I have a b7200 with a d950. I bought it not working and am doing a head job. How critical is the valve recession the manual says 1.3 mm all the intake valves are at 1.6 mm and the seats need refacing. Do I need new valves.
How critical is valve reccesing
- Thread starter Dre
- Start date
North Idaho Wolfman
Moderator
Staff member
Lifetime Member
Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Honestly, critical to a point, as the valves set deeper in the head the compression goes down.
If they do go too far in the compression ratio drops too much and it will make it harder to start and give you less power.
If they do go too far in the compression ratio drops too much and it will make it harder to start and give you less power.
CountryBumkin
New member
Lifetime Member
Equipment
BX2370 w/LA243, Bucket, Grapple, QA Pallet Forks, 60" MMM, rear blade & rake
If the drop in compression is a concern, you could mill a few thousands off the head and restore the compression.
North Idaho Wolfman
Moderator
Staff member
Lifetime Member
Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Yes you could, but because of the way that the pre-chambers are set up it's not a good idea to remove that much material off the head.
It all depends on your assembled height measurement. I would grind the valves & seats as needed & measure to see if it is still within acceptable tolerances. If it is then finish assemble & if not I would replace the seats & valves. This is just what I would do.
Thanks guys. I will be grinding the valve seats next week. The valve seats on a d950 are non replaceable and the manual says replace valve and if it still not within spec regrind or replace head. But is it correct in thinking that the only issue with excessive recession is a slight drop in compression.
NIW has it right! The change in compression ( lower), will effect the cold starts.
When is was in my dealerships shop I did most of the head work. Some for walk-ins, but mostly during engine rebuilds.
Pat
When is was in my dealerships shop I did most of the head work. Some for walk-ins, but mostly during engine rebuilds.
Pat
Dre, I have never meet a cylinder head that could not have valve seats replaced or pockets cut in the case of heads with parent metal sealing surface. Is this the case with your B7200?
If you have a good diesel machine shop in the area go talk to them. Some where there is a kit or seat that can be installed in you head. Get the recession correct, it has a significant impact to compression ratio. Jeff
If you have a good diesel machine shop in the area go talk to them. Some where there is a kit or seat that can be installed in you head. Get the recession correct, it has a significant impact to compression ratio. Jeff
Last edited: