RS Disposal Posted September 15, 2023 Share Posted September 15, 2023 My mechanic tells me that most likely I will be needing a head and possible piston/valves for my trk. It was inadvertently started with throttle wide open and now have a stuck exhaust valve on #4. Engine model # ENDTB 675 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/ Share on other sites More sharing options...
Joey Mack Posted September 15, 2023 Share Posted September 15, 2023 Has the head been removed? If he's a good E-6 2 Valve guy, then maybe you should listen to him.. When you can, post pictures of the head and any thing related to your question.. Welcome to the Dog Pound.... Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538868 Share on other sites More sharing options...
mrsmackpaul Posted September 15, 2023 Share Posted September 15, 2023 At the least I guess you need to pull the head before you go any further Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538870 Share on other sites More sharing options...
RS Disposal Posted September 16, 2023 Author Share Posted September 16, 2023 I haven't pulled the head(s) as of yet. Wanting to see if parts are available before I start spending money on an engine with no hope of repair Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538874 Share on other sites More sharing options...
Joey Mack Posted September 16, 2023 Share Posted September 16, 2023 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538875 Share on other sites More sharing options...
Joey Mack Posted September 16, 2023 Share Posted September 16, 2023 I have an ENDT 673 in my shop.. These are the gasket kit numbers to do a head job and full rebuild. I hope they are the same ones you need.. ''PAI'' is your friend on this one.. Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538876 Share on other sites More sharing options...
Joey Mack Posted September 16, 2023 Share Posted September 16, 2023 I know the head gaskets are, (20 Bolt heads) I bet the others are too.. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538877 Share on other sites More sharing options...
mrsmackpaul Posted September 16, 2023 Share Posted September 16, 2023 I think all parts, possibly including the head are still available Paul Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538882 Share on other sites More sharing options...
RS Disposal Posted September 16, 2023 Author Share Posted September 16, 2023 9 hours ago, mrsmackpaul said: I think all parts, possibly including the head are still available Paul Thats what I am hoping. I can do most of the work that needs done on the truck except engine work, hench why the head hasn't been pulled as of yet. Don't really want to have it towed to a shop and have them tear it apart only to tell me parts are no longer available. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538893 Share on other sites More sharing options...
JoeH Posted September 16, 2023 Share Posted September 16, 2023 Probably just a bent pushrod from valve float. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538896 Share on other sites More sharing options...
JoeH Posted September 16, 2023 Share Posted September 16, 2023 Our '79 has a weak valve spring on one of the heads, the spacer disk on top of the valve stem for the jake brake kept popping out, resulting in excess valve lash. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-538897 Share on other sites More sharing options...
RS Disposal Posted September 24, 2023 Author Share Posted September 24, 2023 On 9/16/2023 at 10:33 AM, JoeH said: Probably just a bent pushrod from valve float. I have pulled one roccker cover and #4 exhaust valve is stuck down (assuming bent). Push rod appears to be ok. The valve spring keeper was broken. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539195 Share on other sites More sharing options...
Joey Mack Posted September 24, 2023 Share Posted September 24, 2023 well, hopefully when you pull the head there isnt any damage.. That would be great.. if you dont have a valve, or cant get one, post the number from the valve head.. I may have some.. (used ones).. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539196 Share on other sites More sharing options...
JoeH Posted September 25, 2023 Share Posted September 25, 2023 8 hours ago, RS Disposal said: I have pulled one roccker cover and #4 exhaust valve is stuck down (assuming bent). Push rod appears to be ok. The valve spring keeper was broken. Sounds like a bent valve then. If you're lucky you just need a valve, don't need a head. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539214 Share on other sites More sharing options...
RS Disposal Posted September 26, 2023 Author Share Posted September 26, 2023 On 9/15/2023 at 6:10 PM, Joey Mack said: I know the head gaskets are, (20 Bolt heads) I bet the others are too.. My heads are 18 bolt Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539320 Share on other sites More sharing options...
RS Disposal Posted September 26, 2023 Author Share Posted September 26, 2023 On 9/24/2023 at 7:54 PM, JoeH said: Sounds like a bent valve then. If you're lucky you just need a valve, don't need a head. Pulled second rocker cover. everything there appears to be fine. I can twist the pushrods no problem. How much of a possibilty is it that I am going to actually need a head and a possible piston. Obviously I have one bent valve, but with light truck gasoline engines (I'm a light truck/automotive mechanic) subject to valve float/bent valve I have seen ones that didn't crack the piston Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539321 Share on other sites More sharing options...
