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Old 03-18-2002, 06:43 AM
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Cool 2.8 L V6

I have a '85 Chevy S10 with a 2.8 L v6 and a 5 spd manual trans. It has 157000 miles on it. I think it is time to replace my main and perhaps rod bearings. The motor will only make about 10 psi oil presure at idle after warm up when the air outside is around 70 degrees F. and about 30 psi while the truck is going 65 mph in 5th. I am using 10w40 oil and it does help some but not enough. How high should my oil presure actualy be?

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Old 03-18-2002, 07:18 AM
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don't forget about those cam bearings
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Old 03-18-2002, 07:33 AM
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Your oil pressure seems to be only about half of what it should be. Normal pressure should be 50-65lbs range at start & highway cruise speed and should be about half that at idle warm according to v6-173/2.8 1985 service manual. Hope this info helps. PS. I've also have seen the oil pickup screens parcially pluged resticting oil pressure in which it has scuffed cyl. walls,pistons,cam bearings ect.It required totally rebuilt to include new pistons,cam & bearings,turn crank,hone-punch cyls.If problem has been going on for some time with the mileage, consider a complete overhaul,less headaches in the long run.

NOVA JEFF
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Old 03-18-2002, 08:36 AM
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I doubt that I have a cloged oil screen as the oil stays prety clean and I know that the oil has always ben keped up properly. Plus my oil presure does start out at 50-60 psi when the engine is first started. In addition I have good compression so my cylinder walls are most likely in good shape. Thanks for the advise. I guess I will have to tear her down and check her out.
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Old 03-20-2002, 09:28 AM
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u better rebuild that engine or something casue they only laset about 150000 miles..... I would suggest SBC swap... thats what i did
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Old 03-21-2002, 05:36 AM
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I am going to tare her apart on Monday evening. I am planing on replacing the mains, rods, oilpump (high volume unit) and timing chain. A small block would be cool but quite unnessisary in this truck. I do not think the old girl could handel the additional torque. Besides she already gets 17 MPG. I can not handel any more gas going through that truck. Hopefully when I tare her down I will find that the only significant ware is in the bearings. I did the botom end on a car I had previously and it saved me a motor change.
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Old 03-21-2002, 08:31 PM
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Those engines had intake gaskets that leaked coolant into the inside of the engine. If it ever did that you can bet the bearings are bad. ROY
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Old 03-22-2002, 08:19 AM
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As far as I know it never did leak coolant into the motor. I am third owner and my fatherinlaw was second owner. He never said he had problems with that. I did a compression test last night and it came out prety good at about 120 lbs. leaks down prety fast so it could most likely use a valve job. Wolnt get it this time though. I am considering replacing cam bushings when I replace everything else that I have talked about. Should I consider a cam as well. The truck runs well and has no miss in it so I do not think it is nesisary. What is your input on this? How does one replace the cam bushingsin a 2.8 V6? If I switch to a mild performance cam and change nothing else will I see much improvement?

Thanks for the help
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Old 03-22-2002, 09:30 AM
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If I were gonna almost rebuild the entire engine I'd replace the cam , considering mileage.also lifters,ck rockers for wear because if the lower end is worn the upper end wasn't gettin it's share of the oil,and you know where all the bearing debre went. through the whole engine. As for cam bearing replacement, if you dont have the tool you can rent one ,but make sure their lined up wright and ck the manual for proper bearing clearences,it.s alittle tough but just take your time,if you don.t want to attept it have an engine shop do it.most likly it will cost about the same.It also depends if your doing an in or out of the vehicle overhaul. Hope this helps in your decision on your overhaul.It also depends on the use, and how much money you want to put in it.

NOVA JEFF
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Old 03-22-2002, 02:59 PM
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Crane Cams makes a cam for the 2.8 computer controlled engine. I don't know if your engine is computer controlled or not but if it is you can get a Crane Compucam cam for it. Also if you have standard hydraulic lifters (not rollers) it comes with lifters and assembly lube for about $160.00. You can order online at <a href="http://www.SummitRacing.com" target="_blank">www.SummitRacing.com</a>
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Old 03-22-2002, 03:44 PM
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You keep adding things to the list. Have you checked with some of the GM engine places you might be better off eith one of those. You have to pull the engine to install cam bearings anyway. If you need a list of places with low price but still new engines let me know. ROY
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Old 03-22-2002, 05:00 PM
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Mike, your cam bearings are where you get most of your oil pressure, so if you have low oil pressure you sure want to replace them, If you just replace the rod bearings and main bearings you could still wind up with low oil pressure if your cam bearings are worn, which with that number of miles I am sure that they are.
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Old 03-25-2002, 03:54 AM
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I have decided on a complete rebuild. I am thinking of geting one of those master kits with new pistons and have her punched out. I am going to yank the motor and trans out tonight. I hope it comes out quick and easy. If there is anything else you guys want to warn me about please let me know. I have never done a full rebuild before. I think I have skiped around enough on other motors that I will have little trouble doing the job. It will just be a mater of combining the skills I have used on diferent motors and using all of it on this one.
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Old 03-25-2002, 04:58 AM
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I really hate to say this but i feel someone should. The 2.8 was one of GM's bone motors. I have customers out there that run them 200,000 miles with no oil pressure. The things usally are just not worth the cash to rebuild. You would be better suited to find a rotten S-10(or wrecked) and swap in a 4.3. They run better .Get better milage. I have had some 2.8 motors cost more than a mod 350 to rebuild. Do a rethink,maybe even a used motor. If it was mine i would run it till it popped.Roy is correct about intakes,sometime in its life it may have leaked(most did) Head gaskets also went. Just maybe think about it.Allways like to see a guy do his own work but 2.8 will drain your wallet for no gain.
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Old 03-25-2002, 07:37 AM
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Motor replacement is tough in this area. If you get a so called good motor they run from 350-800 smackers. And they often tell you on the low end of that range that the motor must be rebuilt. To change out for the bigger motor will require a bunch of changes to the truck. I agree that the larger v6 is better but I just want to drive it and the master rebuild kit is only a little more than 400. And It is cheaper if I do not need pistons. I simply hate trying to hunt motors at junkyards. I have had themm start cars that look better than the car I am puting the motor in and tell me that it was a good motor. The damn thing was knocking like a bill collector on your front door! Good motor, I think not!! If I rebuild it and do everything right I should be able to get a lot of life out of it. I already have a car payment and can not have another until this one is done. That means I need 4-5 years more out os my s'. I did the brakes last winter and I did the body this summer. I just put a new radiator and waterpump in it a couple weeks ago. If I overhaul the motor there will be very little to go wrong and I should be in good shape for some time to come. I have thought long and hard about my options and discussed them with my father (former machineist and fine shade tree mechanic) and my Father-inlaw (Diesel truck mechanic welder fabricator) and they both think given the condition of the motor I am making the right decision. I want everyone to know that I appreciate there advice. Phat, I appreciate what you said about the motor but in my market a good used one would be tough to get if not impossible.

Oh! One more thing that drive it till it pops idea, Not so good. Both my wife and I work and I am taking college classes so risking being without a vehicle is bad. Spring brake this week from school. Tare her down and she will be done and I can put the old girl to work this summer doing construction and odd jobs.

[ March 25, 2002: Message edited by: 57Chevyman ]</p>
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