Do your own timing?

['956Wheel]

Time at 90 BTDC,run it backwards

MGM, I was hoping you would chime in with words of wisdom. I will continue to do so.



Your friend,

Mike

 

[Sled Puller]

Originally posted by Don M

MGM,



I take it you are not concerned with the long term effects of high timing on engine bearings?



Don~

Well Don,

From the race engines I have seen tore down, I am not concerned with bearing wear.

Although I do not have the gold dyno sheets, these engines were well over 700 hp, and did not show extreme wear. When you consider the timing they were running, plus the other extreme factors, I am not concerned about bearing wear with timing around 20. I was at 16 for 2 years.





Oil samples will tell the tale, I have one coming back this week.

If you have a good engine oil, it will take the extreme pressures and not be squeezed out.



Trust your Cummins!

 

[Reddog1]

JoeG,



You forgot to tell the guys about the plastic magnet used to remove the broken timing pin. I just had to say it.





I had a hard time getting the pin to engage. I thought it was sheared off. I worked it in and out several times, it definitely loosened up, and then it went in. Kind of like sex.



I guess if someone had not done the KDP fix, and they had a sheared pin, this would be a good time to do the tab fix.





Wayne

 

['956Wheel]

Magnet??

If one were to break the timing pin off how would you remove the piece? I was thinking pull the pin at TDC, spray contact cleaner on the piece in the hole (hopfully its there) and put a dab of superglue on a dowel and try to get it to sticc to the piece.



Mike

 

[Joe G.]

Mike,



Wayne is just pulling my leg... . AGAIN!

 

['956Wheel]

yeah but Joe

Joe, I remember in this thread you mentioned a brass timing pin that you made and use... did the OEM pin go bye bye?? If so would one have to pull the cover off... deja vu KDP tab fix?



Mike

 

[Joe G.]

The stock pin is ok. I just found it a PITA to work with. The pin I made protrudes from the hole about four inches and it's the treaded part of the brass bolt so it's easy to grip. I have no idea what to do about a sheared off pin.

 

[Jeff H]

If you really wanna find true TDC. Pull # 1 injector. Stick a dial indicator where the #1 injector goes. You will be measureing the travel of the piston. When the dial stops moving you should have found tdc.

 

[LarryB]

Problem is the crank can rotate sometimes 2-3 deg. and the piston won't move because the bottom of the rod is moving horizontal. You need to measure both sides of the stroke equally down from tdc and split the difference to find accurate TDC. You can use a dial indicator for ths too.

 

[Joseph Donnelly]

The stock timing pin is plastic and the plastic tip can shear off, It isn't a tight fit in the cam gear hole so would probably fall out easily. You can take such a pin, or cut the tip off a pin, and drill it for the end of a large nail. Round off the nail and drill the hole just a bit off center. Then you can find TDC by rotating the new pin. the sharp end makes it easy for the pin to drop in and after you locate TDC once, put a paint mark on the dampener in line with the tach pickup.



Removing the stock pin can be a bit hard as there is a star washer gripping the inside of the timing pin housing to hold it in. The coat of paint from the factory plus the 0-ring on the pin seem to hold it just fine without the retainer.



If you have the KD tool for valve springs, remove the rockers for #1, pick the #1E (easier to get to than #1I), compress the spring some, and put a dial indicator on the top of the tool. As mentioned before in this thread, roll through tdc. Put a piece of masking tape on the dampener and a pointer to it (I go underneath for this part). Roll through to determine the max rise of the piston on the dial indicator. Go back say . 020", then roll forward to say 0. 015 and carefully pen a mark on the tape. Roll through TDC to 0. 015" after TDC and make another pen mark. Use your calipers to measure the distance, and make a mark at exactly half way. Roll back more than needed and then forward to tdc. See if the pin is centered in the hole--there the offset nail/pin helps you see it. If you carefully file the taper on the end of the nail, you can get it to where fully inserted it will just rotate 360 degrees when the cam gear hole is centered over the timing pin housing hole. The timing pin housing can be moved around by loosening the two bolts that hold it to the gear housing. The bolts are M5 x. 8 and take a T25 Torx bit.



Retorque the head bolt holding #1 rockers to 120 ft lb, and the little bolt to 18 ft lb.



I recommend going in forward direction only above because of slop induced by bearing clearances, etc. Also, the valves are dead perpendicular to the block face and hit the pistons square, so a mild "bump" shouldn't hurt anything. The method above avoids the bumping, of course.

 

[Reddog1]

Mike,



Looks like Joe G. PMed you on his plastic magnet.



Joe G. ,



You are right. I hope you guys don’t get angry at my sense of humor. I find life is just too serious to take serious.





As I recall, the repair manual says the pin will fall into the gears, requiring the removal of the front cover. I guess it could be ignored, it is only plastic. I would be a little concerned with zero clearance between the gears , even if it is plastic. If the piece were still in the cam gear, I would think Mike’s version of the plastic magnet would be worth a try.



I have encountered more than one person that did not consider the piston dwell that LarryB pointed out.



On finding TDC on our engines, I cannot speak from experience. I would think the various methods used on gas engines could be used. Jeff H has offered an abbreviated version, which I would be comfortable with, measuring before and after TDC.



Joseph Donnelly’s method is unique to our engines and includes the pin.



Guess it depends on what you are after.









Wayne