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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Quick question, I think he called himself spec-ing this engine based on a race motor. He kept telling me I would just as fast as his 500hp 355... I kept trying to tell him with my vortec and lower compression there was no way. He wanted me to buy new heads and all kinds of machine work. Bottom line is it possible he made the clearances like a race engine and the 10w-30breakin oil is just too thin? I told my wife since its raining and I cant work on it I would try her idea of some 15w-40 but if it doesn't hold 10psi at idle the. It definitely would be a bigger clearance issues than just racecar
Oh when oil pressure goes to 0. Oil is still coming out the heads. I found that out when I loosened the valve covers. Like I said any tap of the gas and pressure instantly kicks in. I dont have any knock, squeaking, squealing or anything that I can tell. I figured the oil was worth a try. If it doesn't work, I already plan on taking the motor apart anyway
Last edited by budget builder; 02-16-2019 at 11:03 AM.
It's not really going to work that way I'm afraid. You don't pick oil viscosity based on engine clearances - at least that's really not the primary factor. Viscosity is chosen based on what kind of load the engine will see. Changing from a 30 to a 40 will have negligible effect on pressure. Probably measurable, but negligible. The oil temp will increase slightly, which will offset the thickness somewhat....
Oil viscosity is mostly chosen based on load. 30 weight is fine for most applications. 40 or 50 is often chosen for boosted or nitrous applications..... all the while the clearance in the engines are the same. Pretty much everyone runs 0.002" main and rod clearance as a general rule and that's regardless of viscosity. The same clearances are used with extremely minor differences (tenths.... maybe) for weights from 20 to 60. Going up from a 30 to a 40 *might* be detectable on your gauge but the difference will be tiny and you still won't feel any better about the readings.
GD
Last edited by GeneralDisorder; 02-16-2019 at 11:39 AM.
Why am I finding it's so hard to see a video of someone measuring cam bearings clearance just want to get an idea of what to do and how to do it I believe I can rent the proper tools from AutoZone or Advance Auto
You would need an extended reach bore gauge and a micrometer. It's a bit of an acquired skill though. And I don't think you can rent gauges that will be trustworthy.... It's very easy to get the wrong readings.... if you don't have much experience with precision measurement I would take the block to a trusted machine shop for measurement. With cheap tools an little experience you are likely to scare the crap out of yourself.
The only thing that I can think of right now that could possibly cause this is that the oil pump's relief valve is stuck open.
Did your engine builder weld or braze the pickup to the OP cover. The relief piston is supposed to be removed before doing this.
While the oil is cold and thicker, you have pressure. As it warms and thins out, that bypass passage is enough to drop your pressure to near zero at idle. Tapping the throttle spins the pump momentarily faster and the pressure and volume increases enough to move the gauge needle off of zero.
Just thinking out loud here, but I think there is a way you can test for this without taking anything apart. Your local auto parts chain should have an LS engine preluber tank that you can rent. It is a pressurized tank of engine oil that you inject into your engines oil circuit. Correct me if I'm wrong here guys, but ASSUMING his engine's oil circuit is correct and the OP bypass is closed, then injecting pressurized oil would hold pressure, as it should just like on any stock engine. If his bypass was stuck open, then pressure should have a hard time building up, if at all.
There are 3 possible locations to tap into to try this:
1) the plug just above where the oil filter screws on. You might have a switch or sending unit there.
2) by the base of the distributor on the china rail of the block where the gauge sending unit is screwed into.
3) your block might have this hole above the timing cover.
Your distributor must be in place while doing this because it intersects the passenger side lifter oil gallery.
Last edited by NoEmissions84TA; 02-17-2019 at 12:42 AM.
I understand the theory... I was not there when oil pump was installed... I wish I was but I had to work. U are 1000% correct in your assessment in what the pressure is doing/acting in relation to rpm and gauge...
modern engines use light weight oil and very tight clearance
one of the issues with tight clearance is everything needs to be very perfectly straight.
And nothing is ever perfectly straight, and even if it was it also need to account for running conditions, deflecting, growing, changing shape as it warms up and and changing while it spins very fast under repetitive, varied loading.
So the farther you got back in years for engine block and manufacturing likely the clearances get larger and larger.
As years go by and tech gets newer the new techniques get each engine block/part trans block/part diff etc... tighter and more 'perfect'
So if you have an old block you will use looser clearance because nothing is as 'straight'. The mains from one end to the other for example being shifted by some error no matter how small.
