• Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

93 mack e7 camshaft timing

thepumpguysc

Senior Member
Joined
Mar 18, 2010
Messages
7,445
Location
Sunny South Carolina
Occupation
Master Inj.Pump rebuilder
If it has a "dyna-tard" on the front of the pump?? THAT maybe the cause of your troubles also..
I've had my fair share of those pieces of sh!t..
Does it POP, SKIP & GREY SMOKE like its lacking fuel?? at about 13-1500 & upwards??
 

63 caveman

Senior Member
Joined
Nov 11, 2017
Messages
340
Location
western Pa.
No it smokes and misses at low RPM (below 1800) and gets a bit better when up to normal running temp. but never clears up the way it should. It will not surprise me if there are two or more things wrong causing the problems. This truck has less than 200k on the clock and I think it was the ugly step child of the fleet since new. I'm not a truck driver by trade but have driven a couple of these e7 400s and they pull good when running right, hell a lot of guys are happy with them running with a 25% derate.
 

63 caveman

Senior Member
Joined
Nov 11, 2017
Messages
340
Location
western Pa.
Just in case someone finds this thread I want to report my findings.

I pulled the timing cover and found the cam timing to be correct! All was not a waste of time because after cleaning the cover I discovered it was cracked. After repair (mack price new was over $700) and new seals everything went back together nicely. Pulled the engine and pump position sensors and cleaned and reinstalled them. Went through the wiring and cleaned up the connections, started the engine and no smoke, leaks, or engine malfunction light; So you see blind hogs do get acorns!

NOTE: Talking with the Mack service manager he showed me a page in the Mack "E tec" engine manual that shows they take .100" off the "base circle of camshaft on exhaust lobes for better oiling" but could not remember if the E7 engine were the same.

I hope somebody finds this useful in the future.
 

thepumpguysc

Senior Member
Joined
Mar 18, 2010
Messages
7,445
Location
Sunny South Carolina
Occupation
Master Inj.Pump rebuilder
So, the valve lash was the actual problem{smoking}?? .070 on exhaust..??
Did u use the flywheel ref. marks to set them??
How did u turn the engine? socket on the crank, screwdriver on the flywheel or the actual engine barring tool ??
 

63 caveman

Senior Member
Joined
Nov 11, 2017
Messages
340
Location
western Pa.
pumpguy,
As I stated in response #24 "blind hogs do get acorns!" in addition to having the injectors checked (one popping off at low pressure) and adjusting valves (to timing marks on flywheel doing so while injectors were out so just turned engine over from front crankshaft hub bolt) and sealing up oil leaks (timing cover, crankshaft seal, and steering pump), I also cleaned up electrical connectors and sensors. So I don't know what was causing the troubles for sure. It would be nice to know what was the fix but for now I will take it for a win, maybe you should as well because the next thing may have been suspecting the pump and at that point I would have reached out to you!
 

thepumpguysc

Senior Member
Joined
Mar 18, 2010
Messages
7,445
Location
Sunny South Carolina
Occupation
Master Inj.Pump rebuilder
I don't know why but I'm gonna ask anyway..
Were the valves really off by that much.. or were u reading it wrong {the wrong point on cam}
You know what I was gonna suggest & u might be tempted call BS on this.. BUT.. The TEM that screws into the side of the inj. pump.. where the pointer is.. will cause all sorts of trouble if its not installed correctly/at the correct depth..
It happened to me "1" time.. I set it by the "book".. "screw in till it touches the pointer & back out 1/2 turn."
It white/gray smoked like it was on fire.. I just got done w/ the pump AND injectors..& it came in for a LEAKING pump & low power..
The old foreman came out & I walked him thru the timing & the TEM setting.. He looked at me & laughed..
He grabbed an adjustable wrench, loosened the lock nut, turned the TEM "IN" exactly 1/4 turn..
The smoke cleared up & it ran like a scalded dog..
I wondered WHY he kept asking about the TEM?? He said, YOUR SURE u went 1/2 turn?? Your ABSOLUTLY SURE?? YUP, 1/2 turn, just like to book said..
IF I had been lieing we woulda found out REAL QUICK.. That pointer woulda smashed the hell outa that sensor.. it woulda definatly bent the pointer & probably cracked the gov. hsg..
But just turning that sensor IN 1/4 turn solved all the problems..
THAT was real early in the E7 series.. NOW they have a "stop" on the new sensors.. its not completely adjustable like the old ones..
Real happy that u solved your running & leaking problems.. Keep on truckin'..
 

63 caveman

Senior Member
Joined
Nov 11, 2017
Messages
340
Location
western Pa.
The lash was only a few thousandths off on the timing marks so I don't think that was the problem. I did however take the sensor out of the pump and clean and inspect it and put it back (as you say 1/2 turn out) so it could have been the problem not being set right.

Normally I try to troubleshoot a problem before taking stuff apart but this all started when the owner asked me to pull the injectors and have them tested. I also avoid mack/volvo engines because I just don't know much about them.
 
Top