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V8 Holden Camshaft Timing

V8 Holden Camshaft TimingI 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. Shane.

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308 stroked.

I was told buy a bloke that on his stroked engine he has a cam gear that has multible positions,he said he needed it because he fitted a race cam,750 holly,twin point dizzy and the L34 motor didnt idel very well and it kept over heating.would you be able to let me know why he did this, cause it dosnt sound right. Thanks Barry.PS thanks for that great education on timing so far.....

Multi keyway gears

Multible keyway cam timing gears allow for ease of retarding or advancing cam timing to assist in fine tuning.

ok

Thanks. Barry.

timing a 308

so let get this simple...if I set my No1 piston at TDC, then set the timimg marks 16 "pins" apart (not 9 links)on the oil pump side of the 308 I will have correct timing ??

yes

yes. nobody.

so then to get ignition

so then to get ignition timing I rotate the engine one full turn to get No1 rockers rocking and set the dizzy from there? is that correct?

timing a 308 cam

tryed that, none of it works, nothing lines up, sixteen teeth anit it

no

Well sort of. No.1 will be rocking now, which is TDC Compression Stroke on No.4. But yes, turn it one full crank turn and set distributor timing then to No.1, with No.4 rocking. Clear as mud? nobody.

sussed it, many thanx, ended

sussed it, many thanx, ended askin a m8 in NZ and he confimd the 16 pin idea, Yea Right !! i said, he said just do it and buy me a beer next time im over there & well! you guys were both right, shes barkin and skidin up a storm now, many cheers

Marking

the thread

I'm just pullin my 253 down

I'm just pullin my 253 down and there is no marks on the timing chain so if i get it NO 4 on the rock at top dead center it should be all timed right yeah.

hello, wat if u dont have the

hello, wat if u dont have the coloured links on chain. and how do u no were o is??

308 cam timing

Hi guys , sorry for askin a probably stupid question... Ive set my cam up with the 16 pins meathod . An before i put it all together i just wanna know if taking the slack out of the chain with the chain tensioner would move the cam gear an effect the timing? An if so at what point after piston tdc should the valve start to open? Cheers

timing on a 308 to suit cam that was a special grind

G,day i brought a new cam shaft for my 308 and had it reground to suit my engine its nothing special. I had this done because a old freind told me to but lost contact with him but i rememberd that he told me the number of pins will be 16 and a half. as you can tell i,ve never put one of these together before and i know it takes years to perfect a nice high reving engine if any one could help me with this theory i would much appreciate.


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