For Nissan the years blocks, castings, creations got good was around 92. For chevy the year is approx 02. Some could argue 98 but truly lowest cost ideal manufacturing is 02 because the price difference is negligible and 02+ got serious improvements.
All engines are subject to even minor screw ups. Like leaving a plug out or installing a cam bearing incorrectly, or even just not noticing fatal flaws in the materials or block. That is why I recommend for daily drivers and novice builders to simply purchased a used 02+ engine with already 100,000 miles or more to ensure reliability and avoid all internal potential errors and flaws. This method is even more successful than crate engines.
Ok, take engine out, take off top end, check for obvious cam ,mains and rod bearing problems, if I dont see obvious problems then take it to the shop... ugh!!!!
If you were going to pull the engine:
I would inspect the engine thoroughly for all required plugs and check free passages and test the oil bypass to see if it works properly (using supplied pressure). Inspect the cam bearings I Suppose.
You can't very well inspect every orifice. I wouldnt take apart the bottom end looking for mysterious issues that may not exist.
The main thing people are warning you about is the plugs situation, the bypass situation, oil strainer/pickup, and cam bearing situation. If you do pull the engine make sure to check all those things.
If you try some 15W-50 and the oil pressure comes up to around 4-6psi at idle hot I'd be on the fence about telling you to open the engine at all, unless it was verified that the oil bypass spring used is supposed to maintain at least some minimal level of oil pressure (like an 02 engine is guaranteed 30~psi hot idle I believe due to bypass spring situation)
Fellas you all have inspired me. Seriously!!! You have. I will do just what yall say. I'll pull the timing cover, all I have to do is loosen the oil pan which is no prob since it you have to come off to do the oil pump anyway. Is there a way to test the oil pump bypass? I dont have a ls preluber and dont know if the other places loan them out. I'll have to pull the headers, dizzy and lift the motor to get to the pump. I'll line up tdc before pulling cam gear to check front bearing depth. I'll have to pull cam to check all of the cam bearing orientation. But before I get that deep I'll start with the timing cover
Fellas you all have inspired me. Seriously!!! You have. I will do just what yall say. I'll pull the timing cover, all I have to do is loosen the oil pan which is no prob since it you have to come off to do the oil pump anyway. Is there a way to test the oil pump bypass? I dont have a ls preluber and dont know if the other places loan them out. I'll have to pull the headers, dizzy and lift the motor to get to the pump. I'll line up tdc before pulling cam gear to check front bearing depth. I'll have to pull cam to check all of the cam bearing orientation. But before I get that deep I'll start with the timing cover
You will be able to tell easily if the 3 plugs are there.
Here is a pic from mine:
As for the OP bypass, you could "test" it in a 5 gal pail filled with oil and a drill motor. But you will need to restrict the outlet, and I don't think you will get a valid result - more likely you will take an oil shower!
This pump is SIMILAR. Take the cover off of the oil pump. You will see a hole and in it you should see the end of the metal sleeve up against it's stop - IF IT IS NOT STUCK OPEN. If you see it, use something NOT METAL to try to push it back a little bit. Does it move?
Drive the pin out that is holding the spring and pull the spring out. The sleeve will be inside. Make sure there are no burrs raised where the pin goes. Smooth with a file if necessary. Use an unsharpened pencil or wooden dowel to remove the sleeve. Is it stuck? Pay attention to how it slides out. It should be completely free and smooth coming out. IF there is any binding, then you should have just found your problem.
Last edited by NoEmissions84TA; 02-19-2019 at 01:49 AM.
Kool, I drive concrete trucks and never know when I get off . Not to mention it's a threat of rain here in NC everyday but thk u... I will git r done!!!!
Kool, I drive concrete trucks and never know when I get off . Not to mention it's a threat of rain here in NC everyday but thk u... I will git r done!!!!
I admire you digging into this for yourself. I hope you can get to the bottom of it on your own.
My mom bday party is this weekend so I cang ****** motor this weekend. But what I'm going to do is go ahead and drain oil, take all hoses, elect, motor mount bolts drive shaft, headers , and tranny member and torque arm bolts. So by next week maybe all I have to do is pull engine. Ugh!!!!!!
As yall know in a thirdgen u just about have to pull motor out to do oil pump. Well if I have to go that far then I'm getting some platigauge and I'm checking the mains and rods a d I'm pulling the cam to at least look at the cam bearings. FRICKIN, FRICK, FRICK
"Blow By" means combustion gasses leaking past the piston rings , in your case possibly in an excessive amount , which can dirty your oil very quickly . All engines experience a small amount of blow by , which the PCV system traps and sends back to the intake to burn off any unburnt gas in it . If the rings don't seat properly during the break in of a rebuilt engine you can end up with oil that's black like yours , and that's why the General mentioned it .
