Do your own timing?

['956Wheel]

Have any members ever timed their CTD? If so how did you go about finding "true" TDC? We have all seen posts regarding the lack of timing pin accuracy, so what would be the positive method of finding TDC of #1.



Mike

 

[Don M]

Once you pin that gear in your pretty dern close to TDC. Definantly close enough to time the engine. I hate trying to pin it up. Its a tough job to try to push on the pin behind the pump and bar ir over at the same time. Im thinking you may have been one rotation out when you tried to pin up. The mark on the balancer or wherever you put that dude, can be one rotation out and be 180 degrees off. This will make it impossible to pin. If I remember right the number one exhaust and intake valves are pretty close to fully open at 180 out. You may have timed it 180 out and gotten a bad reading on your dial indicator. That could explain the 16 degrees you found when you checked it and the way it runs now.



Try it again, but this time pin it up. That will insure you have the TDC for number 1.

Since your at it you could go ahead and run the valves too



Remember unpin it before you begin to time it. The pin is plastic, but it would be terrible to break it off and have to replace it.





Don~

 

['956Wheel]

PLASTIC PIN!

Don, One could easily shear a plastic pin... uggh. I thought of the 180 off and went a few times around and never got the pin to go in. I checked the timing with the #1 valves slack (closed) going by my former valve adjustment mark on the harmonic balancer.



Now ya got me wondering if I sheared the pin. Are you certain its plastic?



Mike



**The mark on the balancer was done some time ago with the pin in.

 

[Don M]

Yeah its plastic, Mine is anyway I had it out yesterday because I could not get it to slip in and wanted to check it out. I just pulled it real hard and it poped out. It was plastic.



After I pulled it out the pin was easier to get in the little hole in the gear. I did have to get the wife to slowly bar the engine for me while I pushed real hard.

Do you think you could have been 180 out? If you just pull that little pin completely out you will know if its sheared of.

If not, pin it up and it will surely time for you.

Another thing to consider is the gear may have slipped on you when you torqued it down or when you started it up. It does happen.

Try it again with it pinned. Torque the nut to 155-160 pounds. Have the shaft super dry and clean with brake cleaner.





Don~

 

[Joe G.]

I made a substitute timing pin out of a brass bolt I had. It's longer so I can get a good grip on it. I just remove the plastic one and use the brass one to find TDC. You can get pretty close to TDC if the valves on #1 are loose and the valves on #6 are tight. There is a very small interval where both valves on #6 are tight at the same time the valves on #1 are loose.



You can also find it by turning the #1 intake valve down five turns. Make sure you that you are exact at this. Fabricate a pointer from a piece of wire so that it indicates the crank pulley. Then bring the piston up until it touches. Mark the pulley where the pointer is. Loosen the intake valve until it is exactly where it was when you started. Roll the engine past the first touch point so the that piston is down again. Tighten the intake valve EXACTLY as much as before. Move the piston up until it touches. Mark the place the pointer indicates. Put the valve back like it was before you started. Halfway between the marks is exactly TDC. Check the timing pin. It should go in the hole at this point. Mark TDC on the crank pulley. So if you need to set it at TDC in the future position the crank to the mark and check the pin. If it goes in you are at TDC, if not roll it over one more time to the mark. You don't have to be this exact for a valve adjustment, but you do for timeing.

 

['956Wheel]

Don, were you timing it or doing the valves? If timing where did you set it? Contrary to some members views "hammering" is not a good thing and should be avoided as it will ruin the main and/or rod bearings, this is why I was concerned enough to check the timing.



Mike

 

[Don M]

Im at 15. 5 right now. I may go to 16. 5 for dyno runs or whatever, but not everyday use.

Why bang out mains and even more so, rod bearings? Some people dont get it.

There is a limit to high timing and a benifit for us street drivers.



Don~

 

['956Wheel]

YUP

Don, You got that right... there is plenty of room to have fun with a CTD without having to break it!



Well I am trying to figure where the end of the pin is... I rolled that motor over so many times and could not get the pin in... but I do feel a "lump" at my mark.



Mike

 

[LarryB]

Originally posted by Joe G.

You can also find it by turning the #1 intake valve down five turns. Make sure you that you are exact at this. Fabricate a pointer from a piece of wire so that it indicates the crank pulley. Then bring the piston up until it touches. Mark the pulley where the pointer is. Loosen the intake valve until it is exactly where it was when you started. Roll the engine past the first touch point so the that piston is down again. Tighten the intake valve EXACTLY as much as before. Move the piston up until it touches. Mark the place the pointer indicates. Put the valve back like it was before you started. Halfway between the marks is exactly TDC. Check the timing pin. It should go in the hole at this point. Mark TDC on the crank pulley. So if you need to set it at TDC in the future position the crank to the mark and check the pin. If it goes in you are at TDC, if not roll it over one more time to the mark. You don't have to be this exact for a valve adjustment, but you do for timeing.

