Did I Do this Wrong

Got to thinking bout my engine and TDC. Well i installed a new timing gear set. I turned the motor until the timing mark were aligned (old chain) I for some reason thoguht this is TDC. So i pulled the old gears and chain and installed the new set with the timing marks the same way as the old. So i put th ecover back on and start bolting everything up. So now i am to install the distributer. And I have to find TDC. I am not sure if i am at TDC. how can i tell by looknig at my liftres and cam if i am at TDC? Currently the motor is at "0" on the scale and i know the timing gears are still aligned together at the marks. Am i overthinking this. jsut wondering if i can install the timing gears wrong. Do the marks on th egears align during each of the storeks, or is it only on TDC?

Thanks

 

i looked at the lifters. the lifeters are both down in the bore. if they were up that would mean a valve would be open
i think i got it right, just driving me nuts thinking bout it now since i do not really remember, since i have been doing a little at a time.

 

When Dots are together (on a 225) you are NOT TDC. You are 180 out.

Pull your plugs and turn the engine by hand. I stick my finger in the number one spark plug hole so I can tell if I am on the compression stroke. I then bring the timing mark to the 0 and install distributor. If you want to verify - put a caliper end in the spark plug hole when your bringing it up on compression and measure / mark TDC on the timing. I use silver model paint.

 

HHHHMMMM... looking at the Edelbrock directions, it says to get to TDC of compression. Then install the edelbrock gears. The pictures of the gears show the dots lining together at the closest point in the middle. I just had the stock gears aligned at the marks the same way and then put on the new gears.

 

How can i locate TDC with the heads off? Like stated earlier, both lifters are in their bore, so that would mean the valve would be clsoed, and the piston is at the top of its stroke.

 

Look at the Number 1 cyl Dan and the piston will be at the top and both lifters will be at the lowest point......Call me if need be.

 

That is what i am seeing Billy. They are at the same level, and i do not see them going any lower at all.

 

Sorry Dan - I forgot you were not running a 225.

I believe the dots together and being 180 out are specific to the 225. I got the info from my machine shop when I was having oil problems to the rockers. We pulled the timing cover and gears so we could run a line in the oil galleries to make sure oil was getting up to the heads. This was given to me when we were reassembling – he didn’t want me to put the distro in 180 out after all the hassle we had just been through.

 

The way it was explained to me (I was confused as well) – the dots on the cam and crank are for alignment, and alignment only. The dots were put on to indicate a position in which the cam is in synch with the crank and will allow valves to open and close in the proper sequence with the rotation of the 2 objects…

It just happens that by convention most engines also designate a TDC condition at the same point. The 225 piston #1 is TDC at that point, but it is NOT in the compression stroke (as I understand it). When I put the engine back together I turned it by hand to make sure I was on compression, brought it to 0*, installed distro, and it fired right up.

I don’t have any reason to doubt what I was told based on experience, these guys even came to my shop at my house and helped me since the oil issue was ‘their fault’. I have had several engines worked on by them and everything has been ‘spot on’ what they told me.

 

My GM experience had mostly been on Pontiac, Buick and Chebby V-8s and I think McRuff is dead nuts on. I always brought #1 up to TDC, spun the cam around so that the marks on the timing gears lined up and called it good. No issues with getting a new engine to fire over and time from the get-go.

Just remember guys, that on ANY 4-stroke engine, the cam turns at 1/2 crank speed. That is, for every crank revolution, the cam turns 180*.

Now getting the distributor rotor to point in the right direction may take some doing, but the FSM is petty straightforward.