Put some on a clean white rag and let the oil part soak through, and leave whatever residue behind sitting where it's easy to examine closely. I think you won't like what you see.
Refer to my thread posted above and you can do what I did. You are going to have to clean everything up anyways, so after you pull the engine, leave the oil pan on and everything else related to the oil system, cam & lifters, oil filter, distributor, block any opened oil ports, and the timing set is not necessary. Buy a couple gallons of diesel fuel and pour 5-6 quarts into the engine. Have a mechanical OP gauge connected. Then run the oil pump with a correct pre-luber shaft and 1/2" drill motor or air ratchet. DON'T push down hard on the shaft because you will be grinding the oil pump gear into the oil pump's cover. Now you can actually see inside the engine and find where your problem really is - without guessing. Plus the kerosene will flush the engine for you so that when you take it apart, it is much cleaner.
Last edited by NoEmissions84TA; 02-21-2019 at 09:26 PM.
Put some on a clean white rag and let the oil part soak through, and leave whatever residue behind sitting where it's easy to examine closely. I think you won't like what you see.
I agree that's a possibility. It's really hard to tell from the pics. But it does seem strange that it's got so discolored from 20 miles. You can also cut open the oil filter (don't use anything that will produce filings) and check the element and bottom of the filter can for metal.
If the oil filter has metal in it, then that same metal had to go through the oil pump first. Plan on a new oil pump. Good thing they are relatively cheap.
I just noticed - comp cam xe268h, hydraulic flat tappet. Lobes going bye-bye would be my guess for the black oil.
It only takes 20 minutes to lose a lobe. I can tell you from personal experience that if this is the case, then the cast iron shrapnel from the camshaft is continuously being circulated throughout your entire engine, and it is destroying EVERYTHING. Besides eating the bearings, it is scratching the cylinder walls, imbedding in the piston skirts, etc. It's like if you went to the auto machine shop and got a bunch of their brake rotor cuttings and dumped them into your crankcase.
Last edited by NoEmissions84TA; 02-21-2019 at 09:27 PM.
What the FRICK..... first I will pull motor, then take off oil filter and pan. Then check for metal, then check pump, then check mains and rods then cam bearing and cam, if i see anything i dont like, cant fix , or means a bunch of money back in this block. I'm willing to take my chances with that Ls motor in barn!!!!!!!
This car has been plagued from the start. I've loved them from the time I was 16. I've owned 3 and all of them have been hell to own. At 16 the 88 sport coupe got its tire slashed, the stock drum brakes helped me cause a rear end collision, I lost control of the car on I-40 and slammed a guard rail my dad junked it after I crossed the spark plug wires. The second was a 89rs ragged out v8 car for $600, the interior and exterior cost so much to get into shape I spent twice as much just trying to modify and fix and it was going go take 3k just to get paint, the 305 was so weak it took power braking just to turn the tires over, took it to the shop and got it back just to have fix the engine myself, built this engine and stuck it in over the course of 8mo. Just to wipe a lobe in 3.5yrs. Now in this third one the only time I can work on it is in the dark or in the rain outside on the ground (no shelter) I take it to a friend's house (and this ** friend** happens to be my boss also) because his dad is an engine builder, 9mo later it's still not running. Then they offer to buy it at bottom dollar price ($500-800) for the car... I go get my car put the 600cfm cadb back on figured out that 0 was not tdc and finally get it running and now this and this is after $4800 in parts not to mention money paid for doing the job that still isn't done.... yes I am venting, my name is budget builder and none of this has been budget friendly. I'm starting to believe these cars are cursed or maybe I am....I have a family of four, between me and my mom in law we had to adopt 7 of my nieces and nephews, and I have 3 God-kids. I cant afford this and now without it running I cant sell it. Other than the motor the car is in great shape int. And ext. Needs a paint job but that's it. Sorry about venting but as stated before my wife basically the only one who's truly tried to help me during all of this and I understand her losing her patience. I'm tired....
Where in NC are you? I have an LO3 long block from a 91 RS, absolutely nothing wrong with it. It’s no performance engine, but if it will help you get rolling, you can have it.
Four Oaks, Johnston County? I’m in western Harnett county, right off NC 87. There’s also a guy in Knightdale that has a running Vortec 350 for $500, a much better casting than a 010 block.
