Quote:
Originally Posted by Bob
how do you go about "setting the head" when there is so much slop. when you say setting the head do you mean just centralizing all the bolt holes that go thorough the head-gasket-block by installing like you said the modified bolts and then removing them for the new bolts/studs. that way everything is mostly where it needs to be and all bolts are aligned correctly?
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Yes centralizing the holes on the (ground down used headbolts used as) locating pins. Two are sufficient. Although in your case you may end up with the headbolt holes not centralized but rather up against the edges, in an effort to get the cam sprocket positioned where you want it.
IMHO there is some slop there yes, but not enough that it would impact the coolant or oil passageways if the head was not exactly centralized.
Quote:
Originally Posted by Bob
If i remove the head i will measure the clearance and order an appropriate gasket to suit.
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A good short straightedge and feeler gauges works. Measure along the piston wrist pin axis, both sides F/R of each piston.
More reading material for you, courtesy of Tom Bryant
https://thosbryant.wordpress.com/201...-pump-re-seal/ :
"Tom Bryant says:
April 29, 2016 at 10:42 pm
Jeremiah,
Headgaskets make a significant difference to winter starting, but glow plugs and general engine condition are much more important. Thinner headgaskets also make a dramatic improvement to horsepower and performance. If you do decide to replace your headgasket, you should try for the thinnest one you can get away with. That means that you really must use an MLS headgasket, as you cannot readily predict, or control, just how thick a composition headgasket will be.
Volvo’s original “Green Book” specifications, when boiled down to their basics, call for a piston to cylinder head clearance in the range of 0.58-0.73mm (0.0228-0.0287″). That is an overly-conservative specification. And to make matters worse, engines often left the factory with piston to head clearances well in excess of the maximum specification. I have seen situations where a 3-notch gasket was used when the clearance specifications should have dictated a 1-notch gasket.
Then, to make matters much, much, worse, aftermarket replacement pistons are often about 0.25mm (0.01″) shorter than the OEM pistons, so if they’re used with the original head gasket thickness, the situation goes from bad to intolerable.
The cure is to install the thinnest MLS head gasket you can. I have experimented with many, many, such thinner head gaskets to find out just how small a piston to head clearance I can get away with. The answer is just about 0.014″ (0.356mm). I have had several successful engines with that low of a calculated clearance. And, I’ve also had a few failures with that same calculated clearance. To be safe, I don’t really recommend trying to go below a minimum piston to head clearance of 0.017″ (0.432mm).
To achieve such low clearances, it is generally necessary to remove layers from an MLS head gasket. Such gaskets have 4 layers. You can get away with removing any of those 4 layers *except* for the top layer. You can also get away with using a bottom layer in place of the top layer, but you have to put a sealant on the bare metal side of that layer, which would then face upward toward the cylinder head. I recommend Volvo’s “High Temperature Chemical Gasket” Part Number 1161059-9 for that purpose.
If you decide to go with one of these radically thinner head gaskets, you must measure your piston deck heights very accurately, and you must make sure the piston top is square across (or level). And, you will have to measure the thicknesses of each layer of your MLS head gasket very carefully.
For reference purposes, here are the layer thicknesses that I have measured on Volvo’s MLS head gaskets (which, unfortunately, are no longer available):
Top layer: 0.23mm
2nd layer: 0.87, 0.92, 0.97mm (1, 2, & 3 notch gaskets, respectively)
3rd layer: 0.12mm
Bot layer: 0.23mm
As just one example of how a person can mix and match head gasket layers to obtain a desired thickness, here’s what I used for my latest head gasket replacement: One top layer, and 4 bottom layers. That’s right, I didn’t use the thick “notched” layer at all. The piston deck heights maxed out at 0.030″ (0.762mm), and I needed a thin head gasket, so I used only the corrugated “top” and “bottom” layers. I had several brand new bottom layers that had been removed from previously-installed gaskets. So, I combined four of those bottom layers with one previously-used top layer that had lost its rubber coating. I applied a bit of that special Volvo anerobic gasket maker to both sides of that top layer. The calculated piston to head clearance of this gasket is 0.0153″. It was installed in the engine on 6/24/2015, and to this date (4/30/2016) has accumulated over 7600 trouble-free miles.
Be extremely careful with your measurements, and don’t push the envelope too far until you’re really sure of yourself.
If you do this, and depending on just how thick your old gasket was, you may notice a dramatic improvement in horsepower and performance.
Tom"