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Cam Advance Recommendation?
https://slantsix.org/forum/viewtopic.php?t=15542		 Page 1 of 1
Author:  Walter Lee Jackson [ Wed Dec 28, 2005 12:47 pm ]
Post subject:  Cam Advance Recommendation?
I have a 1963 Dodge Dart GT convertible with 225 cu in slant six.

The engine is newly rebuilt, with a stock block. The head was shaved .10 and Mopar Performance valves installed, with a 3 angle valve job, ported, polished, etc.. I don't remember what size the valves are, but they're larger than stock. I don't know what the flow numbers are.

I've got a JP Performance double roller timing chain set and roller rockers (1.6) from Cox brothers.

The car has a 1987 904 with electronic lockup torque converter. Gear Vendors overdrive and 3.23 8 3/4 Sure Grip rear.

The car is strictly for crusing cruisingl not be raced.

I converted the head to hydraulic lifters by purchasing a kit from Clifford, which includes a 264 hydraulic cam. This cam gives good low end and mid range power, according to Clifford.

It degrees out at 104, but the spec calls for 110.

Should I obtain a bushing kit and degree the cam to spec, or leave it where it's at? Instead of a bushing kit, should I just use one of the other keyways on the JP Performance crank gear? If so, do I advance it or retard it?

Here are the specs on the cam:

exhaust opens: 33
exhaust closes: 7
intake opens: 7
intake closes: 33
exhaust duration: 206
intake duration: 206
exhaust lift: 296
intake lift: 296
lobe center: 110
lift @ 1.5: 444 intake, 444 exhaust
duration: 264
open: 22 intake, 62 exhaust
close: 62 intake, 22 exhaust.

I appreciation very much anyone's thought's on this.

--Walt Jackson
Author:  Charrlie_S [ Wed Dec 28, 2005 12:58 pm ]
Post subject: 
I think you have a problem, before you start. The slant six hyraulic lifters are oiled thru the rocker shaft and thru the rockers, down the hollow push rods, and into the lifter.
How is the oil to the lifters going to get from the shaft to the push rods, and lifters, with the roller rockers?
What was the reason for using an expensive set of roller rockers, with a hydraulic cam? The thinking escapes me.
Author:  Walter Lee Jackson [ Wed Dec 28, 2005 2:47 pm ]
Post subject:  Cam Advance Recommendation
I purchased the roller rockers several years ago when the engine was built, and before I decided to convert to hydraulic lifters. (I'm into my 7th year on this project, and the car is still not on the road!!!)

I contacted the manufacturer, Rocker Arm Specialists, and they told me that there was no problem using the roller rockers, and that the lifter would obtain more than enough oil to function throughout the rpm range.

They provided instructions on adjusting the arms and said that, with their design, once locked down, it would never come out of adjustment. They said there was no reason to used the hollow tube pushrods, either.

I have the hydraulic rocker arms and hollow tube pushrods just in case their wrong.

So, should I adjust the cam to spec, or leave it as is? If adjust, should I take advantage of the JP Performance design and change keyways on the crank gear? If so, how much?

Thanks,

--Walt Jackson
Author:  Charrlie_S [ Wed Dec 28, 2005 3:17 pm ]
Post subject: 
With the numbers you give, the cam centerline is 103 degrees. intake open 7, + 180 + intake closes 33 = 220 degrees divided by 2= 110 - 7=103 degrees. If it degrees at 104, leave it there. You will not notice 1 degree.
Author:  kesteb [ Fri Dec 30, 2005 8:56 am ]
Post subject:  Re: Cam Advance Recommendation
Quote:
I contacted the manufacturer, Rocker Arm Specialists, and they told me that there was no problem using the roller rockers, and that the lifter would obtain more than enough oil to function throughout the rpm range.

They provided instructions on adjusting the arms and said that, with their design, once locked down, it would never come out of adjustment. They said there was no reason to used the hollow tube pushrods, either.

I have the hydraulic rocker arms and hollow tube pushrods just in case their wrong.
There are no provsions in the block to provide a continous oil feed for hydrallic lifters. The lifters are basically splash oiled from the crank and the drain back from the head. This is why the lifters are oiled from the the rocker arm shaft, thru the rocker arms and down the hollow push rods. RAS is wrong in this respect. You will need to use the stock rocker arms and hollow push rods.
Author:  Walter Lee Jackson [ Fri Dec 30, 2005 1:54 pm ]
Post subject:  Cam Advance Recommendation?
Thanks for the tip.

I'll install the stock hydraulic rockers and pushrods. Rather be safe than sorry.

Guess it's time to put the roller rockers up for sale.

--Walt Jackson
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