2000 ch 427 hp low boost

[Mackvette1]

Hello was wondering if I could pick your brain...recently took this truck from 350 to 427 using correct part numbers  on the injectors and turbo , set the valves while is was there and had mack dealer reprogram Ecm.  Truck has only 320000 actual miles on it...before it would only make 19 to 21 lbs of boost regularly.  Now it only makes 20 to 22 lbs regularly.  Truck runs ok but not a power house.. I feel like there is more power there by changing intercooler maybe? Or maybe cleaning a check valve ? Also last 6 of the vin 125886 maybe there’s a data file upgrade?

thanks 

[fjh]

You may be able to change the data file how ever you may have to change the cam key not sure mac pro may chime in on this! Its getting harder and harder to work with older units as the Volvo Turds are busy in the back ground trying to dis mantle the Mack infrastructure! By making it hard if not impossible to do many of the older unit programing sequences! hopefully Pro will chime in!

[880joe]

A pre CCRS engine would need the cam key changed

[Dirtymilkman]

Sounds like possible boost leak or not enough fuel pressure. 

[Joey Mack]

too bad theres not a peep hole in the timing cover to see what the cam key color is, or if it's a straight key.. He needs the "White side" out.... I wonder if you could get a scope inside throught the breather hole ?...jojo

[Vmac3]

Originally this engine had a straight keyway. If a horsepower change is done for this vintage of vehicle then an offset keyway is required. The white part of the keyway should be facing out towards the timing cover. Good idea Joey, if possible get a scope inside and see what the color is on that keyway. Unfortunately I highly doubt the keyway is offset, but its worth a try.

V

[880joe]

I'm surprised that mack dealer would put the 427 file in without changing cam. I tried having a 460 turned down to 355/380 and they wouldn't do it without changing turbo,injectors and cam. He must have a better dealer. Also I thought I read if you didn't change cam key it get hot if you didn't watch it close

[Mackvette1]

Mack dealer put the request in to mack headquarters and never mentioned cam key...ran the truck all weekend here and temp didn’t move off of 180 all day...what does changing the key way do ? Change the timing I assume? What will it hurt if not changed? Also my problem with low boost was there before I upgraded the horsepower.  Also truck is a 2000 amd I read somewhere you didn’t need to mess with key way in that year of truck but I don’t know for sure 

Edited April 26, 2021 by Mackvette1

[Joey Mack]

the offset key gives a 3 degree change. up to 300 HP the key was installed with the red painted side out. (retarded) 350 up to 400 was a straight key, 427 and up was the same offset key but turned around so the white side was out. (advanced)... I dont know when this change was eliminated. I was told here that it was around 2004........ I wish I could remember the procedure, where you bring the engine to TDC on #1 and roll it to 28 degrees and the #3 exhaust rocker is rocked. that tells you that the timing marks were lined up correctly... when i have time i will dig out my E-Tech book and look for it... jojo

[Joey Mack]

well I looked through my e-tech book and cant find the timing check procedure..  I may have printed it off, when I was at the dealership... Mabey Mackpro, V, or F, know this procedure to check cam timing. Instead of the rocker on 3 being rocked, i think i pulled the injector to check TDC on #3... anyway, there is a way to check timing.. I will stand back now and watch.. jojo

[fjh]

11 hours ago, 880joe said:

I'm surprised that mack dealer would put the 427 file in without changing cam. I tried having a 460 turned down to 355/380 and they wouldn't do it without changing turbo,injectors and cam. He must have a better dealer. Also I thought I read if you didn't change cam key it get hot if you didn't watch it close

I know for a fact if you go from 355/380 to 460 you will be short On boost by aprox 8 psi with the stock 460 engine file if the key is wrong ! Been there done that! and Joe never got involved in the cam check procedure ! found out by vins! and trial and error! 😡

Edited April 26, 2021 by fjh

[Joey Mack]

I remember having a 460 in the shop with a low power complaint, it was inframed 6 months prior. I had to pull heads due to a coolant leak at #6.  this job turned into a mess. I tried and tried to figure out the low power issue but didnt find the issue, and the cust didnt want to spend a bunch more money. this was where i found the procedure to check cam timing. the cam was timed in this engine. I will keep watching this thread. I too want to know the answer.. good luck, Jojo

[Vmac3]

I was digging through some old service bulletins and found this offset key bulletin. I will attach it. According to SB-213-018, the off set keyway changed the cam timing 1 degree/2 degrees on the crank from the straight keyway. In this case the engine would be 2 degrees retarded. Here is the procedure I found in a service manual. I copied and pasted it directly from the engine manual for an E-Tech engine.

