I was coming home from work, and the motor started sounding odd. Sounded like an exhaust leak. Cam home and put my stethoscope on the valve covers. Pulled one off and after some investigation, noticed a broken valve spring. I lookes like it held but the valve up prett well, but I am a little worred that the valve may have touched the piston. I guess the only way to tell is a leakdown check after I replace the spring. The motor: 331 SBF with Trick Flow heads. I had these heads on my 289. I had them freshend up for the new motor. He put in new springs for the hyd roller cam. I'll have to dig out the cam specs. They are single springs with dampners. It broke in two places. I'll have to check the milage, but I dont think these springs have more then 10k on them. Why do valve springs break? This car does not get driven hard. I dont think I have gone through all 3 gears flat out with the new motor. Should I be replaceing all 16 springs? Or was this just a weird one time thing and I can only replace the broken one?
Just dug through my old recipts. Did all of the motor work in the spring of '04. I think my machinest might have just shimed the stock Trick Flow springs for the roller cam. Didnt see a charge for new springs, but it mentioned shims. The cam: Cam Research hyd roller In. Ex. lift .536" .536" Ad dur 282 285 @.050 222 226 Recommended valve spring data: Installed ht 1.850" 110lbs open ht 1.250" 310lbs I think he must have shimed the springs to get those numbers. It wasnt in coil bind. I dont think he had to shim them much to get there.
I need to get a good on the head valve spring compressor. I had this one from summit: http://store.summitracing.com/partdetail.asp?part=SUM%2D906784&N=700+4294925139+4294925138+4294853214+115&autoview=sku but it sucked. Bent the first time I tried to use it, so I returned it. I was wondering if the Moroso unit http://store.summitracing.com/partdetail.asp?part=MOR%2D62370&N=700+4294925139+4294925138+4294853214+115&autoview=sku is better and worth the extra money? Or do they make summits for them? Are there any other options?
As far as I know, you should replace them all. If 1 broke, the others are probably getting close to going too. Also, they will then be similar strength and make for even wear on other parts. But you can put the 1 spring on first to do the leakdown.
Replace them all. If one broke the others are close behind. I would consult the cam supplier. They will let you know what they would want to see used with there product. chuck
I would replace all 16.. although spring breakage can often be caused by a stress riser when someone scratches or gouges a spring due to rough technique when installing them.. if this was the case..and no other springs were damaged, then just replace the one.. but its not east to inspect them all properly while installed. they arent dear, id do the lot. an old trick is to take the plugs out, put the piston down the bottom of its travel, fill the cylinder with rope by feeding it in the plughole, then squish it up hard into the combustion chamber, thsi holds the valve closed well enough to change out the springs. Remember to leave the tail of the rope out
Hey Ben, that's a neat trick with the coil of rope into the cylinder - what other old-timers tricks can you tell us. We could start a section on here for them cos we are all DIY's
I was always taught that you do everything in pairs. So if one valve spring busted, then the other's may not be far behind.
I just replaced two valve springs on my sandrail by removing the sparkplug and connecting my air hose from my compressor to keep pressure on the valve.
I don't like single springs on overhead valve engines. With double springs, when one fails, the valve may float, but there is still something there to keep from dropping a valve.
I just had this happen on my 351W. Crate motor with World Prod. heads and a Comp Cam. Cam specs said to use .372 springs but the heads came with Chevy Z28 spec springs and push rods.They are quite a bit smaller than the .372 springs. The motor was put together with the Chevy springs. I flooded the motor trying to start it one day and over rev'd it when it finally fired. I broke a valve spring and bent a push rod. So far I have only replaced the broken spring and push rod and did a leak down test. I've put about 300 miles on since ,but this winter,I'll replace all of the springs with the .372's. We used the leak down tester to hold the valves closed while we replaced the spring. At one point we had to leave the job for a couple of hours ,so we wrapped masking tape around the valve stems to hold them up and shut off the compressor. We also removed the intake valve spring ( it was the exhaust on this cylinder that broke) and used a valve spring tester to match the correct springs from a box of Chevy springs we had.( That's how we found out they were Z28 spec. springs.
