tommypenguin

Summary of Issue: 2001 Corvette Coupe, SC'ed ported 243 heads and stock bottom end with a mild thunder racing cam, 220/220. I posted a thread about a month ago regarding an issue I came across in the reference link below if you want greater detail to help answer my questions.

Long story short, was a block away from my home, started the car after chatting with a neighbor saw 0 oil pressure at idle. Rolled the dice and drove a block to my house where I saw oil pressure get up to where I would expect it to be, then when pulling into my driveway saw the oil pressure fall to 0 at idle.

Troubleshooting:Since that time I replaced my OPS, checked oil pressure from OPS with a manual gauge and drain oil and cut the filter open where I saw a concerning amount of shavings. After seeing the shavings I decided to pull the motor, which I have done and got on an engine stand. I pulled the oil pan off yesterday found just a couple of flakes at the bottom of the pan. I was expecting to see some carnage but none was to be found.

Findings: I did find what appears to be a gum wrapper aluminum foil stuck in the oil pickup tube screen along with a piece of plastic. The plastic piece was stuck to the screen, and the foil was a bit wadded up. Between the two i would guess that 33% of the screen was obstructed by these two items. I had just went to a car show the day before where I leave my hood open and car unattended like many corvette owners and I wonder if someone may have dropped their wrapper in my dip stick tube or something while I was away.

Questions:I will never know how those two pieces got in there. Regardless, I have seen just a little scuff on a cam lobe and aside from that all looks well. At this point is it a safe assumption that an obstruction on the pickup tube screen was causing my low oil pressure at idle and only under load was it able to get pressure? There is a fear a bearing could be trashed but would I need have seen a chunk or shavings at the bottom of the pan or would I have to pull rods to see? If it were your motor sitting on a stand right now and you didn't have the confidence to pull it without damaging the parts what would you do next? Ideally I'm wanting to get my engine back on the road as efficiently as possible, what parts are a must I should be replacing in the block/heads? Thanks guys.






References:
https://www.corvetteforum.com/forums...ed-advice.html

Last C5

My guess is that the aluminum foil is the seal off a bottle of oil. If you hadn't found the shavings, I would say put it back together and go. But, if you saw considerable shavings, something is getting ready to come apart and you'll never be in a better position to find out what it is and get it fixed.

lionelhutz

You really have to go deeper. Pull the rod and main bearing caps and I bet you find bearings with excess clearance. If the crank is good you might be able to save it but You'd have to pull the crank to measure it properly.

The oil pump is a positive displacement type so the volume pumped should be fairly proportional to rpm. In other words, the pump would pump more and more oil at higher and higher rpm's so it's more likely to starve at higher rpm's.

I think the above poster is correct, the foil and plastic are both likely from oil bottles.

leadfoot4

bjones7131

Ideally if could run the engine on the stand that would tell U about oil pressure before U put it back in.

Johnny wangwang

The only time the car has ZERO oil pressure like you said is if the pump is dead. I would not just slap the motor back together. Its not going to damage anything if you take the mains and rod bearings out and check them AND replace them for peace of mind. Get a new oil pump also, check all the lifter rollers and depending on how deep that cam scratch is...swap the cam out also just incase the lifter dug too deep and took out the hardened part of the cam.

If the motor is out don't half *** it. Go through it or youll be doing this all over again in a few.

Johnny wangwang

Also a bearing doesn't have to be spun. It can just be worn and itll still need to be replaced. Ive had that happen before. LS's are very sensitive with bearings. The oil may look good until you actually look at it close and see REALLY tiny copper glitter in it. Check that first. Then the bearings. Your gonna also wanna check the surfaces of your crank anyway since if its not smooth itll need to either be polished or replaced.

tommypenguin

I manned up and disassembled the engine, wasn't that hard just initially looked intimidating. Forgot to mention I have a melling high pressure oil pump 10295 sitting on my work bench to be installed.

