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Old Mar 9, 2014 | 10:20 PM
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Default stroker question

Will 4.0 rods on a 258 crank clear in a 4.0 block
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Old Mar 10, 2014 | 06:42 AM
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I have all the parts specs and will check for you later tonight.
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Old Mar 10, 2014 | 06:54 AM
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http://www.angelfire.com/my/fan/stroker.html
http://www.jeepstrokers.com/forum/
http://www.hotrod.com/techarticles/e...l_summary.html
http://www.jeep4.0performance.4mg.com/stroker.html
http://www.naxja.org/forum/showthrea...ght=crankshaft

Last edited by SeriousOffroad; Mar 10, 2014 at 06:57 AM.
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Old Mar 10, 2014 | 08:21 AM
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Not with a standard pin height piston. You will need to order Keith Black pistons part number IC944.
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Old Mar 10, 2014 | 08:32 AM
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Originally Posted by Lead Foot
Not with a standard pin height piston. You will need to order Keith Black pistons part number IC944.
Or the IC945 which will raise the compression. You'll also need to add spacers to the crank girdle for it to clear.
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Old Mar 10, 2014 | 08:33 AM
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Thank you lead foot so the will clear with 4.0 rods and also what kind of valve to piston clearance will I have with this combo
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Old Mar 10, 2014 | 09:57 AM
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The valves on a 4.0 head are seated above the deck. So as long as you have at least .030 quench height, you will not hit the head and be fine. I recommend decking the block as needed to achieve .040 to .030 quench height and taking as little off the head as possible to achieve best efficiency. You want to keep the combustion chambers big as possible, so just skim the head until its flat.

By keeping the quench height low I was able to run a 10.5 static compression ratio and 9.0 dynamic compression ratio and still use regular grade fuel without predestination. Having the newer Obd2 system helps with that as well. I do run premium anyway though as I notice a smoother running engine and a little more power.

Last edited by Lead Foot; Mar 10, 2014 at 10:05 AM.
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Old Mar 10, 2014 | 10:01 AM
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This is really one of the most useful pages. http://www.jeep4.0performance.4mg.com/stroker.html

For detailed stroker questions you will get great response from jeepstrokers.com
My build specs are here. http://www.jeepstrokers.com/forum/vi...php?f=8&t=4293
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Old Mar 10, 2014 | 10:10 AM
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Originally Posted by Hayden98XJ
Or the IC945 which will raise the compression. You'll also need to add spacers to the crank girdle for it to clear.
If he goes for less quench height, only having the 10cc dish the ic945 has will raise his compression too high in my opinion. He might get away with it depending on cam intake valve duration.
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Old Mar 10, 2014 | 10:52 AM
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OK that brings me to my next question what is the most lift the stock valve springs can handle
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Old Mar 10, 2014 | 11:13 AM
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Depends on the year of engine. The springs can "handle" most common aftermaket cams. The problem you start to see is valve float if the springs aren't stiff enough. Too stiff and you get premature cam failure. I opted for Buick V6 valve springs from the junk yard. Working great. Didn't require machining either.
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Old Mar 10, 2014 | 11:33 AM
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I have a 88 block and I'm gonna run my 96 ho head what can that cable spring support
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Old Mar 10, 2014 | 11:38 AM
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If you are upgrading the cam at all, I would upgrade springs.
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Old Mar 10, 2014 | 11:56 AM
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What liter and year Buick springs should I get
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Old Mar 10, 2014 | 12:16 PM
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3.1 or 3.4 litre v6 with aluminum heads found 94-03 in like Pontiac Grand Prix. Part number vs-1642. If you cross reference that number you can find all the applications. You will also want to grab the locks and keepers.
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