I will be pulling my engine out this weekend and Iam wondering if grade 8.8 metric bolts will be strong enough to attach the chains from the cherry picker to the block? Will i need something stronger like 10.9? Also is 8.8 strong enough to attach the motor to the engine stand?

Zach

 

A cherry picker to remove your engine? ...you lightweight!

Come on!! Just honker down, grab it with both hands, and pull!

 

I used a couple bolts from the motor when I pulled mine. They didn't bend at all. As a matter of fact the block is still on the cherry picker with the same bolts. She's been there about a month now. You will have no problems.

 

Property Class Designation Nominal Size of Product Material and Treatment Mechanical Requirements Property Class Ident. Marking
Proof Load Stress, MPa Tensile Yield Strength, MPa, Min. Tensile Ultimate Strength, MPa, Min. Prod. Hardness, Rockwell
Surface, Max. Core
Min. Max.

4.6 M5-M100 low or medium carbon steel 225 240 400 -- B67 B95 4.6
4.8 M1.6-M16 low or medium carbon steel, fully or partially annealed 310 340 420 -- B71 B95 4.8
5.8 M5-M24 low or medium carbon steel, cold worked 380 420 520 -- B82 B95 5.8
8.8 M16-M72 medium carbon steel, quenched and tempered 600 660 830 30N56 C23 C34 8.8
A325M Type 1 M16-M36 A325M 8S
8.8 M16-M36 low carbon boron steel, quenched and tempered 600 660 830 30N56 C23 C34 8.8
A325M Type 2 A325M 8S
A325M Type 3 M16-M36 atmospheric corrosion resistant steel, quenched and tempered 600 660 830 30N56 C23 C34 A325M 8S3
9.8 M1.6-M16 medium carbon steel, quenched and tempered 650 720 900 30N58 C27 C36 9.8
9.8 M1.6-M16 low carbon boron steel, quenched and tempered 650 720 900 30N58 C27 C36 9.8
10.9 M5-M20 medium carbon steel, quenched and tempered 830 940 1040 30N59 C33 C39 10.9
10.9 M5-M100 medium carbon alloy steel, quenched and tempered 830 940 1040 30N59 C33 C39 10.9
A490M Type 1 M12-M36 A490M 10S
10.9 M5-M36 low carbon boron steel, quenched and tempered 830 940 1040 30N59 C33 C39 10.9
A490M Type 2 M12-M36 A490M 10S
A490M Type 3 M12-M36 atmospheric corrosion resistant steel, quenched and tempered 830 940 1040 30N59 C33 C39 A490M 10S3
12.9 M1.6-M100 alloy steel, quenched and tempered 970 1100 1220 30N63 C38 C44 12.9

 

In generic terms a metric grade 8.8 is equivelent to a SAE (U.S.) grade 5. The diameter will determine if it is strong enough.

 

Just try your best to put shear loads on each of the joints. Stay away from long spans where the load is flexing or bending of the bolt (1" or more of free area is not good). And make sure to be screwed into threaded holes at least 2 times diameter. (10mm bolt thread O.D. = 20mm of threaded engagement)

Rich

 

For whatever it's worth:

Grade 5 steel (3 hash marks on the bolt head is considered engine grade).

Grade 8 steel (4 or 5 hash marks on the bolt head is considered bridge building grade).