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Priming a 351e v6 engine
Hello everybody, I am sure happy this site exists. A relative just gave me a 1967 GMC Dually that has not been started in 6 years. I am a novice mechanic at best and that's probably stretching things. But I am fascinated with this motor and don't want to damage it so I decided to "prime" the engine.
I first poured mystery oil down spark plug holes over a period of several days. and was able to turn motor by hand. I changed oil and filter oil used is a 5w10 or 20 (the thinnest viscosity I could get hoping that it would seap through any dried up parts easier) I live in pa and it's in an unheated garage. As soon as I get it started I will put heavier oil in. I removed the distributor and my first surprise was the type of oil pump shaft it had. It is a long hex shaped rod. I hooked up a drill extension drilled it a couple for at least a minute or 2 a few times waiting to see oil squirt from rockers but nothing has happend. The drill turns at 1200 rpm. I checked a couple times to be sure rod is turning pump. Turning with fingers And it feels like it has the type of resistance one would expect with an impeller spinning in oil. So I think it is making a connection. I have watched dozens of youtube of people priming engines so Now my next thought is to connect an oil pressure gauge but I can't seem to find where it would connect. I have the gmc maintenance book and the engine overhaul book but I don't see any noted places to do this. Can somebody tell me.. Where it can be connected or better yet do I even have to prime it at all. One reason I ask that is because I have read one feature of this motor is some type of pre-oiling it does when starting that saves wear and tear. One other thing. I put 5 quarts oil in but I did not pre-oil the filter. (Could not pre oiling the filter have caused an air pocket that is preventing the oil from getting up to the rockers.) Hope to hear from somebody. Ihave ordered the factory assembly manual which will arrive Monday hopefully that will be helpful in locating the place to connect oil pressure gauge. Opinions,ideas,tips greatly appreciated. |
Re: Priming a 351e v6 engine
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If there is a port on the filter housing, that will work for a gauge. Where ever the oil pressure sender goes is the place to install a gauge, right on the engine, for testing. In my opinion you do need to see oil moving somewhere. Keep the drill going longer. Have you had the pan off to inspect pickup screen? Sounds like you are on the right track. Take out all spark plugs and crank it some. Not too much, just to see if it will crank. Oil may blow out of holes. If it sounds OK and you got some oil to flow at rockers. Start her up. NOTE: there really is no way to tell for sure that you won't mess it up without some dis assembly, but these preliminary steps will help. If something is already broken inside, you may have trouble. If you know it ran good when parked, then these oil and gentle rebirth methods will work. You probably have a spin on filter. Take it off and fill it. Don't run more than a min or 2 max without water/air flow.
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Re: Priming a 351e v6 engine
Thanks for your input.
When you say try to "crank it" do you mean using the electric starter? If that's what you mean should I re-install the Distributor or does that matter? I have marked where the tab was pointing and have not touched the crank by hand since I took the distributor off. (From what I have seen on you-tube doing so could make it difficult to get everything re-aligned again. I'm sure an experienced mechanic could do that with ease but I have to realize my limitations and I fear I could cause a situation that could create a new problem. I have seen where people re-position the crank by aligning it with some type of groove on one of the wheels that hold a belt. (I think it had a belt, I may have to go back and watch that one again if I can find it) with a certain point on the front of the engine. There are so many scenarios and some videos often leave out an important detail or new concept assuming one knows the other details already. It's all new to me and takes awhile to absorb. The maintenance and engine over haul books kind of help but the audience for them was obviously experienced, paid, professional GM mechanics. Thanks again for your help I really appreciate it. |
Re: Priming a 351e v6 engine
Put distributor back on after you run drill long enough to get oil. You can't hurt anything but the drill that way. You can reset distributor if you loose the position, but for you it would be better to reinstall before turning motor. Also you will be starting it after prelim cranking. Yes cranking means using starter. There are other issues here, points, condenser, wires, plugs, etc, involved in an actual start up. You can try however and see if it fires. It does not have to start but should fire. Then you know it's doable with more help. You should wait for other members to give their advice and you should find a friend that knows a little more about motors. The start up of this motor is no different than any other dormant motor restart. Keep checking your post for others to respond besides me. In the mean time report back if you are able to see oil flow with valve covers off as you run drill. You did not answer my question about screen and did not respond to filling filter. You need to answer questions from posters as they try to help. The more I read from you indicates less experience than first thought. Internet help may not be the best for you on this. You will learn a lot, some correct, some not. You need a good ol' boy to help in person. Carlisle used to be the heart of rodding and motor heads.
