[1972ACGT]

OK..I've decided that I want to mill my head to get more compression from my 7.6 comp ratio engine. I read that I need to adjust the cam timing to accomodate for the milling. how much do i need to advance(right??) the timing for .025 and .050, and how do I adjust the cam timing?? is it in the head, or on the bottom end? is it a pain???

 

[Paul]

From whats been posted on both of our Opel forums in the past, the cam timing retards 2 degrees for every .025" milled from the head and/or block. So .050" milled would be 4 degrees. One way I've been told to restore the cam timing is to drill a new cam dowl hole in the cam gear. Since there are 3 cam bolts, there are 3 different orientations the gear could be bolted on to the cam, if the dowl wasn't there. It sounds simple enough to just index the cam gear 120 degrees plus the amount to be advanced and have a new close tolerance clearance hole for the dowl, which is 6 mm, if you can find someone with the right size drill and reamer.

I think I said that right. You should probably wait for a more definate answer first. Evidently there are a couple more ways to accomplish this, but which is the simplest, I don't know first hand.

You shuld also ask the experts how much compression increase you'll get from this.

HTH
Paul

 

[Joe Van Wagnen]

adjustable cam timing

if you deck the block and mill the head it changes the cam timing... there is a company in England that makes a adjustable cam gear that you can compensate for any milling you might do... i have one on my 2.4L.... Roger Wilson at Roger's Opel Engineering got one for me for $125.... it works great!!

 

[opelmark]

Kent Cams Power Pulley

Yeah, I'll second that. The power pulley for CIH 1.9s is the preferred way to correct cam timing for milled heads, but one warning--infinite adjustability can lead to infinite problems, if you're not paying attention. Index it correctly, or pay the price. I needed six degrees of advance in my case, the Kent pulley made it happen. Recommended. Best on eBay. Yadda yadda.

 

[PROPEL]

Piper Power Pulley

Well, my Piper adjustable cam gear arrived today from England. The cam pulley also came with a new crank gear and timing chain. Anybody know if I need to install this new crank pulley, too... or is it just a duplicate of stock (but thrown into the kit for good measure)??? I'd sure HATE to have to pull the timing cover at this stage of the game.

Don't have a spare Opel crank gear to check it against. Though I could also use a spare cam sprocket to index this thing properly.

Walter

 

[72opelguy]

how do i get a adjustable cam sprocket form rogers opel engineering i found an addy or something on the hemmings opel site and it said he doesnt sell parts

 

[baz]

piper chain kits are a full set so all must be fitted together so the cogs and chain are all the same ,you'll be that far into the engin to change the chain anyway so 10 more mins to do the crank cog is no biggy
p.s. dont forget a new chain tensioneror you'll not be happy hith the noise in a week or 2

for vernier can pullys try
http://www.pipercams.co.uk
or
http://www.kentcams.com/index.htm

 

[Gary]

Thanks for the links Baz! I'll add them to our Links database.

 

[baz]

no problemo
any other uk links needed let me know as they are all local for me so thay are all in uk tuning and conversion mags
its a nice change from the top shelf stuff