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XRV8 Gremlin |
Post Reply | Page <1 3536373839 54> |
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amcenthusiast
AMC Addicted Joined: Jul/02/2012 Location: SW Atlanta GA Status: Offline Points: 1778 |
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Last pics of re-worked cylinder heads before they get installed for test run:
The picture makes it look weird; that's Lucas assembly lube on the valve stem tip, not mud! I decided not to run the inner springs during camshaft break in procedure. Choosing the extra work, to install them later and use 'the rope trick' if all goes well. |
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443 XRV8 Gremlin YouTube video: https://www.youtube.com/watch?reload=9&v=2DmFOKRuzUc
XRV8 Race Parts website: http://amcramblermarlin.1colony.com/ |
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amcenthusiast
AMC Addicted Joined: Jul/02/2012 Location: SW Atlanta GA Status: Offline Points: 1778 |
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and...
Stock RV8 heads are limited to about .420" lift by valve spring coil bind with 1.85" install height. These are set up using AMC 360/401 valves cut down to 1.95" intake/1.60" diameter exhaust sizes with +.050" custom cut dual spring retainers to get .500" lift with 1.9" spring install height (about 125 lbs. closed/285 lbs. open spring pressures with Melling VS-500 outer & Sealed Power VS-527 inner springs) Fully detailed and ported with oversize valves, all cylinder head work done exclusively by XRV8 Race Parts. Edited by amcenthusiast - Apr/16/2017 at 7:48am |
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443 XRV8 Gremlin YouTube video: https://www.youtube.com/watch?reload=9&v=2DmFOKRuzUc
XRV8 Race Parts website: http://amcramblermarlin.1colony.com/ |
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304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
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I am sure once a younger gen looks at you engine, they are going to say... WOW, that's one big V6!
One of the oddest parts of looking at the rambler v8 is the lack of one exhaust port, especially when a header is used. Probably get them really thinking, like some sort of Algebraic equation... wha? More ports going in than going out? It just don't add up. I bet many Rambler V8 guys have a laugh when younger motor heads try figure out what their eyes are telling them. |
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71 Javelin SST body
390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker |
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amcenthusiast
AMC Addicted Joined: Jul/02/2012 Location: SW Atlanta GA Status: Offline Points: 1778 |
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A longer explanation to describe and explain the ideas behind siamesed exhaust ports would be appropriate here but I can't seem to make time & effort in order to write it...
But check this out: My plan for the valvetrain set up and the cam worked out 'just right'; I don't need custom pushrods (my calculations were correct) Edited by amcenthusiast - Sep/11/2018 at 8:47am |
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443 XRV8 Gremlin YouTube video: https://www.youtube.com/watch?reload=9&v=2DmFOKRuzUc
XRV8 Race Parts website: http://amcramblermarlin.1colony.com/ |
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amcenthusiast
AMC Addicted Joined: Jul/02/2012 Location: SW Atlanta GA Status: Offline Points: 1778 |
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Getting closer... pretty soon...
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443 XRV8 Gremlin YouTube video: https://www.youtube.com/watch?reload=9&v=2DmFOKRuzUc
XRV8 Race Parts website: http://amcramblermarlin.1colony.com/ |
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19676 |
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With 285# pressure closed you should be able to run regular oil (after break-in) with no issues. Over 300 lbs and cams start to wipe on flat tappet motors.
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Frank Swygert
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73jav
AMC Apprentice Joined: Sep/29/2009 Location: Owosso Michigan Status: Offline Points: 108 |
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If it runs even a 1/10 as good as it looks, you will have a rocketship on your hands. Never seen such attention to detail on every part of this engine. Beautiful work!!
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amcenthusiast
AMC Addicted Joined: Jul/02/2012 Location: SW Atlanta GA Status: Offline Points: 1778 |
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Scott, thank you for your observation with good question. Because, like 304dude's comment, there will be people who are instantly turned off by the sight of siamesed center exhaust ports used by AM's '56-'67 Rambler V8. This question branches off into engineering topics which are not normally studied by the average auto enthusiast. I plan to make a few drawings and post them here so I'll reserve this space for that, to be done in the future. (Thanks AMC Forum for the space) For now, we can look at several other early US V8s that used siamesed center exhaust ports also; We should remember also that Nash and Hudson top of the line models were rival to Cadillac, Packard and Studebaker top of the line cars. (can't find a good pic of a Stude' head right now) '62 Cadillac 390 V8 head: '55 Packard V8 head: '56 Pontiac V8 head: Edited by amcenthusiast - Apr/23/2017 at 8:13am |
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443 XRV8 Gremlin YouTube video: https://www.youtube.com/watch?reload=9&v=2DmFOKRuzUc
XRV8 Race Parts website: http://amcramblermarlin.1colony.com/ |
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19676 |
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A lot of engines used the siamesed center ports, as noted. One reason is that the two cylinders in the center don't fire one right after the other. There is enough time between firing to clear the ports, at least under normal driving. Remember, production engines aren't made for racing, but driving well under 4000 rpm (mostly in the 1500-3000 rpm range). The engineers really didn't care much if it performed well at 5000+ rpm -- that wasn't a design goal (with a few exceptions).
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Frank Swygert
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gremlin1945
AMC Addicted Joined: May/21/2008 Location: new jersey Status: Offline Points: 781 |
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With all the engineering skills you have I'm sure you're capable of making a divider plate like the one made for the 3rd gen 6 cylinder engines (199,232,258). If they're well made they will last a long time. Neat project.
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former NHRA #1945
former IHRA #1945 T/SA |
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