Need HG advice...

phils89sc

Registered User
I am in the middle of pulling my unknown mileage (odo quit due to gear issue before I got the car) engine from my 95 SC. It ran ok before I pulled it, considering the HB was wasted. The question I have is should I replace the head gaskets even though it was running fine when pulled? If I do decide to, I want to use the Chevy 2.8L studs, as I have used them before and they worked well. Another question should be that because it is running fine now, and at some point, someone has either rebuilt or replaced the engine in my car (made obvious my the liberal use of orange RTV everywhere), if I pull the heads properly, do I necessarily have to have them shaved again, or just checked at the least?

Thanks everyone!
 
Without evidence either way means that in that example, it's up to you as a complete flip of a coin, I think. Leave them alone or throw money at it. I'd leave them alone on that year SC without concrete proof you need to go in.

And yes, if you have them off, have a shop take a look. Just make sure they can re-finish to at least RA-20...not all shops have the mill for that.
 
Without evidence either way means that in that example, it's up to you as a complete flip of a coin, I think. Leave them alone or throw money at it. I'd leave them alone on that year SC without concrete proof you need to go in.

And yes, if you have them off, have a shop take a look. Just make sure they can re-finish to at least RA-20...not all shops have the mill for that.

Thanks KMT. IF they do need to be resurfaced, how many times can that be done before the heads are no longer usable? I know this can vary according to how much they were warped every time they need resurfacing... Thanks!
 
According to the 1990 Factory Service Manual:

"Cylinder Heads
Replace the head if it is cracked. Do not plane or grind more than 0.254mm (0.010-inch) from original cylinder head gasket surface. Remove all burrs or scratches with an oil stone.

Cylinder Head Flatness
When a cylinder head is removed because of gasket leaks, check the flatness of the cylinder head gasket surface for conformance to specification. For Specifications, refer to the appropriate engine Section*. If necessary to refinish the cylinder head gasket surface, do not plane or grind off more than 0.254mm (0.010-inch).

*HEAD GASKET SURFACE FLATNESS (head) ........................(1.5645 in.) MAX ....... 0.018mm (0.007 in.)
*HEAD GASKET SURFACE FLATNESS (block) .........................0.08mm (0.003 in.) in 152.0mm (6.00 in.)

HEAD GASKET SURFACE FINISH (RMS)........................... 2.0 @ 0.8 5.5 @ 2.5"

A good shop can tell you if they can go again, I think. Let them decide.
 
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If you already have the engine out of the car, and don't know for sure that the head gaskets have been replaced, I would do them. If you put the engine back in, and had to tear it all back down in 10K miles cause the HGs blew, you will be extremely pissed off. If the gaskets haven't blown, the heads are likely fine, but I would at the very least check them for straightness. This is the straight edge I have and use on heads all the time.
https://www.tooltopia.com/central-tools-central-lighting-6429.aspx

That and a set of feeler gauges from harbor freight will get you checking your own heads for under $100.
 
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