Hi guys,

Just lifted the hed off of my engine and measured up a few bits....

Head height 138.7mm good or bad?

Bore 90.7mm (think thats std bore size ) with about .5mm of piston movement side to side again good or bad?

Pistons have the markings YB0618 on them (and next to that really small is 512 E 0490)....all have a No 2 and a forward arrow on other side.... normal?? std compression?


The engines going in for rebuild soon anyhow as it's not known condition/mileage but just curious.......
Also a jet black buildup on the pistons...really hard crusty pellet like areas that have built up. picked it off and no harm done but what would cause this?? looks to have been overfueling a bit so coudl this of caused it?

Cheers
Dan

 

standard bore size is 90.8

think that head is on minimu thickness now.

 

Ford reconmend 138.5 apparently (found out tonight), but my heads at about 138.3 and have no problems

 

Its carbon, nataural bi product of combustion, made worse by overrich mixture, but all older engines i have seen have carbon build up

 

as long as head is not skimmed to no good i'm happy...rest can be rebuilt by reyland when I get round to taking it down.

Any info on the piston numbers...I'm intrugued as to why all 4 pistons have the No 2 on them

Cheers
Dan

 

The head has loads left on it.

I've used them at 137, just machine the pistons to suit.

Martin would go through all this with you anyway.

The bore size can alter due to wear, what did you measure, piston ?

"black crust" is just carbon build up.

 

the blck crust sounds more like oil being burnt rather than carbon as that is soft and sotty

 

The number 2 is a grading for piston size, you should have a row of numbers where the dizzy fits that relates to bore size and matches.

Steve

 

Apparently its a std bottom end...not been bored or anything which is good......I might get away with a hone when rebuilt as it doesnt look too worn in the bore with only a very slight lip..

I am more worried about the buildup on pistons....I know what carbon looks like but this was like popcorn size pieces built up on the pistons....i'll take pics tonight.

I'm glad its a half decent engine and not on a 1mm bore and skimmed to death!

Cheers
Dan

 

pics of piston buildup....




Like it said before its like a crusty black solid deposit. I've seen carbon buildup before but never this bad if thats what it is.

Anyone know more?

Dan