Offshoreonly.com - Head bolts 454 MPI

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Offshoreonly.com (https://www.offshoreonly.com/forums/)

- General Q & A (https://www.offshoreonly.com/forums/general-q-20/)

- - Head bolts 454 MPI (https://www.offshoreonly.com/forums/general-q/377870-head-bolts-454-mpi.html)

SB	01-02-2023 07:53 AM

Quote:

Originally Posted by AllDodge (Post 4854679)

89 on long and 92 on short

Still not getting notified of postings

Whose bolts ?
I don’t remember torque values this high, but been a few yrs for me on a 454.

AllDodge

01-02-2023 08:15 AM

ARP and torque is 92 long and 89 short

https://cimg2.ibsrv.net/gimg/www.off...8dd801fdc4.jpg

SB	01-02-2023 08:40 AM

That looks like Mercruiser Manual, no ?

Torque values and procedures to use are those of the head bolt or stud manufacturer.

AllDodge

01-02-2023 09:22 AM

Quote:

Originally Posted by SB (Post 4854695)

That looks like Mercruiser Manual, no ?

Torque values and procedures to use are those of the head bolt or stud manufacturer.

Merc yes, APR states torque in passes to 70 then final torque is per OEM

SB	01-02-2023 09:29 AM

No.
Just the sequence is OEM.
Torque value is from the bolt and lube used.

AllDodge

01-02-2023 09:32 AM

Quote:

Originally Posted by AllDodge (Post 4854701)

APR states torque in passes to 70 then final torque is per OEM

The statement from ARP is one which puzzles me some. ARP states the bolts are stronger then OEM but they use OEM spec for final torque. Torque should stretch the bolt so it maintains the clamping load. If their stronger then the same torque would not stretch the bolt the same and provide the same clamping load, or at least IMO

SB	01-02-2023 09:37 AM

Quote:

Originally Posted by DrFeelgood (Post 4853059)

I just used ARP for my Gen VI 502 MPIs.
ARP-135-3601

Here are the directions for those bolts.
https://tech.arp-bolts.com/instructions/135-3601.pdf

underpsi68

01-02-2023 10:15 AM

89/92lbs is a lot on a 7/16 bolt/stud.

1/2" are usually 100lbs.

AllDodge

01-02-2023 10:28 AM

1 Attachment(s)

Quote:

Originally Posted by SB (Post 4854706)

Here are the directions for those bolts.
Attachment 577532

Your right both instructions are the same, we over torqued.
I should have read the paper instead of listening to what my friend said it was saying. So its over torqued.

Will loosen each one at a time and torque to 70

Wonder if it crushes the gasket to much?

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