Broken Valve Spring - Which New One?

[BrianT]

My buddy broke a valve spring on his J headed 360. We don't know much about the engine. He was told it was a 380 hp 360 crate engine when he bought it, but we've since noticed that the heads are a different color than the block so we know they've been off. No idea what cam is in it, but it is hydraulic and has a decent lope at idle.

He has decided to go ahead and replace all of the valve springs while we have the tools out and to prevent this from happening in the future. We know that they can be replaced while in the car and we have an air compressor and hose to pressurize the cylinders. We have two questions.

What tool do we use to compress the springs? Can we get by with the screw type compressor available at the local auto parts store or do we need to buy the expensive tool made for Mopars?

Without knowing what cam is in the engine, how can we determine what spring to use? The ones that are in there now are single springs with a dampener.

Here's a pic for those who like to see the carnage. Thanks for any help you can provide!

 

[Abodybomber]

The tool rental spring compressors,fail every time. Tried both O Reilly's /AutoZone , couldn't handle 300 pound compression springs. Went with Napa/K-D tools part number,2078. It handles Rat Chevy springs,in the 400 pound open zone. Cam specs aren't really important. What is: installed height/ pressure at valve closed/pressure at full lift/maximum lift. Maybe some research on the LA based 380/360 crate engine,would find your answer.

 

[Mopar Tim]

Well IMO replace them all with a known value spring. One broke, WHY? they all might be incorrect with the cam combo you are using. MT

 

[duster360]

I have this spring compressor and it works great.

http://www.summitracing.com/parts/pro-67460/overview/make/dodge

 

[AJ/FormS]

I bought an on-engine spring compressor from Hughes Engines when they sold me their 1110? springs. It works great. It looks a lot like that proform.

BTW; those 1110 springs work great too. They were the recommended ones for their HE3237 cam, which I purchased on the same order. With a quarter turn of preload on their 5003 lifters, and with 1.6arms,that cam just pulls forever. I yank the stick at 7200, but its still pulling.

 

[krazykuda]

The only way to know the specs of your cam are to degree it.

Or wave a magic wand over it, but I'm behind on my bills and my isp has shut off my magic wand and crystal ball signal until I pay....

You need to know what your cam is to get the proper springs....

 

[BrianT]

In a perfect situation ie. last winter, that's exactly what we would have done or even replace the cam and springs with a matched set. Right now, we are thrashing trying to get the car back on the road.

Can we pull a good spring and measure it, then buy one the same size but maybe upgrade the pressure just in case they were too small in the first place? I have a set of brand new Edelbrock springs that came off of my aluminum heads?

 

[Bakerlite]

As long as your original spring was controlling the valve train,
Check for coil bind
Take out spring
Measure installed height if you can, but not absolutely necessary
Put in spring checker to get spring rate.
Measure outside diameter of spring
Go to Comp Cams website , go to spring charts.
Find spring of same spring rate and size as yours.

 

[BrianT]

Yeah, he wasn't floating the valves or anything. It is a cruise night type car that gets hammered on every once in a while. NO strip action.

 

[moper]

The fact one broke doesn;t mean what it has are inadequate. But given the lack of info on it - I agree with the "measure it" and get something that will work. You have toknow what the cam is to really get it right. If the heads are different god knows what's on it. You can also check the pressures of the others and see where they are. My guess is if you measure the pressures on the springs, and measure the cam to get an idea of lift and rate of lift, you may find the two are not compatible and you need more spring. Use of the car means nothing. The engine is either right or it's not. Broken spring to me says it's not and it's lucky it didn't eat anything further.

 

[BrianT]

Yeah, it happened right in front of his house. Spun the tires, pulled in and it was running rough.

I have a full set of NEW Edelbrock 5767 springs, retainers and locks that came on my Performer heads. We are going to try and pull the exhaust spring on that same cylinder using the rope trick and a borrowed spring compressor to get some measurements.