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XRV8 Gremlin |
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scott
AMC Addicted Joined: Jul/10/2007 Location: Wildwood Pa. Status: Offline Points: 3501 |
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We need a picture of what it looks like with the cap off! Why did you delete the vacuum advance?
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amcenthusiast
AMC Addicted Joined: Jul/02/2012 Location: SW Atlanta GA Status: Offline Points: 1778 |
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No vacuum advance because the engine has a 'lopey cam' which creates an erratic vacuum signal under 2000 rpm where it spends most of it's time running due to increased power to weight ratio.
space for comment Edited by amcenthusiast - Feb/03/2020 at 8:55pm |
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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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Other desirable tune up tidbits for Rambler V8:
Above: Accel rotor features much better quality construction and materials. Above: Champion L78YC features 1/16" more 'reach' than stock recommended H14Y or Autolite 437 spark plugs -the stock plugs are about 1/16" 'down in the hole' and as such, they are semi-shrouded in relation to their protrusion into the combustion chamber area. The NGK equivalent to Champion L78YC is B8HS? 'Fine wire' tip Champion equivalent to L78YC is their 'Powersports' 8883 (no doubt) having NGK B8HV interchange? -these alternatives are commonly considered to be 'marine' or 'motorcycle' spark plugs. Above: It is important on all Rambler V8s to index the spark plugs. Mark their ground straps using a black sharpie felt tip marker then sort through a full set of plugs until they install with ground straps facing the exhaust port outlets as shown. -This positions the 'flame kernel' towards the center of the combustion chamber -where it should be. Edited by amcenthusiast - Oct/14/2019 at 10:13pm |
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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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Never heard of indexing the spark plugs. I understand your theory, and it makes sense... at least on paper. I'm not so convinced it's going to make a noticeable difference when driving though. Burn should be more complete in the chambers, so it will likely run just a tad cleaner, and maybe get another half hp out of it.. maybe even a whole one. Cleaner, more complete burn is still a good thing, probably keep carbon build-up down. Not trying to be a smart-azz, just skeptical... I've been wrong before though...
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Frank Swygert
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Jmerican
AMC Addicted Joined: Mar/29/2016 Location: Seattle, Wa Status: Offline Points: 585 |
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That dual point is killer! And yeah, in the one 327 head set I’ve seen, the thought occurred to extend the shell length. You found the perfect length in those marine plugs. I wonder if the original type plug is not common, or if it was just a bad spec on the head thread. Thanks for the clarity on the different chambers. I’ve got a set of late Jeep heads. I’ve got plans for the engine, but no rig for the engine. Hmm. I’m gathering steam. I appreciate the porting report on the AIR lumps. I’ll check in before I grind.
Hey are the dual points set up to extend dwell on all 8 via make/break or did you split the system? I’ve never seen the latter, but didn’t nash do that, back in the day? Yep, nice alkyd or Bakelite and brass parts. Oh yeah, and of course the plugs are indexed! Farna may be a sceptic. But Farna, its well published and tested. Moroso makes indexing washers, if that is telling. Modified electrodes have their place as well. When you know the head chambers, that’s when you index. I always do, within about 30 degrees.
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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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Well, like I said.. I've been wrong before! When trying to squeeze every last possible pony out of an engine I can see if being worth the time and effort, just not so much on a daily driver. As far as the plug length, the manufacturers sometime change the specs over the years and keep the same number. I wonder if the late 50s/early 60s plug specified for the Nash/Rambler (or Gen1 AMC) V-8 hasn't been changed over the years to the one we have now? Maybe the shell was only used for that application and the manufacturers moved to a close shell used in other engines? Of course they could have always been made that way...
Edited by farna - Oct/12/2019 at 9:56am |
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Frank Swygert
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amcenthusiast
AMC Addicted Joined: Jul/02/2012 Location: SW Atlanta GA Status: Offline Points: 1778 |
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Only vaguely familiar with the Nash twin ignition, not sure about details. Concentrating on this engine, the dual point arrangement reduces the time a single point would stay open. (seems like it would be the other way around -like having two, they'd stay open longer ...but no; it's the opposite)
In order to increase the time a single point set would stay closed, the gap becomes too small and does not open far enough to properly 'switch off' or 'break' the circuit (hence the name 'breaker points) In a running system, like this one using a Delco V8 distributor... it goes like this: -When the first set of points open (to the stock single point gap setting) nothing happens because the second set of points is still closed completing the circuit. -However, when the second set of points opens (also set to stock gap specification) it breaks the circuit & triggers flow into the secondary part of the ignition system, but as soon as it does, the first set of points closes (before the second set closes) -In other words, the second-trailing set of points triggers the spark when it opens, but the primary or first set of points only participates by closing early -this is what increases the dwell time, for the circuit to stay closed longer, for more coil saturation time than it would have with only one set of points. -This is more important on V8s because they have eight lobes on the breaker point cam, which reduces dwell time to half what a four cylinder engine gets with it's four lobe breaker point cam. Still, even with dual points, the V8 only gains some increased dwell time -which is very much needed and useful -but on a four cylinder, they already have too much dwell time which tends to only overheat the coil with too much saturation time. ...with a measured steady nine volts to the Accel Super Coil (9 volts from the stock '73 resistor wire) and no added on ballast resistor, the coil on this car never feels hot to touch -slightly warm only. will paste in new group of spark plugs here, time and space permitting Edited by amcenthusiast - Nov/14/2019 at 1:51am |
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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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Where 'X' means 'experimental' (and 'RV8' means 'Rambler V8') what good is an experiment if we don't get to observe the results?
So, after running the engine & two years later... only with much anxiety about seeing the rotating assembly turned orange with rust, I decided to pull the oil pan and do an inspection: Looks good inside, which 'made my day'. Only a few areas, on the crankshaft only, where there indications of moisture induced light surface rust -very low level of concern now after observation. Only two areas, in picture directly above, are there rust spots, where evidently there was some kind of flaw in my paint application. Rather noticeable are the stains under the rust spots, which indicate they 'bleed' contaminants into the engine oil. I'm fully convinced now to paint internal engine parts whenever possible to help create a cleaner crankcase environment for the engine oil. Note that I only used 'ordinary' enamel paint (after intense acid wash and pressure wash cleaning methods) ...and notice how well the paint has held up; very good in my opinion. -This is only one example but I think it proves fairly well that it's ok to use enamel paint inside the crank gallery. Edited by amcenthusiast - Nov/14/2019 at 1:55am |
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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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..Continued observation:
Above; to paint, or not to paint -picture tells a thousand words? Above: About 1/8" down from the dipstick tube, looking closely, we can see the dimple/mark on the dipstick rod -that mark indicates 4 quarts in the pan... ...which is too high: the stroker rod journals strike the oil & cause aeration. So I took many measurements and modified my oil pump pickup assembly and oil pan. Next group of pics will show latest mods to oil pan and oil pump pickup tube assembly. Edited by amcenthusiast - Nov/14/2019 at 3:44am |
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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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g-man
AMC Addicted Joined: Jul/05/2007 Location: Cal Coast Status: Offline Points: 703 |
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You know...I always really enjoy reading your posts.
Just a question for you, as I see that you have given consideration to aeration...Did you ever consider knife edging the crankshaft? I know the next time I build an engine I want to give that a try. Also...Have you considered making a crank scraper, or making a windage tray? This is just food for thought, as I see you do give a lot of thought as to what you are doing. g-man
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AMC only daily driver
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