What caused my cracked rocker arm shaft???

[Hendoo]

I had gotten on my 87 GN and after a small pop I noticed a knock in the engine. With marriage, kids, and career the car sat for a few years. I recently popped off the valve covers and discovered a cracked rocker arm shaft. The plastic retainer that attaches the rocker arm to the shaft was off on the front left and the shaft was cracked about 1 1/2 inches from the end. First of all, what's with the plastic parts? I was shocked when the first thing I found was the broken retainer top. The rocker arm was still sitting on the pushrod which wasn't damaged. I was going to replace the shaft, rocker arms, and pushrods, and oil pump(in case it was an issue) but was concerned if I should worry about any other damage. The car starts at the touch of a key the couple times I had to moved it but I'm skeptical that the fix will not be this simple. It's an inexpensive fix but don't want to throw money away if it's more.
Also, I've heard it's not good for the turbos sit...anyone have any suggestions to make the most out of this possible rebirth. Car is mostly stock with 64,000 miles, original chip, 40lb. injectors, Flowmaster exhaust, Lunati cam.

 

[whitehot1]

The rocker arm shaft breaking is a common problem on these cars.

The shaft's i bought from NAPA when mine broke were a thicker wall design than the factory ones.

I replaced the shaft's,rocker arms,and the plastic retainer buttons that hold the rocker arms on the shaft when it happened to me and it was good to go.

The stock turbo was a good design and plenty durable just keep the engine oil and filter changed every 3,000 miles and it should be fine.

 

[mybuick]

usually one of the 3 bolts comes loose

 

[turbofabricator]

If the rocker shaft bolts are over torqued with a aftermarket HD shaft, they WILL crack and break. I have not been able to source a real HD shaft recently, so it might be time for stock wrecking yard shafts or roller rockers with solid shafts. (and valve covers or RJC valve cover spacers to clear the roller rockers)

 

[Boost231]

i have a stock shaft if you need one.

 

[JST A 6]

Car is mostly stock with 64,000 miles, original chip, 40lb. injectors, Flowmaster exhaust, Lunati cam.

I know it's off topic, but this part caught my eye...I can't say I've ever heard of 40 lb. injectors; who makes them? How does the car run with them being controlled by the stock chip which is designed for 28 lb. injectors? Also, I used to have a Flowmaster exhaust on my car (was on it when I bought the car)--it runs a lot better since I got rid of it in favor of a freer-flowing exhaust without the crossflow design...Not trying to pick your car apart; just an observation about the exhaust and curious about the chip/injectors...

 

[Hendoo]

C'mon Mike!!

I'm far from being a mechanic but who do you think you are criticizing my car!!!! Just kidding...I appreciate the inquiry and could obviously use some help. I was told when I purchased the car it had 40lb. injectors. I did locate some on Postonbuick.com but l found a part number on mine and after a search found that they're actually a Lucas 30lb. set(D1720BA). I assume they would work w/ the stock chip??? Why would my gauge read 40lb. @ idle though? I'm actually, glad you started on these topics! No complaints now but wanted to get the most out of my GN w/ as little headaches as possible!! Would you go with bigger injectors and a TT street chip? I was also considering new headers and exhaust(since you bashed that setup too, any suggestions). No, the current exhaust squeaks whenever I two in the back, and I was considering starting over anyway.

Appreciate your comments and welcome anyone's suggestions!

Mike

 

[whitehot1]

As long as the stock headers aren't cracked i would leave them alone they are a good design and the aftermarket replacements are expensive and will still crack over time. The Hooker exhaust is the best and cost just over $300.00 from Jeg's performance at least the last time i looked they were.:smile:

 

[JST A 6]

I'm far from being a mechanic but who do you think you are criticizing my car!!!! Just kidding...

:biggrin:

I appreciate the inquiry and could obviously use some help. I was told when I purchased the car it had 40lb. injectors. I did locate some on Postonbuick.com but l found a part number on mine and after a search found that they're actually a Lucas 30lb. set(D1720BA). I assume they would work w/ the stock chip??? Why would my gauge read 40lb. @ idle though? I'm actually, glad you started on these topics! No complaints now but wanted to get the most out of my GN w/ as little headaches as possible!! Would you go with bigger injectors and a TT street chip? I was also considering new headers and exhaust(since you bashed that setup too, any suggestions). No, the current exhaust squeaks whenever I two in the back, and I was considering starting over anyway.

Appreciate your comments and welcome anyone's suggestions!

Mike

Bigger injectors and a TT chip certainly couldn't hurt, especially if you ever plan to upgrade your turbo. You'll definitely want to do the other fuel system upgrades too (Walbro or Red Armstrong XP fuel pump plus a fuel pump hotwire kit and adjustable fuel pressure regulator.) TT is the way to go for a chip; there's tons of people on here that will agree. A 30 lb. injector is close enough to stock that it should be fine with your stock chip for now, but if you're going to get a TT chip I'd upgrade the injectors at the same time since the chip has to be burned for whatever injectors you have. And as far as the gauge goes, that's reading fuel pressure--the injectors are rated in pounds per hour. Two totally different things.