Can I get a Freaking Break!!!!!!

**ArmyWarrant** · 06-24-2008, 11:11 PM

I must be f@#$ing cursed, doomed to not own a stang without having carnage happen! I was merging onto I-64 downshifted into 3rd and accelerated into traffic, got up to 5k RPM and heard a loud ping and the car start missing and carrying on. I pulled over and pulled off the hood and started the car and heard stuff banging off the drivers side valve cover so I shut it down quickly and waited for a tow truck. I got it home and here is what I found under the drivers valve cover.

I don't think there is any damage to the valve but I want to make sure that there was no contact between the piston and the valve. Can someone send me a link to the procedures to measure piston to valve clearance. Id appreciate it.

**ArmyWarrant** · 06-24-2008, 11:17 PM

Just to add I checked the pushrod and it straight as an arrow. The only thing I can figure happened was the rockers backed off on those two valves. I would think if there was contact with the valve and piston that the pushrod would have bent prior to the rocker stud snapping.

**Rodeheaver's** · 06-25-2008, 12:08 AM

why do those rockers say sbc???? have you checked the valvetrain geometry?? thats usually the cause of that, or way to much spring pressure due to a huge cam and no stud girdles.....

**ArmyWarrant** · 06-25-2008, 12:32 AM

I don't know, they were on it when I got it. I just got off the phone with a friend in new york an he is sending me a set of crane full roller rockers 1.6. I have access to dial indicators and everything but I need a degree wheel for this process right? I also checked the pushrod and they are stock length pushrods and I just don't think that is right. I was told when I bought the car that it has a z cam in it so I really don't think stock length pushrods are right for it. correct me if I am wrong.

Does a z cam have enough lift to require stud girdles?

I am gonna try and check the geometry tomorrow and make sure that the tip is riding in the center of the valve stem

**Rodeheaver's** · 06-25-2008, 01:07 AM

yes you do need a degree wheel, and the lift didnt break the rocker stud, the stud broke from valve train deflection, that means the stud is moving back and forth till it breaks, i would find it hard to believe that a piston hitting a vlavel would break that stud, it will usually bend a valve or bend a pushrod... And there is no cam that requires stud girdles, there is only big springs required by a big cam that needs stud girdles...and i would think that the correct springs for a z cam would not be that bad, but i would have to look up the number to be sure, and who is to say you have the correct springs???

**ArmyWarrant** · 06-25-2008, 06:14 AM

Thanks for all the info Tim, is there a way to find out what springs are on the heads? Also I think I am going to pull the heads to make sure that there was no damage done and then use the clay to check ptv. It looks like its gonna be down for a while then, I want to make sure that everything is right, while I got the heads off I'll be able to verify that it is a Z cam in the motor. Again thanks for all the info

**Rodeheaver's** · 06-25-2008, 09:59 AM

the only way to find out what the springs are is to check the preasure on a spring checker..... valve springs usually have no markings.. i guess thats why there are only 2 places in the ENTIRE world that make valve springs.....or so i have been told ..

**INSANELY CRAZY** · 06-25-2008, 06:02 PM

Originally Posted by Rodeheaver's

why do those rockers say sbc???? have you checked the valvetrain geometry?? thats usually the cause of that, or way to much spring pressure due to a huge cam and no stud girdles.....

he wanted to go fast so what better way then put chevy parts in the ford motor.....

**Rodeheaver's** · 06-25-2008, 12:14 AM

it is very hard to check ptv clearence with the heads on the car, just about the only way to do that is to put a checker (real light) spring in place of the exhaust and intake spring of the #1 cyl and set up a dial indicator to touch the top of the valve retainer totally parallel (with the rockers off that cyl of coarse), then rotate the engine 15 degrees before and after tdc of #1 cyl, you must check it at 15 before and after TDC... Once you are at 15 degrees in either direction, watch the indicator and push down on the valve and see how far the indicator is moving, you want no less than .100 ptv clearence 15 before and after TDC...

**altoona** · 07-06-2008, 01:19 PM

It's a little hard to see exactly where it's riding in that picture, but I've always been told that getting the smallest possible contact patch on the valve stem is more important than having it exactly in the center.

You can take a sharpie and make a mark on top the valve stem, then reinstall the rocker and turn the engine a couple revolutions. You'll then have a witness mark that will tell where and how wide your contact area is.

**ArmyWarrant** · 07-06-2008, 02:04 PM

Heres a better shot of that rocker

**SK@StreetLethal** · 07-06-2008, 03:15 PM

Loosen the rocker arm stud and adjust the guide plates over a bit. That should solve that issue.

**ArmyWarrant** · 07-06-2008, 03:24 PM

OK, Also I am wondering if the pushrods I have are ok for guideplates? These are the ones I have. It doesn't say anything about being hardened

http://store.summitracing.com/partde...5&autoview=sku

**SK@StreetLethal** · 07-06-2008, 04:43 PM

Those look like stock replacement pushrods. Looks like there allready showing wear. I would make sure the length is right and order hardened ones.

**altoona** · 07-06-2008, 07:24 PM

Ah, not centered side to side, I thought you meant front to back. Disregard my previous post!

From the description it looks like that's a stock non-hardened push rod. I'd call Summit and ask, they could probably tell you.

**ArmyWarrant** · 07-07-2008, 05:03 PM

Originally Posted by altoona

Ah, not centered side to side, I thought you meant front to back. Disregard my previous post!

From the description it looks like that's a stock non-hardened push rod. I'd call Summit and ask, they could probably tell you.

Well no need to disregard your previous post. I just didn't understand what you were saying I guess. I talked to Tim today and he straightened me out on the pushrod length checker. The pushrods that were in the car were 3/8" to short and my valve train geometry was way off. I am willing to bet the roller tip was barely catching the valve stem at full lift. I got it now though, I need to order some 6 5/8" hardened push rods and get the springs checked to make sure they have the proper seat pressure. I also will definitely be pulling the heads now and checking PTV clearance with the new push rods. Hopefully I will see no valve damage and PTV will be good to go.

Thanks Alot to Tim, you have been a huge help!

**ArmyWarrant** · 08-04-2008, 11:25 PM

OK I've redone the valve geometry again with the adjustable push rod and I've found that I can use a pushrod that is 6 3/4" in length measured with a tape measure, I will use a digital caliper tomorrow at work to get exact measurements. I redid the geometry in better light so I could better tell the center of the valve stem and realized the previous measurement was a lil off. I also got my springs checked at my machine shop and they have the following numbers

installed height seat pressure valve open seat pressure valve closed
1.800" 340 130
1.850" 320 115

Are these springs ok for a z cam? Also I am gonna go with these pushrods so I can do it on the cheap so I can get my car running so I can enjoy it a lil this summer. I will be disassembling the motor this winter and reringing and rebearing the whole engine so I will get better pushrods then.

http://store.summitracing.com/egnsea...115+4294778917

**Rodeheaver's** · 08-05-2008, 10:42 AM

the installed height of 1.800 is pretty good pressure for the z cam but you should check bind height of that spring because i thin kthe z cam is like .544 lift...

**ArmyWarrant** · 08-05-2008, 12:57 PM

.552 lift with 1.6 rockers. How do I check bind height? I've rotated the engine to full lift with .040 feelers gauge between the coils of the spring and they had slight drag on the feelers gauge. Is this good or is there something else I need to check.