[TIM LIMES]

Hello, recently had my machinist rebuild my sbc 350. Was going thru about a quart of oil every 200 miles, ouch, after the rebuild. We tore back into the motor last week. Going to rehone the cylinders(they were punched .030 originally), AND REHONE. We initially used sealed power moly rings. We used the speed pro hypereutectic 2 valve relief pistons. After disassembling, the coating on the pistons still looked new but the tops had alot of carbon build up. The cylinder walls were smooth, but didn't really see much of the honing marks. Cost is not a issue as long as it's done right. Was wondering if I could get any ideas on quality rings etc. The car is street driven, not raced. Thanks, Tim

[badknuckles]

childs rings

sorry childs and albert

[TIM LIMES]

child and albert moly?? or ??

[badknuckles]

moley they have plasma moly also

[lluciano77]

I used Sealed Power rings and KB hypereutectics. I didn't have any problems. Did the machinist hone for the moly rings? They hone the cylinders differently for moly than they do for cast.

[TIM LIMES]

Is there any special prep to the block needed for the moly ring to seat? Stone grit for hone? or the way it's honed? Don't want to do this for a 3rd time. Thanks again!!

[Dradee]

The honing not gonna make that much difference,how about how good of a job did they do in clearances? And how about the valve guides?check the piston to cylinder wall clearances and check the ring end gaps of those rings.Also no synthetic oil during breakin or those moly rings wont seat properly.Were the rings installed properly right side up?

[johnsongrass1]

Have you performed a compression check or leak down test to see what what's going on? I'm not convinced the rings were at fault either. There would be smoke at the pipes if it were consuming that much oil.

[TIM LIMES]

Yea, we had performed a leakdown test. Had posted the results here about 2-3 weeks ago trying to get some ideas. Here they are again-cyl#1-150lbs. comp.& 8%leakdown, #2-155lbs. & 7%, #3-145lbs. & 9%, #4-150lbs. & 9%, #5-150lbs. & 11%, #6- 145lbs & 9%, #7-145lbs. & 6 %, #8-145lbs. & 14%. The mech said it sounded like it was going in the bottom end. I put new Dart heads on it with double seals, we're going to go back over them again also. Thanks again, Tim.

[rifraf]

I prefer a coarser stone when using a molly ring,although Im not a big fan of molly rings unless they are needed,they wear the cylinders out faster,but they do have there place. I ran into a problem like that some time ago on a 410 I put together for a guy,I put a 160 thermostat in it to keep the detonation down and ran a big 8 something Holley double pumper,the combination didn't seat after 2000 miles because it was being washed down constantly,this was with plain 30w oil. I then put a 625 carter on it and a hot thermostat in,and wallah,problem solved. once seated I switched back and everybody was happy.

[rifraf]

And as asked by dradee,rings in right? Im not impressed by the sealed power instructions,the more you read em the more confusing they become for identification,I think they have a one size fits all instruction sheet.

[engineguy]

Honing does make a big difference and the cylinder wall should be finished according to the type of ring used. For moly rings to work properly, the finish should fairly smooth. Moly rings will not wear out the cylinders, in fact just the opposite. Moly facing is somewhat "slippery" and is also porous and will help to lubricate the cylinder wall. This is why they are used in performance applications.
The only ring factor that will cause accelerated cylinder wear is excessive ring tension. Ring tension, especially in high performance rings, is carefully engineered and controlled by the free-gap specification.

[rifraf]

If this is so than why is it said to never run a chrome ring on a chrome bore,I have always been told it would destroy the bore,also its my understanding that most factory motors only use them on the top ring only usually ,and last of all,though Im no metallurgist, I think chrome is far harder and less apt to wear than cast is,not to mention less porous.

[engineguy]

The reason for not using a chrome ring with a chrome cylinder, is that the ring would never seat. Chrome is extremely hard, that is why it is used in engines designed for dusty environment, such as Caterpillar, John Deere, etc. with ductile or cast iron sleeves.

When using chrome rings, the cylinder finish must be somewhat "coarser" than a moly ring. This allows the chrome to seat into the cylinder wall. If the cylinder is finished with a smooth surface, the chrome rings will not seat (or they will take a very long time to seat).

[rifraf]

Im sorry, most rings I know of have an edge, not a smooth surface,this is why they have a top side for installation,to create a seal. This edge of chrome,being harder than cast cuts better,or worse if you will. Like finner grade drill bits do. The coarse grit creates a memory of a crosshatch,so to say,so as the cylinder wears,it remains because it does wear,and faster. And yes,chrome on chrome would take forever and a year to seat,and once it did it,if ever, would be dust,but what do I know. Its just another case of give and take in the world of high performance,power vs reliability.