HELP I'M STUPID! TIMING BELT CHANGE- HOW DO I FIND TDC

[RollinonZ34]

1992 3.4 dohc
engine set @ tdc tried on compression stroke and exhaust stroke no change new belt installed removed rear flat hold down tool turned crank 360 or 1 full turn tdc to tdc the rear cam flats are still up (the rear cam flats are turning in sink with the crank. 1 full turn of the crank the rear cam also completes 1 full turn IE,,, starting with cam flats at top =cam flats on top after 360 or 1 full turn should be facing down WTH????

This pig might be on its way to the shop and the for sale lot shame had this car new with 13 miles on it when I bought it only has 92,000 now

Sorry to hear this hurricane, as i thought that i could finally help someone else, instead of just coming to this forum to get advice...

I am sure that there are some Mechanics that visit this forum that could help you or tell you why Cams are spinning at the same rate as the Crank...but they just have not seen this link. Maybe you should start a new Thread asking why this would happen in the Title or Subject so it will be seen right away!...92,000...it's not even broke in yet!!!..Good Luck

[grandprixgtp_91]

ok just to make sure, you are turning the harmonic balancer right and not the intermediate shaft?because the intermediate shaft(bottom gear in the timing setup) will only spin 180* with one crank revoultion. it is a physical imposibility for the cams to spin at the same speed as the engine, they will only spin at half the speed, the only was this is possible is if someone changed the timing chain gear to a 1/1 ratio which i dont even think they sell and i highly doubt happened, my guess is that you are turning the intermediate shaft and not the crank, some people dont realize that these motors have a timing chain and timing belt, so yeah you have to be turning the bottom timing gear, if you are then you have to look farther down and you will see the harmonic balancer , that is what you turn, i am a gm mechanic. and a car is fully broken in after 2000Km . hope this helps

Jake

[RollinonZ34]

ok just to make sure, you are turning the harmonic balancer right and not the intermediate shaft?because the intermediate shaft(bottom gear in the timing setup) will only spin 180* with one crank revoultion. it is a physical imposibility for the cams to spin at the same speed as the engine, they will only spin at half the speed, the only was this is possible is if someone changed the timing chain gear to a 1/1 ratio which i dont even think they sell and i highly doubt happened, my guess is that you are turning the intermediate shaft and not the crank, some people dont realize that these motors have a timing chain and timing belt, so yeah you have to be turning the bottom timing gear, if you are then you have to look farther down and you will see the harmonic balancer , that is what you turn, i am a gm mechanic. and a car is fully broken in after 2000Km . hope this helps

Excellent Point and diagnosis of what is probably happening! and i was kidding about it not being broken in at 92,000 mi. ...but meaning that it still has Very many miles left in it, if taken care of...lol

Hurricane...look towards top of this page at the Pix from WhiteZ34 and you will see what grandprixgtp_91 is talking about...even though, mine did look different than his Pix...it is still in the same place...Turn Crank under the intermediate shaft, and you will see the mark.

This Forum ROCKS...I can't say it enough........Paul

Jake

[grandprixgtp_91]

yeah i figured you were kidding about being just broken in, but i have met some people that thought 150,000km was just broken in, so i thought i would just clear that up in case someone did not know.lol, well we havent heard anything yet so maybe hes out workin on it, thats the only thing i can think of as to why the cams are spining at the same speed.

Jake

[RollinonZ34]

Another Pix

Hurricane, here is another Pix that may help you...if i can get it to download... this will hopefully give you a rough idea in case there is confusion as grandprixgtp_91 suggested... nothing here is to insult intellegence, just help...and yes, i had a lot of Belt shavings crammed into every available place...caught it just in time...Paul

This pix is just for referance, as the Timing Marks are not in this particular pix, it is on the other side of crank when i took this pix, but you can see where to look.

[hurricaine]

Ok guys great news following your suggestions and calmed down started fresh from the start all is correct but gotta get a new 15mm socket I broke mine just short of TDC the rear bank will be face down as soon as I can continue

Thanks all for the help : ]

[RollinonZ34]

Glad to hear it!!! I broke a socket too. The shorter ones are stronger..

Also, that Yellow mark on the Intermediate Shaft should point down to 6 o'clock and at that point, you should see the Mark (line) on the Crank be even with the arrow back behind it on the motor...theres your TDC...breath in...breath out...breath in...breath out...lol

[hurricaine]

The beast lives again and I,ve still got 1,300 in my pocket that GM didn't get turned the key and walla but the idle is high lopes 3,000-2,000 (I didn't change the EGR gaskets think theres 2) but anyhow thanks guys for all the help in gettin me running

[RollinonZ34]

Great News, and it will get even better after computer Relearns new things that have happened...i think...mine seemed to. Also, sounds like your Next project is the Lower Intake Manifold gaskets for the High Idle.
I did that & Timing all at the same time and has not run smoother since New.