S&S pistons

[upjohn]

I have a set of S&S pistons. Number in pistons 2700 also 83115 inside piston. Bought early 90's. Has dimple on side of each piston. Are they cast or forged? Will Hastings rings fit? Which side do the dimples go on. For 4 1/2 stroke. I do not have directions.

[awander]

I can;t find the "2700" piston, but the S&S Flathead Power Catalog states that, "The 92-2720 series cast 37/16” & 31⁄2” bore stroker pistons are designed for use with 41⁄2” stroke flywheels to convert stock knucklehead, panhead, or shovelhead engines to 84” displacement."

From S&S Instruction 51-1028, 4-6-06, "Installation Instructions for S&S® Pistons":

"1. Piston Series...92-2700,...have offset wristpins
and must be installed with dimple in piston dome toward
right or cam side of engine."

[RussW]

The cast 2720 series replaced the cast 2700' s about 1990. According to an old S&S catalog, the 2700' produced a compression ratio of 7.5:1 in a 4.5" stroke Knuck, Pan, or Shovel. The 2720 cast pistons resulted in an 8.25:1 C.R. The piston fit for the two were different, according to the installation sheet. The 2700 series says "Close fit- .001-.0015 Loose fit- .0025-.0035", while the 2720 says "Close fit- .0025-.003 Loose fit .0035-.004" "Max piston and ring life, fit to close fit dimensions. " I can try to scan the install sheet for you if you want

[1951 adam]

I just went thru this with Hastings, There are only 2 sizes they make for HD type piston ring grooves , and oil control ring groove .as per Hastings,,, Measure with a caliper the groove ID , and you can call hastings and order them directly from them , I'm sorry I cant remember what those measure at now. Any way they were GREAT, SUPER CUSTOMER SERVICE, good luck, Adam

[upjohn]

Adam I would appreciate it if you would download it for me. thanks

[upjohn]

Sorry Adam I meant Russ. Thanks for the info from all.

[RussW]

Here you go

[58flh]

I have installed alot of the pistons you described!---GOOD-STUFF!,Always use Piston manufacture specs.!--Tight is better for street riding!--You can use Hastings oil Rings!--IF its a Barstomper- then a looser piston fit is preferred for a nice quick wind-up!---Richie--(Dimples on Right as ANDY said!)----RICHIE

[upjohn]

Thanks fellers. Helps a lot. anyone know what the compression ratio is?

[awander]

7.5:1 per Russ' message above.

[upjohn]

Imma a dumb ass

[awander]

I'd bet most of us have been as dumb, or dumber, at times.

[upjohn]

Replacing timkens on left flywheel side. Some parts places say timken reproduction. Others nos. Where is the best place to order the whole set for 56Pan?