how big can you bore a 6 liter block
12-02-2008, 08:23 PM
#21
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Like I said, it's personal preferance. Different strokes for different folks ::no pun intended:: but if you can't deny the fact that it WILL wear faster.
Last edited by The Beast; 12-02-2008 at 10:13 PM.
12-03-2008, 04:28 AM
#22
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Would it not depend on rod length & compression height of the piston etc?
Surely you could have a smaller dispalcement engine with worse wear characteristics than a larger displacement one?
Surely you could have a smaller dispalcement engine with worse wear characteristics than a larger displacement one?
12-03-2008, 09:48 AM
#23
The longer stroke means more force is placed on the side of the piston, rings, and cylinder (mainly the "contact area" perpindicular to the centerline of the crank and piston pin), and will increse the amount of piston, ring, and cylinder wear i.e. taper and out of round. Don't get me wrong, I'm not saying an increased stroke is a bad thing. It's actually a very good thing, but IMO it's not the wisest choice for a DD due to the increased wear.
Safely, Yes.
Safely, Yes.
12-07-2008, 09:40 AM
#27
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Indeed, you are correct. However, the longer stroke means more force is placed on the side of the piston, rings, and cylinder (mainly the "contact area" perpindicular to the centerline of the crank and piston pin), and will increse the amount of piston, ring, and cylinder wear i.e. taper and out of round. Don't get me wrong, I'm not saying an increased stroke is a bad thing. It's actually a very good thing, but IMO it's not the wisest choice for a DD due to the increased wear.
Safely, Yes.
Safely, Yes.
There are 2 sides to the coin on that scenario. With teh taller deck block, that longer stroke does not have as much "side loading" as with the shorter block. With the taller deck you can run a longer rod for a better "rod ratio".
I think most would agree that with the standard deck height, a 4.00 stroke crank for a daily driver is the "safe" limit. Any more stroke than that, and you get into a real short piston and oiling control problems on the oil ring. You CAN throw more stroke into a stock block for even more cubes, but most would agree that for a DD you are asking for problems on reliability and oil consumption. You can easily look into compression height as the limit on what you can do with a given space:
Stock deck height is 9.24"
Take a 4.00" stroke and cut in half for 2.00"
Rod length (mine is a 6.125")
Add you rod length (6.125) to the 2.00" and you get 8.125"
Now subtract your (rod length+half stroke) 8.125" from your deck height of 9.240 (assuming zero deck height) and you get 1.115" for your compression height. Now, alot of shops like to see 1.2xx for serious power adders. But with today's pistons you can get by with a shorter piston.
You take that same formula and add a 4.100 crank and you get a 1.065 compression height.
4.250 crank and compression height is .990
Now, you can run a shorter rod, but you speed up the piston even more, and on and on and on we can go and Pro's and Con's of why you shouldn't or whatever.
If I was building a motor that I wanted to last 100K miles without ever having to tear it down, I would not even go with a 4.00 crank in a 9.24 deck block however. But, I'm NOT looking to go 100K miles, only a 1/4 mile at a time is why I went 4"
12-13-2008, 09:06 PM
#31
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12-13-2008, 10:27 PM
#32
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Yes. Wanted to try something nobody had done yet and it works for me. I have a few customers that we are going to try the same thing on and I am pulling mine out for the winter and tearing it down to look things over. Our shop is the only machine shop in this region that has done this with success.
No oil consumption that I can see.
Mike
How is the oil consumption with that combo ?
Mike
12-13-2008, 11:02 PM
#33
Yes. Wanted to try something nobody had done yet and it works for me. I have a few customers that we are going to try the same thing on and I am pulling mine out for the winter and tearing it down to look things over. Our shop is the only machine shop in this region that has done this with success.
No oil consumption that I can see.
Mike
No oil consumption that I can see.
Mike
so how much is the block filled?
does it see normal street use/miles?
i can imagine that the cylinders are thin. how much material was left after 4.125 bore?
much blowby?
i personally have gone .060 over on lq4, with no issues whatsoever, no blowby with low tension rings. and will do it again.
not sure about 4.125 bore on a 6.0 for street motor,
please post more info. on your build.
12-14-2008, 09:09 AM
#34
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props.
so how much is the block filled?
does it see normal street use/miles?
i can imagine that the cylinders are thin. how much material was left after 4.125 bore?
much blowby?
i personally have gone .060 over on lq4, with no issues whatsoever, no blowby with low tension rings. and will do it again.
not sure about 4.125 bore on a 6.0 for street motor,
please post more info. on your build.
so how much is the block filled?
does it see normal street use/miles?
i can imagine that the cylinders are thin. how much material was left after 4.125 bore?
much blowby?
i personally have gone .060 over on lq4, with no issues whatsoever, no blowby with low tension rings. and will do it again.
not sure about 4.125 bore on a 6.0 for street motor,
please post more info. on your build.
12-15-2008, 01:27 AM
#36
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Yes. Wanted to try something nobody had done yet and it works for me. I have a few customers that we are going to try the same thing on and I am pulling mine out for the winter and tearing it down to look things over. Our shop is the only machine shop in this region that has done this with success.
No oil consumption that I can see.
Mike
No oil consumption that I can see.
Mike
What is the name of your shop Mike? You can PM me if you like. I may have a motor in my car that you guys built.I bought a car that came from your area.
12-15-2008, 03:12 AM
#37
Indeed, you are correct. However, the longer stroke means more force is placed on the side of the piston, rings, and cylinder (mainly the "contact area" perpindicular to the centerline of the crank and piston pin), and will increse the amount of piston, ring, and cylinder wear i.e. taper and out of round.
12-15-2008, 11:13 AM
#40
my experience in the past with iron blocks with that long of a stroke i oil consumption issues, because the sleeve is simply too short and it brings the piston out of the bottom of the sleeve at the bottom of the stroke, if it were me i would just run a 4" stroke and can it a day, much less headaches in the long run. that is my advise to you