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Discussion Starter · #1 ·
I have a previous post regarding my SBC 383 stroker that recently has been rebuilt for the 2nd time with only 500 miles (previous rebuild had only 1000 miles). It appears the rings have never seated (Hastings standard moly rings using their recomended honing...which actually are a plasma-moly ring). I am dropping it off at the builder's shop for him to evaluate (hot/cold compression and leakdown tests) since it is having the exact same issue previous to rebuilt of blowby (using excessive oil in the order of 1 qt per 100 miles). The first blowby issue was diagnosed as poor cylinder cross hatch (angle less than 20 degrees).He is puzzled since he says he has not had this problem in 30 yrs of engine work.

Anyway he has been consulting with some collegues and he first suspected cylinder wall distortion (.040 over) but now after talking to another collegue I believe he is going down the wrong path !! He is suspecting oil used during breakin (used Shell Rotella T SAE30), this collegue believes this was the problem and that he had the same problem that Shell changed their composition of the Rotella to a semi-synthetic...which I totally believe this is false information and the oil has nothing to do with my problem !! Anybody have any idea of where they got this false info from ? My builder is not going to listen to me regarding oil and wants to attemp ring seal with conventional SAE30.
 

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It's worth a try,many will tell you to break in on conventional oil saying synthetic is to slick to allow the rings to seat.On the other hand many new cars are factory filled with syn and have no issues.
 

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Discussion Starter · #3 ·
barnym17 said:
It's worth a try,many will tell you to break in on conventional oil saying synthetic is to slick to allow the rings to seat.On the other hand many new cars are factory filled with syn and have no issues.
I agree Synthetic should not be used for break in. But in this case conventional diesel oil was (Zn for flat tappet). I think my builder is going to try anything and everything so not to have to tear the engine apart :(
 

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y2k600f4 said:
I have a previous post regarding my SBC 383 stroker that recently has been rebuilt for the 2nd time with only 500 miles (previous rebuild had only 1000 miles). It appears the rings have never seated (Hastings standard moly rings using their recomended honing...which actually are a plasma-moly ring). I am dropping it off at the builder's shop for him to evaluate (hot/cold compression and leakdown tests) since it is having the exact same issue previous to rebuilt of blowby (using excessive oil in the order of 1 qt per 100 miles). The first blowby issue was diagnosed as poor cylinder cross hatch (angle less than 20 degrees).He is puzzled since he says he has not had this problem in 30 yrs of engine work.

Anyway he has been consulting with some collegues and he first suspected cylinder wall distortion (.040 over) but now after talking to another collegue I believe he is going down the wrong path !! He is suspecting oil used during breakin (used Shell Rotella T SAE30), this collegue believes this was the problem and that he had the same problem that Shell changed their composition of the Rotella to a semi-synthetic...which I totally believe this is false information and the oil has nothing to do with my problem !! Anybody have any idea of where they got this false info from ? My builder is not going to listen to me regarding oil and wants to attemp ring seal with conventional SAE30.
30 weight Rotella should be just fine. It's true that modern refining techniques has closed the performance distance between mineral base and synthetic oils but you can get a break-in with pure synthetic as most of todays performance cars such as the Corvette come with a factory load synthetic oil in the engine. So the exact answer to your question is no the oil is not the cause of your problem.

The oil consumption you're seeing would be the result of several potential problems.

- As I recall the builder put an incorrect hatch on the cylinders, I presume he disassembled the engine and redid the hone job. Which of course has done one and or two things:

1) You now have two hatch patterns the original 20 degree with something else imposed on top of it.

2) Or if he ground the original pattern away, you now have a randomly rebored cylinder that may be neither round nor vertically straight. In the latter sense, I mean that continued honing of a cylinder tends to remove more material at one end or the other or in the middle resulting in a bell-mouthed cylinder or one that is bowed out in its center.

- Is a question; did he disassemble the engine when re-honing the cylinders or did he do it with the pistons in place? If he did it with the pistons in place then the hone job is not completely thru the bore nor the area of ring sweep. Plus if he did this all the honing junk went into the rings.

