fjh Posted September 28, 2023 Share Posted September 28, 2023 Just be careful here ! Before you get carried away ordering parts! Check your cam shaft and lifters before proceeding! I Have seen a failed lifter cause this issue! Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539411 Share on other sites More sharing options...
JoeH Posted September 29, 2023 Share Posted September 29, 2023 Time to see what's really broken and pull the head. Also pull the oil pan to get a look at the camshaft and lifters. The carbide faces on these like to break and shave the cam lobes down. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539433 Share on other sites More sharing options...
Popular Post mrsmackpaul Posted September 29, 2023 Popular Post Share Posted September 29, 2023 I must be more gung hoe than most The head would of been yanked of the motor weeks ago if it was mine Not to mind, to me it's pulling a bandaid off, you can stuff around but I reckon I'm best to see the bad or good news right away Yep, yank the head, roll the push rods on a sheet of glass Check the cam Work put whats what and put a plan together Paul 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539439 Share on other sites More sharing options...
JoeH Posted September 29, 2023 Share Posted September 29, 2023 (edited) My strategy is typically remove valve covers and oil pan to get eyes on all the internals. There is a fair amount of manifold work on this particular engine to get the head ready to come off, but it's gotta be done, whether he needs a valve or a head. I'd have that head off right away too, but I think RS is working through a mechanic, so there may be a DIY factor missing. Edited September 29, 2023 by JoeH 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539448 Share on other sites More sharing options...
RS Disposal Posted September 29, 2023 Author Share Posted September 29, 2023 On 9/27/2023 at 2:29 PM, Geoff Weeks said: Is this what you are looking for? Not cheap, but quick way out. https://www.vanderhaags.com/detailview.php?part=24898211 Now that definitely looks like what I am wanting. I will have to give them a call. Going to try and get the head pulled this weekend to access the damage and to decide where to go from there. I really appreciate the link Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539450 Share on other sites More sharing options...
RS Disposal Posted September 29, 2023 Author Share Posted September 29, 2023 On 9/27/2023 at 9:47 AM, Joey Mack said: Try Agkits.com, raneys truck parts, or just use Google to find a P.A.I. vendor... you may get what you need.. Talked with P.A.I and they said they no longer offer thhis particular head, but on the bright side they do still offer pistons if I need one Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539451 Share on other sites More sharing options...
RS Disposal Posted September 29, 2023 Author Share Posted September 29, 2023 1 hour ago, JoeH said: My strategy is typically remove valve covers and oil pan to get eyes on all the internals. There is a fair amount of manifold work on this particular engine to get the head ready to come off, but it's gotta be done, whether he needs a valve or a head. I'd have that head off right away too, but I think RS is working through a mechanic, so there may be a DIY factor missing. I was trying to work thru a shop, but nobody seems to really want to work on this older truck because of the availability issue of parts, so they aren't working too hard in sourcing the said parts. I didn't want to get it to a shop and have them tear it down and then tell me that they are unable to do anything. So I am going to pull the head myself. I'm just a one man show and with my backup truck out of commission being hit by a drunk driver, It's been really time consuming servicing my customers. Truck only has about 150,000 mile on it so hoping lifters and cam are ok. Truck was running great before the mishap Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539452 Share on other sites More sharing options...
Popular Post RS Disposal Posted September 29, 2023 Author Popular Post Share Posted September 29, 2023 Right now I want to take a minute and thank everyone who has given me insight and point and possible sourcing of parts. Being a one man show, as was my dad, I can be a little stubborn when it comes to asking for help. I will post my progress and what I find. Pretty sure I will have more questions. I am a light truck/automotive mechanic so this is my first heavy truck engine to tear into. So far have had no problems doing my own work on power train, suspension and steering on my trucks. 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539453 Share on other sites More sharing options...
Joey Mack Posted September 29, 2023 Share Posted September 29, 2023 I know I can relate to you.. I ran a mobile truck repair SVC. For 13 years, I too was a one man show.. there are a lot of us here that are willing to guide you. Heck, one of us may be close to you, and may know of some locals resources.. Stick around... Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539455 Share on other sites More sharing options...
