About two years ago, my engine (523) developed a misfire. It ended up being a broken valve spring (TA 1125). I, along with other V8 members determined that it was probably just a fluke, so I got a new set of TA 1125 springs and just replace the broken one. Now, 2000 miles later, I was replacing the valve cover gaskets and see that I have two more broken springs. When I had the engine built, the builder used Morel lifters and they were very noisy, so I replaced them with Johnson's. That was probably 8k miles ago in 2017. The original pushrods were 5/16x 8.850. When I measured for new pushrods, I came up with 9.050 and got them from Summit. Right now, with the valve fully open, I have .067" between the coils. I never measured the original pushrods, but the invoice showed that they were 8.850. IIRC, aren't the Johnson rollers longer than the Morel and would require a shorter pushrod? I'm trying to determine why I am breaking valve springs. Here's my combination: TA Stage2 SE Intake valve 1041, Ex 1071, springs 1125, retainers 1450A, locks 1434B-.050, locator 1452B .045 Closed pressure 130lbs, open 370lbs Installed height 1.870-1.875 per build sheet Cam TA 413HLR-14 Int lift .378, Ex .381 TA roller rockers 1.6 ratio This engine has never seen 6k rpm, rev limiter set at 5700
I believe TA recommends TA 1160 springs for smaller roller cams and TA 1195 for larger ones. I doubt the 1125 has enough seat pressure
If the spring rate of the spring(stiffness) isn’t enough for the aggressive roller profile, it can break. The base of the spring can move around so the spring is no longer perpendicular to the head and contorts as it’s compressed, the uneven division of force on the spring can cause it to break.
Those are the springs that they used when they built the engine. I assume that they knew what they were doing, but anything is possible. They are the ones that installed the crappy Morel lifters instead of the Johnson's.
8.850 is what I've used on some bbc motors......just ordered 8 for a gen6 502 with world product heads......the stk one from that motor are 8.550 I dont know how tall the roller lift you ate using but bu on tappet cam with similar lift I think buicks are around 9.200
They should be ok. When I measured for new pushrods, the engine was on a stand so it was easy to get the correct setup. I'll recheck after I get my front springs and install them and get the car off the stands. I thought it was just some minor maintenance this winter!
For best push rod geometry, the adjuster for the roller rocker should be flush or nearly flush with the bottom of the rocker arm.
When I measured for new pushrods, I came up with a .200 longer with the adjusters flush with the bottom of the rockers. After adjusting the rockers, I'm at most, 1/2 of a thread recessed in the rockers so I'm confident that I measured correctly. As for spring installed height, I didn't measure. I just used their build sheet and assumed that it was correct. I don't feel confident just replacing the other 15 springs. I have replaced broken valve springs at the dealer and at that time, we knew that it was just bad springs. When we found one broken spring, we replaced all of them per GM. I lucked out when the first spring broke 2k miles ago because the broken outer spring actually ended up breaking the inner spring and it didn't drop a valve. The only reason I knew something was wrong was because I had a misfire from the valve not being closed. The engine made no noise with just the inner springs not broken. I doubt I'll be that lucky a second time. How do I even know that these springs are correct for my application? How would I know that even if the 1125 springs are correct, maybe they grabbed the wrong parts when they put the heads together? There is no part # on the spring. There were other parts on my invoice that were not the parts that they installed.
Read this. The springs have manufactured recommendations. I’m not sure why they would install 1125 when 1160 or 1195 are their own recommendation. Stuff happens so possibly an oversight causing your issue. The 1125 would have been good for non roller 413
I'm a mechanic, not a machinist and I can see the poor machine work on my engine. I would have been better off buying the parts and building it myself in my garage. When I pulled the engine apart after 1k miles to seal the oil leaks, I realized that they did a terrible job. The first thing I found for my oil leak was that they just rtv'd the front oil pan spacer for the block girdle instead of opening up the front holes on the pan and fitting it properly. When I pulled the timing cover off, they charged me, parts and labor but didn't install threaded plugs. They didn't install a block plug in the left bank for the rocker shaft oiling. I was charged for oil modifications to the block, but the only ones that I see is opening up the hole for the rear main bearing and enlarging the oil hole where the sending unit goes. They didn't even chamfer the oil feed hole to the timing cover. The lifter bore girdle is clearly installed too far forward. When they installed the oil seal from the block girdle to block, in places it was inside the studs and sometimes it was on the outside which caused oil to leak through the oil pan studs. The ring gaps should be .019-.020. Mine varied from .015 .025. I was charged $400 to run the engine to break in cam and check for oil leaks. I have a roller cam and my engine leaked from the timing cover/oil pan as soon as I fired it up. If they did run it, maybe that's when they packed the timing cover with rtv. These aren't the only issues that I had. I waited 32 years to build this car because I wanted to do it right. I expected more for $20k+ and 20 months.
9..050 is typical for pushrod length in that application, and the 1125 spring set is my set of choice for a hyd roller, when I use TA springs. Done a lot of them, never broke a spring to my knowledge. But the installed height to get those pressures from an 1125 spring set will be much shorter than you listed.. unless they were swapping inner springs around or something.. you never know... So that's not an issue. Springs break for a variety of reasons, most of which you should not be seeing with a hyd roller cam. What rpm are you typically shifting at? Sorry to hear of your trouble.. wish I could help more, but you have an unusual situation there.\ I would start by purchasing a valve height mic and verify the installed height, and then take an unbroken spring to a machine shop, and have them pressure test it, with the whatever seat height you come up with, then add .600 lift, which is what your cam has, and see what open pressure you come up with. JW
I just looked in their catalog.I think they did install the wrong springs. I truly believe that all of the specs that they have listed in the spec sheet are just what they should be, not what they are. When I spoke with the builder about why it was taking so long, he stated that he hired a new machinist and he wasn't as precise as he should have been . Boy was that an understatement.
It's an automatic that is in 3'rd gear by 20 mph. This engine has never seen 6k rpm. I will purchase a valve mic and check them. Like I said, I believe that the machinist just wrote down good specs, not actual specs.
