• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Cylinder Head Install Questions

If rusty just soak in oil then wire wheel em and then re use em! Use an extra one to make a headbolt hole cleaner. Take your file and file a slot in the theads of the bolt making it like a tap and use that to clean out your head bolt holes, then air blow em out.
 
If rusty just soak in oil then wire wheel em and then re use em! Use an extra one to make a headbolt hole cleaner. Take your file and file a slot in the theads of the bolt making it like a tap and use that to clean out your head bolt holes, then air blow em out.

That's a pretty cool idea!

I don't get why it seems replacing head bolts is such a big deal if, at least for these motors, it seems to be a non-issue.
 
That's a pretty cool idea!

I don't get why it seems replacing head bolts is such a big deal if, at least for these motors, it seems to be a non-issue.

Torque to yield fasteners, also called "stretch bolts" (extremely dumb nickname, all threaded fasteners stretch by design) have a limited life span. If you re-use them over and over they will fail, period. The 5x re-use limit is what the engineers at volvo decided was a reasonable amount of total yielding they could allow without affecting the final clamping load or ultimate load carrying capacity of the fastener. That being said, I'm sure there is some conservatism built into that number. The head bolts are very likely to keep the head attached after more than 5 uses.
 
There are both kinds. From what I remember, 10mm (?) allen heads are regular torque to spec. #s and 14mm or 15mm head are stretch.

Sheesh, since it seems there are so many different kinds of "factory" head bolts for this motor how the heck do you find out what torque spec you really need for the bolts you actually have? And why the heck did Volvo make so many different types for the same applications??
 
There are only 2 types of "factory" head bolts.

OHCBoltTorque.jpg
 
Ok, that's actually super helpful. It's clear here which bolts are which.

Another thing I find odd is that the red blocks used in Volvo Penta applications are basically the same other then the cooling system. I was reading through a manual for the Volvo Penta AQ125B which is the B230 block with a 530 head. It states the head bolt torque numbers as 44 ft. lbs first step and 66 ft. lbs final.
Any idea why the numbers are different? Are there other differences between the two I'm missing here?
 
^^

I'm betting that 66 lb*ft value is a mistake. Fasteners are designed to be used in a specific range. Ford 2.3 head bolts are the same diameter and require the same torque value, 80-90 lb*ft. The Ford bolts are TTY "stretch" bolts and can be used only once.
 
^^

I'm betting that 66 lb*ft value is a mistake. Fasteners are designed to be used in a specific range. Ford 2.3 head bolts are the same diameter and require the same torque value, 80-90 lb*ft. The Ford bolts are TTY "stretch" bolts and can be used only once.

Maybe it's 66ft.lbs plus 90 degree twist. I thought I'd heard old school Penta bolts got torqued to 120ft.lbs.
 
Here are the exact instructions from that part of that manual I was reading:

"108. Lubricate the cylinder head screw threads and the washers then fit and tighten the screws. The tightening force is 90 Nm (9 kpm) (66 lbf. ft.). The tightening is to be carried out in two stages. 1. 60 Nm (6 kpm) (44.2 lbf. ft.) 2. 90 Nm (9 kpm) (66 lbf. ft.). The screws are to be re-torqued after the engine has been warmed up and allowed to cool for 30 minutes. When retorquing, screws must first be loosened sufficiently so that they turn when being re-torqued. (Static friction must be overcome)."

What do you guys think?
 
I think you are over thinking this. Follow the specifications hiperfauto posted above. He runs a Volvo shop and has for a long, long time. Those are the specs I’ve used on at least 20 redblock cylinder head installations.
 
Back
Top