JoeH Posted September 29, 2023 Share Posted September 29, 2023 (edited) My first "tear in" on an engine was the same motor you have there, same year and all. Our '79 broke a valve seat and it dropped into the top of the piston, ruining the head and piston. Similar business size, it's just my dad and I plus my cousin seasonally, so I can relate. Get the head off and see what's really broke. Many of us have the books with torque sequences and settings, so we'll post info for you as needed. Remember though, DONT SET THE HEAD DOWN ON THE INJECTOR NOZZLES! Edited September 29, 2023 by JoeH Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539461 Share on other sites More sharing options...
JoeH Posted September 29, 2023 Share Posted September 29, 2023 (edited) If you can't get exhaust manifold nuts off, just split them with a hammer and sharp chisel. The water & intake manifold bolts require some tight access to get into, and I believe the intercooler box lid has to come off to get to some bolts on the inside. Edited September 29, 2023 by JoeH Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539462 Share on other sites More sharing options...
Geoff Weeks Posted September 29, 2023 Share Posted September 29, 2023 Before you pull the trigger on a rebuilt head, look and see what can be found in "running core" or used engines. If you have a place to work and store indoors, a spare engine is always handy. I purchased a running core that needed a water pump and a little freshening for less than the head cost. It did turn out the engine needed a fuel pump (855 Cummins) but it ran up and down the road as installed. Point being having a whole engine, even if it needs work, can be helpful to have a ready at hand set of cores to send off or repair yourself. I spent the last 30 years, being a sole proprietor, and almost exclusively doing my own work. Having back-ups so to not disappoint customers when the un planned for happens can be worth the cost. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539463 Share on other sites More sharing options...
RS Disposal Posted October 4, 2023 Author Share Posted October 4, 2023 I finally got some spare time to start pulling this head off So far I have been able to get all the bolts etc and being 2 piece manifolds only needing to pull the back half. Did pull the entire exhaust though. Only thing I can seem to get loos are the hard fuel lines from the pump to the injectors. Got the injector end no problem but the pump end won't budge and don't want to round off the nuts. It doe look like I can snake the head off being the lines do have a fair amount of movement. I know I have problems with #4, but when I pulled the exhaust manifold I had oil run out of both 4 & 5 ports. Ports 1 - 3 look good, dry and just black soot so it look like I'm dealing with just the rear head. Again, I want to that everyone here for their support and suggestions. Like I have mentioned before, I'm a light truck mechanic and have been twisting wrenches from about the age of 6 with my dad, and this is my first heavy truck engine tearing into. I will post here my progress and what I find. Anybody feel free to send guidance and or tips etc. I'm not too proud and know when to ask for help. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539714 Share on other sites More sharing options...
Joey Mack Posted October 4, 2023 Share Posted October 4, 2023 I have 1 suggestion for when you put the head back on...... find some 5/8'' threaded rod and cut 2-4 pieces long enough to stick above the heads to use as guide bolts.. Head gaskets arent cheap and since you had to 'snake' it out, you will have to snake it back in.. there are 2 small 1/4'' deck dowels that stick up a 1/4''. if they are good and round, leave them alone. If you have to remove them you can use a claw hammer. place a small piece of sheet metal on the deck for protection, and place the claw end on it. Then gently drive the hammer into the pin with another hammer and pry the pin out.. they do not require a lot of force.. the pins are in stock at Mack.. Jojo Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539720 Share on other sites More sharing options...
RS Disposal Posted October 5, 2023 Author Share Posted October 5, 2023 (edited) On 9/26/2023 at 12:56 PM, RS Disposal said: My heads are 18 bolt Actually they are 20 bolt. 2 bolts I couldn't see when counting were under the rocker arm Edited October 5, 2023 by RS Disposal 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539751 Share on other sites More sharing options...
RS Disposal Posted October 5, 2023 Author Share Posted October 5, 2023 8 hours ago, Joey Mack said: I have 1 suggestion for when you put the head back on...... find some 5/8'' threaded rod and cut 2-4 pieces long enough to stick above the heads to use as guide bolts.. Head gaskets arent cheap and since you had to 'snake' it out, you will have to snake it back in.. there are 2 small 1/4'' deck dowels that stick up a 1/4''. if they are good and round, leave them alone. If you have to remove them you can use a claw hammer. place a small piece of sheet metal on the deck for protection, and place the claw end on it. Then gently drive the hammer into the pin with another hammer and pry the pin out.. they do not require a lot of force.. the pins are in stock at Mack.. Jojo I was actually able to tie the injectors tubes back no problem and lift the head straight up and off the dowels. They are in good shape. #4 piston is destoryed but no surprise there. Going to take head in to machine shop to see if they can rebuild. I know right off hand after inital inspection that it will need 2 valves, exhaust valve guide and seat and an injector. I am thinking that this damage wasn't necessarily caused by valve float. Leaning more to the fact the valve spring keeper broke, still probably caused by overspeed on engine, which allowed the exhaust valve to drop and strike the piston and break. Just my thoughts. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539752 Share on other sites More sharing options...