Joe G.

Excellent idea! Your method is exactly what I have been trying to come up with. I have a deadstop made from an old sparkplug I use on my planes. You can do the same thing by going almost a full rotation until the piston stops on the other side of the throw. Same, Same. I am going to get a piece of 1/4" tool steel, use a big screwdriver to open the #1 intake valve and insert the tool between rocker and stem. It will be a snap. Better than that stupid pin by a long shot.



WOW, Thanks, Cool idea.





Larry

 

['956Wheel]

Larry & Joe,

One of my books describes the valve to piston method of finding TDC, however they highly recommend pulling the injectors to smooth out the 17. 5:1 to avoid damaging the piston or bending a valve stem, sounds like a small job that got too big. I think I will pull the #1 injector and use a dowel. I am certain the plastic pin is history.



Mike



You are right Larry, the pin is stupid... it sux.

 

[Don M]

yep, pin is a bad and in a bad place.



Don~



if you pull the injector, you gotta pull the lines off to get it out.

YUK!

I got some trash in one of my injectors from removing the lines and somehow not being careful enough. Now,Im downright anal about dirt anywhere.

 

[LarryB]

I'd sure be surprised if one could bend a valve or damage a piston with the barring tool. You would have to really try. I think I will disconnect the battery to preven any costly lapses in thinking though.







How do you use the dowel?

 

[Joe G.]

Larry,



If you use a valve for a dead stop rotating it back around until it hits won't work. The cam will attempt to raise the valve before it gets back up. So you have to back off the valve, reset it, and come back up so that cam is in the same place. A spark plug or something like that doesn't change like a valve does.

 

[LarryB]

Thats true Joe. I would also think using a piece of tool steel will actually work better because it is more repeatable than using the adjuster. And faster.

 

[Joe G.]

You are probably right. I just got the screwdriver slot lined up exactly the same way on both sides so if I was off any, it was only tiny bit. Probably less than . 001".

 

['956Wheel]

Larry, The barring tool engages with the flywheel... right? If so you have got TREMENDOUS gear reduction. Our valve stems are . 312 (5/16) dia. , not so big. That would be a real sick feeling to bend one.



So, what is the best timing for a power/economy? Stock on a '95 (mine) calls for 12. 5 BTDC. CPL 1550. I have a #8 plate in the stock position with the AFC housing a tad from full forward. This one is for towing a 23' TT and daily driver. I do not have a need to break anything and do not need to impress anyone... . afterall its allready a CTD!!



Mike

 

[Joe G.]

I had no trouble detecting when the piston touched the valve when I was locating TDC. In fact, I think you would have to reef on it pretty hard to bend anything with a 3/8" ratchet.

 

[Sled Puller]

Originally posted by Don M

Im at 15. 5 right now. I may go to 16. 5 for dyno runs or whatever, but not everyday use.

Why bang out mains and even more so, rod bearings? Some people dont get it.

There is a limit to high timing and a benifit for us street drivers.



Don~

Don,

Would you be so kind as to tell us what "high timing" is, and what is too high?



And also, a list of the people who don't get it who have had all these bearing failures that concern you so?





This is odd coming from you, because I saw another thread where you took out a perfect set of injectors and put a high dollar set in to gain "8hp",. You were very happy, because you said something like," ... ... not very much hp, but at this level, we do anything to gain a few..... " Is that close?



I know of several trucks running every day, well over 20. With a ton of miles. Nobody else seems concerned about their bearings.



Gene

 

[Don M]

MGM,



You should know by now that the earlier you inject the fuel before TDC the more stress you put on the lower end.

Simple stuff. Street driven trucks are not my idea of a truck that should run timing in the 17 or higher range.

Could many of the guys you speak of be pulling on weekends? Racing? How many of these guys can set their own timing? Many prolly want to have the timing set high because they dont do it themselves and not doing so could cost them a pull or race.



Average fellas dont want or need the timing set high to haul their 5th wheel or horse trailer. The low end damage is not worth the extra power on a long term basis.



Im bettin' your one of the guys that does not set his own injection timing and had whomever set it up high for you when they did it to make more power on the top end. That power will be at an expense in long term durability and the low end power as well. Not to mention the torque will drop off some too. Bottom line is: higher timing is not for everyone.



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



Don~

 

[illflem]

15. 5°