Finished Recent Top end work, few issues remain

[Sgtduckyboy]

I had a stuck lifter. Decided to go in and figure it out on my own and replace what I could. found the lifter, number6, replaced all lifters, honed out the one in 6 that was stuck. replaced rods, oil pump, water pump, cam sensor, oil presssure sensor(it wasnt working the last few years), upgraded the cam and valve springs.
upon first start up, ran ok, nothing weird occured. It did die a couple of times after accel and letting off the gas. I replaced oil the next day, all new coolant as well was added upon rebuild.

what I am experience now: sometimes at idle, the rpm's are unsteady, like its going to die, this occurs once warm. oil pressure at cold is near 40 and at any rpm above idle, cold or warm, its at least 30psi. but when its real warm, i can get a 'oil pressure low' warning. this is freaking me out a little. i do want to explain, i put in the melling 295HV pump. i didnt however, realize there was a 'dimple' on the larger of the two gears and not sure if that is facing in or out. I dont feel this would be an issue since it is working, but I figure, i have a 50% chance its correct. I can not find out if having it in wrong changes anything with the oil pressure or performance of the pump.

as far as the unsteady RPM's at idle, i feel this may be some sort of vacuum leak around the intake. I was thinking, spray some WD40 at it while warm and idling and see if any of it gets sucked in and kills the motor.

i want to add, this engine is running smooth, no noises, just hear the injectors now. I am very pleased with the appearance that this was done correctly. power is great on the low end, due to cam change and acceleration is perfect, no noisy valves/lifters etc.

one thing i read was about the cam bearings, but those guys seemed to be talking in circles so i wasnt sure how to read their information.

one thing I'd like to know, is the oil path this way: oil is sucked from the back of the pan , by the pump in the front, it then goes through the block, back to the oil filter, then it goes up the block to the oil pressure switch, then into the block to all the oil ports/paths for cam/lifters/crank/pistons etc. if this is correct, how can the cam bearings affect the oil pressure at idle, only when warm? wouldnt the pressure be high, then the pressure relief, back at the oil pump,would bypass , thus not lowering the pressure to below the value the pressure relief is set at?

 

[02Lightning]

I replaced an oil pump one time because of low oil pressure at idle when warm, it didn’t fix my problem. I was told the cam bearings were bad. How was your oil pressure before? I would put a mechanical gauge on it and see where the pressure is at.

 

[YukonandtheHOE]

If you knocked a cam bushing out of alignment just a little it will bleed oil pressure out . But 10psi for every 1000 rpm is the still safe limit for low oil

 

[swathdiver]

Which camshaft did you use and what are its specs?

 

[02Lightning]

I also wouldn't think you could change cam shafts without a tune.

 

[swathdiver]

I also wouldn't think you could change cam shafts without a tune.

Generally speaking no, you cannot. Depends on the cam used of course.

 

[rockola1971]

Did you do a idle relearn? I would get a oil pressure gauge hooked up and monitor the pressure. Why on earth would you stick a new cam into used cam bearings? That is false economy and may have caused you more problems than you know.

 

[Sgtduckyboy]

I replaced an oil pump one time because of low oil pressure at idle when warm, it didn’t fix my problem. I was told the cam bearings were bad. How was your oil pressure before? I would put a mechanical gauge on it and see where the pressure is at.

Thanks for the info. I've heard about that Cam bearing issue. Like I said, the oil pressure sensor wasnt working before this work and supposedly put on a higher volume pump too.

 

[Sgtduckyboy]

If you knocked a cam bushing out of alignment just a little it will bleed oil pressure out . But 10psi for every 1000 rpm is the still safe limit for low oil

My pressure is fine as long as i have a few hundred RPM's over idle going. based on the dash guage. I dont hear anything at all, during any rpm's , cold or warm.

