2F piston gap spacing and general assembly questions (1 Viewer)

[myquestoyota]

I guess I should start a "rebuilding my first 2f thread", I have enough questions. My machinist told me .002 was just fine for my main bearings so I dropped the crank in yesterday. Used Lubriplate 105 and she turns over sweet with the caps torqued down. Now on to the pistons. I cannot find any specs on ring gap spacing in my FSM. I know I need to stagger them and there's several recommendations on the interweb on proper spacing but you'd think there would be something in the FSM. Also I find no reference in the FSM regarding pre-lube of bearings and rings and such. Like I said I am using Lubriplate. Should I use that on the cylinders or 30 wt for the rings? Also. do I install all of the pistons and rods before I plastigage the rod bearings or do it one at a time as I go? It's been years since I've done this and don't think I was as analytical the last time.

 

[grant5127]

#1 ring .0079- .0220
#2 .0079 - .0228
Oil .0079 - .0346
Use motor for assy....
Most ring mfg give a stagger chart...

 

[skully3]

Also. do I install all of the pistons and rods before I plastigage the rod bearings or do it one at a time as I go? It's been years since I've done this and don't think I was as analytical the last time.

yes install the pistons and rods through the top and get them lined up to the crank. Make sure all is lined up then plastigauge them one at a time. If you are this far into your motor you should redo your wrist pins also.

 

[myquestoyota]

New 030 pistons and machine shop work done. Head completely gone through. Rods balanced with fresh wrist pins. Crank ground, new cam and lifters. New timing gears, probably reuse the oil pump as I understand these are pretty bullet proof and a new one is $pendy. So excited, having fun and trying to take it one step at a time and stop when I have questions. As far as I can tell the rig gap staggering question is not answered in my FSM.

 

[skully3]

Most recommend 120 deg out.

 

[grant5127]

[If you are this far into your motor you should redo your wrist pins also.[/COLOR][/FONT]

New pistons Man, takes care of the pins... nothing on the rod itself can be done... PINCH bolts Man....

 

[skully3]

New pistons Man, takes care of the pins... nothing on the rod itself can be done... PINCH bolts Man....

you should still check the clearance on all the lower bearings just in case....just to clearify I always do my own pistons and wrist pins. When you get them "new" wrist pins should be made to fit each piston. I always stay .0008-.001 on clearance. But thats me and some ppl may say otherwise.

 

[myquestoyota]

The machinist installed the wrist pins and balanced my rods, one was a replacement from a fellow MUDder. The guy is well known in the area as a premier engine builder so I have faith in his work. His shop is on my way home so I'm lucky there but I see guys in there from the Seattle area all the time that bring their stuff to him. Given all the machine shops between here and there that's a pretty good advertisement. The wrist pins came with the pistons.
PINCH bolts?

 

[donny paradise]

PINCH bolts?

A bolt used to retain pin in rod. These pins float in the piston not the rod like other motors.

 

[myquestoyota]

Got it

A bolt used to retain pin in rod. These pins float in the piston not the rod like other motors.

Add that to my vocabulary. But I should check the torque on those while I can access them now shouldn't I?

 

[myquestoyota]

Well, I found the gap spacing diagram in my FSM. It was right there all the time. Nice simple drawing, I just overlooked it. Got four pistons installed last night, two more tonight and on to the camshaft. The plastigage readings and ring gap measurements were all so good it was tempting to skip those steps for the rest of the pistons but I could hear the MUD chorus in the background saying "Did you check your ring gap? Did you check the journal clearance on ALL of the journals?" Also, taking more MUD advice, I turned the crank after each cap was torqued so I would know which one was binding. Four pistons in and still turning like a dream. Just enough resistance to tell me these are new parts but no binding whatsoever. And by putting the nut on the end of the crank gives me that wonderful pair of dogs from the hand crank to assist my turning. Keep up the good advice!

 

[myquestoyota]

Well, five pistons in, one to go and I open the ring box and find a broken ring. Dang, another stop at the machine shop tonight I guess. It's going well so far, turns like butter....

 

[Fuzzy Logic]

New in box, broken ring? Whats the brand name of these marvelous wonders?

 

[myquestoyota]

The company is ITM and it is where my machinist sourced the 030 pistons, rings came with the pistons. I have faith in my machinist and don't think he was low balling. He's getting me a replacement now. It is the same company he has used when he's built 2F's in the past. The last one he did was the forklift for the local RV dealer.


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