2016 4:22 pm

Is the header warped where the bolt is braking?

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Re: Odd Problem

Post by digginfool » Thu Feb 25, 2016 4:44 pm

I don't believe the header is warped. I bought them new just last year when I installed the motor. Plus, the bolts are breaking in the middle of the threaded portion. Very odd.
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Re: Odd Problem

Post by digginfool » Thu Feb 25, 2016 4:49 pm

Dirtman wrote:Greg are you finding the head of the bolt and also the threaded portion in the boat? Is it always the same bolt on the same cylinder? if its always the same bolt on the same cylinder check and see if the threads are nice and tight not partially stripped or slightly oversized. Could be that the bolt is not holding the torque (if thats the right way to phrase it) and slightly loosening and the vibration is causing it to break. Have never used the header bolts you are using so not sure if they can back off any at all or not.
I should say always the same two cylinders, three different holes. The first cylinder has broken 3 bolts, the second cylinder behind it has broken one; first three mounting holes on the header. The center of the three has broken twice.
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Re: Odd Problem

Post by nomad41 » Thu Feb 25, 2016 5:05 pm

This is just my opinion. I would unbolt that header. Pull it away from the engine and put a known straight edge done the whole length. I have seen brand new headers with a warp in them that puts a lot of strain on one end or the other. Understand that they are stainless steel bolted to alum heads. So they heat and expand at different rates. JMO
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Re: Odd Problem

Post by keebo » Thu Feb 25, 2016 5:29 pm

Nomads advice or opinion is a good start, you also may want to look at studs with locking nuts for your application.
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Re: Odd Problem

Post by swamper2 » Thu Feb 25, 2016 7:55 pm

I would also look at the bolt holes and check to see if the ones that are involved with the breaking bolts have any sign of wear or misalignment condition. all that might have to be done is either take a dremel burr or open the holes up to next 1/32 bigger. JMO
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Re: Odd Problem

Post by loudmouse » Thu Feb 25, 2016 8:37 pm

I would look at the exhaust and make sure it doesn't put pressure on the headers and then look at the tune of the engine(shaking engine). Check all mounts, check gearbox and prop for vibration.
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Re: Odd Problem

Post by skinnypockets » Thu Feb 25, 2016 8:38 pm

swamper2 wrote:I would also look at the bolt holes and check to see if the ones that are involved with the breaking bolts have any sign of wear or misalignment condition. all that might have to be done is either take a dremel burr or open the holes up to next 1/32 bigger. JMO
I have to agree with swamper2, but to be clear we're talking about the bolt holes in the header, not the head.
Also like nomad41 said, the two metals expand at different rates so by drilling the holes out bigger it will relieve the side to side pressure on the bolts that's causing them to break. I would drill all the holes oversize in that header and your problem should be solved.
By the way, don't forget to remove ALL your tools from the engine before you fire it up. :P :P

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Re: Odd Problem

Post by Olf Art » Fri Feb 26, 2016 12:54 am

nomad41 wrote:This is just my opinion. I would unbolt that header. Pull it away from the engine and put a known straight edge done the whole length. I have seen brand new headers with a warp in them that puts a lot of strain on one end or the other. Understand that they are stainless steel bolted to alum heads. So they heat and expand at different rates. JMO
I agree, Bob .... that header flange has to be warped. There's no other explanation for that. The heating/cooling cycle shouldn't make that much difference. The header can probably be saved with planning by a competent shop.
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Re: Odd Problem

Post by Bdriller » Fri Feb 26, 2016 8:26 am

If the bolts are stainless replace them with 8 point header bolts made by arp and see if they break, stainless bolts dont take vibration well

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Re: Odd Problem

Post by skinny99 » Fri Feb 26, 2016 8:41 am

Bdriller wrote:If the bolts are stainless replace them with 8 point header bolts made by arp and see if they break, stainless bolts dont take vibration well
Good advice here. We tried SS on our racecars and didn't have much luck. ARP bolts and checking them often fixed all the issues. Drilling them and safety wiring is also a great idea. JMO
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Re: Odd Problem

Post by digginfool » Fri Feb 26, 2016 9:04 am

nomad41 wrote:This is just my opinion. I would unbolt that header. Pull it away from the engine and put a known straight edge done the whole length. I have seen brand new headers with a warp in them that puts a lot of strain on one end or the other. Understand that they are stainless steel bolted to alum heads. So they heat and expand at different rates. JMO
We have a winner! Now what? That's a hell of a warp. That's got to be over an eighth of an inch gap between the flange and the straight edge.
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Re: Odd Problem

Post by digginfool » Fri Feb 26, 2016 9:47 am

Well, now things go from annoying to uh-oh. I see one cylinder is clean and realize it's obviously not firing. Pull the plug from that cylinder and the adjacent cylinder; not good. I'm hoping it's just a bad plug or coil. Time to get the compression tester out. :banghead:
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Re: Odd Problem

Post by Olf Art » Fri Feb 26, 2016 10:00 pm

You're still OK, Diggin. Go ahead and have the exhaust flange straightened / planned, put he engine back together, and run it again. That other cylinder wasn't in the firing sequence before because it wasn't pulling enough vacuum on the intake stroke. Try it ..... if it works you owe me a beer. :)
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Re: Odd Problem

Post by digginfool » Fri Feb 26, 2016 10:17 pm

Taking the header to Norman. Going to let him straighten it out. Olf, this is a supercharged engine; not using vacuum. Unfortunately, appears I may have a broken oil ring. Used a bore scope today and there are some pretty bad scuffs on the cylinder walls and some pitting on the top of the cylinder. Marine Power is taking charge now.
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