Bottom End Analysis/Plan of Action:All the rod and main bearings were fine, every lobe on the crankshaft feels smooth. All the piston rings and cylinder walls are fine. As preventative maintenance I'm planning on replacing all the rod and main bearings and piston rings on the bottom end. Going to hone the cylinder walls and use the 3m white bristle discs to clean up the head mating surfaces. Ideally I want to be able to eat out of my block before putting it back together.

Top End Analysis/Plan of Action: The cam for sure needs to be replaced along with the lifters as you speculated johnny. I found multiple lobes on the cam that were rough to the touch along with matching rollers that were also rough to the touch. Planning on replacing the cam, lifters, valve guide seals, likely valve springs. Was going to replace with what was in there unless someone has a justification on using different parts.

You're logic makes sense especially given my findings that all the bearings are intact. Got the obstruction in the pickup tube, during a high rpm pull I damaged the oil pump which led to it not being able to pump enough oil at low rpm. Thankfully I caught this early and didn't have a catastrophic failure.

Got some new questions:

What bearings should I go with for replacements just OEM or would you recommend something else?

Anyone know the cheapest place to pick up a comprehensive gasket kit?

Does anyone know what size the hex is for the plug on the right?





If there is something I'm not thinking of that I should be, please let me know, thanks.

175rgr

Because you are supercharged I would HIGHLY RECOMMEND to take the time now, while it's apart, and forge the bottom end. It will be well worth it in the long run. You are supercharged and have a disassembled engine, there is NO REASON to put the stock pistons/rods back in it. Not only will it boost your resale a ton, it will be great piece of mind to know your bottom end is forged with a blower.

The Chev

Also, might be a good time to lower the compression a bit and spin the SC faster.

If that is out of your scope, at least get a ARP fastener kit and hold that crank, rod caps, and head on tight.

Johnny wangwang

Go with the harder Clevite H's. I bought my Rod and mains for $200 shipped off of ebay. Bout the cheapest you can get them unless you wanna order them separate and even then youll only save like $10 maybe and have to wait for them to come separate.

tommypenguin

Got some part numbers for me? Did you upgrade bolts or reuse stockers?

Johnny wangwang

No just look on ebay. Cant remember part numbers. I upgraded the rod bolts to ARP 2000's on my stock rods. But then you have to get the rods resized. If you do arp mains your gonna have to get the block checked also...

Jason913

Wow you got lucky and good catch. Props to doing it right and disassmbling while it was out. I agree... get some forged bottom end parts for peace of mind since youre FI already

tommypenguin

Thanks for all your help Johnny and the rest of the forum, you guys have been extremely helpful in a first timer with no engine knowledge get through this endeavor. Resizing is a deterrent from going with ARP bolts. I take it if I go with new stock hardware there is a less likely chance of that happening? I'm picking up some plastigage to measure the bearing tolerances, assuming all are within spec I should be good. If I measure tolerances and am out of spec with stock bolts, then I'll go ahead and order the ARP bolt set since I will have to resize anyways.

As for the piston ring set, I'm leaning toward mahle unless others have a suggestion, am going to pick up a piston ring filer and make sure they are fitted to be within spec.

If you would have asked me two weeks ago I would have told you that I was going to be looking at a 383 forged stroker kit. However I just found out last weekend I'm going to be a dad for the first time and need to become more selfless. Based on what I have seen my engine was holding up well to my build level and was not the cause for this issue. While forged internals would be great, I'm confident in my stock pistons/rods/crank to continue to hold up and can't justify dropping the extra coin on those parts given my new situation. I'm looking to be cost effective while balancing not being cheap or over the top for my build.

