Just finished an N/A build for a customer's 02 RT and had a very disappointing end result yesterday. We built the car to be strong with the idea of adding a Roe over the winter. The engine was treated to billet main caps, oliver rods, custom diamond pistons, 1.6 and 2.02 valves, 70mm t-bodies, B&B headers, high flow cats, VEC II, aluminum flywheel, centerforce clutch, Baer brakes f&r, hurst shifter, unitrax halfshafts, custom grind billet Crower cam, and a complete Crower valvetrain.
Everything went extremely well with this build and the car was taken to the dyno yesterday for a final tune and scheduled for delivery today. The car was running well and pulling hard on the dyno considering the air temperature and pulled a best of 541rwhp and 544rwtq still felt there was a little more in it. On my last pull of the day the engine made a popping sound on decel and then clearly had a miss.
This is what I found after pulling the rocker cover off. The Crower rocker had jumped off the valve stem and had pressed down on the side of the spring-bending the valve, the pushrod, and ruining the rocker. Apparently this is a common problem with Crower. After doing a search on the Alley and speaking with Crower I know I'm not the only one to run into this-it's been happening for years. Looking back, the decision to run these rockers was a poor one and the new T&D's are on the way.
We build alot of race cars (mostly BB chevy) and the Crower products work great on our 800 hp dry sump motors. I find it very disappointing that Crower would continue to put out a product that has a high failure rate without improving it, we never turned this engine past 6200rpm-I think the stock rockers would have worked better. I guess it could have been worse, the cylinder head is fine, and doesn't appear any other damage has been done. I am lucky to have an understanding customer but just really sucks I couldn't deliver his car for the long weekend. His neighbour just picked up his '07 ZO6 and my customer is pumped to show him how it's done.
Sorry, long post but just wanted to warn everyone before somebody else makes the same mistake.
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Andrew Turner
SPi
www.spi-performance.com
The springs, pushrods, lifters, retainers, locks etc. came as a kit from Crower as a matched set. Unsure on spring pressures-my builder has the spec cards-I'll be able to tell you on tuesday. Thought the pushrods looked weak though.
Sux! I knew a day would come when someone would post this scenario. This kit is flawed in that they should offer pushrod guideplates just in case the valvetrain floats. The valve tip capture setup they incorporated is a novel idea, but just doesn't cut the mustard in the real world. Most likely an engineer with little to no field experience brought this design to the table. What is really amazing is that myself and others brought this flaw to their attention years ago and they still offer the kit. Hell, I even told Dave to use the Isky guideplates back in the 90's before the T&D's came to be.
One more thing... More often than not, Crower installs the camshaft pin 5-10* off which creates massive torque down low, but the car will float or break up around 5,500 rpm. This could have easily caused the problem you're now facing. Good luck!
" This expression meaning "to achieve the required standard" is first recorded in an O. Henry story of 1902: "So I looked around
and found a proposition [a woman] that exactly cut the mustard."
A Yahoo search revealed 2,600,000 results for cut the muster, and 5,444,000 for cut the mustard
I actually thought you might be right, but so far the facts say otherwise.
" This expression meaning "to achieve the required standard" is first recorded in an O. Henry story of 1902: "So I looked around
and found a proposition [a woman] that exactly cut the mustard."
A Yahoo search revealed 2,600,000 results for cut the muster, and 5,444,000 for cut the mustard
I actually thought you might be right, but so far the facts say otherwise.
We installed a shaft mount rocker set-up, one new valve, and one new guide. The car is back together and running really strong. It was delivered to my customer ,has been trouble free and he is really enjoying his new found power. Lesson learned. On another note, these Baer brakes are awesome and I would recommend them to anyone looking for a serious increase in stopping power. The car will be getting new wheels in the near future to help show them off as well as drop.
Looks like a case of installation error. Can't blame Crower for this. Can happen with any rocker if you miss checking one thing, pushrod length.
Wrong geometry
Jerome, you need to read the post. The pushrods and all were sent as a kit. Does this mean you have to remeasure and redesign a kit when it supposeably has been done before you pay for it???
Jerome, you need to read the post. The pushrods and all were sent as a kit. Does this mean you have to remeasure and redesign a kit when it supposeably has been done before you pay for it???
Short answer, yes you always check and recheck what you are doing. No redesign of anything, just making sure to have the proper specs on things.
Anyone who just throws the parts together and hopes, well .....
The original pushrods were not the incorrect length-the rockers are a poor design. Dave Crower says they are good for 6300 rpm, not that I needed to turn it that high, but after speaking to many people on this and even Crower's tech support I have found that they don't hold together much after 5500. It was a poor choice of parts. The new Crower shaft setup works great and we did measure and spec out our own pushrod length.
The BAER brake package will run you approx. $6000.00 for the kit I used. It comes with six piston calipers front and rear, larger rotors with aluminum hats, pads, braided lines, and of course all hardware. The only thing you need is an e-brake relocator or a custom e-brake from Dave's.