I tend to look at things that come in sets, like valve springs, spark plugs, etc. as items that are replaced as a set. Might be anal, but I'm thinking that with valve springs they've all led a similar life in the motor, and are also of similar metallurgy...so if there is a breakage problem due to use, wear or a defect, it might manifest itself again. I wouldn't want to be dogged by having them continue to fail after I've opened it up once so I would do them all. Especially springs...you could easily break one and lunch the motor. I've used a home made adapter (welded an air fitting to a gutted spark plug) to charge the cylinder with compressed air in order to change springs with the head on and it works fine. I've also used the rope method with some old clothes line before I had shop air...and that worked fine too. Less danger of the valve falling in because you've filled up the cylinder with rope, but it also took a little longer. Personally I would use a dual spring setup (possibly with a flat wound damper as well). -Scott
Are they older Trick Flow heads? I had a set of the older SBC Trick Flows and when I pulled them to replace a head gasket all the dampers (Inner springs) were broken. I did some net-surfing and that was a problem with the early heads. Id do um all.
My bother-in-law and I ran a 77 Ford 4x4 with Cleveland 400-M. He had his mechanic stick a mild Norris cam in it. The mechanic, a local hot rodder with a good rep so I'm sure that part was done right. He broke two stock Ford valve springs then the gas crunch came along and he sold the truck to me. I put a slightly more radical, but not by much Crower cam in it. It broke one spring on me. I didn't rev the truck past 4500 rpm. Coil bind was checked after the first spring broke on bother-in-law and when I put the other cam in. No problems there. I talked to Crower about the breaking springs, the guy told me that if things are set up right and springs break, sometimes it's just a mystery. I stuck a set of Crower springs in and no more problems. I heard later that Ford had a bad heat treat on a bunch of valve springs in that particular engine series. Little brother was forever breaking valve springs on his DRCE engine in his drag racing Henry J. About one per run on average. He was running single springs with a damper. He went to dual springs and no more probs there. The 500 cid engine gets spun to 9200 rpm before shifting and the stage chip in the rev limiter is set at 6800 rpm so the big engine is spinning up some serious revs. Most times, you can get away with replacing one spring on a street engine that doesn't see a very high rev point. If you break a second one, it's time to think about replacing the whole set. I'd make a point to check if coil bind was present with the old springs. Most engine guys are pretty good and you can depend on their work. Then . . . there are the guys who call themselves engine guys, but all they do - besides draining your wallet - is give the good guys a bad name. In your case, I'd opt to replace the whole set with a dual spring setup that's the correct "pounds when open" rating. I've had very good luck with Crower springs. Make sure no coil bind is present and check to see if the rocker clears the valve spring retainer when the valve is fully open. When you replace the springs, get yourself a spark plug air line adapter - which is available on the KD tools rack at the parts house, they don't cost much. Neither does the lever tool also found on the KD rack. Depending on how your engine is set in the car, you may have to make a bridge from 1" x 3/16" strap steel that bolts to two of the rocker studs (with rockers removed) and has a hole for another bolt that the lever tool attaches to. Sometimes the Ford engines are far enough back that you can't operate the lever tool. Pull all the rockers prior to starting. That way you don't have to worry about being on TDC since all the valves will be closed. The old white clothesline rope down the cylinder is a good trick, but it takes a while and buying the adapter sure makes life easy.
Take a look here for KD's Ford style compressor: http://www.mytoolstore.com/kd/kdengi13.html#3271 #3087, 2nd from the bottom is the one I have and it works well. Price sure went up from 15 years ago....
I had an old hemi guy tell me to take the tension off the springs when engines sit for along time , like most people I have engines that sit for years on the engine stand waiting for me to finish collecting parts for a project, and of course I'm useing springs that are much heavier than stock. imagine a new heavy spring compressed in a motor for a few years.
as mentioned, follow the cam makers specs, get a set of new springs, and it might help to pull the heads to install them, then you can check everything out. Although it would probably be ok to replace the one spring for now, and do the rest sometime in the near future. It's been my experience that sometimes one spring will break at random, and in other cases the set is worn out and several will break.
The Jalopy Journal
