SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: jamiemwedmore1234 on October 23, 2013, 08:40:52 PM
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I've been running a hei with a CID box for about to years it came out of a hot truck was just wandering if there is a difference between a automotive and a marine distributor as far as a timing curve goes I was told some time ago I needed to have something done to it and I also don't use the vacuum advance on it . Its time at 34 degrees advanced any body see a problem with that !!!!!!!
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the vacuum advance basically needs to be disabled. we dont use it in a boat. if you just unhook the vacuum line, it could bounce around and move the timing around when you're driving. and if you plug it with a cap, pressure builds inside that area from heat/cold and it'll move your timing around as well. so you remove the vacuum advance and you basically put a plastic "plug" in its place to lock the timing at whatever its set at plus/minus the mechanical spring advance.
(https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-prn1/841116_10151329895519833_747287904_o.jpg)
you're replacing this:
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.classicindustries.com%2Fimages%2Fproductimg%2F6%2F66952c.jpg&hash=cd0d0789a4bfd590aa5df5642251157fc5a3732b)
with this:
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.usaspecialty.co.nz%2Fimages%2FProform%2F67022C.jpg&hash=ee9253d3c9c887860409741f46579c5bc38385c9)
its fairly easy to do, just remove the cap and rotor, and then you might have to remove a couple screws to move the electrical board inside out of the way, undo a screw that holds the vacuum advance in, and then put the plastic lockout in its place (make sure to get the little advance arm into the hole in the lockout) and reassemble.
(https://scontent-a.xx.fbcdn.net/hphotos-prn2/1377523_10151756222114833_1875796568_n.jpg)
http://www.summitracing.com/parts/pro-67022c (http://www.summitracing.com/parts/pro-67022c)
$12
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Getting the mechanical advance set is important and it's not too difficult. If you can find someone with an old distributor machine they can get it set up without having to go out and burn up a tank full of fuel making adjustments.
http://static.summitracing.com/global/images/instructions/acc-31041_31042.pdf (http://static.summitracing.com/global/images/instructions/acc-31041_31042.pdf) Accel kit instructions
http://static.summitracing.com/global/images/instructions/mrg-929g(2)1.pdf (http://static.summitracing.com/global/images/instructions/mrg-929g(2)1.pdf) Mr Gasket kit instructions
http://static.summitracing.com/global/images/instructions/mor-72300.pdf (http://static.summitracing.com/global/images/instructions/mor-72300.pdf) Moroso kit instructions
You can also mix the springs to get an advance curve in between the chart ranges.
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The MSD HEI instructions have the best information I've found so far.
http://static.summitracing.com/global/images/instructions/msd-8365_frm30256.pdf (http://static.summitracing.com/global/images/instructions/msd-8365_frm30256.pdf) MSD instructions
Happy reading ;)
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If I remember correctly J&M speed center in riverside has a distributor machine that crew chief is talking about. There all pretty knowledgable there and good people but Steve helped me tune my chevelle in the parking lot there a few years back so if ya can talk to him.
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So I've been trying to find markings to tell me what brand hei I have without pulling it out of the motor no where to be found took the cap and roter off nothing not even a part # any suggestions
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It's probably an original GM HEI. Most everything in the links I posted will work except the lock out bushings noted in the MSD instructions.
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It's probably an original GM HEI. Most everything in the links I posted will work except the lock out bushings noted in the MSD instructions.
where can I find the vacuum advance lock and will it still wrk on a gm distributer and if the motor seems to be running good is it worth the trouble what am I loosing /or going to gain
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http://www.summitracing.com/parts/pro-67022c (http://www.summitracing.com/parts/pro-67022c)
http://www.summitracing.com/parts/dui-333333 (http://www.summitracing.com/parts/dui-333333)
There is a couple of lock outs/vacuum advance eliminators available through Summit Racing.
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http://www.summitracing.com/parts/pro-67022c (http://www.summitracing.com/parts/pro-67022c)
http://www.summitracing.com/parts/dui-333333 (http://www.summitracing.com/parts/dui-333333)
There is a couple of lock outs/vacuum advance eliminators available through Summit Racing.
thanks
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I removed my vac adv then drilled a small hole and bolted the advance mechanism to lock it out. Took about 20 min to do. Just another idea.
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