SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: The Chaz on March 20, 2008, 06:41:16 PM
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Can valve springs be changed without pulling the head off? Will the valve fall down into the cylinder?
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Yes they can be changed while the head is still on. Yes they will fall into the cylinder. An old timer once told me you can stuff rope into the cylinder to keep the valve from dropping.
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Hmm.. I just read something about a tool that will hook to an air compressor and screw into the spark plug hole that holds the valve closed... I wonder if it's expensive or easy to find
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If you put the piston at TDC, and then pump compressed air into the spark plug hole the valve should stay up.
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Yes they can be changed while the head is still on. Yes they will fall into the cylinder. An old timer once told me you can stuff rope into the cylinder to keep the valve from dropping.
That might work too.
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Hmm.. I just read something about a tool that will hook to an air compressor and screw into the spark plug hole that holds the valve closed... I wonder if it's expensive or easy to find
Opps you beat me to it, you can just make one with an air fitting and adapter and use your at home compressor
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OK, I was thinking that at TDC it probally wouldn't fall further than I could grab it anyways, but I could be wrong.
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if you are changing all valve springs why not pull the head...might as well cheap insurance too...you can change the head gaskets and have a look see...if you have one broken spring then i would suggest the air tool deally...just my .02
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Head gaskets are new maybe 30 mis of run time on them. Springs are not broken, just old. They are original from 1969. I am replacing them due to a little valve float at 4500+ RPM's
I think putting new ones will cure this.
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(https://www.socaljetboats.com/cpg/albums/userpics/10041/normal_5-28-07_005.jpg)
(https://www.socaljetboats.com/cpg/albums/userpics/10041/normal_5-28-07_006.jpg)
how are you going to check the installed hight or are you?
but here are some pics
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The springs I ordered were recommended by crane cams for my application/cam. I was told that I could just swap them out without any trouble. They should match the Original height and Outside diameter, or so I was told. If there is something else I need to be doing please let me know. This will be my first spring removal/installation. I am using the same retainers, again I was told they would be fine as long as there are no cracks or damage ??? I hope I'm not jumping into something is going to cause me more trouble
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chaz, you should be fine. i take it they are basically a stock replacement?
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WOOSAH O0
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Harbor freight has a comprossion tester kit its "cheezy" but it has a quick connect coupler that interchanges with all the different plug hole adapters, and it just happens to be the same fitting as the hose end on your compressor, 15.00 bucks and your in there. There are two different fittings, double check your hose end to make sure you have the right one. I used the same setup for a leakdown test it worked great.
When the cylender is compressed with air take a socket and "tap" on the retainer, (not the valve itself) that'll break loose the keepers and you wont lose your compression when you push the spring down. I would also recommend you only do one valve at a time, you pop both springs off and lose pressure you're fawked. The mistake I have made before is when re-installing the retainer I didnt have it alligned with the valve (allow for the arch the tool needs to compress) and opened the valve instead of compressing the spring back into its position, and that little "ting" when the valve drops really sux!! ;D
Dam, after writing this, the rope sure sounds easy LOL
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Do it on the head, It's easy. Compressed air holds the valve up, the engine holds the head in place. You compress the springs, pull the locks and reverse.
Installed height for the two springs will be the same, it's set by the valve length and retainer / lock combo. If you can reinstall the valve spring without compressing it a bit, then you have an issue and should stop immediately. Most likley, you will need to compress the valve spring, and you will have some force on it (that is your seat pressure)
While you are there, just for your piece of mind, measure the fully compressed spring and compare it to the installed height.
installed height - compressed height - .050 = max valve lift.
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Harbor freight has a comprossion tester kit its "cheezy" but it has a quick connect coupler that interchanges with all the different plug hole adapters, and it just happens to be the same fitting as the hose end on your compressor, 15.00 bucks and your in there. There are two different fittings, double check your hose end to make sure you have the right one. I used the same setup for a leakdown test it worked great.
When the cylender is compressed with air take a socket and "tap" on the retainer, (not the valve itself) that'll break loose the keepers and you wont lose your compression when you push the spring down. I would also recommend you only do one valve at a time, you pop both springs off and lose pressure you're fawked. The mistake I have made before is when re-installing the retainer I didnt have it alligned with the valve (allow for the arch the tool needs to compress) and opened the valve instead of compressing the spring back into its position, and that little "ting" when the valve drops really sux!! ;D
Dam, after writing this, the rope sure sounds easy LOL
The issue with the rope is you have to bring each cylinder to TDC (or near as you go) so you have to pay attention with engine crankshaft position.
Lots of back and forth....
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make sure to leave spark plugs rest of holds or motor can turn over from air pressure they make clamp type puller by kd that holds spring and pushes down on retainer cost like $40.00 works good you don't have to pull bar and locks can be replaced real easy, old fart like me need to put locks on easy one bar is ok if you have some help to pull when putting locks on. and keep finger out of way. :banghead:
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The issue with the rope is you have to bring each cylinder to TDC (or near as you go) so you have to pay attention with engine crankshaft position.
Lots of back and forth....
This is the same old timer that told me if I ever break down in the desert due to a bad main/rod bearing all I have to do is take my belt and use a piece of the leather to make a bearing to get myself home. He said he had to do that with a model B he had. I'm talking OLD timer here. :D
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you can put new spring on all ready pulled up and set on spring and retainer locked to geather never droped a valve this way
and chaned many off them this is a screw type puller looks like a gear puller :banghead:
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Wow, thanks for all the advice guys. Now I am am a bit nervous to do this, but... I have said that at every step along the way. I like to do as much of the work on this myself as possible. If I can learn something about my engine then I was successful, even if I have to pay for that knowledge. I just don't want to be boatless because I didn't get enough information before I started something. O0