No Marks on Gears

I am building an O-320 that I did not take apart. I am at the step where you install all the gears on the back of the engine. I am stumped because my crankshaft gear and the idler gear do not have the little "0" stamp marks you need to time the camshaft to the crankshaft. The crank gear is the newer type with the scallops, but there are no marks. Same with the idler gear, which is supposed to have a pair of marks in one location and one elsewhere to set the timing. I have checked very carefully under a lighted magnifying glass and do not see any marks. There is no evidence they were filed or machined off. Can someone advise how I can use the fuel pump lobe as a reference and recreate these marks?

I had a similar problem where some marks were not legible. Found pics on ebay and then counted teeth from other reference points on the gears to recreate.

Idler gear marks can be anywhere on the gear, its the relative spacing between them that is important. The cam and crank gears markings must be referenced to the holes for the indexing pins that hold their radial motion.

If I remember correctly, two dots stradle a low point and single dots go on gear teeth.

Larry

I've dealt with this same thing. What you do is build on. Once you get the cylinders on then its straightforward to put the #1 cylinder on TDC to determine cam timing and validate it by observing valve operation as you turn the engine around on the stand.

Crank Gear

I have a spare crank gear. When viewed from the back the tooth with the O stamped on it is at the 7-7:30 o?clock position when the index hole is at 12 o?clock. I can email pics.

Don Broussard
RV9 Rebuild in Progress
57 Pacer

Crank Gear

Don, I would like to see your pics of your crank gear. I have figured out there are 7 teeth between the single and double zero marks on the idler gear, so I think I can install the idler with the fuel pump eccentric in any position, right? The critical factor is picking the right tooth on the crank gear to engage the idler. Send pics to d dot rohrer at twc dot com. Thanks.

Marks on Gears

Thanks to Don's photos I was able to determine which crank gear tooth should have been marked. The idler gear marks are easy to create, so I am good to go now. VAF is great!