TurdFerguson Posted December 4, 2023 Share Posted December 4, 2023 06 CV713 just replaced heads about 6 weeks ago. Has broken the guide pin on exhaust valve twice since then. We had to pull the head already during install to have re-machined. Is this a valve issue? Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/ Share on other sites More sharing options...
fjh Posted December 4, 2023 Share Posted December 4, 2023 Did it break on the same cyl twice? It could be a valve issue! Did the heads not have a warranty? Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542886 Share on other sites More sharing options...
Joey Mack Posted December 4, 2023 Share Posted December 4, 2023 (edited) Improper adjust ment of the valve yoke reset pin can cause this as well Edited December 4, 2023 by Joey Mack Pore cell fone sperring 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542888 Share on other sites More sharing options...
TurdFerguson Posted December 4, 2023 Author Share Posted December 4, 2023 29 minutes ago, fjh said: Did it break on the same cyl twice? It could be a valve issue! Did the heads not have a warranty? Broke on no. 4 twice. Do you think a valve height issue? Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542891 Share on other sites More sharing options...
fjh Posted December 4, 2023 Share Posted December 4, 2023 46 minutes ago, fjh said: Did it break on the same cyl twice? more a set issue as Joe mentioned! Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542892 Share on other sites More sharing options...
fjh Posted December 4, 2023 Share Posted December 4, 2023 Just now, fjh said: more a set issue as Joe mentioned! That said if the seats were improperly installed there could come an issue with un even ness after being run! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542893 Share on other sites More sharing options...
TurdFerguson Posted December 4, 2023 Author Share Posted December 4, 2023 1 hour ago, Joey Mack said: Improper adjust ment of the valve you rest pin can cause thia as well Solution? Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542895 Share on other sites More sharing options...
Joey Mack Posted December 4, 2023 Share Posted December 4, 2023 Yokes are set to.010" Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542898 Share on other sites More sharing options...
Joey Mack Posted December 4, 2023 Share Posted December 4, 2023 I'm sorry about my poor spelling.. the yokes get set to .010" while you are adjusting the valves or when the rocker shafts are off.. if the yokes are not even, it puts a side load on the bridge/yoke pin, and can break the pin.. I cant tell you how many of those I had removed with a welder and a slide hammer... Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542904 Share on other sites More sharing options...
fjh Posted December 5, 2023 Share Posted December 5, 2023 Yup agreed! Also if you don’t got a 10 thou handy you can set the yoke by putting your thumb on the yoke turn the screw till it touches then one flat of the nut and lock it down! Done this for years on v8 e6 e7 and eteck the best part is you don’t need a dam computer to do it and the procedure never changes!😂 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542930 Share on other sites More sharing options...
Mackpro Posted December 5, 2023 Share Posted December 5, 2023 (edited) If you have the Jacob’s engine brake . The floating pin in the exhaust yoke is worn. I’ll see if I can find pics. This was a big issue and new hardened adjustment pins came out with a special coating on them . Edited December 5, 2023 by Mackpro Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542944 Share on other sites More sharing options...
Mackpro Posted December 5, 2023 Share Posted December 5, 2023 Mack SB-213-027 is the bulletin. This only applies if you have the Jacobs/J-tech engine brake. ETECH style J-tech brake pin.pdf Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542947 Share on other sites More sharing options...
Joey Mack Posted December 5, 2023 Share Posted December 5, 2023 The reset screw part number is 215SB321.. Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542960 Share on other sites More sharing options...
TurdFerguson Posted December 5, 2023 Author Share Posted December 5, 2023 What if the valves were properly adjusted and the yokes set to .010? Where would you go from there? Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542973 Share on other sites More sharing options...
TurdFerguson Posted December 5, 2023 Author Share Posted December 5, 2023 6 hours ago, Mackpro said: If you have the Jacob’s engine brake . The floating pin in the exhaust yoke is worn. I’ll see if I can find pics. This was a big issue and new hardened adjustment pins came out with a special coating on them . Powerleash jakes Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542974 Share on other sites More sharing options...
Mackpro Posted December 5, 2023 Share Posted December 5, 2023 Make sure the little valve cap is on top of the exhaust valve , Item 3 in this picture powerleash.pdf Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542975 Share on other sites More sharing options...
Joey Mack Posted December 5, 2023 Share Posted December 5, 2023 diss regard the kit number I posted.. It is NOT for power leash... power leash valve adjust is a different procedure than Jacobs.... are you familiar with that process? Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542979 Share on other sites More sharing options...
Mackpro Posted December 5, 2023 Share Posted December 5, 2023 Here is a helpful picture of which adjustment screw dose what on the powerleash. Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542980 Share on other sites More sharing options...
Mackpro Posted December 5, 2023 Share Posted December 5, 2023 You have to leave the .045 feeler gauge in place when you adjust the .024 exhaust 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73607-2006-cv713-new-head-exhaust-pin-has-broke-twice-in-a-month/#findComment-542981 Share on other sites More sharing options...
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