Cracked main thrust bearing cap

[wdsj]

I am assembling a 259 for my 59 Silver Hawk. When I torqued the front thrust bearing cap the crank locked up. Upon inspection the thrust bearing cap has a crack in it. Right through the bolt hole.

Anyone know where I can find a 259 thrust bearing cap?

Dell
59 Silver Hawk
62 GT Hawk

[Tom Bredehoft]

It's not gonna be that easy. While the engine was being built, before any other parts were added, All the main caps were installed, torqued down and the hole was line bored, all bores at one pass. No other front main cap will fit your engine, exactly. What you will have to do is find a cap and have them bored again. There's a bit more to that, but I'm too lazy to go into it.

[img=left]http://www.alink.com/personal/tbredehoft/Bothcars4.jpg[/img=left]
Tom Bredehoft
'53 Commander Coupe
'55 President State Sedan
(Under Construction) 134 hrs.
'05 Legacy Ltd Wagon
All Indiana built cars

[Chucks Stude]

If the cap was ever installed backwards, that may have been what happened to crack your cap. That would also explain why the crank locked up. It can only go together one way.

[buddymander]

Replacing the thrust cap is more complicated than the other mains. The hole has to be perfectly round and the top half has to be matched with the bottom half. Neither half is exactly 50% of the entire diameter. On top of that, the front and back of the cap must be aligned with the block to support the thrust flanges of the bearing, unlike the other mains. If you're running this engine in front of an automatic, I'd say bolt it down and see how it fits, but if it's in front of a manual transmission, junk that block because the pressure against the clutch will push that crank forward very hard and make a huge mess when the bearing flanges distort against the broken cap edges.

[Chucks Stude]

Back in "ought '65" I rebuilt one and mixed up two of the inner bearing caps[xx(][8]. Cracked one of the caps. Wound up using the block in a dirt track race engine, and it lived with the cracked cap.
I do not know about the front bearing cap, there is a lot more strain on the front bearing due to accessories etc.
I think that I would find another cap, and get it line bored. You will sleep better at night.

[wdsj]

Looks like I installed it backwards. Embarrassing to admit, but I did it. I have been trying to think of a way to blame it on my son who was helping, no luck, I did it.
I am not a professional, but also not a first timer.

Where do I go from here? Can a machine shop fix it?


Dell
59 Silver Hawk
62 GT Hawk

[Blue 15G]

Back in '84 I had a well intentioned machine shop rebuild a 259 V-8, and they mixed up some of the caps and cracked one of them. The guy brazed it together and said it would work.

We put the engine back in the car and it did run, but he didn't grind enough braze away from the side and with every throw of the crank more and more braze dust ended up in the oil. The oil pressure started dropping before many miles. When I took out the drain plug, the most beautiful metallic gold colored oil came out. [:0] [xx(]

We eventually had to find replacement caps from a junk engine and have the block line-bored. Not to mention replacing all the bearings again, etc. What a nightmare. I hope you have better luck from here than I had!

Dave Bonn
Valencia, PA
'54 Champion Starliner

[PackardV8]

Any competent engine builder/machine shop can line bore your block. Sometimes, line honing is enough. Get another #1 cap and have the machinist check the block and cap alignment and especially both the thrust bearing surface alignment. If the original four caps are just as they should be and new cap is very close, what he can do is take one or two thou off all the caps and line hone them.

BTWBITD, I have seen a replacement main cap come in "close enough for a Studebaker" and be run for another hunnerd-thousand-miles without line-boring or line-honing. A good machinist can make the decision for you and show you why it will or won't work. Because the Studebaker block is very stiff and because on most days, the plant was running only hundreds where GM was running thousands, some of the Studebaker machining was very good and very consistent from one engine to the next.

thnx, jack vines

PackardV8

[wdsj]

Talked to my shop. He says he can fix if I get a new cap.
I have checked all my typical sources with no luck.
Any suggestions on where to look for one?

thanks
dell

Dell
59 Silver Hawk
62 GT Hawk

[gordr]

A new cap should be as close as the nearest scrap engine. I KNOW I have several, and you could have one for nothing from me, as long as you are willing to wait until I can get home and dig it out, and pay postage.

Post your general location, Dell. Maybe somebody nearby will have one.

Gord Richmond, within Weasel range of the Alberta Badlands

[wdsj]

I am in Aiken SC if anyone close has one to offer. Postal service works great to. For UPS anywhere in the country is just a few days away.

thanks
dell

Dell
59 Silver Hawk
62 GT Hawk

[ROADRACELARK]

I live just north of Atlanta. Let me check an old cracked 259 block tommorrow to see if it still has the caps on it. If so, the cap is yours. I'll get back to ya'.

Dan Miller
Atlanta, GA

[img=left]http://static.flickr.com/57/228744729_7aff5f0118_m.jpg[/img=left]
Road Racers turn left AND right.

[Dwain G.]

quote:Originally posted by wdsj

Talked to my shop. He says he can fix if I get a new cap.
thanks
dell

_________________________________________
Make sure he knows this engine uses timing gears instead of a chain. He will know to line bore instead of line hone.


Dwain G.

[wdsj]

Dan, let me know if you have one, be happy to cover your cost

thanks
dell

Dell
59 Silver Hawk
62 GT Hawk

[Mike Van Veghten]

buddymander -

The load on the front main is very simillar wether a manual trans. is used or an automatic is used.
In fact...if a high stall converter is used....more load than ANY hi-pressure clutch could even come close to would be put upon the thrust main!
In other words...ALL transmissions try to shove the crank foward!

wdsj -
As others have said, a good shop should have no problem with this. Also as others have said...MAKE SURE...the shop knows there is only two gears to turning the cam. Not like an aftermarket three or four gear assembly, that ISN'T as critical to cam to crank shaft location.

Strip the block down, find a shop, give them all of the caps and all of the main cap screws. You shouldn't have a problem.
The cost shouldn't break the bank either.

Mike