|07-17-2008 01:57 PM|
|CNC BLOCKS NE||
|07-17-2008 01:34 PM|
|07-17-2008 01:31 PM|
Back from the machine shop.....
I just returned from taking the engine to the machine shop. He (Jeff) looked over the parts and said he could not tell what had caused the damage, except he thought the engine had been subjected to pinging.
He pointed to the brown spots under the head of most all pistons (which I thought were spots of burned oil, and I guess that is right) and told me that the heat had to be really great to travel through the piston like that. No conclusions however.
He pointed out something else I had not noticed.....on Old Friend piston #5 the piston had hit the exhaust valve. It cut a small gouge in the piston top like a half circle. Look at that head and sure enough, the valve had a ring mark around the rim of it where it made contact with the piston.
He said he can take of the gouge and will fix the tight wrist pin.
He told me I need a new cam and lifters.
Here is what he is going to do:
Line bore the crank and cam tunnels.
Check rods for mis-shaped ends.
Hone the cylinders.
Deck the block.
Regrind the crank.
Repair the heads as needed.
Then he will put the stuff together for me as a short block.
He does all of the machining in house except for the crank grind. That he sends out.
His shop has a couple of Sunnen hones, a Bridgeport 9 X 42 mill (just like mine at home) a large LeBlond Regal lathe, big radial drill, and a machine that decks blocks. Oh, and engines everywhere!
After talking with Jeff I am convinced he will do what he says he will and feel very comfortable leaving the parts with him.
Jeff told me that Melling oil pumps are what he sells and uses. My pump is a M55HV. Rather than reuse the old pump, I am going to use the brand new pump (M55HV) sent to me by the place I bought the engine from. This was an extra they sent me when I thought the oil pressure was too high. I just put it away rather than use it. Jeff told me how to clean the old one, but I will just install that new one I have.
So, it is going to be 6 weeks before the work is completed.
I did not even ask what it will cost. Doesn't matter, I need an engine that runs good. I will get the bill 6 weeks from now.
Thanks to all you guys for your comments and help. Great forum!
Now I have some time to clean up the shop and get things back in order. I will have more questions I am sure as I begin to assemble the engine back together.
Meanwhile I will clean up all of the non engine parts and maybe even get in the van to scrub down the engine compartment.............pg
|07-17-2008 12:57 PM|
So when building street/strip motors where u mainly want to be a daily driver but be able to go to the strip on the weekends,which oils would u pros be using when building and running these types of motors.
I have a bbc 468 just got done and is ready for start up its got the edelbrock preformer package in it so the cam is a little lopey it was put together right was just curious what u guys would run in it, and really would like to here from everybody...
not trying to highjack a thread
|07-17-2008 11:31 AM|
yes you are right my friend's camaro does have a roller cam and Lifters in it...
and i agree on the oil... in my hotrod engines with flat tappet cams.. i used to run rotella T 15w-40 but even rotella T as of late has reduced the ZDDP in their oils...
so i run Valvoline VR-1 20w-50 and also the ZDDPlus additive to it..
my only point about my friend's camaro is that all the engine bearings have survived using 5w-30 oil because that engine is factory built with no doubt tighter clearances than most racing shops will do.. as it is built for the street.. it has a redline of 5200 RPM as opposed to the 7000 RPM that race motors typically carry...
the shop that built PG's engine may have built this engine using looser racing clearances rather than OE clearances..
|07-17-2008 11:25 AM|
|CNC BLOCKS NE||
The oil we recomend has 1582 PPM of zinc and is a diesel 15/40 oil and no isses of premature cam and lifter wear.
|07-17-2008 10:21 AM|
I think all of this is a chain reaction that started either with a bad block core? maybe it needed line honed and they didnt do so..
or improper assembly.. rather than a new crank they used a turned and refitted crank... what caused the crank originally to be so bad it needed turned??
when getting a rebuilt engine something caused it to need rebuilt in the first place... could be anything... couldve just worn out from high miles.. couldve been grenaded by over rev... couldve been overheated to the point it seized.. we'll never know how they got this block in the first place....
im kind of in the same boat as my "new" engine has serious problems in it.. but hydrualic lifters dont just clatter all day long and be called "normal".. and for the same reason I dont know where my block came from either.. or why it was in an engine builder's shop... so mine, like yours is on its way to a machine shop for closer inspection....
I honestly dont think you did anything wrong to the engine... my friend ken runs 5w-30(10w-30 in summer) oil in his 1991 camaro and has since they day he bought the car new... it has a 305 in it now with 185,000 miles on it. that has to be one of the quietest, smoothest running small block chevies ive ever seen.... its so smooth you dont even hear a rhythm to that engine..... oil stick is always full at 3000 miles too..
now back to rebuilt engines.. I have often heard that some racing engine builders (drag race)will put looser tolerances on mains and rods noting they want lots of oil flow over the bearings for cooling and also noting these engines are run in short heavy duty bursts, never fully warmed up.
so does this shop normally build racing engines but seels a few "stock replacements" also?
my engine builder even told me himself that he built mine a little loose and then sold it as a "streetrod" engine.. not fully realizing the stress that street use puts on a motor.... I think he feels my engine is fine with the lifters clattering away when the engine is hot.. because if it was a drag race engine it would never be running 15 minutes at a time...
street stress is bad... I know for me my hotrod spends a lot of time idling... drive it to work.. then sit in 95 degree heat idling through traffic with the A/C blasting.. or going through a 30 minute 4th of july parade same thing... and I think a lot of engine builders fail to see the differences required to build a high performance(or stock performance) daily use street engine versus a drag strip engine..
|07-17-2008 09:44 AM|
Now we all know how worn out these bearings are. So yes, there was less restriction than when the bearings were new. (Well, maybe not in my case here ) but you are right.
