383 teardown after 800 miles (pics) and machine shop plan of repair

Some of you may be awar of my posts over the last year regarding oil consumption problems with my SBC 383 stroker....well I got the initial info from the teardown...I composed the following...any comments would be appreciated. Thanks.

**update thanks to the contributers of this forum !!













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Who the hell built this thing?

The cylinders are incorrectly honed, you can also see vertical marks indicating dirt being trapped between the rings/piston and cylinder wall. I'm not convinced that this can be corrected with a rehone, it's going to take another .005 to clean this, by then your .007 to .01 and that's the better part of a worn out cylinder.

The wear on the bearings is way too much for 800 miles, I've seen less on 100,000 mile engines, this looks like somebody put quart of sand in with the oil. The scoring and wear is consistent with filth in the oil not with loading. This has little to nothing to do with pre-oiling a dry start does very different damage. Also dimensions may not be favorable with the crank and bearings check the shaft diameter carefully for taper, and waviness, egging in addition to nominal diameter. This is big time wrong, something in the crank's dimensions is not right. Assembled with dirt under the shells? Watch the bearing shells as they got into the fillets, some of these aftermarket cranks have more fillet material than the OEM, this binds into the outside edge of the bearing. Solution is to dress the bearing edge to provide sufficient clearance or use a narrower bearing. For 800 miles the damage on the crank bearings far exceeds the term "slight"

Yeah I love the rear gasket fold.

The wear on the timing chain, in 800 miles, you've got to be kidding! Again aside from the timing set might be cheap, the condition would be consistent with dirt/debris circulating with the oil. I always recommend a cam button even with flat tappets, I think the lobes and tappets have enough to do without also reacting the cam's thrust loads.

Hopefully, whom-ever is tasked with fixing this, it isn't the person/people that built it. They should be sued out of business.

Bogie

My advice would be not to go picking a cam grind out of thin air until you have measured and computed the exact static compression ratio of the motor and computed the dynamic compression ratio with the intake closing point of the cam chosen.

Further, and I may take some heat for this, but I wouldn't use an extreme energy camshaft. In my opinion, easing up on the lifter rise rate a little with a gentler lobe profile will make the lifter happier. When cams go south, it's the lifter that goes first and then takes out the lobe. If you need more cam, then coordinate the static compression ratio with it and bolt in more cam, but don't ask more from the cam/lifters with an extreme rate of rise than is geometrically sound, again, in my opinion.

I would also take this opportunity to nail down the squish. Measure the stack of parts and the block deck height and find out what the piston deck height will be. From there, you can choose the correct gasket thickness to set the squish. If the block needs to be decked to get the squish right, then deck it. Do it right this time.

Is it possible that you could share the origin of this motor with those of us on the board so that nobody else here will get burned?

Was the bores washed before assembly? The bearings look like hone grit that wasn`t cleaned out of the bores. Many times this is overlooked and this is the result. Any time I get machine work done, I tell the machinist to vat it first, do the work needed, then vat it again when completed. Then when I get it I check over all the surfaces, especially the bores. WD40 and a paper towel in the bores tell you if there clean, if the paper towel picks up gray, it`s not clean. After start up it doesn`t take long before the oil and friction of the rings to pull the grit out and stratch up the cylinder bore, the rest falls into the oil pan where`s it`s picked up by the oil pump, usually the oil pump has enough pressure to have the filter in bypass mode so you guessed it, it gets pumped into the bearings killing them. Being you have scored cylinders and wiped out bearings I think this was likely the culprit. Take a ring off a piston and use the piston to slide it down 1 inch into the bore, if the ring has excessive wear the gap will be rather wide.

A good reason to put your motor together yourself. Whoever did the bore/ hone needs to be sent to machine shop prison.

Bogie I respect and appreciate your posts !! And your willingness to post in detail and share your immense knowledge. I am not an engine builder and I tried with the best of my ability to "communicate" the info from the machine shop (took it to a pro). By the way it is not the same person that built the engine, it is a local performance shop that only operated on referalls....been in business for 30 yrs etc etc. Anyway I talked to the assembler today who is blueprinting everything. I did express my concerns on the crank and hone (if enought material) he insures me the hone will be fine and that the major issue is the cross hatches are like at a 25 deg angle not good for ring sealing etc etc. Anyway as far as the crank he did measure it and all he did was polish it, ready for new bearing which he will assemble, rotate crank, tear down and then inspect for wear. Exactly what he told me about the "fillets" and the reason to go with a narrower bearing (clevite 77 to clevite H). He said it could of been avoided if the original installer would of checked the bearing and all they needed to do was shave or chanfer the bearings to clear the fillet. Eagle (bottom end) is aware of the potential issue but leaves that up to the assembler's responsibility to check clearances and not just throw stuff together. I don't know what to think about the bearing wear cause...dry, dirt etc...I think their might be differing opinions but in the end as long it is done right now what really happened really dont matter too much. I probably did incorrectly describe damage as "slight". Basically getting a completer rebiuld and the shop is selecting the parts. Some may not be top top of the line but hopefully they are not junk. Thanks.

