V8 Holden Camshaft Timing
I have been asked three times this week, how to set up 253/308 timing marks and have seen it asked here many times. Whilst it is a very simple thing to do, unless you can see it done, it sounds really hard and very confusing, especially as every one has their own way of doing and explaining things. I'll try to make this as simple and easy to understand as possible.
There are many different theories and ways of how the distance between the two dots is achieved. Some count links, some count pins, some say one is at such and such o'clock, some measure with a ruler and so on. BUT one thing is for certain, DON'T take the coloured link theory for granted.
There is an engine from the USA (Buick I think) that has the same length chain as 253/308 but with a different amount of links between the coloured ones. These chains have been here for years and all that I have seen are sold as replacement chains, not chain and gear sets. The chain for the Buick or whatever it is, will be fine in the Holden engine, just don't use the coloured link theory.
The most common problem I find people have with cam timing, is they set the timing on the wrong side of the engine. Some say it's the left side, some say it's the right. Some have their engine upside down on a stand. It's the oil pump side. If the engine is upside down, or the person fitting it can't tell the difference from left to right, it doesnt matter. The oil pump is always on the same side.
As some Manuals state there will be "X amount of links between dots", this confuses the issue more, as in the picture there is "Y amount and two half links". Always count the pins. No matter how many links, (some say seven, some say eight, some even say nine?) there will always be sixteen pins between the dots.
To confuse the issue even more, I haven't used the dot originally stamped on the crank gear. This cam has been advanced, and requires a different timing mark to be fitted. Hence white paint. For every key way off zero, the new timing mark will be two teeth off zero, in the same direction. In the picture, it shows that the cam is advanced 4 degrees. Two key ways, four teeth. Double check this by making sure that the key way you have used, is directly opposite the new timing dot you have made. (only works for V8 Holden. Don't try the opposite trick on SBC)
Don't try to fit distributor now as the position of cam is on TDC number 4.
Always double check by winding engine over two crankshaft revolutions, and checking timing by recounting pins. If you used the coloured link trick, it's about now that you will be scratching your head and saying WTF. Coloured links are no where near their position that they were before.
Also with multi key timing chain sets, each tooth on the crank gear off zero, represents one camshaft degree either advanced or retarded. This is ONLY the case when used in conjunction with the correct key way. Don't think that by moving the dots a couple of teeth on a STD timing set will advance or retard the cam timing a couple of degrees. For every pin either side of sixteen between dots, is 7.5 camshaft degrees.
Hope this answers some questions and doesn't confuse the issue more.