solog1977

On 8/24/2018 at 9:19 AM, fjh said:

On truck one you say the rockers are fine rule that out  I have  only 3 thoughts  The Valves were set wrong to start with if thats possible ! Or the cam gear has slipped on the cam its self never seen that happen.............. The valve guides were to tight of tolerance  when assembled if they are reman that is possible and have seen it happen! observation!

\As for truck two Judging by the work done my guess will been incorrect liner height !  low  spec is 22 which is borderline usable! in my opinion!  your allowed 00.2 thou between liners under one head This is some times hard to acheive when  shimming liners you need to sometimes drifit them several times to get it right I believe the guy who installed the liners didn't spend the time to check his work the finished product before the heads went on ! Have also seen this happen There are things the Book don"t tell you and this is double check your work BEFORE the heads go on A good liner height for these Is 24-28 anything in between or slightly above is OK! and the spec between liners should be strictly adhered to! Zero Variation is best In my opinion but not always attainable  This is where your issue lies in my opinion! Could be right out to lunch on this but judging from your comments its my guess!

 

Just my 2 cents!

2

Zero Variation would be my preference as well. I dont want anything coming back thru these doors once it leaves. We have 31 trucks in our fleet and all but 7 are RDs these steeringwheel holders are very hard on them.

I appreciate the input guy's, the truck with the pressure issue is on its 2nd set of heads. Originally I had reached the conclusion that a head was getting pressure from the turbo into a coolant passage, so we replaced both heads and went from there. The liner height is definitely a possibility I didnt stand over the mechanic from Transource that came down to help us out. Pai supplied the heads & we've gotten bad heads before so thats a possibility as well. (Id like to add its not overheating)

Far as the motor with pushrod issues, I pulled the front cover off and put eyes on the timing gears & it looks like the cam gear has slipped atleast for now it does, the pump gear has visibly slipped ive yet to pull the cam or cam gear off to check the key. Regarding the flywheel it is doweled but, (E7 manual lacks this) when the timing arrows at front are lined up the flywheel pointer is 20-30 degrees just past Valve setting marks 1&6. Shouldnt TC or some mark on the flywheel correlate with the engine timing marks? I tried to upload a picture of the cam & gears theres a paint stick mark on the cam & gear that has moved.

Truck#1

1996 Mack RD/690s

E7 300 Electronic Engine.

Bending Pushrods,

After converting from mechanical injection to electronic injection on a replacement motor, my former supervisor forgot an oil drain plug in the bottom of the econovance housing.

So the extreme buildup of oil caused the pump timing to advance wildly to the point where the truck would not start. In the attemps to start, starting fluid was sprayed and pushrods were bent.

We replaced those pushrods and found the plug, removed it and when setting the valves pushrods bent again.

Found binding springs in the heads and had heads remanufactured, replaced pushrods and yet again when setting valves the pushrods started to bind.

Camshaft appears okay, rockershafts look like they are moving correctly with piston stroke and cam lobes. Whats my next move, taking the front cover off and checking timing gears? Whats the chances of it jumping timing. 

Truck#2 

1994 Mack RD/690S 

E7 300 electronic

On this truck, coolant is pressurizing and blowing out of lower overflow (2 tank upper/lower).

I first replaced air compressor, then water pump & housing, new steel upper reservoir, radiator, then cyl heads, new sleeves & pistons installed because a couple had chipped where the fire rings seal, the coolant stopped pushing out for the first cpl days afterwards.

Because of a radiator hose blowing out it lost coolant, after repairing once again same ol problem more coolant pushing out, replaced air compressor with a higher end one hoping it was defective. It still pushes coolant out, theres no exhaust gas in coolant been checked 3 different times & if you run the truck with the radiator cap off you can see large bubbles constantly coming up and making coolant come out as the air purges which pressurizes the system. Im stumped my coworkers are stumped, I removed the pistons & sleeves, Mack came and installed the new sleeves/pistons. I know he checked the sleeve height, cant help but wonder if the blocks deck isn't right or if the water jacket pitting was too much. 

Anyhoo, any input on either of these trucks issues would be appreciated. 

Thanks! Solomon

After you press the on/off switch 3 times, do you set the idle speed via pedal or the accel/dec switch followed by pressing clutch?