Camshaft timing can be checked using either the
cylinder No. 3 or No. 4 inlet valve. For example
purposes, the No. 3 cylinder will be used in the
steps below.

1. Remove the cylinder head cover over
cylinder No. 3.
2. Locate the inlet valves for No. 3 cylinder (the
sixth valve set from the front of engine). Bar
the engine to position the No. 3 piston at top
dead center (TDC) of the compression
stroke.

3. Loosen (back off) the inlet valve rocker
adjusting screw jam nut. Ensure that the
valve yoke is correctly adjusted. Adjust the
inlet valve to zero lash.
4. Position a dial indicator (magnetic-base
type) probe on the valve spring retainer.
Preload the indicator to 1/2 indicator plunger
travel.
5. Bar the engine in the direction of normal
rotation and carefully observe the direction
in which the indicator needle travels. Use the
dial indicator to determine when the inlet
valve is fully open.
6. Stop rotating the engine when travel of the
dial indicator needle stops. If the dial
indicator needle reverses direction, the fullopen
position is passed. Repeat the
procedure if this occurs.
7. Remove the timing hole cover from the
flywheel housing so that the flywheel timing
marks can be viewed. Engine timing should
be approximately 26 degrees. A difference
of approximately 10 degrees indicates that
the crankshaft-to-camshaft timing gears may
be mismatched one tooth.

If an offset keyway is installed, then the engine would be 2 degrees +or-.

V

Sb213018.pdf

[Mackpro]

Only the pre-CCRS /ASET engines used the off set can key . Not sure if it causes low power but I know in a 2000 RD bumped  from 400 to 460 will over heat in the summer . I know cause I did it . Lol.  Winter And spring we’re ok but the summer heat was to much ,  putting in the off set key way fixed the overheating. 

Edited April 26, 2021 by Mackpro

[Mackvette1]

Thanks everyone...So what is the process of changing the cam key? 

[Joey Mack]

its basically the same as doing a cam job... sorry. I dont know if there is a gear puller that can pull the cam gear in the block, then good luck seating the 450 degree cam gear properly...   jojo

[Mackvette1]

Yesterday it seemed as air temps got warmer in the afternoon i was consistently lower on boost and ultimately power than in the morning....now this mornings ride to work the truck seems to be “normal” but still maximum of 24 lbs...just for the hell of it I took the check valve off on the return fuel side and inspected cleaned and put back in(didn’t find anything in there)...leaning towards changing the intercooler first before changing the cam gear since I was lower on boost before I didn’t the hp increase...t

thanks for input!

 

[Joey Mack]

did you pressure test the C.A.C. and intake manifold? if you have a one piece intake manifold, the gasket may be blown out near 5+6.... jojo

Edited April 27, 2021 by Joey Mack
More content needed

[880joe]

You're going to spend alot of money changing cam gear for a little bit of hp just my opinion. If it were me I would put the 355/380 program in it and leave cam alone a whole lot cheaper and same amount of torque

[Mackvette1]

Ya might be an option once I get the boost issue figured out...I did not pressure check it yet, also has 2 price manifold 

[fjh]

1 hour ago, Joey Mack said:

did you pressure test the C.A.C. and intake manifold? if you have a one piece intake manifold, the gasket may be blown out near 5+6.... jojo

 

Good point Joe ! We may have been side tracked by the original post thought!  how ever it should be trailing smoke under load and pyro should heat up quickly if a leak exists Just a another thought ! A stock 350 should make roughly  24 - 28 PSI boost ,a stock 427 somewhere around 30-32

Edited April 27, 2021 by fjh

[Mackvette1]

Also note that when air compressor is pumping I lose 1 to 2 lbs of boost

Edited April 27, 2021 by Mackvette1

[Mackpro]

The air compressor gets its fresh air from a hose coming from the back of the intake manifold. If the hoses or piping are leaking you will have low turbo boost , 

[Mackvette1]

Pressure check intercooler and found no leaks and it passed the leak down specs...so onto the air compressor intake pipe...plan to just use 3/4 inch hose to test it for a day and see what happens 

[OldRedMack]

2 hours ago, Mackvette1 said:

Pressure check intercooler and found no leaks and it passed the leak down specs...so onto the air compressor intake pipe...plan to just use 3/4 inch hose to test it for a day and see what happens 

Did you pressure test just the intercooler? Or the whole intake? Need to pressure check the whole system.  I take the air inlet pipe off of the turbo and pressurize the whole system, just bump the engine over till the valves close and it won't take much psi to find a leak.