Effed it all up - Drilled too far into engine

B

brewfox

Member
I took my 2005 dodge sprinter to a repair place (mistake #1) to replace the exhaust manifold gasket. They broke off 3 bolts and wanted to charge by the hour to tap and die them.

I said forget that, brought it home, and tried to extract the bolts myself (mistake #2). I didn't drill straight (mistake #3) and drilled too far, a couple inches (mistake #4) into the cylinder head. Once I slipped off the bolt, I drilled easy like butter for 5 min or so. I should have realized I wasn't on the bolt anymore (mistake #5). Now it's leaking coolant from my hole.

I'd like to not make any more mistakes and get this van functional again.

I have two competing ways to fix it and it depends if I can be confident I didn't drill into anything critical. Additionally, does anyone know of a good 3D diagram that might show how much head metal I have to work with? I have a shop manual, but so far no luck finding a diagram that would help with this decision.

#1 would be to drill the rest of this bolt out, tap a hole into the jacket, and put a bolt with sealant in there to stop the coolant leak (maybe a helio-coil?). Then either attach the manifold with 1 less bolt (10 instead of 11, affected bolt is the very front one), or try to find some kind of excellent bolt that could seal the jacket hole, and still attach the manifold to (not sure how possible this is, as I drilled at an angle).

#2 is replacing the cylinder head with a used one off ebay, not worrying about the other 2 broken bolts. Quote from a mobile mechanic was $2500 parts/gaskets included, which seems reasonable (if expensive).

What do y'all think? Please don't remind me how dumb I am, I'm well aware.
 
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J

jamesc76

New member
really to me that would be a engine out and strip it down to asses damage internally, if you went into the cylinder then i recon the block is goosed!
 
M

Midwestdrifter

Engineer In Residence
It's a tough call without getting a direct look at the damage. If you can recover the hole enough to install a new stud then I would just install a new stud with sealant. Pressure test the cooling system to make sure its leak free before moving onto the next stage of repair. :idunno:
 
L

lindenengineering

Well-known member
brewfox said:
I took my 2005 dodge sprinter to a repair place (mistake #1) to replace the exhaust manifold gasket. They broke off 3 bolts and wanted to charge by the hour to tap and die them.

I said forget that, brought it home, and tried to extract the bolts myself (mistake #2). I didn't drill straight (mistake #3) and drilled too far, a couple inches (mistake #4) into the cylinder head. Once I slipped off the bolt, I drilled easy like butter for 5 min or so. I should have realized I wasn't on the bolt anymore (mistake #5). Now it's leaking coolant from my hole.

I'd like to not make any more mistakes and get this van functional again.

I have two competing ways to fix it and it depends if I can be confident I didn't drill into anything critical. Additionally, does anyone know of a good 3D diagram that might show how much head metal I have to work with? I have a shop manual, but so far no luck finding a diagram that would help with this decision.

#1 would be to drill the rest of this bolt out, tap a hole into the jacket, and put a bolt with sealant in there to stop the coolant leak (maybe a helio-coil?). Then either attach the manifold with 1 less bolt (10 instead of 11, affected bolt is the very front one), or try to find some kind of excellent bolt that could seal the jacket hole, and still attach the manifold to (not sure how possible this is, as I drilled at an angle).

#2 is replacing the cylinder head with a used one off ebay, not worrying about the other 2 broken bolts. Quote from a mobile mechanic was $2500 parts/gaskets included, which seems reasonable (if expensive).

What do y'all think? Please don't remind me how dumb I am, I'm well aware.
Click to expand...
OK
I know exactly what you have done and frankly its a new head if you want it to be a reliable repair!
Don't feel bad as a DIY'r, I fired a Pro mechanic on the spot for doing this very same thing a couple of years ago and not adhering to good engineering practices & shop policies. As a professional shop we simply installed a new cylinder head on the customer's van FOC. We dicked it up , no lame excuses, we had to fix it!
Its that simple our idiotic mistake !

Now looking back in our case the mechanic in question did not bother to heat the exhaust nuts up to cherry using the shop oxy torch and #5 nozzle . This frees the nuts and doesn't distress the thermal hardened (already hard) studs which will snap like carrots if you ignore this vital first step.

