exhaust manifold to head bolts


BeefStew42791

BeefStew42791

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Hey everybody, I'm at the point in my project where I need to tackle some broken bolts. I tried an easy out on one..never doing that again:annoyed: but my plan is to drill and tap them out. What I was wondering is if anyone knows for exactly sure what size tap I'll need. Drilling to the inside threads is 1/4", I know that for sure, but the 8mm - 1.25 tap I got is not very snug at all (too big of a gap in the bolt threads. Please help if you can, it'd be greatly appreciated. Thanks!
 
ok, lets try this..

does anyone know of a place where I can order a set of brand new exhaust manifold to head bolts? Fomoco wants $17 per bolt and I don't really feel like putting out over $200 just for bolts, so I'm hoping they aren't the only ones who can get ahold of em..
 
So you just need the bolts to attach the exhaust manifolds to the heads? If so just go to your local store and get threaded rod. Cut em to length. Get locking washers, nuts, and flat washers. Should only cost about 20 bucks in the end. Thats all I did to my 3.0 and it works great.
 
I size on my 3.0 heads are 8mm and 1.25 pitch. Sounds like you need to bump it up to 10mm.
 
I will end up doing the hardware store thing if I need to, but if its at all possible I'd rather go with oem or near oem hardware just to be safe. If all else fails I'll drill the hole on the flange out even larger and throw grade 8's in there, but that obviously won't work for the actual heads.
 
oem bolts are the same as hardware store, dont get suckered. all you need to do is match length and grade.

you should do everything you can to remove the old bolts rather than drill and tap.

when drilling the holes have to be PERFECTLY straight and its pretty hard to get them straight when you still have the head on the engine.

try to drill inside the bolts to a size that is just under touching the threads. use an easy out and it should come out.

been there, ****ed up, new head, done that
 
which is why I was hoping for at least one oem, to be sure I wasn't dealing with a stretched bolt or buggered up threads or anything.

I hear what you're saying too about gettin them out, but honestly..the only way they'd come out at this point is if I melted them lol. I don't understand why they're rusted in there so bad either..it doesn't make any sense, the other side wasn't nearly as bad. Drilling should be easy at this point though, my pilot holes are all straight and true so now I'm just waitin on the nation to wake up so I can grab the right sized drill bit from the store down the street..sometimes, labor day is such a pain.

and btw, easy outs will never come across my finger tips again-_- talk about ****ing something up, there ya go..
 
ok, I've come to the end of this fiasco..the thread count turned out to be 8mm x 1.25, just like it should be. Praise napa for their nifty bolt size tool (various sized nuts stuck in a board). The reason things wouldn't fit too well though was because there was some pretty significant wear on them. It wasn't like they wouldn't work or anything, it was just more difficult for some nice new threads to fit in there.

So, end of story is that if anybody comes into this problem again, you'll need an 8mm x 1.25 tap along with equally sized bolts.
 
8mm x 1.25 Stainless bolts.

ARP 761-1001 Bolts

http://cgi.ebay.com/ebaymotors/ARP-...ItemQQimsxZ20091010?IMSfp=TL091010151008r5268

I am considering these ones so they do not rust and they seem reasonable just make sure you give the guys the correct measurements. Maybe mail them two of the bolts so they can match them exactly.

I don't have the time so I will probably just use chewing gum on this $#%& again. Or get your woman to scream at the truck it scares the %#$& out of the gremlins.
 
Ive never had much success drilling and tapping exhaust bolts. They are hardened from many heat/cool cycles and are a real bastard to get out. I have had pretty good luck with a product I bought from Sears. It basically has several different sizes of tool. Match to the closest diameter of the broken bolt, Drive that sucker on there and use a wrench or socket on the outside of the tool to turn the broken bolt out. It is a hollow tool with sharp, hard splines on the inside that drives over the bolt. Unfortunately, it won't work unless you have enough sticking out to grab. Cheap if I remember correctly.
 
BeefStew42791 said:
ok, I've come to the end of this fiasco..the thread count turned out to be 8mm x 1.25, just like it should be. Praise napa for their nifty bolt size tool (various sized nuts stuck in a board). The reason things wouldn't fit too well though was because there was some pretty significant wear on them. It wasn't like they wouldn't work or anything, it was just more difficult for some nice new threads to fit in there.

So, end of story is that if anybody comes into this problem again, you'll need an 8mm x 1.25 tap along with equally sized bolts.
Click to expand...

Thanks for the info. I have a 95 B4000 and new to the scene. Hopefully its the same motor and etc. So 8mm x 1.25 right? And we can get them at Home Depot or local hardware store correct?

Mind telling me if you went the hardware store or OEM route? I have 3 of them to replace on my driver side manifold. And where you able to drill and tap successfully?

Any information would be much appreciated. Thank you.
 
traviss76 said:
ARP 761-1001 Bolts

http://cgi.ebay.com/ebaymotors/ARP-...ItemQQimsxZ20091010?IMSfp=TL091010151008r5268

I am considering these ones so they do not rust and they seem reasonable just make sure you give the guys the correct measurements. Maybe mail them two of the bolts so they can match them exactly.

I don't have the time so I will probably just use chewing gum on this $#%& again. Or get your woman to scream at the truck it scares the %#$& out of the gremlins.
Click to expand...

traviss76,

20mm is the lenght you used? or if you remember the actual lenght that would be much appreciated. thanks.
 
Whatever bolts, rods you do use - use "Never Seize" on them. Good lubricant and good to 2000 deg F.
Dave
 
8x1.25 is the correct thread pitch. I ran into the same problem while installing my headers. I ended up doing a complete head swap because of those damn bolts. Even after taking the heads off with the manifold attached, I cant get 2 of the bolts off of the driver side head, thank god for a buddy giving me some free freshly machined heads. So if anyone wants a good set of heads with one driving side manifold attached, i will let them go for cheap!
 
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