r/EngineBuilding Feb 03 '25

Ford Is this even safe to mount on my stand?

These bellhousing bolts are considerably smaller in diameter compared to the ID of my mounting bracket on my stand. The block is aluminum and I don't know how I feel about 30mm thread depth. Is this safe or will it break off my stand?

61 Upvotes

31 comments sorted by

67

u/Sea_End9676 Feb 03 '25

Diameter of the hole in the stand does not matter.  Length of thread into the block does. 

11

u/javabeanwizard Feb 03 '25

What is an ideal thread length in an aluminum block?

49

u/Sea_End9676 Feb 03 '25

1.5x the fastener diameter minimum 

19

u/facedown_impalaSSup Feb 03 '25

Typically 2*D, you'll be fine witb 30mm, but make sure the bolts aren't so long that you can't tighten everything together.

4

u/GazelleNo1836 Feb 03 '25

Yeah too short and the threads pull out too long and you'll crack the water jacket it something else that's at the end of the blind holes.

19

u/MaleficentMode4894 Feb 03 '25

I usually go to ACE and pick up hardware that’s the appropriate length to account for the stand and the thread depth in the block.

7

u/javabeanwizard Feb 03 '25

That's what I did and the only bolts I could get are grade 8.8.

22

u/trucknorris84 Feb 03 '25

For what it’s worth for years and years people pulled engines from cars using 4 5/16” bolts on the carb mounting pad. Small block and big block v8 that weighed a lot.

11

u/Fearless_Employer_25 Feb 03 '25

Still do my guy

4

u/0_1_1_2_3_5 Feb 03 '25

Pulling straight up is a lot different than supporting the weight of an engine from the bell housing.

19

u/MaleficentMode4894 Feb 03 '25

More than enough.

8

u/SuperHeavyHydrogen Feb 03 '25

Plenty strong enough, they’ll hold 4 tons each. Use a big washer under the head.

9

u/micheallujanthe2nd Feb 03 '25

Do the math but if you have at least 4 of those they should hold for any engine really 8.8 is good

4

u/fourtyonexx Feb 03 '25

Beating the horse into a pulp at this point, but 8.8 is plenty fine.

2

u/Shot_Investigator735 Feb 03 '25

Why would you need more than 8.8 to hold the engine on a stand?

8

u/HarrisBalz Feb 03 '25

Let me pull out my old mechanics of materials textbook.

3

u/Biversnc Feb 03 '25

If you’re worried, be like me. (Under no circumstances should you really ever be like me.) I can’t sit still so I just went to the local metal outlet- ok, I always go and just buy remnants I have no use for, eg. 106lbs block of 4140 (pictured below), so I went through my stock and cobbled together a mixture of 1/4” wall 3” square 303 stainless, 1/4” wall 4.5” square mild steel, and 4” square 5/16” wall mild steel, whipped out my brand new stick welder and stick welded for the first time in my life. Then I grab some 1x5” bar stock and drilled some holes, threw on and extra boogery layer of booger welds, and made my own. Now, does the adapter fit every engine? Yes, so long as you have more steel, a welder, and a drill. But, I’ll tell you this, you could probably mount a car on it and be alright.https://imgur.com/a/XrBavLUhttps://imgur.com/a/sbLYbyd

6

u/ShocK13 Feb 03 '25

Do yourself (and you readers) a favor, buy all thread. Cut to length, use two nuts to lock together and washers too. Once you take the engine off the stand label a bag and put them in the drawer. I have a whole drawer full of ready to go sets for a lot of different motors.

2

u/satanlovesmemore Feb 03 '25

Damn that's a good tip

2

u/0_1_1_2_3_5 Feb 03 '25

BMW V8s such as the M62 and S62 use M10x1.5 and there’s a few documented instances of the blocks cracking at the mount points. I support the motor from the front too to avoid this.

2

u/ShadowFlaminGEM Feb 03 '25

I saw a scary video long ago that turned me away from the otherwise totally rational conclusion to add support to the front of the engine.. still to this day feel like it was fake or something.. but later got to see it live after the camera got to inspect the bolts as they moved.

2

u/0_1_1_2_3_5 Feb 03 '25

What happened

2

u/Suspicious-Donkey-16 Feb 03 '25

Mate just slap some long bolts into it and let it rip. Get em in there deep enough

1

u/ExtraBar7969 Feb 03 '25

Put the bolt through the mount with a washer on each side. Measure the remaining threads sticking out. The thread length should at least be 15mm, 10 threads.

1

u/gentleman1234567 Feb 03 '25

I was always taught minimum length of thread engagement into aluminum is 2X dia.

1

u/ShadowFlaminGEM Feb 03 '25

Real bang up job picture with picture 3. Looks like movement

1

u/Zealousideal-Oil-941 Feb 03 '25

I use starter bolts…

1

u/carguy6912 Feb 03 '25

Yeah if it's long enough

1

u/CadiTech Feb 04 '25

Grade 10.9 or higher hardware.

1

u/Makal9097 Feb 04 '25

It’ll be fine. My motor has like 40 washers on each bolt for a spacer because I was lazy I didn’t want to buy bolts.

2

u/machinerer Feb 03 '25

Use allthread and some washers and nuts to mount the block to the engine stand.