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#1
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When can you use 4.125 pistons on a 400 block?
I am considering using .005 oversize pistons on a block that appears to have very little wear on the cylinder walls. I have a dial bore indicator gauge, but l am not a machinist. Best I can tell the cylinder appears to be right at that measurement now. And forged pistons require 4 to 5 thousands clearance which can be done with honing?
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#2
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You could hard block it. That requires a extra .002.
extra ring gap too. |
#3
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Yes you can hone the cylinders for 4.125 pistons. It might not be enough to make the cylinder round with a torque plate.
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The Following User Says Thank You to PAUL K For This Useful Post: | ||
#4
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I had no problem running 4 1/8" pistons in my blown alky mini-puller, using a '67 400 block honed to 4.125". Turned 8,300 RPM on most runs. I heard a lot of "Didn't know Pontiac made a 401".
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Anybody else on this planet campaign a M/T hemi Pontiac for eleven seasons? ... or has built a record breaking DOHC hemi four cylinder Pontiac? ... or has driven a couple laps of Nuerburgring with Tri-Power Pontiac power?(back in 1967) ... or has a Pontiac born the same year as Jim Wangers? (1926} |
The Following User Says Thank You to Jack Gifford For This Useful Post: | ||
#5
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Is this filling the water jackets?
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#6
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This is interesting, does filling the block add heat to the top of the piston?
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Tim Corcoran |
#7
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Yes, filling them to the bottom of the water pump holes.
If you do it, get it done before you hone the block and its best to let it cure with a head-tq plate torqued down. |
#8
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Quote:
So I have .006 piston to wall and around .023 end gap. Thing is, Dan said I might hear the pistons before it warms up but it sounds normal. And AWESOME too I might add. Taking a day off today to get a 4 day weekend to work on my car. Finish fuel pump, fuel cell install. Finish new smaller brake booster and proportioning valve install along with a auxiliary vacuum pump for the brakes. Put my PTC converter back in. Install new 1350 front yoke. And re install my headers I just got back from being coated. That will be a chore getting them in without scratching (700$ to coat) Think I will wrap them in blue painters tape first then take off. And if I get around to it put in a Fantz by pass filter to go along with my K&P wire mesh oil filter. Made a fuel pump cover with 1/4" nipple to get the oil back in. My old 455 I ran forever. Its .060 and I am planning on hard blocking it and running a .065 over piston and ridged hone with plate. The extra .002 might be useful for me and might help the OPs situation too. |
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