Cam/Rebuild Question

E

edmonds27

Member
Joined
Feb 1, 2010
Okay Guys, I'm rebuilding an 85GN motor for the street/daily driver. It's mostly a stock rebuild except for the cam. My big question is will this cam work okay in this application? Here's what it looks like we're going to end up with:

.060 over bore
10/10 Crank
Clevite Tri-Metal P Series Bearings
Stock Rods
Federal Mogul Cast Pistons
Moly Rings
Stock heads (previously milled)
Stock Turbo (or clse to it... still have to find one, mine is locked up)
Comp Cam k69-248-4: Hydraulic flat tappet
1,200-5,500
260 int./260 exh.
0.459 in./0.459 in.

Anyone see any problems with these parts? I see some post in here about changing the converter, etc... with some mods, just trying to plan ahead for that kind of thing. Is there anything I HAVE to change or ????
 
edmonds27 said:
Okay Guys, I'm rebuilding an 85GN motor for the street/daily driver. It's mostly a stock rebuild except for the cam. My big question is will this cam work okay in this application? Here's what it looks like we're going to end up with:

.
Stock heads (previously milled)
Stock Turbo (or clse to it... still have to find one, mine is locked up)
Comp Cam k69-248-4: Hydraulic flat tappet
1,200-5,500
260 int./260 exh.

Anyone see any problems with these parts? I see some post in here about changing the converter, etc... with some mods, just trying to plan ahead for that kind of thing. Is there anything I HAVE to change or ????
Click to expand...

You are going to get MANY different opinions on cam related questions.
There are different phylosophies on cams . . .

Personally :eek:, I would not go with a cam that big. No bigger than 206/206. Also consider the Speedpro 204/214. Even better yet, save up and go roller. :cool:
If however you are set on a cam that big, I have a good used comp 212/212, with marked/matching lifters. No break in required. :cool:

.
 
What is the the duration at .050 lift? the numbers you listed are at .006 lift the .050 numbers are more meaningfull for comparison
 
fastblackracing said:
What is the the duration at .050 lift? the numbers you listed are at .006 lift the .050 numbers are more meaningfull for comparison
Click to expand...

Actually, it is listed @0.050".
This is the same cam I have for sale. :tongue:
I went roller. :cool:

Cam Style Hydraulic flat tappet
Basic Operating RPM Range 1,200-5,500
Intake Duration at 050 inch Lift 212
Exhaust Duration at 050 inch Lift 212
Duration at 050 inch Lift 212 int./212 exh.
Advertised Intake Duration 260
Advertised Exhaust Duration 260
Advertised Duration 260 int./260 exh.
Intake Valve Lift with Factory Rocker Arm Ratio 0.459 in.
 
I agree with the others; consider converting to a rolling valvetrain. The new mineral/synthetic motor oils don't have the lubricants (e.g., Zinc) that earlier versions did. Result; cams & lifters wear out too soon. Some folks buy a zinc oil additive to compensate. Buick GS Club of America has info on this. BGSCA also sells roller cams.
 
So Jerryl, how was that cam in the car? I don't really want to go roller mostly because of the extra expense and the aggravation of changing all the valvetrain geomtery, pushrod length, etc... especially since this is for a street application. But, I've never built one of the GN motors before, and this kind of feedback is the reason I posted the question so I guess I'll at least take a look at the rollers. So what exactly is the problem with the cam we had picked out? Too rough an idle for the street, too much stress on the valvetrain, or what's the deal???
 
edmonds27 said:
So Jerryl, how was that cam in the car? ........ So what exactly is the problem with the cam we had picked out? Too rough an idle for the street, too much stress on the valvetrain, or what's the deal???
Click to expand...

The cam idled fine, but a little higher (around 825 rpm), and had about 14-15 inHG.
The FT cams work fine "if";
1- You break the cam in correctly
2 - Have a good oil additive
3 - Run springs that do not have seat pressures too high.

T us the cam for the intended design, you will need ported heads, transmission shift point adjustments, stall converter, and more turbo.
If the stock cam is fine, I would leave it alone.
 
The stock cam has some damage so we're going to replace it. Plus this engine will be for my 16 year old son's first car so we wanted it to sound COOL, and the performance gain is always welcome. As for those upgrades, the ported heads maybe, but all that other stuff probably not. That's the kind of stuff I was trying avoid which is what prompted me to create this post. I guess I need to back down on the lift/duration a little. What's puzzling is that Comp says that this cam is a "Good replacement for Turbo-Charged Grand National". In my experience Comps recommendations have always been very good. Wonder what the lift/duration is on the stock cam?
 
edmonds27 said:
The stock cam has some damage so we're going to replace it. Plus this engine will be for my 16 year old son's first car so we wanted it to sound COOL, and the performance gain is always welcome. As for those upgrades, the ported heads maybe, but all that other stuff probably not. That's the kind of stuff I was trying avoid which is what prompted me to create this post. I guess I need to back down on the lift/duration a little. What's puzzling is that Comp says that this cam is a "Good replacement for Turbo-Charged Grand National". In my experience Comps recommendations have always been very good. Wonder what the lift/duration is on the stock cam?
Click to expand...

Stock cam specs:
Advertised Duration : 258/262
Duration at .050" lift : 192/196
Lift .384/.408
Lobe Separation 107 degrees
Overlap 38 degrees
Quick Reference Page For the '86/'87 Turbo Regals and '89 Turbo T/A

You may want to look into the 204/214 or 206/206 cam.
I have personally seen the 204/214 run 124 MPH and, the 206/206 has gone in the 9's. (If my failing memory recalls correctly)
Stock cam will get into the 11's n the IC'd cars all day long. :eek:

Many times you do not get the full story on the cam questions.
Contact one of the board vendors for the cam.
FULL THROTTLE SPEED - All Brands
GBodyParts.com Online

PS:
If you want the "COOL" sound typically associated with a SBC, pull the V6 and drop in a SBC.
Can't get the SBC sound with with a little V6 that is quiet and kicks the SBC in the pants. :eek::wink::cool:
 
Buy the time you get a cam that has enough duration to sound good in one of our cars you have will way too much cam unless your deep in the nines, 200 to 206 degrees duration max, with a 109 to 111 lobe centers and around .430 lift would be good imo. comp cams has good recomendations [Ive used many in other cars] but they dont have experience with our turbo regals.
 
........ comp cams has good recomendations ..... but they dont have experience with our turbo regals.

Jerryl said:
I almost wrote the exact same thing . . . ;)
Click to expand...

True for the most part, however you can get a good comp cam from some of our vendors. i have a great comp cam in my car. Get ahold of nick micale at ArizonaGN and he will set you up with what you need. they have goten the specs down for our turbo cars
 
you guys are killing me:frown: your making think second now when im putting my motor together becuase ihave a huge cam!:eek: comp cam custom grind 69-000-5 they claim its 224 at 50 with .493 lift maybe i should sell it. i wanted to go for a rumble at idle but still be streetable
 
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