uhhh so this is bad right....?????

[duratothemax]

when you notice that all...yes...ALL of the motor mount-to-block bolts are missing on one side????

I had my truck up on the lift changing the oil, and thought I would check it, because I only had 3 in on that side (forgot one when I put the motor in), and noticed that all 4 driver side motor mount bolts are missing.

What is the size and thread pitch of the bolts that go through the mount into the block? Supposed to drive to florida on sunday to pick up a boat...I havent looked if the bolts fell out or sheared off...but if they sheared off, any ideas how to get them out of the block...? Without pulling the motor?? ARRGHH. Why does this always happen to me.

ben

 

[Kat]

Here is Johnboy's fix

http://www.duramaxdiesels.com/forum/showthread.php?t=2976&highlight=johnboy's+ghetto

 

[duratothemax]

yeah thanks Kat I saw that...but my motor mount didnt actually break...the bolts that hold the motor mount to the block are all missing/broken.

 

[RENODMAX]

Pull the mount if you can (assuming the bolts just plum fell out). Then go from there. I'll scratch my head fromthere for you Ben:hug:

 

[TrentNell]

I doubt they sheared Ben , probably just came loose and fell out . If no one else answers i can check the bolt size and pitch when i get home later . Its getto but if you had to................. to get to florida and back you can strap that side of the motor but that would probably take just as much effort as putting the bolts back in .

 

[duratothemax]

all but 1 of them fell out, luckilly. The upper forward one on the driver side looks like it broke, but theres plenty of thread exposed to where I can get at it with vice grips. I found an extra bolt in my misc piles of dmax parts...if Im really lucky ill be able to find 3 more so I wont have to run to the hardware store, but at least now I know the dia, pitch, and length.

I guess thats why my passenger fender inner (metal) shroud has a round dent in it, from the big turbo hitting it when the motor rocked to the passenger side...

 

[duratothemax]

ok I could only find 1 actual motor mount-to-block bolt...but I found a couple others that fit... I have no way of getting to the hardware store so what are your guys' feelings on using:

a) exhaust manifold bolts (ill have to cut them down a bit)

or

b) torque converter bolts (they are 1-2mm short though)

ideas?

ben

 

[duratothemax]

the real bolts are grade 10.9, torque converter bolts are grade 9.8...exhaust manifold bolts are unmarked.

 

[duratothemax]

I just talked to someone at merchant auto (it wasnt eric? new guy I guess? I was pleasantly surprised that he was able to help me out with this question tho) and he said the better bet was to use the torque converter bolts as opposed to the exhaust manifold bolts...

does anyone here feel differently? Like I said the exhaust manifold bolts are unmarked as to their strength...

 

[Mike]

Wow Ben, that sucks. Good thing you caught it.

10.9 grade 19mm length from washer 10mm x 1.5 thread and pitch.

Good luck.

 

[Mike]

Torque converter bolts for sure, just torque them to the specs called for by the grade on the head.

 

[duratothemax]

the tc bolts, being slightly shorter...as a rule, I generally anti-seize EVERY bolt that I take out on the truck. (yes, even the caliper to spindle bolts, even though GM stupidly says to loc-tite them )

should I not anti-seize these? If I dont anti-seize them im afraid that some time down the road Ill wanna do the "motor mount bolt trick" or replace the bolts with the correct ones...and the tc bolts will be rusted in there. And I do anti-seize them im afraid that they might come out do to their 1-2mm shorter length...???

ben

 

[duratothemax]

ok it seems a 9.8 metric bolt is somewhere between an SAE grade 5 and grade 8, closer to a grade 8.

It'll be fine.

 

[Mike]

Loctite helps more than I'd ever thought. Ever hit a bolt head with a hammer then backed off? Otherwise that bolt was stubborn and only stripped. That same vibration but of course smaller, happens as that engine is running. Some places are effected more than others. JMO

 

[sweetdiesel]

the real bolts are grade 10.9, torque converter bolts are grade 9.8...exhaust manifold bolts are unmarked.

I wouldnt be afriad of using any grade bolts its better than what you hadMust be all the TQ from the stock tune:joker:

If you use a lower grade bolt your better off anyways then they wont snap they will just stretch.

 

[sweetdiesel]

ok it seems a 9.8 metric bolt is somewhere between an SAE grade 5 and grade 8, closer to a grade 8.

It'll be fine.

4.6 grade bolt:
Made from: low or medium carbon steel
Proof Load Stress 225 MPa
Tensile Yield Strength 240 MPa
Tensile Ultimate Strength 400 MPa

4.8 grade bolt:
Made from: low or medium carbon steel, fully or partially annealed
Proof Load Stress 310 MPa
Tensile Yield Strength 340 MPa
Tensile Ultimate Strength 420 MPa

5.8 grade bolt:
Made from: low or medium carbon steel, cold worked.
Proof Load Stress 380 MPa
Tensile Yield Strength 430 MPa
Tensile Ultimate Strength 520 MPa

8.8 grade bolt:
Made from: medium carbon steel, quenched and tempered
Proof Load Stress 600 MPa
Tensile Yield Strength 660 MPa
Tensile Ultimate Strength 830 MPa

9.8 grade bolt:
Made from: medium carbon steel, quenched and tempered or low carbon boron steel, quenched and tempered.
Proof Load Stress 650 MPa
Tensile Yield Strength 720 MPa
Tensile Ultimate Strength 900 MPa

9.8 grade bolt:
Made from: medium carbon steel, quenched and tempered or low carbon boron steel, quenched and tempered.
Proof Load Stress 650 MPa
Tensile Yield Strength 720 MPa
Tensile Ultimate Strength 900 MPa

10.9 grade bolt:
Made from: medium carbon steel, quenched and tempered, or medium carbon alloy steel, quenched and tempered, or low carbon boron steel, quenched and tempered.
Proof Load Stress 830 MPa
Tensile Yield Strength 940 MPa
Tensile Ultimate Strength 1040 MPa

12.9 grade bolt:
Made from: medium carbon steel, quenched and tempered, or medium carbon alloy steel, quenched and tempered, or low carbon boron steel, quenched and tempered.
Proof Load Stress 970 MPa
Tensile Yield Strength 1100 MPa
Tensile Ultimate Strength 1220 MPa

 

[duratothemax]

Must be all the TQ from the stock tune:joker

thats what I was thinking too! :rofl:

 

[duratothemax]

its all back together. A lot easier than I would have imagined. I probably pulled the motor mount, put it back in, and put all the bolts back in within 20 minutes. Turns out all the bolts had simply fallen out, none were broken off.

thanks for the bolt info simon, maybe put that in the specs/part #'s section too???

 

[sweetdiesel]

Did you use loctite on them?

 

[duratothemax]

no I used anti-seize...we'll see what happens, if they loosen up after 100 miles of driving ill pull them out and loc-tite them.

I just went for a drive and everything is great, man what a difference putting those bolts back in made, feels a bit quicker. EGT's are a little lower too.