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I broke an intake manifold bolt in the head. It's the first bolt on the front passenger side. I had to drill it out and put in a helicoil. I'm concerned about what is under that bolt hole. Does anyone know if it goes to anything?
The intake bolts go into through holes, exiting into fairly large chambers on the reverse side of the cylinder head. I have not had my LS1 apart, but google references indicate those chambers coincide with the rocker valleys. Not the good news I was hoping for.
Not good news. Guess I will be pulling the head. At least I have the winter to do it. Thank you for your help!
Before you pull the head you should verify that the front intake bolt actually goes into the valley area. The middle bolts do go into that area. The first intake bolt may not align with the lifter tray and may be outside of the lifter tray/valley area. You could always get a cheap boreoscope and see what's in there.
You could always get a cheap boreoscope and see what's in there.
That is an excellent suggestion regardless of other parameters. I will note I’ve tried the very low end scopes that are basically small cameras on a cable to use with the phone, and the control, lighting, contrast, and resolution were very poor. I ended up with a Whistler borescope — from Costco as I recall — and it is a world better while still well under $100.
That is an excellent suggestion regardless of other parameters. I will note I’ve tried the very low end scopes that are basically small cameras on a cable to use with the phone, and the control, lighting, contrast, and resolution were very poor. I ended up with a Whistler borescope — from Costco as I recall — and it is a world better while still well under $100.
I have a borescope but don't think it will fit down that small of a hole.
Push rod hole is bigger than the bolt holes, and pulling even a couple of rockers would be better than a head. Don’t know if I can get back into the shed in the morning, but if I can I’ll check the diameter — though I see several references to 3/8” pushrods.
Push rod hole is bigger than the bolt holes, and pulling even a couple of rockers would be better than a head. Don’t know if I can get back into the shed in the morning, but if I can I’ll check the diameter — though I see several references to 3/8” pushrods.
That would be great if so. Could use a magnetic to see if anything comes out.
I find the pushrod holes to be larger than 3/8", but smaller than 7/16". Best drill I have in between those is .390" and it's a loose fit, so probably on the order of .4" diameter. I think that would clear my Whistler camera, and I think I could fab up a 3/8" vacuum tip.
The forward most intake bolt is very nearly 1" aft of the forward most cylinder head bolt. That distance, and the gasket witness marks I see on the head lead me to believe the bolt hole leads to the lifter tray.
That would be great if so. Could use a magnetic to see if anything comes out.
Is there any way to shine a fairly bright light down there? If it is bright enough, you should be able to see light thru the holes w/o the broken bolt. Obviously, you couldn't see the light thru the broken bolt! But if all the others have light coming thru, I'd say the one with the broken bolt also goes thru. No reason to doubt redzg. This would've been an excellent opportunity to have tried an easy-out. Just couldn't drill all the way thru the broken bolt. Maybe you didnt have much bolt length left on the broken piece still in the head, so it would've been tough to not drill thru it. For a machinist, blind threaded holes suck. But GM did a great job on them in the head bolt holes. Too bad they didnt use them for the intake.....
I was able to go through the push rod hole with the borescope. I had a couple different magnet tools and fished out any metal shaving and inspect that all were removed. Saved me a ton of time. I appreciate everyone's help on this!
I was able to go through the push rod hole with the borescope. I had a couple different magnet tools and fished out any metal shaving and inspect that all were removed. Saved me a ton of time. I appreciate everyone's help on this!
Without going back thru the entire thread to see if you already have a (good!) magnetic drain plug, I strongly suggest if you dont already have one, you get one asap. It will tell the tale as to whether you got the vast majority, or not....
Without going back thru the entire thread to see if you already have a (good!) magnetic drain plug, I strongly suggest if you dont already have one, you get one asap. It will tell the tale as to whether you got the vast majority, or not....
Just make sure you buy a STRONG magnetic plug. Rare earth mags are best. I think I got mine from Ecklers years ago. It will hold an 18" long flat blade screwdriver......
2004 C5 Corvette Broken intake manifold bolt