 

[Sgtduckyboy]

Which camshaft did you use and what are its specs?

something that works with stock tune, supposdedly, MTC-7 cam by Melling. as close to a Crane cam as i could find, without the price. http://www.melling.com/News/News/ID/442/New-Class-II-RV-Torque-Camshaft-for-GM-485357-60-Engines

 

[Sgtduckyboy]

Did you do a idle relearn? I would get a oil pressure gauge hooked up and monitor the pressure. Why on earth would you stick a new cam into used cam bearings? That is false economy and may have caused you more problems than you know.

well, based on the several dozen articles and videos , not one person mentioned that. some were reputable shops/mechanics, some were billy bob redneck. also, no one mentioned the little dimple on the oil pump gear that must be facing out when installed. of course I didnt find that out until i started to research my existing condition. so, why did i do it,, even if i had known 'you should' do it, it still doesnt state you 'have to'. and besides, every thing i looked at in the heads and piston bores, showed little to no wear. crosshatch was till in the piston bores. no reason to believe i had any issues with the can bearings. plus that involved removing the engine, which wasnt in the scope of me doing the work. the stuck lifter damaged the existing cam lobe. no other issues were found on the old cam. we didnt measure the cam, but nothing looked out of place/different/worn. I had an experienced small block chevy guy with me and he also said, when i asked him of this question you asked, 'its ok, i believe, no reason to believe it would be an issue, but it could be.' he also doubts i have an issue and when i put in some 10w40 oil, it has a good chance to disappear. I could also increase the idle RPM by 100 since that also seems to stop the light from coming on. also, this has only came on a few times, not every time i drive it. Anything else you can add or ask to get me more informed. thanks!

 

[swathdiver]

Why on earth would you stick a new cam into used cam bearings? That is false economy and may have caused you more problems than you know.

I thought about this and then realized because its generally not necessary. Nobody who deletes the DOD system with the engine in the vehicle replaces their cam bearings and tens of thousands of people do this. Of course they should have the sense to inspect the journals to see if anything is amiss. Many moons ago we tore into a great many V6s and unless doing a complete overhaul, we reused the cam bearings too. We also reused the stock cams as the aftermarket ones were junk back then.

 

[Classehoe]

I would suspect the vlom is leaking or the oil pump pickup tube o-ring is wrong/leaking.

 

[Sgtduckyboy]

I would suspect the vlom is leaking or the oil pump pickup tube o-ring is wrong/leaking.

i do not have VLOM, this is not an AFM engine. I triple checked the pickup tube during its install. the first time i installed it, i saw it was crooked, so i loosened up the oil pump again, and removed the tube, then reconnected, this time being extra careful to get the tube in straight and fully. when the oil pump cover and gears are removed, you can see the pickup tube inside the pump and easy to determine if its inserted fully. that is my impression of this task, anyway.

 

[Classehoe]

i do not have VLOM, this is not an AFM engine. I triple checked the pickup tube during its install. the first time i installed it, i saw it was crooked, so i loosened up the oil pump again, and removed the tube, then reconnected, this time being extra careful to get the tube in straight and fully. when the oil pump cover and gears are removed, you can see the pickup tube inside the pump and easy to determine if its inserted fully. that is my impression of this task, anyway.

Sorry didn't pay attention to which section I was in. Low oil pressure at idle is pretty much a weak pump or some sort of excess leak such as drawing in air on the pickup, loose bearing clearance, or a leaking oil passage.

 

[ezstriper]

Ok, did not see what year ? cams have been installed in old cam bearing hundreds of times, as long as the they are ok. On later years there is a small screen below the oil sending unit that clogs and will mess up OP reading. If you installed a non factory cam you will need to get tuned to get it to idle.

 

[Sgtduckyboy]

Ok, did not see what year ? cams have been installed in old cam bearing hundreds of times, as long as the they are ok. On later years there is a small screen below the oil sending unit that clogs and will mess up OP reading. If you installed a non factory cam you will need to get tuned to get it to idle.

