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Category: Heavy Equipment
Satisfied Customers: 3621
Experience:  16 Years working on Cummins Diesel engines,
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Trying to set the timing on cummins big cam 855. Fairly certain

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Trying to set the timing on cummins big cam 855. Fairly certain that we have timing tool set up correctly. If we install maximum gasket shims allowed (0.081 ") and an offset key on camshaft gear it still would only work out to 0.050" push rod travel and we have to be at 0.070". Any idea of something we could be doing wrong or some problems to look for on the motor?
hello have you ever attempted this before? You need to be 100%positive the timing tool is installed and set up correctly. what did you change in the engine that the timing has to be reset? what was the number on the old gasket?
Customer: replied 6 years ago.
The engine has a different block. The gaskets on the old block were 0.034" (2x0.017"). Installed the gaskets the same as before and only had 0.030" push rod travel. As far as the set up of the tool we just followed what it says in our cummins engine manual. No, we have never done this before.
This is a PIA i could be here all night, I suggest you start all over. Making sure all is set right. are you on the compression stroke (both plungers will move up at the same time when you are)and in either 1 3 5 cylinders? and rotating clockwise at you at 90 deg after tdc? it is (marked on the tool (nh-nt).
Customer: replied 6 years ago.
We have started all over 3 times and always get the same result. We are on the compression stroke and have done the number 1 and number 3 cylinders. When you say rotating clockwise you mean when you are standing on the gear case side facing the engine. That is the way that we have been doing it. PIA???
PIA = PAIN IN THE ASS i have seen guys take hours to get this right. Its not easy to do and even harder to talk someone thru it. what or should i say where did you get the block what was the part number? any of these?3050471 ---3060622------(NNN) NNN-NNNN----3081283-------3801743
i'm asking because you should not have that much trouble you install the same thickness that came off and start from there. There is not anything you could of done to the motor to affect this.GO TO PAGE 196 IN YOUR BOOK LOOK AT THE OFF SET KEY CHART THIS MAY HELP YOU.
Customer: replied 6 years ago.
The number stamped on the block we got is(NNN) NNN-NNNN We got the block from the shop that supplied the rebuild kit. The timing offset key, they have several to retard, and only one to advance. Even with that installed plus the maximum number of shims would not give enough push rod travel. Does not make sense how we can be this far out of adjustment. We did use the same thickness of gaskets as we took out initially and with that we were only at 0.030". Can you think of any other possible issues that may affect the timing this much?
Cylinder Block
Base Parts for 855 series Industrial Engines with low Volume Piston Cooling has Soft Block. NOTE: The(NNN) NNN-NNNNCam Follower must be the Front Follower Assembly on Block.

Block, Cylinder
1 (NNN) NNN-NNNN Block, Cylinder 1

Well from i can see you have the wrong block for the application. because i can see your engine doesn't use that cam follower. I would call the place that sold it to you and have them run your engine serial number and see what the part number for the block is suppose to be. The only logical reason that i see is that your taking a timing code from the 11310701 serial number and trying to use the FI code on a different block. common sense. hence different timing codes for different applications.
Customer: replied 6 years ago.

So to clarify, the cam followers from my old block will not fit my new block? Or do we just need a different timing code for the new block? Old block serial # XXXXX New block serial # XXXXX there is no data plate on the new block and that is why we used the timing code from the old block. We would call the shop we got it from but is a holiday here and they are not at work until tomorrow and we are behind on this job anyways. Anymore help that you can offer will be greatly appreciated. We will pay you a more reasonable rate because this has gone over a $20 question.


yup i was right wrong block in fact wrong engine all together look while i get you the correct timing code. not sure the followers will work ill keep researching
Engine Serial Number 11414059
Shop Order # SO38158
Plant CEP - Columbus Engine Plant
Build Date 18 Jul 1987
Warranty Start Date 05 Feb 1988
Customer Number 1374
ECM Code Not Available For This Engine
Fuel Pump Part #(NNN) NNN-NNNN
Fuel Pump Calibration 9364
Film Card F
Engine Config # D093437CX02
*****CPL # CPL553
Marketing Model Name NTA-855-C360
Service Model Name NH

old block

Engine Serial Number 11310701
Shop Order # SO20671
Plant CEP - Columbus Engine Plant
Build Date 04 Nov 1985
Warranty Start Date 24 Dec 1985
Customer Number 56200
Customer Name XXXXX XXXXX
ECM Code Not Available For This Engine
Fuel Pump Part #(NNN) NNN-NNNN
Fuel Pump Calibration 9239
Film Card F
Engine Config # D093511BX02
******CPL # CPL676
Marketing Model Name NTC-400
Service Model Name NH

Edited by DR.Cummins on 8/2/2010 at 8:55 PM EST
this timing code is BU -.065 is the timing code. for the newer block, and that application cam followers part number is(NNN) NNN-NNNN (updated) and are the same but the block is only for industrial applications. not sure what parts your using over but i hope you have all the correct parts for this engine and not a mix of 2 different engines

Edited by DR.Cummins on 8/2/2010 at 9:22 PM EST
DR.Cummins and 3 other Heavy Equipment Specialists are ready to help you
Customer: replied 6 years ago.

We are using all the parts from the old engine. The only new part is the block. So the cam followers we have from the old block are(NNN) NNN-NNNN Do we need to get the(NNN) NNN-NNNNcam followers to make this work?

no that number is XXXXX for the followers i just dbl checked
I'm not seeing anything else that would stop it from getting timed correctly. are you sure your reading the gages and doing the steps to a tee if that tool is cocked a bit it will throw all off.
Customer: replied 6 years ago.

We tried it all again from the start and got the same results. We are stumped. I guess we'll just have to wait until tomorrow and call the shop we got it all from. Thank you for all of your help.