h2odrx
Anti-O
ok if small cracks are in the seats and it pressure tests ok what will be the problems down the road?
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Intake seat cracks?
- Thread starter h2odrx
- Start date
sle2115
NRA LIFE MEMBER
I appears to me that the crack is only isolated to the seat. If that is the case, the seat can be cut and a new seat put in. The new seat would be approximately 1/8 inch thick from the inside or hole of the seat to the outside. Maybe the pictures aren't showing the crack extending past the seat.
Really kind of weird in that the intake usually doesn't crack as it is cooled by the air coming in. Usually a crack like that is caused by heat and the exhaust sees the most heat.
Really kind of weird in that the intake usually doesn't crack as it is cooled by the air coming in. Usually a crack like that is caused by heat and the exhaust sees the most heat.
h2odrx
Anti-O
sle2115 said:
Yes it is weird, and that is what the shop was saying to me when i went to picked them up, he would not put a new seat in due to the chance of cutting the water jacket? if it holds pressure can i run it like it is?
of course there is an IH shop 30 min from me so i might take the day off and go see them next week?
sle2115
NRA LIFE MEMBER
h2odrx said:
Yes, you could but the crack will probably continue and eventually reach water, that may be in a year or it might be 20 years, who knows. From a machinist point of view, I would approach it like this - I will cut them, but fear the worst, I will install new seats and pressure test the heads to make sure I didn't cut into the water jacket.
h2odrx
Anti-O
thanks,
well i guess i load the heads up and stop by the big truck shop on monday, they also have a machine shop so i've heard? i guess i'll take my injectors too, might just take a IP or two and make sure they are ok? i sure hope it works out and cheap!!
well i guess i load the heads up and stop by the big truck shop on monday, they also have a machine shop so i've heard? i guess i'll take my injectors too, might just take a IP or two and make sure they are ok? i sure hope it works out and cheap!!
EvergreenRanch
In Transition
i know i would be paranoid as hell to know there was a ticking time bomb in my engine.......for your peace of mind if nothing else, fix it the right way...whatever that may be.
I had a cracked seat on one of the Moose Truck heads, and the machine shop put a new one in without nary a concern. When I got my heads back, the guy told me "It had a cracked valve seat, so we put a new one in." I just said "OK. Great. Thanks." I always assumed after that that they were pressed in and replaceable. So you mean they aren't?
h2odrx
Anti-O
mel,
i guess they mill them out, i took the heads to the guy that does the heavy duty trucks in my area and he was saying the same thing as my local guy. the early castings 84-85? where thin water jacket at intake seats if he cut them out and then tried to press a new one in it might not work?
I took them back to the local guy and he is going to pressure test them and if they hold he will do a valve job and i'm going to run it? I just seem to think as long as it holds 40psi and i keep my temps in check i should have no problems, then take my extra block and do a complete rebuild so i have a stand by motor!!
i guess they mill them out, i took the heads to the guy that does the heavy duty trucks in my area and he was saying the same thing as my local guy. the early castings 84-85? where thin water jacket at intake seats if he cut them out and then tried to press a new one in it might not work?
I took them back to the local guy and he is going to pressure test them and if they hold he will do a valve job and i'm going to run it? I just seem to think as long as it holds 40psi and i keep my temps in check i should have no problems, then take my extra block and do a complete rebuild so i have a stand by motor!!
Valve Seat Insert Removal
The intake and exhaust valve ports in the cylinder head are equipped with removable valve seat inserts. Remove and replace inserts that are cracked or loose, or that show excessive wear. Use the following procedure to replace valve seat inserts:
A. Use Valve Seat Puller D84L-6084-A or equivalent to remove damaged or loose seats. Position remover collet into insert and rotate collet nut clockwise to expand collet jaws under the lip of the seat insert.
B. Remove insert with Slide Hammer D79P-100-A or equivalent.
NOTE:
Valve seat inserts are available for service. There are four sizes: standard, 0.254, 0.508 and 0.762mm (0.010, 0.020 and 0.030 inch) oversize. Refer to Specifications at the rear of this section.
NOTE:
If an oversize valve seat insert is required, the cylinder head should be sent out to a qualified machine shop for insert counterbore procedures. Counterbore dimensions are shown below. Make sure that the valve guides are clean and within specifications as they will be used for the pilot.
Valve Seat Insert Installation
A. Chill service valve seat insert in dry ice for approximately two hours prior to installation.
WARNING:
DO NOT HANDLE VALVE GUIDES OR DRY ICE. DISPOSE OF DRY ICE IN ACCORDANCE WITH SAFETY AND EPA REGULATIONS.
B. Install the inserts into the head using Valve Seat Replacer T87T-6084-A (exhaust), T86T-6084-A (intake) and a hammer.
Valve Seat Refacing
1. Measure the width of the valve seats and reface the seats if they do not meet the specifications.
2. Measure the runout of the valve seat with a suitable gauge. If valve seat runout exceeds 0.063mm (0.0025 inch), reface the seat.
NOTE:
Reface the valve seat and face at the same time so the finished measurements correspond to specifications.
NOTE:
Valve seat refacing stones used successfully are: Sioux Tools No. K-491, Course cut and K-421, Fine cut.
Remove only enough metal from the seat to clean up the pits and grooves, or to correct the seat runout. After refacing, the seat should measure to specifications. If the refaced seat exceeds the specified width, narrow the seat by removing stock from the top or bottom of the seat. If the seat measures less than this width, widen the seat.