Maybe I should PM this but the reason I'm not is because I want the world to know there are good ppl out here. I would love to use your block , i will PM u to discuss (get a concrete understanding of price and address) but with yours I can use my upgraded vortec heads and intake, buy a cam. I might need a flex plate mine is for a 2pc rear main seal. Some gaskets and I'm good. Yes I'm frustrated I wont lie. Thk u all for the help, advice, and most importantly listening.... hwy 87 is nowhere from me. I can be there tomorrow evening with no problem. Thk u. I'm at work so I'll have to talk to u later.
That's one of the reasons the bottom end of my engine was done at a machine shop that also does race car engines. Even though I'm a mechanic, I don't have the time or tools to "build" a proper bottom end. There's a big difference between building and assembling an engine. If it's built properly, it will be assembled and disassembled a few times before it's finally finished.
Specs may say a tolerance needs to be between 2 measurements. If you're assembling an engine, how do you go about changing it if it's not correct? A machine shop has a lot more resources to properly build an engine and expect it to last a long time or they won't stay in business for very long.
I've assembled a lot of engines but unless you're building it as a basic stock replacement, you're always going to roll the dice if it's going to last or not. Something simple like a missing plug or something plugged off that isn't supposed to be can cause all kinds of problems.
Machine shop work isn't cheap. Even your own time to assemble an engine isn't cheap. In the long run, it can be much cheaper to buy a crate engine. Even a short block then you install your own heads etc to finish it. Maybe a cam swap if the pistons allow it. Unless you have a lot of time and free resources at your disposal, even a junkyard engine to rebuild isn't really worth it. A junkyard LS engine with a cam swap is still cheaper but once you start digging into it to change things, the price can skyrocket.
I have an LQ9 6.0L sitting on an engine stand beside my toolbox at work. Been there since last summer. I know what's wrong with it but haven't jumped into tearing it down yet. Needs more that a cam swap. I don't really have anything right now to put it in so I'm in no rush.
Big thx to *** ty92*** and everyone for your help and advice. I found this and will just put my .525 vortecs on it and get me a xe284 cam since I have a 3kstall and 3.42 gears already.
I talked to my wife and together we decided this would bwothe best route. https://www.ebay.com/itm/CHEVROLET-1...AAAOSw1NJbLRns
Hope it came thru... will void warranty by changing cam and heads but at least we kno the bottom end is put together reliably. Thousands of positive transactions and hundreds of these engines sold
Last edited by budget builder; 02-23-2019 at 06:30 AM.
Will hit them up on Monday. I hate to say it but I feel stupid. If I had known that I a crate or a good base engine was so affordable I could have been riding CONFIDENTLY years ago... thx buddy
If you are just going to buy another engine anyways why not run that motor as long as you can first, unless you want to sell the parts instead I guess. I'd say if the motor you have's internal parts cost/sale value is negligible to you, and if you see oil coming from all the rockers and it seems like its truly pumping to the head everywhere, then just run it with a thick oil if you can get at least 4psi on the gauge at idle... with thick oil at high temperature. Like 15-40 or maybe even 20-50, but make sure to test at 212*F or at least 200*F for at least 3-5psi hot idle.
unless its already all apart and ready to part out
What the FRICK..... first I will pull motor, then take off oil filter and pan. Then check for metal, then check pump, then check mains and rods then cam bearing and cam, if i see anything i dont like, cant fix , or means a bunch of money back in this block. I'm willing to take my chances with that Ls motor in barn!!!!!!!
There is one plug in a oil passage that is not visible on the outside of the motor and frequently gets over looked. It's under the rear main cap and prevents oil from bypassing the oil filter. You can move it with a long 1/4" rod from the china wall at the top but you have to remove the rear main cap to get it out and replace it. Under the rear main cap there i 3 holes and only 2 are for bolts. The oil plug is upwards in that hole. It's frequently forgotten to be removed when cleaning the block and of course not replaced often also.
I don't think that would explain your good pressure when cold but you can't overlook this plug.
87-95 350sbc hei electric FP
This is after camshaft breaking ~2300 rpm
Idle ~1000rpm
Headers were cherry red, I hav e to get a jet kit
274h cam, vortec, 700r4, 3k stall, 3.42gear, holly 600 vac sec
1 5/8" primary to 2.5in y-pipe
I know the cam is too big for max power but it sounds wicked sick and I'm not racing
02-16-2019, 10:54 AM
Hi budget builder ,
