janarvae

Title says it all. '91 L98 auto. Changing the intake manifold gaskets, had all the bolts, except for the rear-most on each side of the intake, out without much effort. Went to remove these two rear bolts and the heads tore off from the corrosion caused by the intake leak.

Now what do I do? I picked up a cobalt drill bit and a square extractor and cutting fluid. Does this sound like a good idea? I will spray both bolts liberally with PB Blaster before beginning any drilling. I should have done that as soon as I saw they were giving me a hard time.

I don't want to destroy the threads in the heads (or maybe I do so I can get new heads ). What happens if my screw extractor breaks off in there? What would the next step be?

Oh, and now that I have some more down-time I'm getting new bolts. Bolts are T-45 3/8-16 x 1 1/8 in. long. Problem is nobody really makes 1 1/8 bolts. None at the hardware store and Summit uses washers to get the same effect. Time to upgrade to 12-point or allen-head? (Nothing below a Grade 8, of course). I saw the thread on SS bolts, but heard they may be too soft.....

Of course after I finish my transmission rebuild, I see the coolant leak and just had to tackle it "while I'm in the general vicinity"!

Thanks in advance,

Jonathan

janarvae

Oh, and I have about 100 or so pictures of removing everything to change the intake manifold, TB, runners, EGR tube, EGR valve, and thermostat gaskets. As well as TB bypass and block plug, knock sensor, over fill tank and surge tank removal.

Jonathan

racebum

some of those you have to drill out fairly large. like nearing the outside of the broken bolt. by doing so you reduce pressure on the threads. a thread chaser should be enough to clean up your holes. try drilling small & using your remover. the last one i had to do wound up being drilled almost the same size as the bolt, had to be really careful. next i pounded in a torx and out it came. buy a pack of stainless ARP intake bolts when you do the re install. they aren't very expensive and prevent this from happening again.

MikeC4

Dayum....I feel your pain. As long as you have good vertical access with your drill, you should be fine using EZ-out. As you stated, let that PB blaster sit in there for a good long time. I broken suspension bolts before, and always had good results with EZ-outs.

Maybe these guys can help you with your bolts:

http://www.boltlocker.com/

M. Schumacher

Jon, I was wondering what happened to you. Never-ending can of worms, eh? I know the feeling.

The best extractor I've found is actually a Torx socket. You choose an appropriately sized Torx socket, drill a hole slightly smaller than the bit, and drive it in with a hammer. The many splines of the bit will bite into the work and very often allow you to spin it out.

The key to using any kind of extractor is to get the hole drilled perfectly accurately, on center. You will want to begin with a small pilot bit and work your way up.

Obviously, in your current situation, what happens with the drill filings is an area of concern. Can't have them falling into the engine.

Good luck!

janarvae

While waiting for the PB blaster to set in, I searched the archives for threads concerning intake bolts and found one where SS bolts were used and they stripped themselves. I'm leaning towards some 12-pt ARPs with black oxide coating to look more like stock than stainless. Lazy SummitRacing - closed on Labor Day! Who do they think they are?

From your and M.Schumacher's advice looks like I'm going to sacrifice one of my Craftsman torx bits. I wonder what they'll say when I warantee it?

I've also heard to not use RTV on the bolts, use RTV with anti-seize, or just use thread sealer (I have some Permatex high temp thread sealant) when replacing the bolts. Which is correct?

Thanks,

Jonathan

janarvae

So I looked through Summit and ARP's website and the bolts that look right (specifically for TPI) aren't available in less than sets of 34. I only need 12.

Here is a link to bolts Summit thinks are right for me (only ARP brand): link

The ones available in full thread and black oxide are six-point though. (link)

Is six-point enough of a disadvantage from the 12-pt that it necessitates buying Stainless Steel ones (in fully thread though)?

I guess my question is if I can use the standard (half-thread) bolts (1 1/4 in length) with washers in the intake?

Thanks again,
Jonathan

86PACER

You're pretty much F'ed if that happens. Extractors try to expand the bolt while removing it. The smaller sizes break easily, so be careful.

M. Schumacher

As i read the article the black one comes in either six or twelve point. Purely cosmetic, IMO.

pologreen1

this is why I use PB first on these old parts !!! it SUCKS to go through this I hope all ends well!

