Perkins cylinder head

[BASS]

Greetings all, I have just had my 1980 6354 head tested and have been told the pressure test was ok. When i asked about the flatness, i was told that due to the multiple waterways it was difficult to test with a straitedge etc. He suggested a 5 thou skim to ensure flatness. My concern is altering the compression ratio. I have inquired about a thicker head gasket without luck. Am i worrying unduly? Any thoughts appreicated.

 

[mtb]

thats a load of cods
If he can skim it he must there fore have a dial gauge and can use that to check it.
Get a steel ruler look for your self, it's a very basic thing to do any more than a couple of thou then get it skimmed.


cheers
Mick

 

[LittleShip]

5Thou wont make a great difference to the engine but, ask if you can get away with less. You never know you may need to do it again in a couple of years.

Tom

 

[volvopaul]

You can skimm it no problm up to about 25 thou, after that the valve seats will need to be pocketed, or refaced as the valves will be closer to the pistons and may contact at high rpm due to valve bounce, 6 cylinder perkins are an excellent engine, i did my apprenticeship with a perkins dealer in the 80,s. would get it skimmed to be on the safe side also remove the valves, reface them and the seats, check the guides for wear, especially the exhausts as they wear and pitting of the seats so not to loose compression.

 

[BASS]

Thanks for your promt replies, I think I will collect the head and take it elsewhere for a second opinion. Anyone know Freedom Marine in Kent?

 

[ipw]

Whilst the head is off --reface it ,fit guides were necessary ,new springs ,reface seats ,fit 12 new valves ,they should cost only £6 each ,they are quite thin to start with and they take the most stick in the engine. If you want pm me for more info .ps if you face 20 thou off the face and face 20 thou off the seats you don,t gain any compression.

 

[burgundyben]

When you come to re-assemble, the perkins head gasket is a copper affair and very prone to leaking oil and water around number 6 cylinder.

If you purchase the Payen gasket set the head gasket is a composite jobbie, my copper gaskets lasted a year on new blocks and reface heads, the composite ones have been in there 4 years now and are oil and water tight.

when you come to fit rocker gear, be extra specially attentive (like you would an attractvie woman, ahem) with the push rods, its very easy to get them not seated properly, hand crank engine a few turns, hard work but not impossible, before cranking on starter to check they are home.



HTH.