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I really don't want to use a sleeved 5.3 for an 8000 RPM NA motor - even with the vacuum pump. Just seems like setting myself up for sub-par results.
I'll just screw it together and see what it does.
How?
Because
If your Worried about The Measly breathing with the Structure of the 5.3 vs tha Ls7 block or something along those lines....Re Sleeve 5.3 will hold the bore together Better = better Ring seal = HP
Funny!
If you need tha block....u need it.
Build what U got send it.....
Worried about windage costing hp with a sleeved truck block since there’s no bay to bay breathing.
I see your edits - yeah there are pros and cons to either.
I just can’t lose that much of an investment with my block without at least trying it. The cost of sleeving was bad enough at this point but to scrap the block entirely I’m not doing until I give it a shot.
ER said send it I thought you followed his lead haha.
Worried about windage costing hp with a sleeved truck block since there’s no bay to bay breathing.
It's not much and Brother Steve would make it bay to bay 😑 Dart block doesn't have bay to bay. Iron Block ftw LoL
I see your edits - yeah there are pros and cons to either.
I move fast...it's like running water and having paid the bill. 🤔 ER's old Ls3 having cylinder movement and not keeping it's form and the Solution
I just can’t lose that much of an investment with my block without at least trying it. The cost of sleeving was bad enough at this point but to scrap the block entirely I’m not doing until I give it a shot.
I'm with U 100%
ER said send it I thought you followed his lead haha.
Don't ask a question u already know the answer to 😝
Yeah, you could run it and see what you get. Maybe ER can provide more insight based on personal experience. If you're really looking for more of a max effort combination, you might talk to BES if you haven't already. Tony can likely give you insight as to what to expect with current platform and your goals. Always best to start with a platform that at least meets, but better it exceeds, expectations. Just a thought.
The bay to bay breathing issue is something you can easily change with the 5.3 blocks Spanks. Take Darths current build for example. His block is an LS7R block. Not many of them out there, and they are built like the truck blocks without bay to bay windows....the windows weaken the blocks tremendously by the way. His block has holes machined in the bulkhead walls under (or over depending on which way the engine stand is turned...lol) where the windows are on car blocks, which allow bay to bay breathing. Personally after having my hands on his block and talking to Steve at RED about the issue at hand, I’d rather go with the 5.3 block and cut these holes myself. Really easy to do with an angle drill or angle fixture. Doesn’t have to be sent out to a shop and spend hundreds. You can do this your self. If your block is as bad as your saying, I’d sell it off and go with a Darton sleeved 5.3, especially if your going for a max-effort build. Ring seal is everything.
Chevelle? Doesn't all Factory Ls blocks have space machined in the main caps when it sits in the block where the windows are on car blocks, which allow bay to bay breathing....
Chevelle? Doesn't all Factory Ls blocks have space machined in the main caps when it sits in the block where the windows are on car blocks, which allow bay to bay breathing....
Lq4,Ls2,Ls3 etc
Yes, the caps has the “notch” which allows some air to move, but the “bays” are located between the bulkhead register and the bottom of the sleeves. They are half moon shaped openings.
Here’s a pic of my 434 sleeved block. The bays are visible just at the bottom of the sleeve, below the main studs, left hand side of block here. You can’t see the right side bays because the block is turned...
Worried about windage costing hp with a sleeved truck block since there’s no bay to bay breathing.
I see your edits - yeah there are pros and cons to either.
I just can’t lose that much of an investment with my block without at least trying it. The cost of sleeving was bad enough at this point but to scrap the block entirely I’m not doing until I give it a shot.
ER said send it I thought you followed his lead haha.
You might could drill through the bulkheads to help windage. Or just run a vacuum pump.
LS7 blocks just seem to have a negative aura around them, seems there’s alway a repair issue with them. I would do a Gen4 5.3 resleeve if given a choice, there’s more metal in them, thickest bulk heads, about 60%+ the cost vs new LS7 block.
I'll redo the shortblock it if it has problems on the dyno it isn't a permanent decision. I won't likely ever use an ls7 block again unless it falls into my lap though. LS7 blocks can't be hot garbage - SBE LS7's are some of the best performing LS engines out there. There are 8 and 9 second NA examples out there.
I will say if my bores aren't perfect I at least am giving it the best chance possible to seal. I have thin 1mm rings that will have a better chance sealing to an irregular bore. Also have gas ports and a vacuum pump to improve sealing.
Great info on the breathing holes you can add on the 5.3 block, thanks for those details!
