18RG Head with no serial number!!??

[Silly Rabbit]

......well after blowing the engine at Winton 2 months back I have finally gotten around to pulling the car apart to remove the engine. After having the car 10 years and never once having played with the engine for more than routine stuff I found something a little strange but may not be to the more learned Toymodders on here.

After taking off the front of the car (bonnet / bumper / radiator) I checked the front of the engine to see what serial number the head was. As I have a replacement engine ready to go I know where it is and wanted to see if it was different. Funny thing was however that it started with the usual 11111 - but then had nothing.

The numbers are cast into the heads and not stamped / pressed in and there is no sign of these being removed / ground back. Does anyone know of the Yamaha heads not having any sort of identification?. Is it some special factory up specced version or more than likely just something early or late in the piece.

If someone could shed some light on this that would be great. It has the Yamaha logo and the 11111 - but nothing else except for a number 147 stamped a few centimetres underneath quite small.

I will try and get some pics up possibly if people want more info but hopefully someone knows this type of thing straight off.

Cheers.

[Turdinator]

This is from the toysport 2tg and 18rg tech notes page. Maybe its an early race motor...

The first race engine based on the 2TG was made by TMC (Toyota Motor Corporation) in 1970 and was known as the 100E. Toyota built about 25 engines with full racing specifications- specially casted head (11111-______) yes, blank numbers!, special intake manifolds, dry-sump oil system, 50mm Mikunis, ND igniter and instrumentation, ND fuel pump and some other trick stuff. Of the 25 engines- 8 went into Corollas (Levin and Trueno), 10 went into Celicas, and the rest were spares. Eventually TOSCO (Toyota Sports Corner) was organized and some parts from this project became available individually. TOSCO later became TRD.

Take it off and take some pics

[Silly Rabbit]

...Oooooh interesting..........i'll get some photos of the head still in the car and then when the strip down happens I'll post some more up if it proves to be anything special.....me thinks it ain't going to be the 1 in 250,000 head that is reported above but hey it gives me more impetus to pull it out and strip it down.

Anyone else got any other theories??

[GT1978]

Bugger theories, pull it down and take measurements. We must know! Would be great to know valve sizes and any cam specs you can get. Also lots of photos would be nice. Photos that show head reinforcing oil passages anything that may have been changed from the standard head.

Glen

[Turdinator]

Did you ever take this apart and see what was the go?

[Omegaman]

come on Rabbit, what happened with this?

[Silly Rabbit]

....took it apart and it was standard standard....very strange.......well worn standard as well.....certainly a good enough head to use again but the valves were worn and it needs a good overhaul........certainly nothing to suggest it was TRD / TOSCO special part.........no porting / larger valves etc.....oh well she ran well for the 10 years I had her