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03-25-2021, 08:19 AM | #1 |
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Join Date: May 2010
Posts: 90
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Model A or B block relieved like V8
Has anyone ever heard or relieved 4 banger like we would V8
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03-25-2021, 09:18 AM | #2 |
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Location: albany
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Re: Model A or B block relieved like V8
No tony. The valve seat is flush with the deck unlike a v8. It would serve no purpose
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03-25-2021, 09:36 AM | #3 |
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Re: Model A or B block relieved like V8
"Just a little deuce coupe with a flat head mill
But she'll walk a Thunderbird like it's standin' still She's ported and relieved and she's stroked and bored. She'll do a hundred and forty with the top end floored". I question the 140 part but...If it was in the song ... it must be true Heh? |
03-25-2021, 11:00 AM | #4 |
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Location: Temecula, CA
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Re: Model A or B block relieved like V8
What jetmek says is true. I have rounded the edge a little before but can't say it helped, and you can't go very deep or you will run into the rings area.
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03-25-2021, 11:07 AM | #5 | |
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Location: Eastern Tennessee
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Re: Model A or B block relieved like V8
Quote:
#1, The top edge of the bore can be radiused slightly on the edges where the fire ring is not touching. This will aide slightly in transitional air flow. #2, while it may seem counterproductive because it slightly lowers the compression ratio, often times the volumetric efficiency can be increased if the valve is unshrouded on the backside by opening up the valve clearance area in the cylinder head. #3, having a multi-angle seat machined (3-angle, 5-angle, infinite-angle) allows the gasses to better flow over the sharp edge of a 45° angle. Ultimately, look for ways to allow the incoming and egressing air/gas to happen more efficiently. |
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03-25-2021, 11:21 AM | #6 |
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Re: Model A or B block relieved like V8
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03-25-2021, 11:40 AM | #7 |
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Location: Fresno, Ca.
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Re: Model A or B block relieved like V8
What everyone else said..PLUS THIS,...there isn't enough deck thickness in a A,..and
it's worse in a B/C block..! djm |
03-25-2021, 03:14 PM | #8 |
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Location: Wa.
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Re: Model A or B block relieved like V8
Yes, the top fuel FLATHEAD 4 banger that won the Antique Nationals was relieved.
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03-25-2021, 05:45 PM | #9 |
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Location: Eastern Tennessee
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Re: Model A or B block relieved like V8
How far down the hole was the piston, -or more specifically, was the top ring lowered to get it out of the heat some??
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03-25-2021, 06:09 PM | #10 |
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Location: Wa.
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Re: Model A or B block relieved like V8
The piston came deck height. The top ring was .200 below the edge of the relief. Same as the V8's.
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03-25-2021, 06:10 PM | #11 |
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Location: San Antonio, Texas
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Re: Model A or B block relieved like V8
Relieving has been done but the builds for this likely use custom made everything for the build. Relieving for the V8 engines was originally done to lower compression ratios on truck engines. Crow foot cylinder heads were made that work with a relieved block on the V8s. Most folks have been going the blower type supercharger route to get flatheads to breath. It certainly works better than normal aspiration in most cases. On 4-bangers, going overhead valve is generally the first choice to make the 200 cid Ford get up and go.
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03-25-2021, 06:31 PM | #12 | |
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Location: Wa.
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Re: Model A or B block relieved like V8
Quote:
And definitely, a racing engine has "custom made everything" in it as noted by the similar cost to a NASCAR or WoO engine. |
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03-26-2021, 03:37 PM | #13 | |
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Location: South California
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Re: Model A or B block relieved like V8
Quote:
If mostly stock engine... little to gain if any, and lots to lose. The A/B blks were thin when new and even thinner the older they are. So intentionally removing metal from that area is not a good idea ...unless you don’t mind cracks and leaks. When I eventually learned and saw A/B crack potential ... where relieving takes place... well your choice ! |
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03-26-2021, 06:33 PM | #14 |
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Join Date: Dec 2019
Posts: 1,196
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Re: Model A or B block relieved like V8
It's not about increasing valve relieving..its about valve lift and timing, raising compression and adding fuel.that where the money is..flathead V8? Meh, lousy power to weight ratio, propensity to run hot and burn oil..a well-built and tuned model a will make a fool of it..
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