136.5mm valves to be replaced with 130mm valves

[camoit]

I don't see why you couldn't do it. It's only 0.0065" shorter. You might need to cut the head for the springs just slightly to keep the same rate. And shorten the valve guide. Other then that they should open the same amount once adjusted. Does it have hydraulic adjusters or mechanical? Call a machine shop and ask what there thought is. I'm unsure on the diesels. But it can't be much different then any other engine. Why are you looking to go with a shorter valve?

[miked50]

I don't see why you couldn't do it. It's only 0.0065" shorter. You might need to cut the head for the springs just slightly to keep the same rate. And shorten the valve guide. Other then that they should open the same amount once adjusted. Does it have hydraulic adjusters or mechanical? Call a machine shop and ask what there thought is. I'm unsure on the diesels. But it can't be much different then any other engine. Why are you looking to go with a shorter valve?

mechanical valve adjuster .....how about changing the valvesprings designed for 130mm valves? the primary reason i'm thinking of going to a shorter one is to lower the compression ratio. but still debating myself on this one. don't know yet what will happen with the power band? how would the hp and torque behave with a lower cr?