For more context I have ARP hardware for the heads and valley cover. The car will see likely 3000 miles a year and no track time or high rpm pulls. I don't think I have taken my motor beyond red line yet, I have gone through one jug of methanol in the 4500 miles or so I've put on the car. I don't abuse the motor and typically only get into boost for pulls getting on the highway or the occasional drop down a gear pass on the highway. I do not care about resale value, this car will likely be the last sports car I'm allowed to afford for a long time so I will be holding on to it forever if possible. A large reason this time around has been so expensive was because of having to spend a lot in tools I did not own. If I had to rebuild the motor even a year or two down the line it would be strictly spent on parts allowing me to go bigger if I wanted to.

Here is a link I found to the clevite bearing set on ebay I am looking to pull the trigger on, was going to go with the standard size...

http://www.ebay.com/itm/Chevy-LS1-5-...-/190574042868

Johnny wangwang

Yup that's them^^^! And Yeah forging a motor doesn't really up the Value or want of a car to me. If anything it scares me more. You don't know who did the work or if it was done properly. Also people tend to feel like forged motors are bullet proof and abuse them more. Its never been a selling point for me.

Youll prob need standard sized ones. But I wouldn't pull the trigger Until you at least get the crank checked and MAYBE polished.

I was looking into buying a Dial bore gauge off amazon myself. They are pretty cheap. Im getting tired of taking all my stuff to the local machine shop and trusting them to measure clearances right. The head guy is pretty Old, with all due respect, and Im starting to suspect that he cant see very well. Plus I take motors apart enough that It would pay for its self.

175rgr

If anyone is searching for an already forced inducted vette or a modded vette the first thing most with experience look at are whether it has forged internals or not. I would never buy a FI car with stock internals, but maybe that is just me.

I understand what it is like to have life come in to play right when you want to mod/fix your car, but I'm telling you that you may wish later on down the road that you would have put forged internals in the motor while you had it apart.

I speak from experience on this, I've blown holes in plenty of stock hypercraptic pistons and destroyed motors with stock bottom ends. I've been down the road of trying to save a dime here and a dime there by skimping and half assing where I thought I could get away with it.

10 years of building LS cars later, I've realized to do it right the first time, and take the opportunity while it is there.

The only reason I'm posting this is because I'm hoping to save you some cash later down the road, I don't want to watch you put the stock pistons and rods back in this car and throw boost at it and watch them come apart. If that happens not only will you be wishing you have went forged in the first place, there will be a lot more damage the second time around, it wont be a "lucky" catch when that happens.

At the end of the day it is 100% your decision and whatever you choose we the forum will be here to help you along the way, I just don't want you to make the same mistakes I did.

That's a lot of work to do twice if you could have avoided it in the first place.

Johnny wangwang

I guess that's just the difference between you and me then. I would never buy an Already turbo or supercharged car that didn't come that way from the factory. ESPECIALLY a Vette! Don't really care if it has forged internals or not. Its more in the tune then it is what the motor has done internally. Ive seen forged motors blow up quick while guys with stock Blocks run for YEARS boosted because they actually know what they are doing with the car.

I also would pull my ls6 and boost an Iron block 5.3 before I risked putting a hole in my aluminum block. The 5.3's are a dime a dozen......But that's a convo for another thread lol.

The Chev

You just touched n a topic that has been bugging me for a while.

This seems to be the trend. Vette owners want to buy a stock car. So people often, I watch the parts for sale threads, put their car back to stock before they go up for sale.


So, how much care and love do you think they put into going back to stock? I bet they put thrice the care and love putting the parts on than they do putting the car back to stock. Then, you bought a ragged out once was supercharged car that was thrown back to stock by a PO that was just trying to get rid of it.

I would rather buy a car that is exactly the way the PO drove it. The thought of it getting thrown back to stock for a faster sale sickens me.

Johnny wangwang

Your putting words in my mouth. I bought my car with 39k on the clock. It had a Vararam and Long tubes installed. Everything else was bone stock never modded. It was never taken back to stock. Those mods were fine with me. But like I said Id never buy a car someone else has had aftermarket forced induction added on. Its just my Opinion.