rocker arm broke
- Thread starter johnnyrod
- Start date
unclebrad
Active Member
Regarding the Cam, see Picture below. Also other information regarding the rebuild that the seller provided
I have put about 200 miles on the engine. I bought it from a guy outside of Seattle, who rebuilt it. He said that he ran it on an engine stand for about two hours before I got it. He showed it running on video as well. Sounded great. No smoke.
I had a look at the studs for marks. thankfully, they are painted or anodized black, which makes it it easy to do. I am not seeing any marks.
The studs are 7/16.
Something about the smoking issue that I didn't mention - Most of the smoke is coming from the driver side pipe, while the broken rocker is on the passenger side. The pipes do not connect under the truck.
Thanks.
B
I have put about 200 miles on the engine. I bought it from a guy outside of Seattle, who rebuilt it. He said that he ran it on an engine stand for about two hours before I got it. He showed it running on video as well. Sounded great. No smoke.
I had a look at the studs for marks. thankfully, they are painted or anodized black, which makes it it easy to do. I am not seeing any marks.
The studs are 7/16.
Something about the smoking issue that I didn't mention - Most of the smoke is coming from the driver side pipe, while the broken rocker is on the passenger side. The pipes do not connect under the truck.
Thanks.
B
Since your heads have 7/16 studs, you have options on the type of rocker to use. Most guys use a roller or a roller tip rocker. Your stamped steel rockers are probably a Chevy big block maybe made by Comp Cams. You can purchase one and see if it matches what you have. Hopefully they are not an unbranded cheap aftermarket piece. Replacing the one broken rocker will at least get you running. Some of the other guys can give you a better recommendation than me when it comes to roller rockers.
Before starting you really need to know if your getting oil to the valve train. Best would be to remove the distributor and prime the engine. You'll need a priming tool specifically for a W motor or make one out of a old distributor. If you don't have adequate oiling you will continue to have valve train problems - wear, heat, failure.
Although your cam is relatively small in lift, you should check the springs for coil bind. Since you didn't build the motor, it's hard to say what springs were used. Your cam card tells you what Crane recommended with their cam and the specs of the springs. If it's the Crane spring, the cam card states it should have a blue strip. Might be an indicator. You can also measure the installed height. The list shows Lunati lifters with the Crane cam, so maybe another brand of springs.
Make sure you get the valves adjusted properly. I just follow the service manual and adjust them on TDC of cylinders 1 and 6. Simple and it worked for Chevrolet.
After all of the above is taken care of, then address the smoking problem.
Before starting you really need to know if your getting oil to the valve train. Best would be to remove the distributor and prime the engine. You'll need a priming tool specifically for a W motor or make one out of a old distributor. If you don't have adequate oiling you will continue to have valve train problems - wear, heat, failure.
Although your cam is relatively small in lift, you should check the springs for coil bind. Since you didn't build the motor, it's hard to say what springs were used. Your cam card tells you what Crane recommended with their cam and the specs of the springs. If it's the Crane spring, the cam card states it should have a blue strip. Might be an indicator. You can also measure the installed height. The list shows Lunati lifters with the Crane cam, so maybe another brand of springs.
Make sure you get the valves adjusted properly. I just follow the service manual and adjust them on TDC of cylinders 1 and 6. Simple and it worked for Chevrolet.
After all of the above is taken care of, then address the smoking problem.
unclebrad
Active Member
Thanks for the advice.
The slotted rocker arm ball should be a great help in my search for a replacement rocker arm, but I haven't seen one yet. I did go to the comp cams site and was unable to find a steel rocker arm for a 409. They just had rollers.
My next step was to buy a stock rocker arm from show-cars, but it turned out not to be a match.
I also sent an email to the guy who sold me the rebuilt engine, hoping that he remembers what brand he put in. Waiting for a response.
The slotted rocker arm ball should be a great help in my search for a replacement rocker arm, but I haven't seen one yet. I did go to the comp cams site and was unable to find a steel rocker arm for a 409. They just had rollers.
My next step was to buy a stock rocker arm from show-cars, but it turned out not to be a match.
I also sent an email to the guy who sold me the rebuilt engine, hoping that he remembers what brand he put in. Waiting for a response.
The stud slot on what you are using is obviously wider. SC only shows their 8693 in a "stock type" rocker. It says 348/409, 1.75. My guess is that it is for the stock 3/8 stud. The have 7/16 nuts & balls, but no stock type rocker that says for 7/16 stud. Another guess is that you have stock 1.7 ratio BBC rockers since you have 7/16 studs..
Jeff
Jeff
unclebrad
Active Member
I stopped by one of our local machine shops and showed them the broken rocker. The knowledgeable guy there dug a BBC rocker out of a bin to compare. He wasn't sure whether it was from a 396 or 454 but it looks like a very close match. Even though the body dimensions are slightly different, it looks to me like the contact positions are the same.
He gave it to me, but I decided to order one of each from Summit just to see if I can get a closer match. They should be here Friday.
Stay tuned.
He gave it to me, but I decided to order one of each from Summit just to see if I can get a closer match. They should be here Friday.
Stay tuned.
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