filling holes in pistons

[eibargum]

This is for Smiffy rearly but anyones oppinion is welcome , got 2 MB pistons with 4 extra lube holes drilled in them in line with the exhaust bridges on the RBs, can these holes be filled in with Devcon or some other way with out it dropping out due to the expansion/contraction of the piston so they can be re-used ,whats the best way, cheers.

[Chutney Brownlove]

Why do you want them filled back in, are they no longer in the RB?

[Diablo]

Sticky uses a piston from a TRX in his CRM motored Lammy. The holes are there too. He gets Harry to weld them then carefully dresses them back to smoothness.

[eibargum]

Why do you want them filled back in, are they no longer in the RB?

They,r going to be used in the future in the RB but ive alterd the exhaust port, a mate welded it up and its been re-shaped by Chiselspeed then re-plated, TBH ive never been overly inpressed by the plateing .although the origanal exhaust port has served me well.

Sticky uses a piston from a TRX in his CRM motored Lammy. The holes are there too. He gets Harry to weld them then carefully dresses them back to smoothness.

. Could get a mate to weld them up Diablo, but was worrid incase they worped, if no better ideas come forth i,ll try one and see if it worps, anyone else any thoughts.

[J1MS]

Ive used Devcon on many parts of the casing, inlet and barrel, this when porting to help blend, But I have never dared to use it in the piston for fear of it falling out. so I have always had them welded up if needed

but I believe Devcon is supposed to have similar expansion rates to the alloys used on engines...

[shocky]

get them welded did loads in the 90.s (DT 175 PISTONS)

[RinB]

This is for Smiffy rearly but anyones oppinion is welcome , got 2 MB pistons with 4 extra lube holes drilled in them in line with the exhaust bridges on the RBs, can these holes be filled in with Devcon or some other way with out it dropping out due to the expansion/contraction of the piston so they can be re-used ,whats the best way, cheers.

Ay up m8

Ive just done the same conversion to 2 RB22's and a RB25, welded aux exh up ( recomend stapping bridges out to get a proper weld.) Re-ported exhaust to one big mother then had them ceramic lined. On RB22's altered transfer angles to be symmetrical.

As for piston holes Ive left them as it on one engine as they wont have any real detrimental effect.
But if you can get some one who is a good ali welder to spot weld them on the inside go for it. Must really heat piston up
before doing it.

Smiffy

[eibargum]

Cheers Smiffy, welding it is then. Could you post up some pics of what youv done to the RB 22s tranfers smiffy, if you have them to hand , regards, gary.

[RinB]

Pic from my thread of what I did to my RB

Remember the Barrel with fingered aux Exh ports etc,
Ie the one I was running in at the Euro as I went passed everyone with arse in air round Lincoln ring road




Left transfer fettled to angle gas stream as per the right. Becareful not to go through to stud hole, but it can be done

Smiffy

[RinB]

The next project Im on with is attacking a RB20 :bouncing:
This one is for me for a change