Unknown Camshaft
- Thread starter T70turbo
- Start date
jpwalt1987
Well-Known Member
- Joined
- Nov 9, 2003
The 314B part reminds me of the old ATR roller cam part numbers. Dont know any other info... sorry.
87buickracer
Member
- Joined
- Dec 2, 2004
This is a atr hydraulic cam(flat tappet) -specs
advertised duration
intake 264/exhaust 256
duration @ .05 lift
intake214*/exhaust 208*
lift w/1.65 rockers
intake .495*/exhaust .480*
lift w/1.55 rockers
intake .465*/exhaust.451*
lobe seperation 109*
overlap 46*
notes: smooth idle,modified engines
price was $169.95 new
This was the bigger of the two flat tappets they sold..
good low 11sec to 10sec cam with 1.65 rockers and good combo
if the motor is blown and you're rebuilding it i wouldn't put that cam back in. flat tappet cams aren't reusable unless you're reusing the same lifters. and it seems silly to do all that work and put used lifters and cam back in. the risk of wiping out the used cam and lifters is really high. save yourself the aggrevation and get a new cam and lifters. new flat tappet pieces aren't that expensive.
Thanks for the advice on the Cam Ryan.
Hey JPWALT just took a look at the pictures of your head ports and I have to say they are the best ports I ever seen on a Buick. What type of heads are these? If it's sounds like I am salivating, yes I am. All my life I have been building 500-800hp toyota motors (2jz's,3sg's and 3TC's) A GN has always been on my bucket list and finally got an opportunity for one, I have to say that my biggest disapointment was when I saw the ports on my 8445 castings they look so tiny and ineffecient compared to toyota heads, but there is alot of info on porting these and definately will take advantage of this forum. After I break this motor I am building (precision t76 Q trim,88lbs injectors,FAST standalone) next on the wish list will be a set of heads.
Hey JPWALT just took a look at the pictures of your head ports and I have to say they are the best ports I ever seen on a Buick. What type of heads are these? If it's sounds like I am salivating, yes I am. All my life I have been building 500-800hp toyota motors (2jz's,3sg's and 3TC's) A GN has always been on my bucket list and finally got an opportunity for one, I have to say that my biggest disapointment was when I saw the ports on my 8445 castings they look so tiny and ineffecient compared to toyota heads, but there is alot of info on porting these and definately will take advantage of this forum. After I break this motor I am building (precision t76 Q trim,88lbs injectors,FAST standalone) next on the wish list will be a set of heads.
You will find that the sticking point will be the amount of spring you can get on the production heads rather than the port flow when you get up around 140mph trap speeds. Keep in mind your dealing with an overhead valve design that will make peak torque under 6000 rpm on a really crazy build. You need to build around that fact and get the car to take advantage of the torque through proper torque converter selection and gearing.Make sure you do a lot of reading on here so you are ready when you build your next one. Go 4 bolt tangential on the turbo and run the full size HPS turbine. Not the Q trim.
What springs should I run on these 8445 heads, I saw a set of 100lbs springs with chromemoly retainters for $100 and I have also been advised on using chevy LT1 springs?
This turbo is a big frame turbo, large shaft, 360 degree thrust, 76mm impeller 4 inch v band exhaust, I use to program this car when it was not mine, I got it to run a 10:34 at a GN meet in bradenton FL, then a guy from cotton performance offered to program it for my buddy and did get it to run a 10:06 but only once, the crank bent on the second pass with this same turbo. It did take a little nitrous (75 shot) to get the turbo t spool with the 3500 stall conveter.
This turbo is a big frame turbo, large shaft, 360 degree thrust, 76mm impeller 4 inch v band exhaust, I use to program this car when it was not mine, I got it to run a 10:34 at a GN meet in bradenton FL, then a guy from cotton performance offered to program it for my buddy and did get it to run a 10:06 but only once, the crank bent on the second pass with this same turbo. It did take a little nitrous (75 shot) to get the turbo t spool with the 3500 stall conveter.
You will have a hell of a time getting it to go over 130mph with a flat tappet and only 100lb on the seat springs. If you go higher in pressure you will wear out the cam lobes faster. Id run conical springs shimmed to about 105 on the seat. You have to check every spring. I havent found a set of comp 980 springs where all were at the advertised spec. most were 5-10psi under spec. The solution is to go to a roller cam and keep the rpm to under 6000. If you use a roller id use the 26918 spring shimmed to about .030 from coil bind for max rpm on them. Comp 941 springs @1.75 with titanium retainers will go to 6000 rpm if the boost is kept under 30psi on iron heads. Ive ranthem and they worked well. Id stay with around .500 lift for any iron head and .550 for any aluminum head that has room for more spring. I like the 26120 springs myself for the aluminum heads and hydraulic cams up to .550 lift. If you want to go over .550 lift then id just go to a solid. Stick with comp 3300 lobes for hydraulics.
jpwalt1987
Well-Known Member
- Joined
- Nov 9, 2003
The heads are GN1s that were ported by Mckenzie Cylinder Head near Duttweilers shop in Cali. They flow 249@.600intake and 219@.600 ex. He said it was a "street/strip" port job. The valve springs are BBC stuff setup for the 224/224 .560 lift solid roller cam i have. Not sure of the seat and open pressures. I use T&D 1.6 roller rockers too. I told him the specs of the cam and he set them up. It pulls to 6700rpm
:biggrin:When you refer to "Comp" springs are you refering to "Comp Cams" brand springs?
Also I know these engines have issues with low oil pressure, What is the recomended main bearing to crank clearance and connecting rod to crank clearance for a street strip motor? and is the high volume oil pump that cotton performance sells a good option for improving the lubrication on these 109 blocks or are there better options out there besides a dry sump?
Also I know these engines have issues with low oil pressure, What is the recomended main bearing to crank clearance and connecting rod to crank clearance for a street strip motor? and is the high volume oil pump that cotton performance sells a good option for improving the lubrication on these 109 blocks or are there better options out there besides a dry sump?
sinister87GN
08 trailblazer ss
- Joined
- Feb 28, 2005
I also have an ATR cam would you know the spec on the other flat tap cam ATR sold i can not remember and i need to match to a converter
thank you