Dont the rings rotate on pistons? Im confused bout how the thinner rings help better chance of seal.
I thought thinner meant less drag, n less drag meant less seal?
Dont the rings rotate on pistons? Im confused bout how the thinner rings help better chance of seal.
I thought thinner meant less drag, n less drag meant less seal?
So the ring tension is what sets the drag and the tension comes mainly from the back cut of the ring. With a smaller ring face you get more pressure on the ring face with the same tension - since you shrunk the area of contact the unit load is higher. A thinner ring is not necessarily a low tension ring - the Mahle ring pack was surprisingly stiff that is one of the reasons I bought Total Seal rings to run instead - and I also wanted the gas ports. A thinner ring is also more flexible and will conform to irregularities better instead of fighting to hold it's shape. With better materials and coatings they're all the way down to .8mm top rings in high performance applications that can go 100k miles+.
With a vacuum pump you can run a much much lower tension oil ring which really frees up horsepower - the vacuum pump aids the oil falling back to the pan, and also improves the performance of the rings. OEM rings tend to have high tension oil rings because you have to run 15,000 miles on your oil these days and unless we're going back to 1998 people don't like putting a quart of oil in their LS1's every 1000 miles. The vacuum pump also pulls against the top ring to keep it seated against the ring land helping prevent flutter which improves ring seal. Gas ports increase the sealing pressure against the ring during combustion tremendously and is basically one of those free lunch kinds of things.
Lastly, if your bore is not perfect, if you average the diameter of two points in your cylinder the thicker ring is going to have a tougher time sealing because the face is being asked to seal against a larger delta.
The black is an exaggerated tapered bore - red is a thick ring and orange is a ring 1/3 the thickness. You can see the orange is almost across a uniform diameter where the red has a much larger change in diameter to try and seal against.
Thinner rings conform to the bore better to help seal against irregularities.
Most of your ring drag comes from the oil ring.
Thinner rings weigh less and when the piston changes direction, it’s less mass to change directions. The inertia from that change in direction will distort the rings.
LS7 blocks just seem to have a negative aura around them, seems there’s alway a repair issue with them. I would do a Gen4 5.3 resleeve if given a choice, there’s more metal in them, thickest bulk heads, about 60%+ the cost vs new LS7 block.
This was what I was advised when I spec'd my engine build.
You have to measure the bores with the same exact torque plates the shop uses. This was the reason I bought my own torque plates so many years ago. Eliminates ALL the finger pointing and excuses
In fact I usually bring the block to the machinist with my torque plates torqued in place and the main caps torqued in place and instruct them not to remove the plates after its honed.
I purposely dont request a hot hone because I dont want to hear that excuse also (not many places even offer that)......I need to check the machine work and having no variables are the key to successfully doing so.
To be real honest....if your close to a thou out of round your probably better than average. Nobody does really good quality work anymore and finding the shops that do are hard to find.
Hell you need good equipment to just keep that tolerance.
Getting close to a half a thou is well above average and all you could possibly expect. Most average enthusiasts don't have the tools or the means to check and if some of you know what you really did have you wouldn't be happy but its still running and making power.
My big question is were you better than you measured or possibly worse.....without having the same plates and the same head gasket torqued to the exact same spec you wont ever know.
If your serious about shooting for perfection and keeping the shop honest buy or rent torque plates and bring the engine there with the plates installed.....take it home when its done and measure. Now at least you will have the real skinny on how close the machine work actually was
Whether your happy about what you see is another story.....LOL
I drive myself crazy shooting for perfection....it's really tough finding excellent machinists that are as fussy as some of us tend to be. And you need expensive well maintained equipment to achieve some of the clearances we hope to see......keep that in mind.
Btw....you could hone the LS7 block a few thou and get custom pistons....there is nothing really wrong with the block. If your making under four digits with the build you should be just fine with an OEM LS7 block (the OEM pistons are more the weak link in the LS7 OEM engines)
Hope some of this helps
-Tony
PS.....If you find a good guy tip him up front. To really do this right you have to get the block really close and then let it cool and chase the last few tenths. Its alot more time to achieve close to half a thou tolerance....you really have to sneak up on it. Its not your typical drop the block off for a hone type of job if your looking for super exacting tolerances. Expect to pay more to get it
There’s a machinist in Nor Cal with a Rottler computerized hone machine that claims he gets within 1/10 of .001 in the length of the bore, should I call B.S on him, Tony?
He does do LS blocks with dual plates. He claims this machine is “state of the art”
02-14-2021, 06:42 PM
