fjh

When you pulled the heads the fire rings looked to be in the correct location right? can you post a picture of the top of the liner ?If you look at the top of the liner does it look as it could use the stepped ring?Is there an odvious step ? If new liners were installed as the directions state the liner has one narrow high spot in at the middle of the outer flange That high spot has the same heigt either side of the ridge that ridge cuts its self into the ring as the head is tighted down !You'll notice there is grooves cut in the head as well make sure thous are clean. Also check the heads for cracks at the ends near the freeze plugs. If you get the new gaskets get them from a dealer have them pull up the tsb service buliten for the steped fire ring! Damit this is a real pain wish this guy had left the heads alone there was no need to pull them! When you get the new gaskets install them on shiney clean surfaces block and head I use hitack spay on both sides of the gasket as an extra safety but not nessary.Chances are because the job was so halfassed the first time once the gasket leaks like that its impossible to seal it properly!

If its not a head gasket I beleive you'll find you have cavitated block not totaly un heard of on these older engines!Pull the side coves that should tell the tale!

Mack Canada demo unit I beleive. just doing the mods for the show.so far. So far we've lowered the turn outs 4 inches to tighten the ugly gape at the top and we are installing a raised bulkhead rack behind the cab all decked out with stainless trim! should look cool.I hear also it wll be geting some bigger paws for the steer axle.The small skins arent usful here with our dumb road laws.

Just a note we got the truck today !Its quite the unit! It has some oddities thou the cab mounts on the front are strange and the tail frame makes no sence what so ever for what needs to be done! good news is theres some big logs left! I'll try post some finished pics before it goes to the truck show here!I beleive this is to be a Mack Canada demo unit when its completed!One thing for sure if you want to torcher test somthing It came to the right place .

Couple of things! Your going to have to pull the heads anyway! I kind of think you may have the wrong fire rings having said that if the engine has had new liners installed at some point the rings will be wrong for sure, one or more has come dislodged while asembling Or as I stated the fire rings came doubled up in the package one mre thought is were never removed from the get go from the liners the first time!?

Why did he pull the heads to do the cam? Where exsactly is the coolant coming from! between the heads .the sides rear. 16 - 20 hours to do a cam job in the back yard is more than enough time weeks of time is rediculus! i have see the gasket come packaged accidently with an extra fire ring! Also in that era there where two diffrent style fire rings for two diffrent style liners!are you sure you got the corect ones

Its been my observation that your better off to replace with a used leaf rather than new unless your replacing the stack. IF you can find one.

Yup! Herd we might be getting it soon just roumors thou. They better get it here fast the big logs are almost all gone!

I beleive if they could have ,they would have!But that would have opened them up to law suits!Too many just mack dealers! If you had the volvo and the mack line you would have to keep your trap shut!But if you had Just the MacK line then you would have lots of amo!They will likly starve the dealers for parts and do other things to make it not worth while to be a macK Dealer!They will get it done!

Yup By pass the trans cooler for now Change out the oil in the trans .run it for a day change out the oil in the trans once more install a new cooler or just leave it disconected!

injectors, pump, and turbo between the 400, 440, 450, and 500. Correct! There were some liner oring diffences on newer blocks.

I have to agree with this!Staying with the fuller would be likly alot less costly time and price wise! the 8 trans housing would likly fit the 18.

I have seen the tps cause power problems with out throwing codes but its very unlikly!

Yup like i said the short list!The trans housing for the mack and I beleive some older western stars also mount the same as the mack However the clutch arm is always beneth on a mack!

If you have the time to be down have your heads rebuilt by a reputable machine shop! Down side to that is mack heads have a one year warrenty I believe. Trans!Heres the short list , u need to replace the stick and air line stuff and the Mounts and clutch arm are another concern! A lot of little stuff to think on!

I will say this one more time!!! THE TURBO CAN COME OUT OF TUNE and Will not throw a code Have it recalibrated and make sure its going full stroke!Have em watch the lever and push it full stroke if need be!The computer remebers the stroke in the recal sequence.Have em use the advance display in the vmac 4 program and make sure the egr flow and turbo are reaching their targets! The two wire plug you speak of throws a 270 code if faulty (compressor discharge temp code.)

Go to a dealer have em recalibrate the VGturbo and clean out the egr cooler if its not been done latly! see if that will help!

Do you have two sticks Or air shift for deep reduction? The front section can pop out of gear if its air shift and you won't be able to tell!The shift fork is likly worn! the trans has to come out to repair this !I would pull the drain plug and see if you got any peices coming out , ball bearings are the most common failure on a 12 sp

Just proove out what and if you have a problem !Disconect the line to the bimboe on the fuel pump cap it off and run it with a load and see if you power is better on hills if so the reversing relay for the puff limit is likly fubared! The limiter may be working but incorrectly

Get on It Pal!The early bird gets the worm!

If its not going into the pan then its gong out the exhast or into the trans oil thru the trans oil cooler! odviously you preasure checked the system for External leaks?Checked the trany latly? Low liners is another comon thing in that era.Liners were set at low spec (19 thou) alot of the time low spec is to low as time has shown.460 HP engines had more problems with this than the lower HP engines!High spec is 29 thou! Alot of diffrence!

And stop full off!

COOL! Good find Monty What I liked about the challanger was it was mechanic friendly ! the hood fliped straight up out of the way not butterfly like the mack and hayes and pacific! the engine was on a crate inside the frame on the first model and the engine and trans could be pulled as a lump out the front on its own engine stand so to speak.John was sort of a Wrench him self so he new the things needed to service properly.

There aint nothin left on the thing thats mack now anyway No one would want it! the only thing on the truck now that is truly mack is the cab + Hood!You can still get the diffs and trans but for how long who knows.The hydralic clutch linkage to be added shortly is next!We still got a cable something that works and is adjustable ,We can't have that!

Your welcome and yes the favorite engine was 12 71, I had the opertunity to do a V8 transplant on one of these made it a ture mack e9 and a 12 sp all but maybe 2 were born with 12s the others had KT cummins special order ,husby forest still runs some now with I beleive ser 60 repowers. Our shop handled or pdied most of these units there where a large amount of updates to do before they were put to work We modified fuel tanks, planitarys had a few glitches and the mack wheel lock was disposed of for a more tire man friendly setup.there where a bunch more tidleeys done to many to list! All In All second only to the challenger It was the best of the fat trucks! The guy that built th challenger was rumored to have sold the company and plans to the ausies for an ore hauler!They even hired his engineer. Rumors rumors!