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Post by 69Rebel on Jul 16, 2023 7:17:39 GMT -8
OK, so I'm thinking about swapping out the heads on my Jeeptruck. Between the exhaust leaks due to broken bolts and the shitty Motorcrap carburetor, it's making me nuts. Thing is, I have never set up bridged rockers. If the heads have been surfaced, will I need to shim anything?
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Post by landbarge on Jul 16, 2023 7:44:08 GMT -8
I'd say no. They didn't remove any sizeable amount to make a difference of a couple thou that a lifter can't take up for
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Post by spud on Jul 16, 2023 8:08:34 GMT -8
I’m saying check the preload. Reground valves and seats cause the valvestem to move up, which in turn causes more preload on the lifter. So with reworked heads its common to have varying valvestem height. Heads that have neen milled cause the same thing to happen. Your set of pushrods just may have an odd length pushrod in them. Your pushrod length might be generally ok, but maybe not so ok on one or more valves. I dont disagree with barge. Your probably ok, but you dont really know how ok, or if ok. I would expect (possibly wildly) varying lifter preloads with anything that is not a picture perfect factory head. Fixed rockers were ok on new stuff. Thats not what anyone has anymore. So its like diving into unknown waters. You best check it out. You dont have too. If theres a problem your gonna find it. How you go about it is your choice.
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Post by 69Rebel on Jul 16, 2023 16:52:26 GMT -8
Dangit, spud, that sounds like work.
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Post by spud on Jul 16, 2023 18:18:53 GMT -8
Everything is. Just check it on one pair. Chances are the rest might be ok. Whats the worst that can happen? Eat a cam or drop a valve?
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Post by 69Rebel on Jul 16, 2023 18:39:11 GMT -8
Eating a cam or dropping a valve probably wouldn't make me very happy.
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Post by Captain Awesome on Jul 16, 2023 20:56:13 GMT -8
On the heads being shaved, what's the thickness of the stock gasket to the Felpro?
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Post by 69Rebel on Jul 16, 2023 21:27:34 GMT -8
I think I have a pair of Enginetech head gaskets on hand. I'd bet that they are maybe a touch thinner than stock. I should just order a shim set before I even get started. I don't want the damn thing sitting for a week while I wait for small parts.
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Post by spud on Jul 17, 2023 4:52:08 GMT -8
Even more reason to check
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Post by hurst390 on Jul 17, 2023 5:01:32 GMT -8
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Post by landbarge on Jul 17, 2023 5:38:29 GMT -8
I'm surprised that you're putting heads on it seeing that all the AMC V8's engines are rolling time bombs with that poorly designed oiling system
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Post by 69Rebel on Jul 17, 2023 8:11:39 GMT -8
There are two things wrong with this motor; it has the factory intake that only accepts a Motorcraft carb, and the center exhaust manifold bolts are broken off flush. I tried drilling them out, but whatever they are makes grade 8 hardware look like putty. Original engine from 1978, never been apart.
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Post by spud on Jul 17, 2023 12:06:13 GMT -8
If you have a mig welder you can try welding nuts to the broken bolts. That usually works , but being in the chassis makes it pretty tough to get a solid weld. If they are stainless bolts u can get carbide bits that can cut through them stainless heat hardens to some serious hard to drill metal.
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Post by 69Rebel on Jul 17, 2023 12:09:11 GMT -8
There isn't anything to weld to, spud. They are flush with the head. Not to mention it's dinky little 3/8" bolt, tough to get a good weld inside such a small space, even if I could even see it to weld it, which I can't when the motor is in the frame. Whatever they are made of, it is harder than woodpecker lips. Hard steel like that doesn't tend to weld very well.
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Post by spud on Jul 17, 2023 12:14:37 GMT -8
Flush is still do-able, you need something to hold the nut in place. A 7/16ths nut is better, you can wire weld it to the flush boltshank, it wont stick to the iron. Squirt wd40 on it to cool it. Oh hell i’m no cheerleader. Yank the heads. It aint worth tearin up your neck.
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