Saddles in a BAE Block

Could someone advise what is the process that is done when someone places saddles in the block on the mains. And is this a good thing or should the block be replaced. Is the block just as strong,

 

As long as they are the drop in style, with no screws, I have had no problems. The saddles that are held in with screws are a problem, the main tends to crack along the tapped holes.

 

Just out of curiosity, could someone please post what a drop-in saddle looks like when done proper?

I'm surprised that a srewed or pinned saddle would crack, but maybe expansion/contraction, I guess.........

 

The saddle doesn't crack, the tapped hole makes a path for the main web of the block to crack. I'll try to attach an image of what the saddle should look like.

http://s96.photobucket.com/albums/l179/ksitko

 

Got it. Thanks........

 

this my sound stupid to some but...
What is the advantage of using a saddle over welding and re machining the block?

 

The saddle does two things. One, you don't put all that heat into the block so the heat treat doesn't change. Second, once the saddle is installed, if you ever spin a bearing again, usually you can just replace the saddle with no machining.

You can weld the block (I have done it), but you just have to watch how much heat you put in it.

 

I would like to make a general comment on the saddle deal. There is a better way, in my opinion, than the tab type saddles that require you to machine the stud area of the block, and you can make your own out of aluminum tubing. You must have access to a good linebore machine like a Berco BC4, etc. If you have been doing this type of work, it is exactly how you repair Mack diesels, except you use aluminum tubing instead of a cast sleeve, and use pieces of aluminum welding rod instead of rivets. Of course you can still use the bought saddles, just cut off the tabs. We have done lots of them this way, with no problems.

 

I use to work in an engine shop and i have to ask... even without the ears on the saddle, why pin it?
If you replaced the main cap with a new one but used the old cap to do the machine work on the block to fit the OD of the saddle with a slight amount of crush,then installed the block half saddle and the new cap then re machine the saddle and new cap to the finish size wouldn't the new cap adequately retain the upper half saddle?

 

Sure, but some random installed pins keep the insert from falling out, make it possible to "turn in" an upper bearing at the track, etc. It also lets you touch up the inset with a file at the part line to get a good fit. Would be no chance that the insert could "walk" forward or back and block oil hole. No doubt there are other ways. This is just how we do it.

 

Good point on rolling a bearing!

 

Sbc

Don't the SBC guys do something similiar when mixing 400 and 350 parts? I was thinking they had some sort of "bearing spacer". Can anyone elaborate on this?

 

I have used them before to build a few nitrous 377"s and they worked fine.
all they are is a set of 400 main bearings that have had the thrust removed off the rear bearing and they have a slot machined for the bearing tab at the parting line.
They were a lot cheaper and easier to find than the thick spacer bearings.

I dont know how they would work in a real high horsepower blown application ,but then again you wouldn't use a stock 400 block in a all out engine.

 

would it be a good idea for the manufactures to make the blocks with the saddles already machined in , then if you spin a bearing all you have to do is change the saddle , no machining . no real cost .
also why dont they make the blocks with window plates so if it kicks a rod there is more chance of not have to repair the block just change the window panel , just a few ideas.

cheers

 

Torino....very good idea..dave
www.myspace.com/daveloweswr

 

Brought this back from the dead. Where can I purchase these saddles?

 

The Fontana/Miner Bros motors use a skirt on the block that sticks down close to four inches from the actual normal pan gasket. It is sacrificial so if the rods are kicked out most of the time you can just replace the skirt. Sort of a burst panel for the lower portion of the block. Dave Germain

 

Call whoever made your block , they should have them .

 

the idea behind the flange of a saddle is to put the main cap back in its centerline according to camshaft to crankshaft distance.