Seizure on a cast barrel

[mick1]

This was the seized piston on my 225 Rapido (on this years C2C). I continued to to do another 300 miles after my sieze before stripping it down (i'm amazed it ran so well !!).

[eden]

whats going on with the bottom of the inlet skirt?

[Special X]

if you wana nip up the first time you give it some throttle for a while go for 3.5 if you don't go for 4

My preference would be 3.5 thou for a 150/175, and 4 thou on a 200/225. Can't see how 4 thou would harm a small block though.

[Strummer10]

wow Mick 1, also amazed that kept running.............did you heat seize a number of times ? AND on analysis of your situation what was the conclusion ?

Thanks

[Rich_T]

I don't think this is a heat seizure. It,s on the inlet side (which is the coolest) and the ring land does not look that hot.

To me, it looks like a foreign object has gone down the inlet and marred up the side of the piston.

Don't know what is going on with all that clag over the barrel studs and the piston skirt don't look straight. The rod also looks unusual, is it standard? Case transfers look to be worked a little bit.

[mick1]

It was running an opened mouth PHBH so foreign object a possibility. I was using an Indian GP200 gearbox so it had a 5.2 final drive and I was travelling at nearly 60 for about 10 miles (guestimate/no speedo) I eased off the throttle and it seized. Grabbed clutch and went for hard shoulder, tried releasing clutch in second but wheel locked. Left the engine to cool and took plug out, lovely colour definitely not running lean. Put plug back in and it fired 1st kick ?? The "clag" on the studs is Loctite silicone and the piston is a mystery ? I didn't fit the piston but think it's a Mitaka that was fitted after a holed piston 4 years ago. The crank is an SIL with an uprated big-end bearing fitted at Rayspeed.

I've now changed the top-end to an Avanti and the gearing is now 4.6, just done 300 miles on it this weekend and it runs smooth and sweet.

[Strummer10]

Avanti kit.....now your talking, probably the best kit out there......not over tuned, but punchy enough to sit with Ts1's

[Rich_T]

Was the inlet of your cast barrel tuned in any way?

[mick1]

Certainly not by me, but it was second hand when I got it so who knows. I will take some pics of the barrel and see what you make of it.

[Rich_T]

So the barrel and piston are of unknown quality or origin, what did you do to insure the clearances and build were right when you put it together?