I understand pressure, volume flow etc, but I think the pump was still letting all of the bearings get plenty of oil, even though the gaps were massive.
If the oil was insufficient, then I would think there would be some blue spots indicating over heating in some part of the engine, but there is none of that anywhere.
I have to lay the cause of the problem at the feet of the guy who did the build of course. What I would like to know is what this person failed to do properly when he built it?
Today I finally have everything loaded in the truck and will head to the machine shop shortly. If here is any earth shaking news from them I will post the info for you guys to kick around.........pg
|07-17-2008 08:59 AM|
I would say that even a good filter will miss quite a bit of smaller particles.. and that van is heavy enough that it is working the engine at low RPMS to get it up to speed.. and I'll bet its not taching very high out on the road either....
ive come to the conclusion that I got a CRAP engine for my monte carlo.. its coming out to go to a machine shop for teardown as I dont have the extensive knowledge to tell where my excessive valve train noise comes from..
but I do know that when I drained the oil pan I could see what looks like very slight metallic swirls in the oil so I know there is serious mechanical damage going on...
Also oil PRESSURE isnt everything.. im gonna venture to say that the dash gauge Port on this engine is right back by the oil filter.. so what you are getting is a pressure reading right off the oil pump.. all that says is that the pressure at that point is proper.. doesnt mean you dont have an oiling problem farther along in the oil circuit... and most likely that engine being thrown together like it was probably had pretty loose tolerances.. that once the wear starts creates even looser tolerances... a HV oil pump does just that pumps a lot of oil and in doing so builds up pressure..
but think of this analogy.. if you could put a pressure gauge on your garden hose and turn on the water.. you can cover up the end of the hose with your thumb and the water will just trickle out.. but the pressure would still read high.. uncover a little more of the hose and the pressure may ver ywell stay the same but you will have more water flowing because the hose and the water source (your well pump or city water as it may be) can handle the volume you are flowing.. take your thumb off altogether and you'd see a pressure drop but have Lots of water flowing..
pressure builds up as a result of a restriction thats just a fact of physics.. so the PLAN is that the restriction in an engine that creates pressure is the bearings / lifters themselves.. but if the tolerances are too loose you would see a drop in oil pressure.. so most install a HV (high volume) pump.. and get that feel good feeling because the dash gauge reads 55 on the highway 40 at idle... thats great as long as the pressure is really the bearings.. but what if you are just pressurizing against the oil gallerys themselves.. the passages are only so big in an engine.. with these worn out bearings the tolerances wouldve gone to heck in a handbasket and oil should just Flow out.. causing a reduction in pressure.. yet the gauge pressure didnt show any drop... so i think we have a classic oil starved motor here.. shoddy work gone bad that causes a compounded issue then of oil starvation at the bearings....
so one could say the lifters should rattle.. however it doesnt take much oil pressure to pump the lifters up.. lifters will stay quiet at 5 PSI.. or perhaps the lifter gallery passages were fine and tis just the main / crank oiling that was bad..
my main point here is a couple things.
1] just because the pressure at the gauge sender is high doesnt mean we have oil everywhere..
2] I wouldve certainly thought we would see some kind of oil pressure changes with worn out bearings like these.. we have bearings that have had to add .005 - .010 or more in tolerance to the journals... thats a lot of area for oil to flow through and reduce pressure...
|07-17-2008 02:42 AM|
hi guys , i haven't posted in a while because i have been going hot and heavy on the chassis, suspension, drivleline, plumbing and mods on my C2-GS clone. just about finished with that and getting ready to start on the body.
piniongear, welcome to hotrodders. here's my take, (and i had no intentions of posting tonight):
as always, i totally agree with oldbogie.
what i see in your excellent pics in this thread is supreme shoddy workmanship.
1-from the main bearing pics it looks like you have a bent/warped crank
2-from the rod bearing pics it looks like you have bent rods or a disasterously machined crank
3-adding weld to the crank holes to balance is just wrong.
4-the engine seems to have been assembled with a bunch of machining debris left inside
5-the lifters in the pics are toast, and therefore the cam is toast.
6-think about where all that metal from all those worn parts is hiding in your engine.
7-think about all the wear on the parts you didn't inspect yet from all the metal circulating through the engine.
