howdy fellas, i just had a head reconditioned to put on my 1200 motor in my 1000. The head was from a 120y motor and the motor in there is an early 1200 type.

The problem -

After adjusting the tappets to specs - .25mm they still tap a lot

after taking off the rocker cover to readjust them i noticed there is no oil in the top of the motor. i could have it running and there was no oil squirting out

any suggestions???

I remember reading about mperdue having this problem, in searching I found this.

http://datsun1200.com/modules/newbb/viewtopic.php?topic_id=26729&forum=1

Wish I could find the thread mperdue started...although I don't think he sorted his problem.

Is it too obvious to check you have the thin head bolt in bolt position no.1?

The A10 & 1200 engines used a drilling in the block up to the deck to provide oil to the rockers. There is a matching hole in the gasket, & in the gasket face of the head. Another hotizontal drilling takes the oil across to a head bolt hole in the head & up to a passage that takes the oil to the rockers.

When the engine was redesigned for 1974 they simplified the method of transfering oil to the head. To do this, one of the head bolt holes was made deeper. This allowed them to drill out a small amount of the thread in that hole & send a small drilling from near the top of this head bolt hole diagonally down to the oil gallery. This brought the oil straight up to the same head bolt hole & everything was fine.
The previous drillings in the earlier heads were no longer needed & were deleted from the manufacturing process.

You have now fitted the later head, with no oil holes, to a block that feeds up to the deck & needs these drillings. Result? Oil makes it to the deck, but goes no further. Rockers run dry & eat themselves to death. Sometimes valve stems & guides suffer from the same malady if they are dry for long enough.

Actually, you would have been better off rebuilding the A10 head & using that. Same valve sizes, same port sizes, & the heater fitting hole is in the right position. [different in later heads]

Interchangeability
A10 & 1200 heads on later blocks.... YES
Late heads on A10 & 1200 blocks.... NO [unless the head is modified]

I've done that,
I had to drill and tap a gallery into the head,
I've noticed some heads have a casting and some don't..

bugger, so i have to get the original head done

anyone want to buy a fresh late model head? just been pressure tested and skimmed came up trumps... all you need is not the engine that i have

Quote:Orrrrrr,... you can perform a simple mod to this head & put it back on.

Some people use a gasket to identify the location of the undrilled hole in the face of the head, then create an 'oil channel' across to the nearest head bolt hole. If it can be done in a mill with a small ball cutter, then it's all good, but others have used other methods.

Plan B
If your head has the cast-in boss on the side, like on your original head, then you can drill your own passages to duplicate the early heads & use a threaded plug to seal off the entry hole at the side.
These mods will not prevent use on a late model block later on.

how long would it take for damage to be done to the engine if it was driven with this problem?