MikeC4

I would not recommend using Torx bit to extract a siezed bolt. I doubt they can handle the torque required to break the bolt free. It may work fine, but if the torx breaks you are screwed.

jsup

Take it to a machine shop and let them helicoil it. Safest and least expensive way to go. You can try yourself and if you screw it up still do that.

racebum

they can provided you create a hole large enough to let some of the pressure off the threads and you use a decent quality torx. if you feel the torx twisting you can still pull it out before it snaps. so far i've never had one twist. also, SS bolts are fine in ARP. i would never trust a no name stainless bolt since many are soft. arp has a 12pc set of these. you just want the 12pc SBC set. nothing corvette specific. intake bolts are only supose to be torqued 20-30lbs if i remember right. black oxide is fine too. any of the ARP bolts are top quality.

janarvae

I've heard about the helicoils for aluminum parts, but the car is currently out of commission. I've been spraying PB blaster every 30 or so minutes and hopefully that will help some. I live on an island and I don't even know any machine shops in this area. If worst comes to worst, can I remove both the valve covers and the rest of the appropriate hardware and lift the heads + intake out of there without removing the intake? (As an aside - Damn that AFR thread is one-of-a-kind! )

I checked the ARP site and they are rated to 170,000 PSI and grade 8 is a minimum of 150,000 PSI. I don't really like the look of stainless or polished parts in the engine bay (except for maybe some nice valve covers ), so I think I'll end up getting the black oxide bolts. If I get get this job done successfully, the next time I'll remove the intake will be for new heads and intake and then it won't matter if I destroy anything.

And I believe you're right - the torque is 32 or 35 ft-lbs for the bolts. So it doesn't matter if they are only partially-threaded then?

Today I focused on cleaning all the parts - runners, TB, coolant tanks, and will tackle the drilling tomorrow.

Thanks to all and I'll update tomorrow or Wednesday,

Jonathan

convas

Is your inlet manifold still on or were you able to get ot off with the busted bolts in place ?

In my case I only had one busted bold and could lift the inlet manifold off, we then welded a nut onto the part of the broken bolt that was still sticking out of the head and got it out.

racebum

oh no, you want the whole bolt in. the black oxide ARPs are extremely strong as you have noticed. whatever they do to their stainless bolts, they aren't bad either. what i was getting at with the torque numbers was that you won't break either of the ARP's. you should be able to drill out any bolt that's in there if you take the dirll big enough. if it's a real pain in the ... bolt i would drill as much material out as possible without hitting the threads. this should free up most anything. pound that torx in really good and slowly back it out. if the torx spins, beat it in harder or drill out more material. helicoil is the fix-it if you screw up. with any luck you won't need to go that direction.

jsup

Sorry, didn't realize the manifold was still attached to the head.

Hmmm.... you do run the risk of cracking the manifold getting the bolts out. I don't envy you

Can you drill enough to just get the intake off?

M. Schumacher

Oops!

I have the feeling that all the responders assumed the manifold was out of the picture. I did.

I was assuming that the bolt snapped off close to the head and the manifold was removed. Now I guess that just the head broke off of the bolt.

Can you move the manifold at all? The bolts are probably somewhat fused to the manifold. If you can break them loose you may be able to get the manifold off, and then the rest of the bolts out easily with vicegrips. Pry around the manifold to break the gasket seal and see where that gets you. Hold off on the drilling for now.

janarvae

Oh my gosh, I didn't realize what you three just said!

I didn't think that the heads hold the threads and NOT the intake! No wonder they sell half-threaded bolts as standard for the intake! I took a shower already, but I'll go and try now. The rest of the bolts expect two are broken loose and the heads are broken off ABOVE the manifold.

I see that if they broke off at the head (engine, not bolt head) that would be a HUGE PITA!

I'll update in 10 min or so....

Thanks a lot,

Jonathan

janarvae

So I went down to the garage and tried my luck. Unfortunately, the bolt nearest the thermostat also broke and the one opposite it on the passenger side stripped its torx head.

In summary, the four corner bolts all broke at the intake manifold exterior surface. Would it be right to suggest a water pump and rear intake leak caused these bolts to rust while all bolts one into the interior of them did not?

Best way to remove a stripped torx head? Drill? And if the head snaps after drilling, will it lift off?

Thanks again,

Jonathan