Joey Mack Posted September 26, 2023 Share Posted September 26, 2023 Minimal chance of interference.. would be my guess. Is the valve bent or possibly gummed up? Just being hopeful here. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539322 Share on other sites More sharing options...
JoeH Posted September 27, 2023 Share Posted September 27, 2023 I'd bet your head is fine, and piston may have a tiny dent in it that needs to be deburred. When you take the head off, DONT set it down right side up, you will crush the injector nozzles! You will probably just need the one valve, maybe the guide, and maybe a valve seat? 2 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539344 Share on other sites More sharing options...
RS Disposal Posted September 27, 2023 Author Share Posted September 27, 2023 19 hours ago, Joey Mack said: Minimal chance of interference.. would be my guess. Is the valve bent or possibly gummed up? Just being hopeful here. pretty sure bent. When I grab onto it with a pair of pliers it doesn't move at all Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539346 Share on other sites More sharing options...
RS Disposal Posted September 27, 2023 Author Share Posted September 27, 2023 40 minutes ago, JoeH said: I'd bet your head is fine, and piston may have a tiny dent in it that needs to be deburred. When you take the head off, DONT set it down right side up, you will crush the injector nozzles! You will probably just need the one valve, maybe the guide, and maybe a valve seat? I am keeping my fingers crossed as to what extent of damage there is. Im just trying to source parts for a worse case scenario just in case. Looks like I need to go to the dealer and see if he can give me some part numbers. Nobody seems to be able to pull up anything on the truck from the VIN, which in the past with other parts the dealer has had no problem finding the trk thjru the VIN Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539347 Share on other sites More sharing options...
Joey Mack Posted September 27, 2023 Share Posted September 27, 2023 Try Agkits.com, raneys truck parts, or just use Google to find a P.A.I. vendor... you may get what you need.. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539349 Share on other sites More sharing options...
Geoff Weeks Posted September 27, 2023 Share Posted September 27, 2023 You will not know till the head is off. Not much room between the valve and piston at TDC. I have the head of a valve that broke off and planted itself in the piston crown on my wall of shame. Wasn't a Mack but a Leyland 680, which looks an awful lot like a Mack. I hope you get away with just a new valve, but I would be surprised if that is all it took. If you need to get the truck running ASAP, cost be damned, then get a head, have it gone through and a piston and tear into it. If you can wait, then disassemble and see what you need. I've "patched" a lot of engines where parts were not available, but it is never a quick process. If your loosing money every minute the truck is down, then sourceing used parts and new gaskets while they are coming tear the engine down is the way to go. IF the valve hit the injector tip, then you'll need one of those, but you can't tell until the head is off. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539351 Share on other sites More sharing options...
RS Disposal Posted September 27, 2023 Author Share Posted September 27, 2023 So far it looks like the head is no longer available (still looking though). Pistons and the associated rings, valves etc. are. Guess I need to pull the head and actually access the damage. Quick question, is there a trick to getting the exhaust manifold nuts off? Would it be a problem heating up the nuts? Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539355 Share on other sites More sharing options...
Geoff Weeks Posted September 27, 2023 Share Posted September 27, 2023 Try finding anything for a Gardner or Leyland in this country. Start calling yards, Even if you don't need one, finding out what can be had is money in the bank.ld If it were I, a used head, that can be re-worked, would be something I'd be looking for. It doesn't have to be new or rebuilt, just no cracks and good valves. There are my ways to repair guides and seats can be replaced. I guess it comes from working on old, orphan engines, you 1st look for what is available then go from there. Cracked heads can be repaired, but not cheaply. Rings can be ordered by size and shape, even if full ring sets are not available. Heat the nuts, slit the nuts, there are many ways to go forward. Look at what is important, The nuts aren't as important as the studs, and are easier to replace. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539356 Share on other sites More sharing options...
Geoff Weeks Posted September 27, 2023 Share Posted September 27, 2023 Is this what you are looking for? Not cheap, but quick way out. https://www.vanderhaags.com/detailview.php?part=24898211 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/#findComment-539357 Share on other sites More sharing options...
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