Case decking n bearing checkin

[Timas]

Hello all.
I have going on about my first engine build in various forms
and realize that I am beginning to really over think things.
With that being said I wanted to ask where the line is drawn for needing vs not needing to deck my case halves.
Just so we are all on the same page, what you see in n the pics wasn’t done by me….well, at least most of it

The next question is regarding my main bearing.
I seem to have oil gallery holes on both halves?
Is this relevant to any potential problems?

I plan on replacing these and the cam bearings as well.

If I wanted to go with a web cam 107i

Do I need to have a special cam bearing set?
I’m sticking with hydraulic lifters. They’re what I have and I barely have over 1300 miles on em.


Thanks everyone.

[Bruce.m]

To make sure we are talking about the same thing… you can get the outside of the case where the cylinders sit machined to get a parallel surface (in line with the crank). The T4 case can “sink” a bit with age between the cylinders. Put a straight edge across the two holes in the case half to get some idea if there is a dip.

You don’t machine the mating faces of both case halves. If the case saddles for the bearing have sunk, you get the case machined for oversized bearings. Typically the T4 lasts well in that respect.

I’d fit the bearings to the empty case & torque it to spec (main bolts plus the perimeter nuts). Then measure the inside diameter of the bearings with a bore gauge. Then measure the crank journals with a micrometer. The difference between those is the clearance and there is a spec for that in the manual.

[Timas]

Thanks Bruce.
Does that spec reflect both cam and crank clearance?

Curious if there is a gap specification between rod and crank ? Or possibly a way of checking if the larger section of the rod is ok.
My rods wiggle, but I don’t know what would be considered “normal “

I’m concerned about piston slap.

Thank you again.

[Bruce.m]

Crank to rod side clearance is fairly loose by bearing standards. 0.1-0.4mm is build spec & 0.7mm is the wear limit.

[Bruce.m]

To check the rods radial clearance. Use a micrometer to measure the journal and a bore gauge to measure the rod ID. Or use plastigauge if that’s all you have access to.

You’ll need a manual (typically online for free with a bit of hunting), or just buy the Bentley manual.

[Timas]

Thankfully I was given a Bentley with my bus.
When the info and diagram are 1975 -1977 it is awesome.
I am a very visual person.
I will check what the specs are and then report back.

As for the original question for decking the case, is there a thicker preferred gasket maker that can fill in the imperfections?

If I can avoid pulling dowels/ studs that would be awesome.
Of course I will do whatever is suggested as being the “proper “ way to do it.

Appreciate your time with the help.

[Bruce.m]

I’d take a “stone” to the case flange and gently remove any burrs or high spots (around a dent for example). Small indents shouldn’t be a problem as long as there isn’t a deep grove that crosses from inside to outside.

The sealer for the case is subject to many views & opinions . Just don’t use a thick layer of a setting sealer like RTV. It will squeeze from the flange & set into nasty lumps.

[Timas]

I don’t know where you live Bruce, but I owe you a beer