Aluminum Main Cap install--PITA

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RAMM

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Just wanted to share last weeks work menu. I've been line-honing a little longer than line boring and the two go hand in hand but line boring is seldom necessary. However when installing aftermarket caps with .100"+ to remove line boring is an absolute. Before I was capable of this operation I had to source it out--and No joke, I NEVER EVER received a perfect job back. There was always some issue with it. I once sent a SBC with splayed caps out for line bore and it came back with one of the caps backwards!! I had to machine a bearing tang (notch) into the opposite side to correct it. The worst one was a SBM (408) that was line bored .017" incongruent with the decks front to back! I only paid $600 19yrs ago for that one. The pictures here don't show the 16 hrs that I can't fully charge for which sucks but that's what I get for wanting to nail the dimension 2.9423" . I don't think I'm going to accept aftermarket cap installs anymore--it's just too much time I don't have. J.Rob

Alumcapprettyshot.jpg


lottacapstock.jpg


Linebore440OP.jpg


Maincapchamfer.jpg
 
You would think aftermarket caps specifically made to employ ARP studs wouldn't have to be machined on the #3 cap for thrust adjustability, but they do. -Annoying. J.Rob

Maincap1732.jpg
 
I overshot the first line hone by a thou and a half and had to cut the caps. I used my flycutter in the mill and this is first thing in the morning and when I should have gone home and worked around the house. The CNC calved on me--so I farted around with it for about an hour before I went to plan B which is the ole Sunnen cap grinder--which sucked because I had to dress the stone for every cap-and it made a huge mess and I hate wearing a dust mask and it isnt near as or accurate/nice as the milling machine. Oh and it's way slower. Oh and by the end of the day I just couldn't accept that the CNC was actually broken--so I opened the back panel and I discovered the X-axis servo amp connector was loose! I plugged it back in properly and back up and running! I didn't trust the cap grinder job so back in the tool maker vice and indicated and fly -cut them all to the same dimensions. Re-torqued them and snuck up on the target dimension. I burned 5 hrs by not doing what I should have in the first place and that was fix the milling machine. J.Rob

Maincapflycut.jpg
 
Before I was capable of this operation I had to source it out--and No joke, I NEVER EVER received a perfect job back.

This is alarming. How would the average DIY gearhead know if what he was getting back from his local machine shop is adequate or not?
 
So in the end, why go to aluminum caps at all? What do you gain?

Supposedly it's easier on the block because the main caps have an very small amount of flex. In my opinion if you're using a factory OEM block to that point you just need to step up and buy an aftermarket block.

Tom
 
Nice work, Im guessing its all getting surfaced and girdle installed when your done with caps ?
Is SDC and BCR one in the same ?
 
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I certainly commend you on your quest for perfection. So many out there just don't give a crap.
 
Supposedly it's easier on the block because the main caps have an very small amount of flex. In my opinion if you're using a factory OEM block to that point you just need to step up and buy an aftermarket block.

Tom

Agreed, or a girdle, at least with those you usually don't need to mess with the main bores just machine the tops of the main caps so it sits flush with the oil pan rail.

With the little machining and prototyping experience I have, that looks like a nightmare @RAMM ... just put some rubber washers under the stock main caps to absorb the forces from the crank :lol:
 
Are they the ones from Jerry? I installed some of his caps.. They sort of suck in my opinion. Same issues with the ARP stuff not fitting, (bolt side clearance issues too). And the bearing tabs were virtually non existent after machining. In fact the caps looked they were machined off center.
Don't think I'd use them again.
 
Are they the ones from Jerry? I installed some of his caps.. They sort of suck in my opinion. Same issues with the ARP stuff not fitting, (bolt side clearance issues too). And the bearing tabs were virtually non existent after machining. In fact the caps looked they were machined off center.
Don't think I'd use them again.

Absolutely spot on. Bearing tangs are barely there-also agree on the off -center comment/ also agree on the--"sort of suck" comment. I'd never use 'em again, that's for sure. J.Rob
 
Dude Rob, you have some interesting threads .
Keep em coming, I'm 1 year into my machining career, so I really enjoy your posts.
 
Dude Rob, you have some interesting threads .
Keep em coming, I'm 1 year into my machining career, so I really enjoy your posts.

Thanks, Here's a couple of photos of the current dilemma. No more bearing tang notches. I will have to machine them deeper. Think I'm gonna go with a commonly available router bit chucked in a tool holder in the mill. Hope I can find one. J.Rob
1291-2_large.jpg


Maincapnotchgone.jpg


p.s. Thanks for the kind words.
 
The guys been selling these now for quite a number of years. You'd think he'd have this sort of issue sorted out.
Seriously, it's a bit of a joke.
Guess when this happened to me, I should have flamed the crap out of these caps on as many forums as I could, maybe bad publicity would have got the issue corrected by now.
 
The guys been selling these now for quite a number of years. You'd think he'd have this sort of issue sorted out.
Seriously, it's a bit of a joke.
Guess when this happened to me, I should have flamed the crap out of these caps on as many forums as I could, maybe bad publicity would have got the issue corrected by now.

Agreed--See? Its your fault they're still like this. LOL. JK. J.Rob
 
I overshot the first line hone by a thou and a half and had to cut the caps. I used my flycutter in the mill and this is first thing in the morning and when I should have gone home and worked around the house. The CNC calved on me--so I farted around with it for about an hour before I went to plan B which is the ole Sunnen cap grinder--which sucked because I had to dress the stone for every cap-and it made a huge mess and I hate wearing a dust mask and it isnt near as or accurate/nice as the milling machine. Oh and it's way slower. Oh and by the end of the day I just couldn't accept that the CNC was actually broken--so I opened the back panel and I discovered the X-axis servo amp connector was loose! I plugged it back in properly and back up and running! I didn't trust the cap grinder job so back in the tool maker vice and indicated and fly -cut them all to the same dimensions. Re-torqued them and snuck up on the target dimension. I burned 5 hrs by not doing what I should have in the first place and that was fix the milling machine. J.Rob

View attachment 1715941540


Damn that's a nice vice .
 
Funny, I picked up on that immediately too...

My buddy that does mostly Mopar engine machine work put caps on a Hemi recently... Huge PITA...

It really and truly is probably the most tedious and time consuming operation in the whole block machining process. There just is no easy way to speed it up other than a big $$$$$ CNC $$$$ right angle head and even then the line hone will still be necessary to finish it off. It truly is a HUGE PITA. J.Rob
 
It really and truly is probably the most tedious and time consuming operation in the whole block machining process. There just is no easy way to speed it up other than a big $$$$$ CNC $$$$ right angle head and even then the line hone will still be necessary to finish it off. It truly is a HUGE PITA. J.Rob


so i guess on my next rebuild 4 bolt mains is out LOL .
 
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