Outbehindthebarn Posted September 29, 2015 Share Posted September 29, 2015 My engine has two different head bolts on one head. Can anyone explain why? You can see two smaller head(ed) bolts on the bottom, and a larger head(ed) bolt above to the right..... Quote Fun is what they fine you for!My name is Bob Buckman sir,. . . and I hate truckers. Link to comment Share on other sites More sharing options...
AZB755V8 Posted September 29, 2015 Share Posted September 29, 2015 Definitely not factory on an E9. Looks like it had some head work done and damages the head bolt threads or broke bolt. Instead of Helicoil insert they taped it to the new larger bolt size. Quote Link to comment Share on other sites More sharing options...
Outbehindthebarn Posted September 30, 2015 Author Share Posted September 30, 2015 Definitely not factory on an E9. Looks like it had some head work done and damages the head bolt threads or broke bolt. Instead of Helicoil insert they taped it to the new larger bolt size.So the smaller head(ed) bolt is the 'newer' or "older"? Quote Fun is what they fine you for!My name is Bob Buckman sir,. . . and I hate truckers. Link to comment Share on other sites More sharing options...
AZB755V8 Posted September 30, 2015 Share Posted September 30, 2015 Small are the correct ones Quote Link to comment Share on other sites More sharing options...
Outbehindthebarn Posted September 30, 2015 Author Share Posted September 30, 2015 Small are the correct onesWhat does it mean to you then that I only have three small ones on one head, and all the rest on the engine are the bigger ones?I'm still looking into some sort of furnace cement and wrap to stop exhaust leak, just can't bring myself to tear it all apart for one leak.... I know we discussed leaks before.... 1 Quote Fun is what they fine you for!My name is Bob Buckman sir,. . . and I hate truckers. Link to comment Share on other sites More sharing options...
AZB755V8 Posted September 30, 2015 Share Posted September 30, 2015 Lookin at your profile page you have a 1005 which is a early E9. I have both 866 and E9's. My 866 has the large head bolts and the E9's have the small but mine are 1990's vintage E9's. The fact is that your engine has been worked on and has a mix of bolts. Mack is know to change spec at any time.Looking in the overhaul procedures manual it looks like both sizes of head bolt were used on the E9 but only one torque spec. That indicates the same size bolt but with a different head size. Head bolts have been a problem from the beginning and should be replaced when the head is pulled. The small head bolts are the only ones listed now. I wouldn't worry about it until the head is pulled the next time. Don't fix it until it's broke. 2 Quote Link to comment Share on other sites More sharing options...
Outbehindthebarn Posted September 30, 2015 Author Share Posted September 30, 2015 Lookin at your profile page you have a 1005 which is a early E9. I have both 866 and E9's. My 866 has the large head bolts and the E9's have the small but mine are 1990's vintage E9's. The fact is that your engine has been worked on and has a mix of bolts. Mack is know to change spec at any time.Looking in the overhaul procedures manual it looks like both sizes of head bolt were used on the E9 but only one torque spec. That indicates the same size bolt but with a different head size. Head bolts have been a problem from the beginning and should be replaced when the head is pulled. The small head bolts are the only ones listed now. I wouldn't worry about it until the head is pulled the next time. Don't fix it until it's broke.Best guess would be that those 'newer' bolts were used to replace broken bolts? I've heard that broken bolts have been a problem.... Quote Fun is what they fine you for!My name is Bob Buckman sir,. . . and I hate truckers. Link to comment Share on other sites More sharing options...
Yoos Brothers Construction Posted October 4, 2015 Share Posted October 4, 2015 The bigger ones are original for the age of your truck. Generally head bolts break when the head gasket starts leaking antifreeze and the antifreeze gets under the head bolt and pops the head off. Quote Link to comment Share on other sites More sharing options...
Outbehindthebarn Posted October 4, 2015 Author Share Posted October 4, 2015 The bigger ones are original for the age of your truck. Generally head bolts break when the head gasket starts leaking antifreeze and the antifreeze gets under the head bolt and pops the head off. I have heard that they should be changed every time a head is pulled.... I know this engine has been apart, but they must have reused most of the bolts. As a course of preventative maintenance should that be a concern for a truck I'd like to put to work? Quote Fun is what they fine you for!My name is Bob Buckman sir,. . . and I hate truckers. Link to comment Share on other sites More sharing options...
Back In Black Pulling Posted October 5, 2015 Share Posted October 5, 2015 I have heard that they should be changed every time a head is pulled.... I know this engine has been apart, but they must have reused most of the bolts. As a course of preventative maintenance should that be a concern for a truck I'd like to put to work?I Was told to replace head bolts at 700,000 Quote Link to comment Share on other sites More sharing options...
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