Is machining my 440 with NON-original main caps cost prohibitive????

[19bee70]

Time has arrived to start my 440 build. It's going to be a street only car. 70 B body with 833 and 8.75 w/3.91. I have a couple of 440 blocks to work with but neither have their original main caps. I know I can get used OEMs or aftermarket billets but from you guys with machinist experience, what am I facing to get them "matched" to my block?

 

[vance.dykes]

line bore and line hone.

 

[Cranky]

Time has arrived to start my 440 build. It's going to be a street only car. 70 B body with 833 and 8.75 w/3.91. I have a couple of 440 blocks to work with but neither have their original main caps. I know I can get used OEMs or aftermarket billets but from you guys with machinist experience, what am I facing to get them "matched" to my block?

Align bore and hone....common thing to do anyways but the caps need to be somewhat close or the machine operation can take longer. Labor = $$$

 

[19bee70]

The machine shop suggested that because he can do it, but I think he's preferring not to run up the tab! He would prefer that I locate another block with caps.

 

[Cranky]

The machine shop suggested that because he can do it, but I think he's preferring not to run up the tab! He would prefer that I locate another block with caps.

That could cost more than the machining operation.....

 

[19bee70]

OUCH! So I guess it's likely I should try to find something else? Is there a way to measure the alignment of the bore BEFORE cutting into anything? Would that be too much to ask the shop to do?

 

[Cranky]

OUCH! So I guess it's likely I should try to find something else? Is there a way to measure the alignment of the bore BEFORE cutting into anything? Would that be too much to ask the shop to do?

The chances of non original set of caps being on the money is pretty close to 0 but I've found some before that were really close. Only way to find out is to check the ones you have. Easy to 'feel' if the parting line is off by a lot or just a little. Does the machinist have the replacement caps? If so, he should be able to do a 'feel' test. If you get another block, it could be worse than the ones you have. If he's experienced, he can tell you pretty quick what's what.

 

[19bee70]

Hmmm.... ok, I'll test fit them first myself and if it seems like a "maybe" I'll have him check or maybe get another opinion from another shop. Thanks Cranky and Vance

 

[beanhead]

My guy here (where most everything costs more) charged an extra $300 for that process. $175 for the setup and block work and $25 per cap.
Not peanuts but really not bad considering total costs, plus the peace of mind knowing they're on the money..

 

[Dajkzo]

Line honing and if needed, line boring is the primary step for blueprinting and engine. Everything else is relative to the center line of the crank.

 

[19bee70]

well guys, still seems cheaper than another engine purchase!

 

[69Bee]

I just did a LS block that spun 2 mains. Got another #4 cap, and the parting line we real close. Number 2 on the other hand, was way off, so I turned it around and it was much closer. Block align hone fine, and got the crank in (turns fine), and the timing chain is still snug. Things to be aware of:
1) Not all blocks go thru the machining process equally which is why it is difficult to get matching caps.
2) Billet caps are ~0.020" smaller in the bearing bore so they can be line bored to get close to the original bore, then finished up with the align hone for a good finish.
3) Unless you have a machined bar of the correct diameter, you would have to install a crankshaft (preferably ground so it is indexed), and see if there are tight spots when it is spun. A bore gauge will only tell if the bore is round and to size, not bore alignment.
4) Remove too much from the block and you will need a -0.005" or -0.010" timing chain set.

Not sure about Mopar without looking it up, but billet caps (Milodon) usually only contain cap 2/3/4, and not 1/5. All BBM caps are the same, so kits might contain all 5 for Mopar. Hope this helps.

 

[19bee70]

I just did a LS block that spun 2 mains. Got another #4 cap, and the parting line we real close. Number 2 on the other hand, was way off, so I turned it around and it was much closer. Block align hone fine, and got the crank in (turns fine), and the timing chain is still snug. Things to be aware of:
1) Not all blocks go thru the machining process equally which is why it is difficult to get matching caps.
2) Billet caps are ~0.020" smaller in the bearing bore so they can be line bored to get close to the original bore, then finished up with the align hone for a good finish.
3) Unless you have a machined bar of the correct diameter, you would have to install a crankshaft (preferably ground so it is indexed), and see if there are tight spots when it is spun. A bore gauge will only tell if the bore is round and to size, not bore alignment.
4) Remove too much from the block and you will need a -0.005" or -0.010" timing chain set.