8-CNC NE + MST know their stuff, so if they don't agree, i will bow to their superior machine shop knoledge.
i hate to be the bearer of bad news, but toss that engine in the nearest trash can and buy another 350, they are cheap enough, you will be many $$$$ ahead and you will save yourself many future headaches.
i have thrown away many trashed engines in my time, sometimes it's just better and cheaper to start over...
EDIT: and i would never ever use 5W-30 in any engine, i have always used 20W-50 and have recently switched brands for the higher ZDDP content...
|07-17-2008 12:20 AM|
|07-16-2008 11:58 PM|
|CNC BLOCKS NE||
You may want to listen to some of us guys who build engines for a living and have some pretty good advice to follow.
The problems your having we don't seem to have so I would say your doing something wrong.
|07-16-2008 08:49 PM|
|machine shop tom||
The pictures of your lifter bottoms is consistent with improper cam break-in oil, pre-lube, procedures, or a combination of those.
The lines in the less damaged bearings came from very small foreign material circulating through the engine. The more damaged bearings exhibit symptoms of bearing distress caused by particle damage that compromised the bearings' load carrying cababilty.
The fine scratches in the cylinder(s) came from material from the cam lobe and lifters.
That HV pump is doing nothing to help you.
I will take my 30+ years in engine repair and 25+ years in machine shop experience and leave you to your extensive background.
|07-16-2008 04:55 PM|
The engine is in a van, not a dump truck or wrecker.
Most of the driving is at 75 mph out on the highway, so while that is not a lot of rpm, it is enough to get me a ticket if I'm not careful.
I have used 5-30 since the day it came out. As I said in an earlier post my driving time is 43 years with 4 different Chevrolets covering 747,000 miles.
I use either Valvoline or Pennzoil and a Fram filter and nothing will change my mind on that........pg
|07-16-2008 04:29 PM|
Now a series of "experts" are gonna come outa the wood work when I say what I'm gonna say; but that watered down oil just isn't good enough except in little ole lady driven vehicles. A lot of folks will jump on "watered down" and go on about the oil is rated at a 5 weight at some large sub zero degrees and a 30 weight at 212 degrees so that nothing really changes. Yet, I have never put that stuff into an engine that it didn't show a loss of oil pressure, primarily at low RPMs where I've always felt that GM engines were marginal to start with. My long standing concern has been engines that pull hard at low revs just don't have adequate protection in the crank bearings for the loads they're seeing. The problem is not so apparent at high RPMs, even in racing engine because by then the pump's delivering a lot of oil and pressure is up on the bypass valve. But when you're expecting the engine to grunt against a 6000-8000 pound load at 2000-3000 RPM there just isn't enough oil pumping thru the bearings to hold a good hydro-dynamic wedge and cool the interface. You will note that your bearings show the heaviest wear in the zone of heaviest loads right where I'd expect high loading to blow the oil wedge out. High load occurs twice a stroke; coming down under the power stroke to BDC and going over the top at the end exhaust stoke where it wants to keep going out the top of the engine as there's noting to buffer its acceleration so as the crank comes over TDC the rod get one heck of a jerk in the opposite direction to where the piston is flying toward.
Now a previous entry I speculated as to whether the failed cam and lifter may have put in the gunk that caused a situation where the rod bearings failed, or whether the failed rod bearings put in enough gunk to fail the cam lobe and lifter. I also stated that either could be related to neither. This seems to have set off a great exploration of filter mania. All that aside, the relationship between these failures is probably the 5W-30, again, this stuff doesn't have the Extreme Pressure (EP) element is sufficient quantity to protect a sliding tappet lifter and cam, this situation is compounded by low RPMS because it extends the time of loaded contact. This is a situation where the maximum load is present for a long duration of time, permitting the lubricant time to escape from the applied load and also generating a lot of local heat. In this situation the weak link will give up. Lots of people think that high loads and heat come with excessive RPMs, this isn't a singular truth. These are also common to situations where the speeds are too slow for the applied loads. The specific cause of the failure will be somewhat different, but the result will look a lot the same when you pick thru the wreckage.
The apparent lack of ferrous material collecting on your pan bolt magnet shows the filter was doing its job and the amount of material accumulated in 3000 miles was so small as to go un-noticed by your visual inspection. The failed bearing material would not be magnetic thus would not show on the magnet till the copper was worn thru to the steel backing. The bearing material would have been well mixed with the oil, if the filter didn't get it first, to where it would be hard to see, especially if you didn't know what to look for which would have been faint metallic streaks in the drain oil.
The only thing I'll recommend, is that you don't use any of that 5W-XX swill in your next engine, save it for grandma's Sunday goin' to church Buick. I can't tell you the number of engines all the manufacturer's have had to warranty with that stuff in 'em. It's there to get their "Corporate Average Fuel Mileage", as tested to government rules, up as high as possible, no other reason than that to reduce the power used for internal pumping losses. This is passable for motors that don't work too hard. If you expect them to do work in the day to day world with these mini weight oils in them, you've got to expect some bearing failures and certainly if you're running a flat tappet can some lobes and lifters are going to eat it. Fill the crankcase with a good 15W-40 or 20W-50 and save the bearings, lobes and lifters and forget the sellers and recommenders of "skim" oil.
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