Valve Spring Install Height 1.890???

[TurboBuRick]

I'm working on a car with M & A heads. The motor will not go past 5100 rpm. The logs show nothing. Car pulls clean to 5000 then it breaks up. So I started to investigate the valve train.

Back when the car was sold the add said: Crane 212/206 Roller Cam, lifters, springs

So I yank of a valve cover and pull a valve spring. Start to do some measuring and found the install height is 1.890. The mystery spring is a single coil. I have not got over to the machine shop to measure spring tension but the installed height seems too high. Just doing some basic searching on the net I don't find much.




Any insight?

Rick

 

[bison]

Depends on the spring Rick. If it's close to 1.25" od chances are it's set up way too loose and youre going in the right direction. It's also possible the heads have a set of .100" taller valves like the race heads come with. Gn1r, etc. Those valves allow the use of much larger double springs where you aren't at the mercy of installed height and seat pressure issues. If I remember correctly the MA heads had very small spring seats. Let me know the size of the spring seat on the heads and the valve guide is where the seals are installed and I can better advise.

 

[TurboTdr3.8]

The mystery spring is a single coil

Probably has beehives springs on it , that's what my car is doing hits the wall at 4900 to 5200 rpms then breaks up

 

[TurboBuRick]

Brian, I was hoping for your reply.

Yes the springs are 1.25" And the pockets are not much bigger. Maybe 1.30". I can't get the caliper in there.

The guide is .500".

Not beehives.

Rick

 

[bison]

Probably has beehives springs on it , that's what my car is doing hits the wall at 4900 to 5200 rpms then breaks up

I ran 26120 conical for 2 years with zero issues. If they are the right pressures they are as good as any other spring. I still have the set I ran for 2 years. All but one were within 3% of the rated pressure. The one that wasn't was off about 5% but was still well within range. Conical springs offer some advantages over other springs. When used with a locator they can be shimmed almost to coil bind and offer very good stability compared to other springs. The ones on my engine were about .020" from coil bind! The car went 137+ in the quarter and was regularly revved to 6000rpm.

 

[bison]

Rick let me know if you want a set of springs/retainers that will get it done.

 

[TurboBuRick]

Set me up bro.....

 

[qws2000]

Turbo,
You and myself are in the same boat, I also have Bee Hives on mine and can't get rpm's above 5200... I would guess you are frustrated like me, Brian set me up with new springs and also gave me a sheet of paper with install ht. Check with him, he helped me so much

 

[bison]

Set me up bro.....

Verify the geometry is correct with the current setup. How are the rockers mounted?

 

[TurboBuRick]

The rockers are mounted to the suds individually. Like chevy rockers.

Come to find out my measuring tool is made for bigger retainers and threw off the reading when I measured. After realizing that little detail, the insall height is actually 1.750.

I want to go check a few of the spring tensions tomorrow.

What kind of spring pressure do you like to run on higher rpm roller cam set ups?

Rick

 

[bison]

Depends on rpm and the intensity of the lobe. I spring more for intensity than rpm on most of these engines. With a cam like that it probably isn't doing much over 5500rpm unless the heads are really good and the boost is really high. 150-160 on the seat and about 390-400 open should easily cover the needs there.