- What are the ring sizes? Does it have the proper ring for the bore i.e. a .030 over bore with a stock size ring? Some ring sets come in .005 over the standard overbore, they are intended to be file fitted to the bore, if these were used, were they fitted, if not they are binding at the butt join and are twisting in their lands, you'll never get a seal. With a too small ring the butt ends leave a large leaky gap and the ring also is buckled such that it can't seal the lands on the piston. The rings have to do two sealing jobs 1) the seal of the bore diameter which we usually think of it doing, the other, 2) it must make a gas tight seal to it's lands or grooves in the piston. This seal alternates between the upper land when the piston is decending and the lower land when the piston is rising. This demands properly sized and finished lands as well as properly sized and finished rings.

- Does it have broken rings? Were any found to be broken when the engine was disassembled for the honing operation, which begs my earlier question as to whether the engine was completely disassembled before the honing was done?

- Does it have low tension and or narrow rings. These are intended for competition engines, they work best with a piston that has gas passages drilled thru the crown from the combustion chamber side to the back side of the upper ring land.

- Did you use a 6 inch rod? These cause the pin to intersect the oil ring land requiring a supporting ring under the oil control ring to bridge the gap over the pin bore. If this is missing or damaged the oil ring cannot wipe the bore sufficiently clean.

- Incorrectly sized piston for the re-bore. One could assume that its a .030 over piston because it's stamped .030 but has anyone bothered to measure. In a related situation, what is the skirt clearance to the bore? Too much clearance will result in a lot of side to side movement of the piston allowing it to kock (I'm defeating the dirty work checker with phonic spelling) over breaking the ring seal to the wall and to the lands.

Lastly, I'm not so sure I'd take this back to the original builder, he doesn't sound very competent.

Bogie
 

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Yeah. Brief recap of the latest iteration of this unhappy engine:

1. Speed pro flat 2 notch H860CP 4.040" pistons with final bore 4.042 (closer to 4.0415); clearance .002"
2. Hastings Plasma moly .045 file fit rings ring end gap .016/.019 second
3. Compression 10.4:1
4. run 93 octane ;no pinging
5. Oil SAE30
*note previous build had wrong angle hone and it took .005" or so to clean up and provide correct hone (going by what was told)
*AND*

The heads (new 1000 miles ago) where went through and cleaned and got new viton seal. The builder worked on my engine tearing it down, cleaning, taking specs, re-hone, polishing crank, meticulous assembly and taking the extra time to get it right. He also contructed custom baffles and as per his recommendations I ran a push in breather. Spent a good week just on my engine. As far as I would suspect the rings were installed correctly and the hone was also done with the correct 45 deg cross hatch and recommended finish as per Hastings recommendations.
It would seem that if the original honing that was nearly flat- degrees-wise- wasn't completely removed, there's enough residual honing left to have caused oil retention in the left-over honing.

In that going 0.060" over would have required new rings, pistons and all machining, the option to rehone the badly honed block was made. In the end, this could well be the fatal mistake of this second "rebuild".

If nothing comes from breaking in the rings w/30W and carefully inspecting everything shows nothing out of the ordinary, the block (either the honing- again- or the cylinder walls themselves) should be considered suspect, IMO.
 

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Discussion Starter · #6 ·
Bogie and Cobalt327...thanks for taking the time to give some insight on the issues. I am dropping the car off after work for diagnosis etc to the 2nd builder. To clarify this is a different builder than the 1st (who also used a 3rd party machine shop to perform all the machining e.g. overbore from 0.030 to 0.040, hot tank, stroker clearance, hone etc) the 2nd did a complete teardown to bare block and inspected all components...he did his own machining and cleaning, which in this case was just a re-hone and polish the crank and meticoulously clean the block. He diagnosed my problem as incorrect honing. I know he has 30 yrs experience for what it's worth and "appears" to know his stuff but I have butted heads on the break in oil issue just because he talked to somebody who he trusts and is leading him down this path. I have essentially paid 2xs to get this engine right (the first time built into price of car) and at this point I am not prepared to take it to 3rd builder. Anyway I will mention the potential problem of the re-hone but not sure if he will be too open to that. :( I need to get some more info about how he did the re-hone.
 

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Discussion Starter · #7 · (Edited)
Update

1) You now have two hatch patterns the original 20 degree with something else imposed on top of it.

2) Or if he ground the original pattern away, you now have a randomly rebored cylinder that may be neither round nor vertically straight. In the latter sense, I mean that continued honing of a cylinder tends to remove more material at one end or the other or in the middle resulting in a bell-mouthed cylinder or one that is bowed out in its center.