Not sure about Mopar without looking it up, but billet caps (Milodon) usually only contain cap 2/3/4, and not 1/5. All BBM caps are the same, so kits might contain all 5 for Mopar. Hope this helps.

Yes 69bee, I see the availability of the AM caps. Some are sold in sets of 3 and some are 5. It would seem that probably anything not original to the motor would need massaging...in some form. If the labor is the same either way, I could hopefully just use an OEM set and save the $$$ on AM billets then. I certainly don't 4 bolt caps either.

 

[493 Mike]

I just did a LS block that spun 2 mains. Got another #4 cap, and the parting line we real close. Number 2 on the other hand, was way off, so I turned it around and it was much closer. Block align hone fine, and got the crank in (turns fine), and the timing chain is still snug. Things to be aware of:
1) Not all blocks go thru the machining process equally which is why it is difficult to get matching caps.
2) Billet caps are ~0.020" smaller in the bearing bore so they can be line bored to get close to the original bore, then finished up with the align hone for a good finish.
3) Unless you have a machined bar of the correct diameter, you would have to install a crankshaft (preferably ground so it is indexed), and see if there are tight spots when it is spun. A bore gauge will only tell if the bore is round and to size, not bore alignment.
4) Remove too much from the block and you will need a -0.005" or -0.010" timing chain set.

Not sure about Mopar without looking it up, but billet caps (Milodon) usually only contain cap 2/3/4, and not 1/5. All BBM caps are the same, so kits might contain all 5 for Mopar. Hope this helps.

A question on that LS cap: did you cut another bearing tang relief to match the correct OEM location or is it installed opposite the other tang?
Mike

 

[kramer]

Anther option if you have access to 361,383,400 main caps for cheap as opposed to aftermarket caps, you should be able to use them since the main register and bolt spacing are the same as 413,426,440 blocks you would just need to align bore them to 440 size and if I remember correctly the bearing tang area on the in the low deck main caps is deep enough that when you bore it out to 413,426,440 blocks you shouldn't have to recut the bearing tangs. The thrust main area changed a little bit over the years so look closely at that are as well for interchangability.

 

[WileERobby]

Listen to these guys ^^^ ! You got some great advice here. Line bore and hone, you're starting at the CORE, don't play games.

 

[Outsider]

Done a couple with stock cap replacements. As long as within about .001 with initial replacement check, shop should be able to grind cap and align hone to make right. Not a big fan of align bore unless no other choice.

 

[69Bee]

A question on that LS cap: did you cut another bearing tang relief to match the correct OEM location or is it installed opposite the other tang?
Mike

The tangs are opposite of each other. It is no big deal with this, and to be honest, the front and rear cap have two tang grooves cut into them anyway. The ONLY purpose of the bearing tang is to locate the bearing in the cap. The tang does NOT prevent the bearing from spinning in the bore, crush does. I have done modern engines that have no tang grooves or bearing tangs for location. You have to center the bearing as best as possible when installing them, and as stated before, the bearing crush is what holds it in place and prevents spinning in the bore.

 

[PsyOps]

The performance machinist I use does line bore & hone as a routine. His pricing is middle of the road but the work is outstanding & I would hesitate to go anywhere else. I think the members here have pretty much covered all the bases. Now you need to decide what you are going to do next.

 

[19bee70]

WooHoo.....I can't believe it. I actually found the original main caps in a box buried in my shed. Sadly all 10 caps are in the same box for both 440s I have but I'm guessing the machine shop can figure out which ones go where. After all, being numbered, there's only 2 options for each cap! WOW..what a relief! I did learn a bit here tho. Never buy a block without it's caps!