lapping valves...

[gutierrez9287]

rebuild being done on engine with 350xxx. 910 springs being installed, would you guys recommend just lapping the valves or would you guys replace them? If you guys would replace them is there any particular valves you guy recommend? Thanks in advance for the input!

 

[kyle43335]

rebuild being done on engine with 350xxx. 910 springs being installed, would you guys recommend just lapping the valves or would you guys replace them? If you guys would replace them is there any particular valves you guy recommend? Thanks in advance for the input!

if theyre not pitted bad? i just cut the seats,and valve. then lapp them in. done.

 

[4.0l sahara]

Check the valve guides with that many miles.

 

[PowerstrokeJunkie]

My old engine had some pretty sorry looking intake valves at around 180,000 miles when i put on the ported heads. They had worn where the valve seals against the seat so bad, the lip on the outermost diameter of the valve was thin enough to cut stuff, dont know how many more miles it would have gone before the spring would start to pull them up into the port.. *shrug*

 

[golfer]

I would measure the valve recesses...and see how far 'sunk' the valves are into the heads.

new spec is @ .055" recession...

with that number of miles, I would be FLOORED if they were less than .070"...

also, there is a HUGE airflow difference(reduction) as the (intake) valves recess further & further into the heads...so if this is a performance engine...you could literally be losing a ton of flow through the (more shrouded) intake valves.

 

[gutierrez9287]

I will inspect recess tonight...
Alone the thought of loss flow has me steering in another direction...

If not in spec i already contacted a Machine shop they want 295 per head for head work that would include:
injector cups
Seats
Guides
Springs
valves
Cleaning
And pressure testing
Is this a fair price?
Also since I would provide my own valve springs they want me to provide my own shims and valves for liability reasons????? Shim I already have but what would you guys recommend as far as valves go?

 

[kyle43335]

I will inspect recess tonight...
Alone the thought of loss flow has me steering in another direction...

If not in spec i already contacted a Machine shop they want 295 per head for head work that would include:
injector cups
Seats
Guides
Springs
valves
Cleaning
And pressure testing
Is this a fair price?
Also since I would provide my own valve springs they want me to provide my own shims and valves for liability reasons????? Shim I already have but what would you guys recommend as far as valves go?

thats actually to cheap imho. i would be worried about material quality,and labor practices...

unless theyre just cutting the seats,and valves,then lapping????

even still thats cheap.

 

[golfer]

you need to pass on anyone installing valve seats into your heads...especially if this engine is anything remotely akin to a performance engine...

I didn't see that the heads were being surfaced flat.

And I would ask for thick wall bronze valve guides

(not sure what they're providing you with/quoting you since the OEM heads have no (replaceable) valve guides).