Noisy valvetrain

5ive.oh

Founding Member
Feb 23, 2001
195
0
0
Rocky Mountain House, AB
So here's the low down:
I have an 86 GT, it's got GT40P heads, Crane RR's, longtube headers, flowmaster exhaust, weiand stealth intake, edelbrock 600 carb, a monster cam of some type. I raced a stock 90GT, well 4.10's and shortie headers (first race in this car) and lost by 4-5 lengths four times. So I think to myself "Somethings amiss here". I proceed to call the mustang shop I got the heads from (they are ported BTW) and they recommend a camshaft http://www.cranecams.com/index.php?show=browseParts&action=partSpec&partNumber=363941&lvl=2&prt=5

I put this cam in and new lifters and BLAM. I got no power, but I do have noise in my valvetrain. I adjusted everything correctly as I did when I swapped the heads. The lifters took an hour to remove from the drivers sied as it seemed they were swollen and I needed pliers to get them out. The car idles great, revs fine, doesn't smoke, I have 145-147 compression across the board, spark plugs are nice tan coloured. The cam is way less agressive then the one that was in there. I am stumped.
 
The oil should be flowing pretty easy unless the valves are too tight. And did you swap the springs when you swapped the cam? You can only go so big cam-wise with those P heads before they run out of efficiency. You have no idea what cam it had before? And finally, what are the specs for the cam in there now?
 
http://www.cranecams.com/?show=browseParts&lvl=2&prt=5&Vehicle_Type=Auto&Cylinders=8&Engine_Make=FORD-MERCURY&Year=1975&Engine_Size=221-302%20C.I.&partNumber=363941&partType=camshaft

There was no noise before I installed this cam. The cam idles a whole lot smoother then the old one did so I am assuming it's not as agressive. The only numbers off the old cam are 6250 and 900820 stamped in the back. 6250 is a ford basic number for a cam so I am thinking it's a FRPP cam. The springs are new FRPP springs, the heads were rebuilt and ran on a 320hp 302 before I got them. If there was an idle, smoke, backfiring problwm I would be able to narrow it down more but everything is good except the damn noise. It's not a sewing machine type noise, it's a tapping sound, like if you hit the end of a pen on a table only metalic. :shrug: I am assuming there is a problem with this cam as it mushroomed one set of lifters. The whole damn reason I did this swap was because the other cam robbed my compression. I was down to 105-110 psi because the cam was not degreed correctly. I don't know the specs so I don't think I can properly degree it without the spec sheet can I?

:SNSign:
 
Decided to stop screwing around and removed the cam. It isn't a pretty sight. The drivers side lifters are beat all to hell. Looks like someone took a hammer and gave it to them like a red headed stepchild. Passenger side is great, not a mark. All the noise was coming from the drivers side. Yes is is a flat tappet cam, but I wonder if it was a factory defect, or did I do something looey?
 
Alright here's the scoop. The heads came assembled and ready for a roller cam not a flat tappet. Therefore the spring rate on the cam was 95lbs closed and 268lbs open, the springs in the heads are double springs set for 135 lbs closed and 394 lbs open. Voila instant cam/lifter destruction. Now I wonder why the mustang shop I bought the heads and cam from did not inform me of this information before I installed the cam? I did tell them what I was up to, I guess they saw a uninformed person and took advantage.