If a broken stud is encountered it rarely is a clean break; but is often a cup 'n cone fracture or shelf style snap. In either case getting a centralized cut on such a work piece is almost impossible without special tools.If you ignore this vital second step the drill often wanders and its "job curtains" on the repair show!:thumbdown:

Now from my engineering career I have various special tools for this removal business but you can get something in 8mm from Matco Tools--Called Bust n Out:-
https://www.matcotools.com/catalog/product/ZB312/BUST-N-OUT-FOR-5-16/

As you will see there is a carbide bit that will flatten the torn work piece, then a follow up bit that cone centralizes the broken stud end face at is softest point; and then a fine broaching drill to puncture the broken stud work piece sitting stuck in the the head pocket @ dead centre without drift in the meat of the head.

With that cut at 3mm (1/8) it is then a simple job of using a L/H carbide/cobalt steel jobbing or mechanics drill bit to drill out the remaining stud fragment and recover the hole without mechanical incident. This is all very fresh in my mind as I did something just like it last Friday!

A big mistake to make and expensive to boot but i hope this written narrative will help those in the future not to do what you have done.
All the best
Dennis
Mechanic
 
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NevadaBlue

NevadaBlue

Member
I was paid to be a heavy equipment/diesel mechanic for quite a few years. I would hire a mechanic. This CAN be fixed, but doesn't seem to be something that is going in the right direction right now.
 
L

lindenengineering

Well-known member
In that areas there isn't much meat to take o/s stepped studs etc once a silly mistake like this is made .
The internal design of the water jacket is in close proximity to the stud pocket blisters in the casting.
Even if you do get it (a new stud to bite) it will pull out under the manifold nut torque setting when bolting up. The whole area is marginal at best and has no room for mistakes.
Dennis
 
AdrianD

AdrianD

Member
lindenengineering said:
OK
I know exactly what you have done and frankly its a new head if you want it to be a reliable repair!
Don't feel bad as a DIY'r, I fired a Pro mechanic on the spot for doing this very same thing a couple of years ago and not adhering to good engineering practices & shop policies. As a professional shop we simply installed a new cylinder head on the customer's van FOC. We dicked it up , no lame excuses, we had to fix it!
Its that simple our idiotic mistake !

Now looking back in our case the mechanic in question did not bother to heat the exhaust nuts up to cherry using the shop oxy torch and #5 nozzle . This frees the nuts and doesn't distress the thermal hardened (already hard) studs which will snap like carrots if you ignore this vital first step.

If a broken stud is encountered it rarely is a clean break; but is often a cup 'n cone fracture or shelf style snap. In either case getting a centralized cut on such a work piece is almost impossible without special tools.If you ignore this vital second step the drill often wanders and its "job curtains" on the repair show!:thumbdown:

Now from my engineering career I have various special tools for this removal business but you can get something in 8mm from Matco Tools--Called Bust n Out:-
https://www.matcotools.com/catalog/product/ZB312/BUST-N-OUT-FOR-5-16/

As you will see there is a carbide bit that will flatten the torn work piece, then a follow up bit that cone centralizes the broken stud end face at is softest point; and then a fine broaching drill to puncture the broken stud work piece sitting stuck in the the head pocket @ dead centre without drift in the meat of the head.

With that cut at 3mm (1/8) it is then a simple job of using a L/H carbide/cobalt steel jobbing or mechanics drill bit to drill out the remaining stud fragment and recover the hole without mechanical incident. This is all very fresh in my mind as I did something just like it last Friday!

A big mistake to make and expensive to boot but i hope this written narrative will help those in the future not to do what you have done.
All the best
Dennis
Mechanic
Click to expand...
Thank you for the information !

Assuming a DIY mechanic takes on this job, equipped with the Bust-n-out tools and an oxy torch, would it be a good idea to remove the old studs and install new ones? Or would that turn into drilling out all of the studs?

And for future attempts at removing the manifold, is applying copper paste on the studs a good idea?

The manifold on mine is leaking and whistling when accelerating up hill, there is one broken stud and at one point I will attempt a fix. It's also strange that these get so work hardened, on my old diesel the manifold nuts came off without any sort of problems, multiple times.

Regarding the stud hole length, I read somewhere that it's 27mm deep.
 
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L

lindenengineering

Well-known member
Well I have a policy to replace them every time.
That means exercising care with a stud extractor and some gently heat to get them to move.
Remember steel has tendency to lock in alum castings so a sharp tap on the end before attempting a turn is often beneficial to jarring the stud in the pocket.

If one won't budge I simple leave it alone and clean it with a thread chaser die nut.