Techinspector thanks for the info. The shop picked the cam (from experience and standard builds); he wanted to go with a custom grind but going with a boxed cam saves me some coin. Thanks for the opinion, I will defineately look into this. I know he went with some better lifters and the heads do have stiffer springs but I may need to ask more about the cam selection. As far as the squish the block has not been decked and I will be using a felpro 1003 (.041) what was previously used with the alum heads. Just going to be for street apps, not hardcore enought really. I insure you nobody will get burned....builder is just a hobbyist and not a shop, I just bought his personal ride.

Ok...I just used a DCR calculator and it says the SCR is 10.4:1 and the SCR is 7.2:1 using that cam...for what it is worth.

y2k600f4, thanks for sharing this whole episode w/the forum- there's a few things to be learned here as well as a refresher for the more experienced.

And good that you haven't gone Postal on someone for this abomination!

You mentioned your carb being a 4160-type 750, I'm guessing a 3310.

Anyway, I would hold off on rejetting the carb just yet.

The 3310's come w/a 72 primary jet- you have a 70 in it now, going all the way down to a 67 might just be too lean.

I would keep the 70's in it, providing the carb is sound otherwise, leave it alone until you see what the plugs and engine tell you to do.

Thanks to many of you on the forum you have taught me a lot through this ordeal. Next time I know what to do and not. Thanks for the pointers on the carb...the shop just mentioned that they were going to tune the carb. Actually going to come over and do the cam break in and experiment with jetting (he was thinking of dropping down 2 jet sizes would work). He said that the primary jets were 72s but it was I after reading the carb instruction sheet that said the 3310 had 70s ?? Not sure what are in there...I am guessing whatever came with the carb (0-3310-11)...know soon engough. Thanks again.

Cool. My info only goes up to 3310-7; -2 through -7 all use 72's.

They will get a handle on it, I'm sure.

Rod bearing down to copper in 800 miles is sign of deonation very badly as well your main bearing too.

Appreciate, I'm looking at the bores in photo not first hand. The first thing that sticks out is the angle, I don't have, or at least I don't think I have, much of a complaint with the depth of the hone marks. I hope they clean and if your new builder thinks they will, I can't do better than that. My concern was that it may the the removal of so much material to put a proper hone on there ,that the piston to wall clearance is getting rather wide. This upsets the ring seal by allowing the piston to snap over to take up the clearance, it also puts a pretty good instant load on the skirt which can lead to cracking the piston. So where I was coming from is since you gotta fix so much, may be it's just smarter to take the bores to the next oversize and start over. But your new builder sounds like he's got a handle on it.

The bearing wear is typical of dirt and lots of it. A dry run forms welds between the journal and the shell, it looks altogether different from these scratches leading to shiny spots. A dry failure will also usually feature temperature induced discoloration in blues, browns, and/or black. These bearings simply look "sanded" with a lot of heavy, but shiny wear in the thrust direction where the forces would bear down between the journal and shell closing the clearance distance trapping the grit in there. On the lighter loaded, thus greater clearanced side, you see the original Babbitt flash overlay is just scratched which is from pieces of stuff to big to get out the clearance on that side till it gets ground up going round and round between the shaft and its bearings. How'd you like that in your coffee cup? yuk!

On your parts choice, I really don't think you need a calmer cam for how your gearing the vehicle, but your cam and lifters are probably no better off than the bearings were looking at, so need replacement anyway.

Yes there is a difference between engine builders and engine assemblers. One of the guys I often collaborate with on builds is from India, he's so meticulous it even drives me crazy, there's nothing he's checked that he won't check again. You just wait till he's happy with his work. Needless to say we don't take Raj to the track where you often just have to piece things back together, but he's the guy you want building in the back room, assuming you've got all the time and money in the world.

Bogie

After reading through this post and looking at the pictures. My question is, is there anything the OP and all of us beginners can do to avoid things like this happening to us. Shotty machine work and assembly???

A lot of guys go to shops that don't really do performance work period they have no line honing equipment, good decking equipment don't believe in plate honing and don't know how to fit bearings ETC.

Looks like there was an issue with the balancer moving by the looks of the front of the lower gear did they even balance the assembley, Did they clearance the rods both ends, clearance the pin bores of the pistons??? Or did the take the parts out of a box and put it together.

By the looks of the bearings the oil filter bypass was not plugged and the oil galleys may have not been cleaned properly.

I am sure you didn't have much money tied up by the looks of the work done

Good info !!! Totally makes sense regarding the dirt. I too hope the hone cleans up, I know he mentioned they bores are on the tight side and should be plenty of material...I guess we will see, he is going to blueprint everything. I would of liked to save some $ and kept the cam (if it is in good shape) but my builder mentioned that I had too much cam that probably was a cause of washing down the cylinders with gas contributing to the rings not seating (amongst other things)...also causing cylinder wall glazing. The comp XE262H is rated at 1500 + RPM and the sum-1106 cam that is rated at 3000+ RPM applications.