RS Disposal Posted October 5, 2023 Author Share Posted October 5, 2023 On 9/29/2023 at 9:28 AM, Geoff Weeks said: Before you pull the trigger on a rebuilt head, look and see what can be found in "running core" or used engines. If you have a place to work and store indoors, a spare engine is always handy. I purchased a running core that needed a water pump and a little freshening for less than the head cost. It did turn out the engine needed a fuel pump (855 Cummins) but it ran up and down the road as installed. Point being having a whole engine, even if it needs work, can be helpful to have a ready at hand set of cores to send off or repair yourself. I spent the last 30 years, being a sole proprietor, and almost exclusively doing my own work. Having back-ups so to not disappoint customers when the un planned for happens can be worth the cost. I haven't had any luck so far in finding a used head as of yet, but honestly haven't spent a lot of time in that direction yet. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539753 Share on other sites More sharing options...
RS Disposal Posted October 5, 2023 Author Share Posted October 5, 2023 On 9/27/2023 at 8:29 AM, 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? Got the head off. Goping to take it to the machine shop and have it check. Needs at least both #4 cylinder valves and at least one seat and valve guide & an injector.. Piston is destroyed. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539763 Share on other sites More sharing options...
Geoff Weeks Posted October 5, 2023 Share Posted October 5, 2023 Pictures? Important to know WHY it happened, was the spring break a result of the collision or the cause? Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539764 Share on other sites More sharing options...
Joey Mack Posted October 5, 2023 Share Posted October 5, 2023 So you can use the head gasket part number I posted earlier.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539766 Share on other sites More sharing options...
RS Disposal Posted October 6, 2023 Author Share Posted October 6, 2023 On 9/29/2023 at 6:49 AM, RS Disposal said: Now that definitely looks like what I am wanting. I will have to give them a call. Going to try and get the head pulled this weekend to access the damage and to decide where to go from there. I really appreciate the link As with everybody else that shows the head on their website, It isn't currently available Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539808 Share on other sites More sharing options...
RS Disposal Posted October 6, 2023 Author Share Posted October 6, 2023 (edited) On 10/5/2023 at 9:11 AM, Geoff Weeks said: Pictures? Important to know WHY it happened, was the spring break a result of the collision or the cause? My machine shop agrees with what I feel was the cause. Keeper broke and caused valve to drop and hit piston. From wear marks and the way the keeper broke it appears the valve stem wore to the point the rocker was hitting the keeper resulting in it breaking. Obviously the piston is destroyed. Machine shop says if head cracked there is a company they deal with that specifically specializes in repairing cracked diesel heads. Not cheap but at this point my only option is to have this head rebuilt. Hoping to find the time this weekend to get the pan pulled Edited October 6, 2023 by RS Disposal 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539809 Share on other sites More sharing options...
Geoff Weeks Posted October 6, 2023 Share Posted October 6, 2023 If it were me, I'd be shopping for a core engine. Preferably a "running core". I have had one "repaired" head, and it failed. 6-71 that had a head crack. I know Cummins are fairly easy to find, I don't know about Mack's of that vintage. $1300-$1500 is what I paid. With the core engine, you get two heads, and plenty of other spare parts. I don't think you'll find a head for that. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539810 Share on other sites More sharing options...
JoeH Posted October 6, 2023 Share Posted October 6, 2023 Wow that's some carnage. I'd say you need a head. Here's a piston from my '79 R686 that dropped a valve seat. Bits of the seat are embedded in the piston. Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539812 Share on other sites More sharing options...
880joe Posted October 7, 2023 Share Posted October 7, 2023 2 hours ago, JoeH said: Wow that's some carnage. I'd say you need a head. Here's a piston from my '79 R686 that dropped a valve seat. Bits of the seat are embedded in the piston. Would a head from a 84 or 85 2 valve e6 be the same? Quote Link to comment https://www.bigmacktrucks.com/topic/73314-looking-for-1979-mack-engine-head/page/2/#findComment-539819 Share on other sites More sharing options...
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