This cam is designed to work with the stock tune. Melling MTC-7. However, I am not totally convinced that to be the case. My biggest hunch is i have an air/vacuum leak in the intake manifold. this weekend, my neighbor is lending me his garage and we are going to do a few things. remove intake, check the gasket, decide to replace the new one which is of a style that 'grabs' the head bolts on the top of the head to align it. this is different than the stock ones, which are supposedly reusable and I wish i kept them. i ordered a new set of the old style, that snaps on the manifold. Then i will put it on carefully, doing my best to align and not 'jar' the gasket as I am placing it into position. This is kind of hard with that semi-rigid plastic tube that runs the length of the manifold and has to be wiggled through the fuel rail crossover. I am also going to clean the MAF. (i had had a few pending codes with the MAF, P0101). I am contemplating removing each injector and checking the screen is clear from debris. This seems to be overlooked by a few articles I have read, but I can do this when its back together, but will be easier to do while the intake is out. I am also going to put in some high strength fuel injector cleaner from GM that I have leftover from my wife's car. that will go straight into the fuel rail before I power the fuel pump on. I will let that sit for a while, then start the car without plug wires attached so the cleaner gets a few squirts into the nozzles, then let the car sit a while longer, reconnect plug wires and start. Hopefully at a minimum, I have fixed my air/vacuum leak and hopefully added some fuel throughput, or balanced them out enough to make the cylinders more equal. I have a gas smell at startup and during the warm up at idle. its not so noticeable once warmed up and idling.

 

[Rocket Man]

i do not have VLOM, this is not an AFM engine. I triple checked the pickup tube during its install. the first time i installed it, i saw it was crooked, so i loosened up the oil pump again, and removed the tube, then reconnected, this time being extra careful to get the tube in straight and fully. when the oil pump cover and gears are removed, you can see the pickup tube inside the pump and easy to determine if its inserted fully. that is my impression of this task, anyway.

There should have been 2 different O-rings for your oil pump and you need to make sure you use the correct one. Also, if you installed the pickup tube crooked the first time, you might have put a nick in the O-ring. This is a common problem when installing a new oil pump, especially if you don't remove the pan so you can install the tube easier.

 

[Sgtduckyboy]

There should have been 2 different O-rings for your oil pump and you need to make sure you use the correct one. Also, if you installed the pickup tube crooked the first time, you might have put a nick in the O-ring. This is a common problem when installing a new oil pump, especially if you don't remove the pan so you can install the tube easier.

Yeah, i am sure of the 0ring being the correct one. I received one set with the new oil pump and another with the gasket set, both said to use the Green one as i had the Red/Orange one on originally(if i am remembering it correctly). i tried to look at the ring when i had to pull it back out, from the parts of it i could see, mostly where it would have been pinched too, it looked fine. I also moved the bolt to the left/higher side by notching out the 'key' so i can flip that single bolt bracket around. I'm not ruling out that could be an issue with the oil pressure, I am finding it to be a slimmer chance at this point. I'd believe the cam bearing issue to be of greater liklyhood at this time. luckily, the weather is so cold, its not getting warm enough to get too thin. its staying up around 10psi when warmed up the last few days. I'm probably overreacting to this since i did use conventional oil, i need to change it in a few days to a week back to synthetic and probably go to 5w-40, that 40w should hold better once warm, its worth a shot at least.

 

[Rocket Man]

I just went back and re-read your original post and noticed you talk about a "dimple on the larger of the two gears"- please explain. Are you talking about your timing gears? That's the only thing I can think of that matches what you're talking about, since there's nothing on the oil pump itself that you can turn around backwards. And if so, I don't see how you could have got the timing correct if you didn't have dots to line up on the upper and lower timing gears. But... if you did install the upper timing gear inside out, that's most likely your problem. My Cloyes timing set came with a camshaft thrust washer and it needed to be installed correctly or "it will cause a severe wear issue". I'm not sure of what would happen if you reinstalled the stock upper timing gear inside out but I don't think it's a good thing at all.