New build for the Mistress

56taskforce

Member
Mar 30, 2014
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Any reason you chose the comp STG1 versus any other brand? Is it keyed already?
Actually using the stg2 that was a misprint. Yes three reasons 1. I have been a Competition Cams fan for many years and was happy to see offerings for Duramax from them.
2. They provide the cams profile information so I actually know what I am using. 3. Price I trust their quality yet they are half the price.
 

56taskforce

Member
Mar 30, 2014
967
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Next part to this build has been ordered. A 2020 L5P oil cooler and everything needed to install it.
This engine is now a LBZ/LML/L5P mutt...
 

KyleC4

Tech
Dec 30, 2016
312
3
18
Bay Area
Looking good. Did machine shop say, if at all, how much line boring they had to do? Just curious how “untrue” per-se a brand new block is. It would also be fun to know the measurements they got when they torqued the girdle and mains down. And did you happen to mention if Comp keys their cams? I didn’t see that mentioned when I glanced at their website
 

56taskforce

Member
Mar 30, 2014
967
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Looking good. Did machine shop say, if at all, how much line boring they had to do? Just curious how “untrue” per-se a brand new block is. It would also be fun to know the measurements they got when they torqued the girdle and mains down. And did you happen to mention if Comp keys their cams? I didn’t see that mentioned when I glanced at their website
No block is going to machine shop next week. I sure that the new block is right on. There is quite a lip on the non machined caps SoCal gives a lot of material to work with. The block will probably not be touched I believe the cap will only me matched to the block.
Yes the Comp LST cams are keyed, if interested and you use spotify there is some more info here.
The Diesel Podcast an interview with Comp Cam.
 
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kidturbo

Piston Tester
Jul 20, 2010
1,227
14
38
Somewhere On The Ohio
www.marinemods.us
Looking good. (y)

On your parts list above, the only thing I wouldn't go with again, coated pistons.. The TBC adhesion just didn't pan out. Luckily we caught it right after the dyno runs. Can't speak to the "gold" coating, but I'm rolling polished tops ovals these days.
 

56taskforce

Member
Mar 30, 2014
967
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Looking good. (y)

On your parts list above, the only thing I wouldn't go with again, coated pistons.. The TBC adhesion just didn't pan out. Luckily we caught it right after the dyno runs. Can't speak to the "gold" coating, but I'm rolling polished tops ovals these days.
Thanks. The decision on pistons is still up in the air. Also up in the air with whether to go stock valves (stg1) SoCal heads or step up to stg2
I don't want to ruin drivability.
 

56taskforce

Member
Mar 30, 2014
967
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Well having trouble finding a trust worthy machinist in my local area who will do diesel. Talked to Scott at SDP and he could not recommend anyone either. It's the line bore for the billet caps that is the big hold up, looking like I may have to pay shipping and send it to SoCal.
If anyone has knowledge of a good shop in Western Washington I would appreciate the reference.
 

56taskforce

Member
Mar 30, 2014
967
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Thank you.
If I can't find a machinist and I have to send the block to SoCal I will put that off and work on the rotating assembly first. I can get the balancing done local and then I'll send the block and heads together.
However it would be nice for all us Western Washington diesel enthusiasts to find someone here...
 

ikeG

Oughta Know Better
Apr 19, 2011
2,177
2
38
Western PA
www.griffithautosales.com
Actually using the stg2 that was a misprint. Yes three reasons 1. I have been a Competition Cams fan for many years and was happy to see offerings for Duramax from them.
2. They provide the cams profile information so I actually know what I am using. 3. Price I trust their quality yet they are half the price.
Comp manufactures cams for many other companies. Some companies will disguise it, and not disclose cam specs either. Years ago we had a single cam made by comp to our own specs. Took forever, but didn't have to pay markup. In fact, if you fronted enough money and made a minimum order, you could have your own cam line like 'joe blows 3/4 cams'.
Wagler cams even come in the Comp cams box, with the cam card.

Sent from my SM-G960U using Tapatalk
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
17,163
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Phoenix Az
Looking good. Did machine shop say, if at all, how much line boring they had to do? Just curious how “untrue” per-se a brand new block is. It would also be fun to know the measurements they got when they torqued the girdle and mains down. And did you happen to mention if Comp keys their cams? I didn’t see that mentioned when I glanced at their website
It’s not that they are un-true. They are actually extremely close from factory. The home is needed after main studs and caps due to the extra torque and very minor mfg differences from bullet main cap to stock block. Even just studs in stock main caps needs it due to squish.

Same reason a torque plate is best when honing cylinders due to distortion with head studs. It’s not a ton and torque plate is it required but it will true the cylinder the best for ring sealing.
 

56taskforce

Member
Mar 30, 2014
967
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James more than a line hone is required for installation of billet caps it must be line bore and then honed.
There is substantial overlap of material between the original bores and the block. It is also not an easy cut as material need to be cut from the cap without cutting the block and moving the crank center line. You can see from the picture this causes an interrupted cut which if not done right causes tool chatter and product damage. 15945895444144053791414623403531.jpg
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
17,163
30
48
Phoenix Az
Did you center those? That is an extreme amount from what I see in the pic. Maybe it’s just the pic I see? Your still limited on bearing thicknesses and from what I’m seeing, your taking well more than .001-.002 off but may just be the pic
 

56taskforce

Member
Mar 30, 2014
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They fit very tight they are where they are there is no centering to be done. The lip you see is the same on the other side. Here is a picture of the same thing on a big block Chevy project in my shop right now as well.
15945914050992201375268267509212.jpg
Note: aprox the same this is normal
You have to excuse the rust and dust this was a two to four bolt conversion and ended up finding a good four bolt block so here it sits.
 

56taskforce

Member
Mar 30, 2014
967
7
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That is a block that has been sitting in my shop for years. It was a two bolt to four bolt conversion I was doing when I found a good four bolt block so there she sits. It was going to be used to build the 496 stroker in my 56.
 

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