347 locked down.

[Shakin66]

I am normally a part of the classic forum but need some help from you 5.0 guys on my cam's lift. I have a 347 with GT 40 Irons and am trying to run an Anderson cam with .544 lift with my 1.7 rockers. The car ran for 2 hours and then at idle it hit an intake valve and locked down. I disassembled it and talked to ford's tech line and they stated these heads are off of a 93 cobra and it should be fine for that lift. I stated that the heads had 2 springs and they said that I needed new springs, ret, & keepers. which I have just changed. Am I missing something? Valve spring bind? I dont want to hurt the lower end if this happens again.

 

[R2D2]

you didnt check piston to valve clearance before assembling? If not thats the first no-no. Also what spring is it, where did you buy it from? Near .580 thou of lift with the 1.7, assuming the .544 is with a 1.6 rocker

 

[PoopDawg]

What kind of pistons are you running? What's the duration of the cam? Lift means nothing in piston to valve clearance, as the max lift is happening when the piston is all the way down in the cylinder. Duration under 230 degrees at .050 will be just fine if you have the stock type pistons with the small eyebrow cuts for valve clearance. I see you have a 347, so I would assume you'd have more of a cut piston for more valve clearance.

If that doesn't work, I would check to make sure the cam is degreed ok. If it is way out, it can cause p to v problem even with a factory or small cam.

If not that, then I would check for a broken valve spring. With the smallish intake valves the GT40 heads have, I don't see how valve float would even cause p to valve issues, but it could. Check the spring installed height and seat pressure. Make sure the springs are up to par.

Good luck brotha!,
Nick

 

[R2D2]

What kind of pistons are you running? What's the duration of the cam? Lift means nothing in piston to valve clearance, as the max lift is happening when the piston is all the way down in the cylinder.

If not that, then I would check for a broken valve spring.

Nick

sounds like something I would say if that head has a stock spring hes got issues at near 580 thou. Thats where I was going. Who knows the deck height of the block, what head gasket, heads been cleaned up?

 

[Shakin66]

What I did was not as good as checking it myself but I did call Ford's technical line and spoke to them about the combo. It looks as though there wouldnt have been a problem since with these 1.7s I am at .544 but someone had changed the springs to doubles before I bought them. I bought the engine assembled so I hope the cams not the issue.
Looks like the Duration is below 230


Cam spec sheet here:
http://i32.photobucket.com/albums/d6/scatpro/scan0001.jpg

 

[PoopDawg]

That's a great little cam shaft you got there. It should be just fine. Call AFM and they will set you up with the correct springs for your application. If you don't know what springs are on the heads, then chances are they probably aren't right.

 

[R2D2]

Fords tech line is not gonna do you any good, as witnessed by what has happened. You yourself need to use either of the 2 methods to verify the clearances. You also need to know what spring is on there, is it a true dual spring or a single with a flat wire damper spring on the inside? Also like stated need to see if the cam was advanced a few degrees which will increase chances of clearance issues since that changes the timing events. Time to step back and tear it all the way down. Ford doesnt know if the block was decked, if the heads were cut etc.. Call them if you have a question on a part they sell, thats it.

 

[bubba-dough]

Fords tech line is not gonna do you any good, as witnessed by what has happened.....Time to step back and tear it all the way down. Ford doesnt know if the block was decked, if the heads were cut etc.. Call them if you have a question on a part they sell, thats it.

+1 And just to throw my $0.02 in....when I bought my 347 kit Coast told be to stay under .550 lift.

 

[Shakin66]

Well I talked to Anderson and ford and they both agreed that I needed to dump the double springs (2 springs with a flat dampner between them) and go with M6513-A50 springs and the other correct ret, & keepers. I tried something new as I was having problems withthe putty method and dont flame me it was not effective....I removed the springs and used just the inner spring so that I could move it by hand and then bolted the rockers back up with a feeler gauge set to .120" under the roller. I did this on both the ex. & intake valves and then I rolled the engine over by hand making sure I had the .100" needed. So did I do any good?

 

[PoopDawg]

Sounds good to me. I had problems also with the clay method. It always stuck to either the piston or the valve. A good street motor should have .120 on the intake, and the exhaust won't really be a problem. One thing is you need to check p to v clearance with either a dial indicator or using a solid lifter. I used a solid lifter cause I was running a flat tappet cam