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Originally Posted by SB
(Post 4308483)
Exhaust valve 100 times more common to seize than intake...or more.
You ever find out what caused the 1/4" or more clearance from dist to dist pad on intake ? Reason for asking I never heard if you checked intake port flange to see if a bunch of material was milled off from last build....or deck was cut considerably....or ? You ever check lifter bore to lifter clearance ? How did you determine pushrod length ? Any pics of the rockers installed ? Lifter bores .0012-.0015 on starboard, .0018-.0020 port engine bob m and Johnson both said .0012 -.0015 ok and was told "sweet spot" for them.. Pushrod length done half lift met kind I will see for pics... 5 people said I was ok there I get many things can happen but this is not right I am lost but I don't see any sign at all of detonation here |
Originally Posted by SB
(Post 4308484)
Guide could be trashed now from the trama anyway. So, I don't think checking the guide vs valve right now would show accurate results.
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Originally Posted by Full Force
(Post 4308486)
It does with cylinder that was not damaged....
Make sure to put some lube on the valve that won't burn off at 400F when you check it. |
Tim, I would bring the heads to your machine shop. Have them check the guide clearances. Also, I'd have them check the SEAT WIDTHS. In marine applications, you want a nice wide seat margin to aid in cooling the valves.
Theres a reason Teague marine machines their AFR heads before they sell them. You pay a little extra for it, but they aren't out of the box car heads, mass assembled, with inconel valves thrown in and called "marine" heads. Although, I will say, in AFR"s defense, they specifically told me in an email regarding a marine application, that for marine and boosted applications, that it is the engine builders responsibility to size the guides accordingly. Here is the email from them Joe, Based on the engine combination, power range and Marine application, you should look at our 305 Magnum heads. Our 305 head is designed to generate optimal airflow translating to stout horsepower, torque and throttle response specific to your application. You will need to special order your heads with our #8002 “spring exchange” to suit your hydraulic/roller camshaft. Note: We do not size our valve guides specific to Marine/boost usage. It is the engine builders’ responsibility to check for correct guide clearance per their Marine/boost application. We recommend that you special order your heads with an “Inconel” exhaust valve upgrade, better suited to marine exhaust temperatures and the possibility of exhaust reversion. Hope this helps. Please call if you have questions or require further assistance with your order. Rob Wood Air Flow Research 661-257-8124 ext.123 [email protected] |
Tim , how did the oil look ? An excessively tight guide and even a little moisture in the oil will gall and weld the valve to the guide . Dont ask me how I know........ Good luck , you'll get to the bottom of it !
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You never answered my question - one wideband per motor or two? And if one was it on the side of the motor that let go? I keep going back to the previously milled intakes. Are you sure they were flat milled and not angle milled? I'm not trying to point the finger at you at all, but you still have one motor that hasn't lynched, so getting to the root cause of why this one let go is imperative. As far as I know the only thing reused on these motors were the intakes. I still think the fact you dropped an intake valve instead of an exhaust valve points away from tight guides short of a quality control issue. 10 seconds at close to peak cylinder pressure before it let go really sounds an awful lot like detonation.
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Originally Posted by MILD THUNDER
(Post 4308499)
Tim, I would bring the heads to your machine shop. Have them check the guide clearances. Also, I'd have them check the SEAT WIDTHS. In marine applications, you want a nice wide seat margin to aid in cooling the valves.
Theres a reason Teague marine machines their AFR heads before they sell them. You pay a little extra for it, but they aren't out of the box car heads, mass assembled, with inconel valves thrown in and called "marine" heads. Although, I will say, in AFR"s defense, they specifically told me in an email regarding a marine application, that for marine and boosted applications, that it is the engine builders responsibility to size the guides accordingly. Here is the email from them Joe, Based on the engine combination, power range and Marine application, you should look at our 305 Magnum heads. Our 305 head is designed to generate optimal airflow translating to stout horsepower, torque and throttle response specific to your application. You will need to special order your heads with our #8002 “spring exchange” to suit your hydraulic/roller camshaft. Note: We do not size our valve guides specific to Marine/boost usage. It is the engine builders’ responsibility to check for correct guide clearance per their Marine/boost application. We recommend that you special order your heads with an “Inconel” exhaust valve upgrade, better suited to marine exhaust temperatures and the possibility of exhaust reversion. Hope this helps. Please call if you have questions or require further assistance with your order. Rob Wood Air Flow Research 661-257-8124 ext.123 [email protected] |
Originally Posted by donzi matt
(Post 4308514)
You never answered my question - one wideband per motor or two? And if one was it on the side of the motor that let go? I keep going back to the previously milled intakes. Are you sure they were flat milled and not angle milled? I'm not trying to point the finger at you at all, but you still have one motor that hasn't lynched, so getting to the root cause of why this one let go is imperative. As far as I know the only thing reused on these motors were the intakes. I still think the fact you dropped an intake valve instead of an exhaust valve points away from tight guides short of a quality control issue. 10 seconds at close to peak cylinder pressure before it let go really sounds an awful lot like detonation.
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Full Force, I would recommend starting a new thread pertaining to your issues. Others might be better able to offer help, and hopefully your post-mortem on your engine will reveal the issue and help others avoid the same thing. I'm very sorry to hear about your bad luck! Hopefully you will be able to find the cause and get this motor back in action soon to salvage the season. I sure hope it's an isolated problem and the other engine does not have a similar issue. Good luck with it!
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Tim, did you have 4-7 swap cams?
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