G/day guys, your thoughts/experiance please ... Ive just picked up my M750 barrels from the engineers, they were diamond honed ready for a new set of FBF. When fitting new pistons/rings, in the past, Ive always oiled the pistons/rings/bores, however, the engineer advised me to just CRC the bores and compression rings and only oil the lower scrapper on the oil ring as this would help bed the rings and nikasil bore in better, leaving it less likely to burn oil ... What do you do on your builds ?
I've always lightly oiled the lot but it probably is different with modern Nikasil linings, so I could be behind the times. By lightly oil I mean wiping an oil soaked rag down the bore and oil can the piston and rings wiping off the excess. You can buy bedding in oils from some suppliers.
Curious what the latest process is.
In one of the 2 seminars I attended, the Master Tech used 15W50 and rubbed it on the cylinder and piston by hand . . .
Ask the guys who make the rings.
Pretty sure the FBF pistons use rings made by Total Seal.
What's the part numbers on your rings?
Rings part no 00614/KP/KP/8767 Made in Japan 8800XX
WISECO rings it looks like by part number. The ferracci pistons have been wiseco so that would make sense.
I have always used oil or assembly lube (klotz) a thin smear on the ring lands and then a thin coating on the cylinder walls. you will see the rings push most of it off on the install but it leaves a bit in the cross hatch which is what we want. It is only there for the first start up and turning the motor over by hand before start up. Any residual will be gone quickly at first start up, do expect to see some smoke off when it first starts but it should go away pretty soon.
All the race and street motors were done this way at the dealership I worked for and we did plenty of motors. I assume you had the nikasil replaced or did they just break the glaze in the cylinders?
Be sure to measure piston to wall and ring end gaps.
molly paste the wrist pin holes and do not forget to install the wrist pin clips.
What is CNC?
Just busted the glaze with a diamond hone to help the rings bed ... CNC, that is a typo, I meant to say CRC lube spray ... I will amend my first post. BTW thank you everybody for your input [thumbsup]
all the major car engine repair jobs i do at work, i always prime the engine for oil before starting. disable fuel and ignition system and pull the spark plugs and start doing extended cranks.
when somebodies around and i start cranking the engine i always say" oops. no compression, the valves are bent".
I've never understood keeping rings dry during engine assembly, but just because I don't understand it doesn't mean it's wrong. Seems to me that the rings will only stay dry for about one revolution and no seating is going to take place in that short of a time. Or, if they do stay dry they're just going to get spots of micro welding at the high points where there's metal to metal contact. For assembly I just use basic SAE 30 oil on the bore, rings and pistons. But I'm a long ways from being a professional or even a serious amateur engine builder.
Bob
The first time I heard about dry assembly was in the 70's when Gietl and Schuster built the BMW superbikes. Supposedly steel liners, dont rember what type rings. The idea was to quickly run in the rings and liners. If I remember correctly, they reported less blowby, but I'd have to dig out old Cycle Magazines to be sure.
Nicasil type coatings are very smooth compared to a honed steel liner and rings are relatively simple and low-tension. I would not recommend dry assembly on nicasil coatings, there's not much of a running-in effect anyway.
Went with your advise guys and oiled, top end is now built [thumbsup] ... Once again, thank you for your input and Brgds
Quote from: Von Eisen on September 24, 2016, 09:25:30 PM
Went with your advise guys and oiled, top end is now built [thumbsup] ... Once again, thank you for your input and Brgds
Always greasing the top end with some oil is always a good measure. Just remember to not start it up for the first time in the garage. Might be a little smokey.