Club G40 Forum

Technical => Engine and Transmission => Topic started by: N1CKY on July 07, 2012, 11:01:42 PM

Title: Melted Piston
Post by: N1CKY on July 07, 2012, 11:01:42 PM
Took the car home because it was running on 3 pots, Took number 3 plug out to find the electrode had snapped/melted off.

Took the head of and found a melted piston, Then took the piston out to find the destruction.

Any ideas what could of caused it ? Just a dodgy plug ? Timing was all spot on, never skipped a tooth or dropped a valve etc. Valves are mint. All this after 300 miles after a full engine rebuild.

Title: Re: Melted Piston
Post by: Robin on July 07, 2012, 11:28:20 PM
Running too lean is the most common cause of this on G40's.
Title: Re: Melted Piston
Post by: Andy on July 08, 2012, 07:37:24 AM
Or the wrong plugs, or too much ignition timing.
Title: Re: Melted Piston
Post by: N1CKY on July 08, 2012, 09:16:01 PM
plugs are super 4 bosch r6 982 the timing is what it as been on what i have been told 8 deg when warm an temp blue plug disconnected

i need a piston any one got one thanks
Title: Re: Melted Piston
Post by: Andy on July 08, 2012, 09:18:57 PM
1. Those are the wrong plugs.
2. That base timing is too advanced.
Title: Re: Melted Piston
Post by: N1CKY on July 08, 2012, 09:37:00 PM
what are the correct plugs an what is the correct timing
Title: Re: Melted Piston
Post by: Andy on July 08, 2012, 09:58:41 PM
1. Bosch W5DP0
2. 5° (+/-1°)
Title: Re: Melted Piston
Post by: Jacque on July 09, 2012, 11:04:11 AM
Hi i have a question related to this result :p (running to lean, dont know)

My polo does an average of +- 33.5 mpg for the last 7000 miles (since i bought it +- 2 years ago)

it has an SLS chip (140hp) on 68mm pulley, bosh sparks (came with the kit) and standard injectors.

my wallet loves the mpg, but i m a bit concerned about wether is uses enough fuel and not to few.

i think it's about just ok, just would like a second opinion.

anybody? :)
Title: Re: Melted Piston
Post by: Andy on July 09, 2012, 11:14:35 AM
Sounds about right.