2tg/3t hybrid problem

**anty109** · 23-08-2015, 04:34 PM

Whats the pin height on those pistons

**TA22 GT** · 23-08-2015, 05:33 PM

There at the shop now but i think its 35mm

**TA22 GT** · 26-08-2015, 07:15 AM

Any update. Did you find the issue?

**73GTV** · 30-08-2015, 11:27 PM

So let me get this straight,

**73GTV** · 30-08-2015, 11:56 PM

Originally Posted by anty109

Hi I just bought this 2tg engine that has a 3t crank in it and 1mm over size pistons so 86mm bores. I turned the engine over bye hand on the stand just to check i got the timing chain right and that the engine turned over with no interference.
All was ok. Started the engine up and all was good then a tapping noise started up. I rechecked the timing chain and made sure the cam caps were tight. Started engine again and it was ok no noise. When i rev the engine the tapping noise comes back. When the head was off i had double valve springs installed and the head was checked and everything was ok. The valve reliefs on the pistons looked like they had some markings on them but the valves were fine so i thought nothing of it.
I used a cometic head gasket H0894SP7043F which is .043'' thick. apparently engine was running fine and was used for a couple of races and the head was pulled off to check compression ratio for a possible turbo conversion. and then i bought it and reassembled it.

does anyone know what the noise could be or what to check from here.

So let me get this straight, you installed the 3T crank and failed to clearance the walls of the block to account for the rod interference (30mm from oil pan edge = down 30mm making a 38mm long by 17mm wide funnel) and the 16mm round by 2mm deep rod bolt, top of bolt interference to the block next to the piston bore?

That is how it was done in the "Old days" when using a 2t series block instead of a 3t series block. (Carboy 1983)

See, the 2t block had to be used in japan because if the block was changed the amount of paperwork required and fees attached made changing to the 3t block an expensive process. the solution was to clearance the 2t block to account for those interference points, this may be where your tapping sound is coming from. Skirts of the piston were also modified.