are splayed 4 bolt main caps worth the money? i have a 355 (all forged) and a huge cam (6800 rpm shifts) and excellent heads and a TNT 250hp kit going on my friends car but should i get a set of splayed 4 bolt mains for him (i'm building the car and he will drive cuz its his car) but are they worth the money and where do i get a set?

 

You can do normal non splayed ones and they will also be strong.

You have to line hone it to get them to work. I can get you some nice ones for $120 for the middle 3.

Bret

 

do you have any pics of them and are they splayed or straight? i will also need to know what they are made out of and if you can get the main studs for the 4 bolt mains and will they mount a windage tray

 

I'm also interested in the answer to this. Why/when are splayed caps required. When do 2-Bolts caps just not add up to enough.

 

Splaying a block is expensive, this is true.

All i know is I burnt a bearing wth only lt4 hotcam, heads, boltons at 84k miles

If your rebuilding a block, and if you have the opporunity, I highly recommend you get the block converted to 4 bolt main caps.

Chevy cranks like to walk. Ford 5.0's are 2 bolt mains and are stout bottom ends but They use a girdle. So getting them will be a huge insurance to spun bearings and scorching the crank.

ARP sells the studs, the caps you can get froma bunch of places.

Call your local machine shop, they will steer you in the right direction

 

First,

Here are the 4 bolt main studs to use w/ a windage tray.
http://store.summitracing.com/partdetail.asp?part=9814

You can also get a set of 2 Bolt studs and a set of 4 bolt bolts. That is a much easier setup to install. It's only $8 more.
http://store.summitracing.com/partdetail.asp?part=10063
http://store.summitracing.com/partdetail.asp?part=9809

I have one extra set of 2 bolt windage tray studs around so I can have a full set becaus they only come with 5 windage tray studs and my windage trays use 6.

The 4 Bolt Caps are Splayed @ 22 Deg. They are a Steel Billet. I'm not sure what grade steel (i.e. 4340, 8620)

For me doing a splayed setup vs. a straight setup costs about $10-20 more to do since I have to set up the head of the mill to do them.

2 Bolts are o.k. for 400-450rwhp, but even then I would rather do 4 bolt caps.

A 4 bolt setup will take the conversion to drill and tap the holes plus the line hone. So with the $78 studs, the $120 caps and the machine work you are looking at $400

Bret

 

I bought the Scoggin Dickey 383, it has splayed Milodon mains. Last weekend I spun all three center main bearings. I took it to a friend of mine that builds pro stock engines. He showed me why he doesn't use them. The caps don't fit tightly in the block. Mine were loose and floated around. He is going to machine mine for standard 4 bolt mains. I also use a Canton road race pan. It has a teflon coated windage tray, I had to cut notches in it to clear the mains. Last of all the dipstick tube had to be cut because it also hit the main caps.

 

The fact that your caps do not fit tight are not the fault of the splayed type cap, but rather the incorrect method of installation/machine work or the wrong type cap was used on the block. Properly installed, you have to tap them with a mallet to remove them once the bolts are removed. Most caps have to have the register (notch) machined to fit in the block. Take too much off & they will not live long.

 

Another possible reason for the loose caps would be due to the main bearing failure. There is enough heat generated when the main bearing spins that the caps will become "pulled in", which makes them loose in the register. You can check the register of the cap with a straight edge. If the cap is flat, it was most likely fitted to the block poorly. If it's not flat, it's possible that it's a result of the failure, rather than the cause. Failure analysis is very difficult, and requires that you look well beyond just the most damaged part. I'd hate to see you repair the damage, only to have problems again.
Good Luck

 

Lonnie and Joe hit the nail on the head with that.