I ran these two scenarios by my builder and first asked him how he did the re-hone. I beleive he said he used some fine stones to remove the old incorrect crosshatch and took a total of .0005 (1/2 of 1000th inch) of material from the bore including with the new hone and said taking off that little material would not cause a "bell-mouth" cylinder and agreed it is an issue especially if you start taking off more material from the bore. Also I believe he used a bore gauge to check multiple places in each cylinder after the hone...would this potential problem been caught if he did the correct measurements? I was led to beleive that the bores were speced after the hone and were well within acceptable limits. Take this info for what it's worth...still don't really answer the problem at hand...
 

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y2k600f4 said:
still don't really answer the problem at hand...
Unfortunately, this is the truth. If the engine does not break in properly- using whatever oil that is decided on- it's a fair assumption the block needs:
1. More work. Like bored to 0.060".
2. Thrown the hell away.

That said, I personally would not opt for a 0.060" over 350. There's too many good blocks to be had for cheap to warrant the "savings" of using a block bored to 0.060"

Plus, if this is a bad block (core shift, or whatever), 0.060" will be devastating, AFA break-in goes.
 

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The only time I have had an engine with that sort of oil consumption that ran OK was when using low-tension oil rings, especially the 3rd ring expander. I have used Rotella to break in engines until recently when the zinc was removed from it also and now use the Brad Penn oil for break in with flat tappet cams. I still use mineral oil for most break in mainly because of the cost but have not seen a problem with ring seal using Mobil 1.
 

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From A Shade Tree Mechanic

I have following this thread with interest because I have had issues with blowby in my quick re-ring and cheap bore job engines. I think you get what you pay for when it comes to amateur or professional machine work. Mr.oldbogie and Mr.cobalt327 have your issue nabbed. If it makes you feel better, run it hard for a while, the rings might give you a better seal with time. I did a 468 big block a while back, talked to a yahoo machine shop about ring seal issues with moly faced rings. He said; Yea, you need a real smooth bore for them moly rings and because you're wanting to put them forged dome pistons in to pick up the compression, they expand alot so we'll plateau hone that sucker just enough to create the clearance for the new pistons, you will have a sweet setup. Is this sounding like your engine builder? Well, I fell for it. I put the engine together myself, the .065 rings did not need to be filed they were just under the max. gap. Now you mind you, this was the first roller cam engine I ever built so precision was pretty important. I let the big ring end gap slide figuring loose is good. Man i didn't think them rings was ever gonna seat cause that sucker smoked lightly for a lot of garage hours. I tuned the carb and timing, still smoking. Took it for acel/decel runs on our street, still smoked. I was on the point of admitting defeat on the engine, I have had my share of bad rebuilds. It don't always go your way, sometimes you screw it up. Then you do it better the next time. Happy ending is, the last time I ran it, the rings seated and it stopped smoking and oil use dropped alot, about a qt. between oil changes. This is pretty normal for a quik revin loose motor. May be you can be lucky on this one, maybe you can save the rotating assembly for a good block and take the beating and build another. I hope this makes it easier. OLNOLAN :thumbup:
P.S. I don't think the oil has anything to do with it, shell rotella is about the finest oil with the good additives still in it that you can buy over the counter today. Till somebody convinces me it ain't. I did chew two flat tappet cams in the 468 before I new about the changes in the oil additives. That is what led to my first roller cam engine build. good night.
 

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Discussion Starter · #11 ·
Unfortunately, this is the truth. If the engine does not break in properly- using whatever oil that is decided on- it's a fair assumption the block needs:
1. More work. Like bored to 0.060".
2. Thrown the hell away.

That said, I personally would not opt for a 0.060" over 350. There's too many good blocks to be had for cheap to warrant the "savings" of using a block bored to 0.060"

Plus, if this is a bad block (core shift, or whatever), 0.060" will be devastating, AFA break-in goes.
I agree to #2 !!!!!!!! :thumbup: . I am letting him do his tests and troubleshoot (in the shop now)...but in the end I have prepared myself what will end up happening is another 350 block, 040 over (which was the original suggestion of my builder before he talked to somebody) and swap over everything...parts will be minimal, all labor.
 

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Y2K, I have to tell you this: IMO, you've held your composure very well during all this. I can't recall you ranting and raving over any of it- not to say you weren't obviously disappointed and even miffed- but never "over the top".

