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3.4 DOHC timing


HipPieFarmer
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The head gasket on my 1994 CS 3.4 DOHC blew, has been replaced, now needs timed. I got the cam hold down tool and a degree wheel. I have a chiltons and a good working knowledge of cars. Am I missing anything?

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Apparently you're talking about camshaft timing, not ignition timing.

 

To START with, you'll need a new timing belt kit with pulleys (about $120 or less on Amazon) and fresh synthetic oil in the spring-loaded timing belt tensioner. You'll need a small screwdriver to retract the tensioner plunger, and a repurposed paper clip to hold the tensioner in the retracted position. Don't forget to re-install the two rubber plugs in the tensioner--or to remove the paperclip.

 

I think your '94 uses a different cam sprocket locking system than my 93. Can't help you with that.

 

First Guess: You can chuck the Chilton's manual in the trash. I suggest a REAL GM service manual instead. Typically about forty dollars on eBay, but sometimes much less.

 

I really hope you replaced BOTH head gaskets and planed the heads flat again, while you had the engine apart. Especially if your head gasket popped on cylinder numbers one or six, where the head seems to have a weak spot that promotes gasket failure.

 

Note one head gasket bad enough to wet cylinder #1, while the failure on the other head gasket was just a few miles away:

Lumina_Head_Gasket_02.jpg

 

Lumina_Head_Gasket_03.jpg

 

PS: The exhaust valves of these engines look like shit in 150,000 miles. I hope you inspected for burnt or leaking valves, too.

 

Lumina_Valves_01.jpg

Freshly-reground exhaust valve on left, 150,000 mile exhaust valve on right.

Edited by Schurkey
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The head gasket on my 1994 CS 3.4 DOHC blew, has been replaced, now needs timed. I got the cam hold down tool and a degree wheel. I have a chiltons and a good working knowledge of cars. Am I missing anything?

I feel bad for you, its a pita but you should replace your intermediate chain and timing belt while your at it (while its all apart)

Ive never done it but have heard the worst stories but it doesnt look tooo bad, but would help if your hands are smaller.

-O and make sure you bleed the hydraulic tensioner correctly as in the manual (dont wanna ruin all the hard work!)

-Your manual will cover eveything you need to the last detail, just make sure you have all your tools needed, be patient (your not getting paid by the hour,though i know you want your car!)

-ALWAYS DOUBLE, TRIPLE CHECK WORK! especially if you dont have an assistant,

-Replace pulleys if the feel rough

Im sure theres more but you get the idea

Good luck

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Double and triple-checking is always a good idea, but replacing the intermediate chain...unless there is suspicion of a problem, I'd probably leave well enough alone, pulling the timing cover isn't a very fun job.

 

And Shurkey is correct, your engine, and later ones do use a different sprocket locking system, it's a tapered split ring the sprocket bolt compresses. Getting those sprockets loose can be a pain--and a sprocket holding tool is very useful, I stripped one of the hold-down holes trying to get away with not using one, and destroyed a homemade hold down tool. Finally, I broke down, and bought a Kent-Moore specialty toolset from Ebay, worth every penny.

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Not lookin to replace intermediate chain but replaced the other parts plus the tensioner( it was bad also) .im gonna look into getting gm service manual. Plus I got talked into only changing the 1 head that showed a pressure leak and its back together now except for timing so...fun. Thanks for the advice guys.

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