Using something like copper slip doesn't hurt, but remember the new nuts are clenched bronze.
The pocket depth is more like 17 mm.
Dennis
 
S

smcguyer

2006 3500 Cab chassis. With 12' Box.
I would definitely contact Dave with Casting Repair Services in Tyler Texas, and explain the damage. This fellow is old school and has probably seen just about everything. Specialist in aluminum head recovery/ aluminum head welding. Telephone: 903-592-7195 Email: Dave9565@att.net Address: Casting Repair Service 2720 W Erwin St Tyler, TX 75702-6619 I would not hesitate to ship him a head if he thought the possibility of success was high.
 
B

brewfox

Member
You guys are all amazing, and I love the varied feedback and suggestions.

I think I'm going to try and remove the bolt again (if I mess up the cylinder any worse, the worst case is just a replacement....which is where I'm at now). I found that a "crimping" style coax cable connector would actually work really well as a guide for drilling. The outside casing fits snugly into the manifold, and the center inner diameter matches my LH drill bit. This whole problem started because getting a straight hole into a hardened bolt is REALLY hard. A guide would make it muchhhh better.

Then put in JB weld (thickened), held in by something (wood seemed to work). If I can get the bolt out, maybe even use all 11 manifold bolts. Otherwise, use 10 and fill this one in with metal epoxy to stop the coolant leak.

This plan banks on that I didn't hit any critical components in my original drilling mishap (besides violating the coolant jacket). I probably really only went in < 1".

Major reasons for this: This engine has 250k miles, and rust from MN. The whole van cost $7k. It's not really worth it to me to spend 2.5k+ on replacing the cylinder head, esp if there are more broken bolts or problems along the way. The failure mode of this repair should be pretty obvious and slow (assuming I didn't hit anything critical).

Not a professional repair by any means, but it should work and is a hell of a lot cheaper. If i mess up the cylinder any worse, I just replace it.
 
surlyoldbill

surlyoldbill

Well-known member
A trick my brother told me is to use plastic drinking straws, slit them down the side and start layering them in the hole until it's a snug fit between the bit and the wall. And be carefull with that first bit so the broken bolt becomes level and centered. But, if you have a metal guide that is close to fitting, that would be better!
 
T

Tooth Fairy

Away with the fairies.
AdrianD said:
The manifold on mine is leaking and whistling when accelerating up hill, there is one broken stud and at one point I will attempt a fix.
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I have (still, as I havent had the time to fix it) the same problem, Ill bet the manifold is not straight on the mating face, thats why it happened to you too. :hmmm:
 
B

brewfox

Member
NelsonSprinter said:
I guess flushing the coolant of metal filings is in order,
to prevent water pump damage, rad blockage
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Do you think metal filings got into the coolant even with coolant pushing out of the hole? I guess they might when I continue drilling it out now. I haven't drained the coolant yet, and it still seems to be trickling out.

I'm not even sure how I would flush it. Something else to research, thanks!
 
D

Deleted member 50714

Guest
Just my two cents: I have freehand drilled literally thousands of holes in all types of materials, aluminum, Cres steel aka stainless, inconel, titanium and exotic composites. Blueprint call outs for holes vary, type 1,2,3 or 4 holes. Type four holes are precision interference fit requiring inspection with a no-go-gauge. Percision freehand drilling requires a drill block, appropriately sized reamers and drill bushings. The drill block is fixed using adjacent holes with temporary fasteners called Clecos. Perhaps in this case adjacent stud(s) could be used to attach a drill block?

I recall working with a rookie who snapped flush a bolt in a ram air scoop. Out of curiosity, I priced the scoop at $25,000 with a three month lead time. The scoop was machined from a solid billet of aluminum. Anyway, I told him I would take care of it and ran it over to the machine shop and they used Electrical Discharge Machining or EDM to pierce and extract the bolt.

Bob
 
2

220629

Well-known member
brewfox said:
Do you think metal filings got into the coolant even with coolant pushing out of the hole? I guess they might when I continue drilling it out now. I haven't drained the coolant yet, and it still seems to be trickling out.

I'm not even sure how I would flush it. Something else to research, thanks!
Click to expand...
Since you asked.
Most of the swarf will follow the twist drill drill out. Getting bits out of the jacket chamber will ne hit or miss at best. Most bits will settle to corners/dead spots.

It is important too lower the coolant level. The drain is a pain. I just popped a lower hose.vic
 
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