It shows a lot of character and maturity on your part (your Mama did good! lol), and I just wanted to let you know it hasn't gone unnoticed.
 

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I'd look for another builder too, yes even a third one. Shade tree mechanics are a dime a dozen and for every ten "engine builders" there may be ONE decent one. You need to find taht decent one.
 

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Could have nothing to do with rings this time.Maybe intake gasket leak or something simple don't give up on it yet.Of course you could just swap the moly rings for cast and be done with these problems.
 

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oil burner

if you used a molley based lube on the cam as recomended then the shell oil with adetive pack for modern diesel engines along with molley rings they will never seat, pluse you probly ideled the engine no load 2000rpm wont work no matter of cyl finish. drain the oil put in regular 10 30 run the hell out of it like torq stall or if std trans start in second shift to 4th early with full throttel right up to 3000 3500 rpm. do this sever al times. if it still burns same amount of oil, the last hope is administer small amount of bonamy threw the carb. no more than 2 table spoons , use a salt shaker, once in do the load thing after that fresh oil and filter. good luck cliff
 

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Discussion Starter · #16 ·
cliff tate said:
if you used a molley based lube on the cam as recomended then the shell oil with adetive pack for modern diesel engines along with molley rings they will never seat....
Interesting statement Cliff. Just curious why would you think that the moly lube and diesel oil would effect the seating of moly rings ? Thanks.
 

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There is hope as we had one that we put in a work truck..that thing smoked from the get go but since we did not wish to do it over we just ran it..low and behold at about 5000 miles the rings finally seated and that truck just took of and now runs like stink..some of those moly rings just do not seat very quickly..

Sam
 

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Discussion Starter · #18 ·
UPDATE: DAY 1 in Shop

Car has been in the shop for a day and following done/told:

1. pulled all plugs...cyl #1, #3 and #5 oil fouled...others not as bad
2. Cold compression test exactly 185 PSI in every cylinder (done 3 times)
3. "leak down test" in worse cylinders...well if you want to call it
a leak down...basically pumped from 10 to 130 PSI in cylinder using some sort of gauge set up and listened for air escaping. Extremely faint using tube in ear with other end inserted in valve cover. Sound intensity did not vary when pressure changed. (was going to do hot but decided not to based on results).
4. New plugs
5. PCV valve tested and was told not closing at all, completely removed
6. test drove...smoking mostly stopped (probably burning out of exhaust still)...some smoke still coming more out of driver's side exhaust (side with cylinders #1, 3 and #5)

Upcoming:
1. Longer test drive, watch oil consumption, oil color etc
2. run a (2) breather setup
3. pull valve cover on drivers side and look at valve seals especially on cyl #1, 3 and 5
4. read plugs

Some thoughts from builder:
1. (3) cylinders could of not been firing causing blowby
2. PCV was probably sucking a lot of oil
3. external breather was dry and if it was ring blowby would suspect it would be oil soaked. Also the small amount of smoke coming out of the breather hole (when breather is removed) is normal especially with a high compression engine.

Further diagnosis and tests will be done, but from builder's experience he does not supsect seating of rings to be a problem as of now. Well seems too good to be true it is not the rings. As of right now I am not getting overly excited until I know for sure that the problem is fixed. :rolleyes:
 

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ring seating

y2k600f4 said:
Interesting statement Cliff. Just curious why would you think that the Molly lube and diesel oil would effect the seating of Molly rings ? Thanks.
Rings to seat must wear to conform with cylinder wall finish. when using a molley faced ring they have very low drag so seating is more critical than castiron rings,the molley aded to the cam lobes is to provide supperior lube qualities so as not to scuff the cam lobes and allow for a gentle breakin,then ad the diesel desighned lube to the equasion you have so much friction reducer in the lube system that ring seating is unlikely. remember if machine shop finished the cyl walls for molley rings it will be a finer finish than for cast iron rings. my experience comes from rebuilding and supperviseing same at a cat dealer for30 years.example was 3208 cats with only 2 rings top being molley if cyl wall finish was not to molley spec short life oil burners etc i have built many gas engines as a hobby and have had great sucsess, initial runin is critical. at cats engine plant new engine goes on dyno and goes to full load soon as temp and oil pressure is up(they fill with hot water and oil, they run for approx 7min make the power and removed for paint and work, few oil burners. cliff
 
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