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Re: Priming a 351e v6 engine
Thanks for input. I will take the filter and reinstall with oil. I will see if I can get at the oil pump next. Fortunately, I do have an older gentleman "local good ole boy" type mechanic who owns a small shop who I am quite certain prefers these older vehicles. He works on another older truck I have. In fact once I got it started I was planning on driving it down to his shop and having him look at other things that will need worked on. The truck only has 70,000 miles on it. It was a special factory order and then the owner had a frame attached mini motor home type camper on it. Like many campers, it had lots of early use and then sat around. I may just have to have it towed down there and leave this issue to him as well.
thanks. |
Re: Priming a 351e v6 engine
This is probably supremely stupid, but I am afraid I can't see how the distributor drive would turn at all.
At some point it would have to be attached to a drive gear for both the dist and oil pump. |
Re: Priming a 351e v6 engine
Jim, not sure what you are saying but: The distributor has a gear on it's stem which engages a gear in the motor. (cam shaft gear) The distributor also "engages" a pump rod which is turned by the distributor because the distributor is turned by the motor gear when motor is turning. When the distributor is removed, nothing will drive the pump rod, so a drill is used to circulate oil. I'm not sure what you mean by "distributor drive". The pump rod is a hex shape, in many engines it's a slotted shaft. If he turns the engine with distributor out, the cam gear will turn and that changes the position of the distributor vs timing when you put it back in. If someone has marked everything before removing dizzy, they usually don't want to rotate motor. As I said, it's not the end of the world, it can be pretty easily reset by finding TDC cyl 1.
Teddy: Taking it to him sounds like a good plan. At the very least explain what you have and what you are doing and see what he says. 70K mile? WOW, that's neat. Should start right up with the proper procedures. Do you know if it was running when parked? How did you attach a drill? Long shaft with hex socket? My motor started showing oil at rockers with turning with starter motor, so I didn't use drill. I did cover everything with oil and cleaned the screen and put some oil in plug holes before cranking. NOT WD40. |
Re: Priming a 351e v6 engine
Aiken: By the way, since we're discussing this subject. I went to autozone looking for a primer shaft that would fit this hex rod and got into a conversation with a kid working behind the counter. ( Who was absolutely fascinated that a big block v6 ever even existed.)
He told me that he gets chewed out for doing this by coworkers and some mechanics but his method of priming a motor is he just takes the valve covers off and pours oil all over on top of the rockers and everything else and let's it seap down. At first I thought oh great now that I spend about a week or so learning all about distributor removal etc. etc. And building a small scaffolding set up so I could to see and work way back in the engine compartment he tells me this quick,cheap and easy engine prime method. I'm just curious is that an effective method to do this also? |
Re: Priming a 351e v6 engine
Well it's not a bad idea but it's done just so that there is not a dry initial few seconds before a dormant motor primes up and starts delivering oil thru passages. It does NOT prevent a big problem from a bad pump or oil distribution to all the other critical parts. It is not a substitute for being sure the pump and passages are open and working. You are not wasting any time and he is playing with fire. He gets chewed out by mechanics and co-workers and pays no attention? Does that tell you anything? You can't pour oil on the "everything else" he is talking about. You should, by all means, see oil moving up there either by drill or no start cranking, period. And that is not even fool proof. But that ,with an oil pressure gauge (reading 30-50 lbs +/- while running) would be as safe as possible for a dormant startup. Knowing the history of the motor when it was parked, if possible, is also important. A known noise or freeze up is a big warning.
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Re: Priming a 351e v6 engine
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Although they're pricey, an alternative to spinning your oil pump shaft with a drill is to install a pre-lubricator like MasterLube http://www.masterlube.net/classic.htm sells. They're good for protecting engines that sit for long times between start-ups. I've got one on my 401. |
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