3. Rotate a new or refaced valve in the seat using Prussian Blue or equivalent. Evaluate seat width and valve overhang by the transfer of Blue to the valve face. If the Blue is transferred to the valve face outside of seat width and overhang limits, raise or lower the seat.
4. Check the valve recession using a dial indicator. Valve recession must be 0.84-1.32mm (0.033-0.052 inch). Failure to maintain this dimension may cause the valves to strike the pistons.
NOTE:
Valve recession is the distance the valve sits beneath the surface of the head.
5. Exhaust Valves: Lower the exhaust valve seat by removing metal from the top of the seat with a 30 degree grinding wheel. Raise the valve seat by removing metal from the bottom of the seat with a 60 degree grinding wheel.
6. Intake Valves: Lower the valve seat by removing stock from the top of the seat with a 15 degree grinding wheel. Raise the seat by removing stock from the bottom of the seat with a 45 degree grinding wheel.
The intake and exhaust valve ports in the cylinder head are equipped with removable valve seat inserts. Remove and replace inserts that are cracked or loose, or that show excessive wear. Use the following procedure to replace valve seat inserts:
A. Use Valve Seat Puller D84L-6084-A or equivalent to remove damaged or loose seats. Position remover collet into insert and rotate collet nut clockwise to expand collet jaws under the lip of the seat insert.
B. Remove insert with Slide Hammer D79P-100-A or equivalent.
NOTE:
Valve seat inserts are available for service. There are four sizes: standard, 0.254, 0.508 and 0.762mm (0.010, 0.020 and 0.030 inch) oversize. Refer to Specifications at the rear of this section.
NOTE:
If an oversize valve seat insert is required, the cylinder head should be sent out to a qualified machine shop for insert counterbore procedures. Counterbore dimensions are shown below. Make sure that the valve guides are clean and within specifications as they will be used for the pilot.
Valve Seat Insert Installation
A. Chill service valve seat insert in dry ice for approximately two hours prior to installation.
WARNING:
DO NOT HANDLE VALVE GUIDES OR DRY ICE. DISPOSE OF DRY ICE IN ACCORDANCE WITH SAFETY AND EPA REGULATIONS.
B. Install the inserts into the head using Valve Seat Replacer T87T-6084-A (exhaust), T86T-6084-A (intake) and a hammer.
Valve Seat Refacing
1. Measure the width of the valve seats and reface the seats if they do not meet the specifications.
2. Measure the runout of the valve seat with a suitable gauge. If valve seat runout exceeds 0.063mm (0.0025 inch), reface the seat.
NOTE:
Reface the valve seat and face at the same time so the finished measurements correspond to specifications.
NOTE:
Valve seat refacing stones used successfully are: Sioux Tools No. K-491, Course cut and K-421, Fine cut.
Remove only enough metal from the seat to clean up the pits and grooves, or to correct the seat runout. After refacing, the seat should measure to specifications. If the refaced seat exceeds the specified width, narrow the seat by removing stock from the top or bottom of the seat. If the seat measures less than this width, widen the seat.
3. Rotate a new or refaced valve in the seat using Prussian Blue or equivalent. Evaluate seat width and valve overhang by the transfer of Blue to the valve face. If the Blue is transferred to the valve face outside of seat width and overhang limits, raise or lower the seat.
4. Check the valve recession using a dial indicator. Valve recession must be 0.84-1.32mm (0.033-0.052 inch). Failure to maintain this dimension may cause the valves to strike the pistons.
NOTE:
Valve recession is the distance the valve sits beneath the surface of the head.
5. Exhaust Valves: Lower the exhaust valve seat by removing metal from the top of the seat with a 30 degree grinding wheel. Raise the valve seat by removing metal from the bottom of the seat with a 60 degree grinding wheel.
6. Intake Valves: Lower the valve seat by removing stock from the top of the seat with a 15 degree grinding wheel. Raise the seat by removing stock from the bottom of the seat with a 45 degree grinding wheel.
another way to remove the valve seat is to use an arc welder to run a small bead around the valve seat, carefully so as not to touch the head itself . let it cool and the seat will fall out. IH used to have a tool that was piloted by the valve guide and was tapped with a small hammer to lightly peen the metal around the out side circumference of the seat insert to further anchor the insert. it appearers that is not used in this application. run that cracked seat and it will eventually fall out. sooner or sooner and when it do de valve wont close and it just gets better and better from there
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ttman4
Last Nite's Dream..
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.....I can just see it now!......everything down hill from here......obinella said:
h2odrx
Anti-O
SOOO... this is not something i can do at my house????? 
h2odrx
Anti-O
Good news!!!!!!
The shop called me last week to say the heads are ready!!!
It seems the hairline cracks in the intake are not a problem, the intake are part of the casting and not inserts.. so they can't fall off!! He said " money well spent on these heads!" should not see a problem!
So total bill for heads and valve job plus head set and intake $415.00 now for the studs and i can get this baby back on the road for the 07 rally!!!!!:Sly
The shop called me last week to say the heads are ready!!!
It seems the hairline cracks in the intake are not a problem, the intake are part of the casting and not inserts.. so they can't fall off!! He said " money well spent on these heads!" should not see a problem!
So total bill for heads and valve job plus head set and intake $415.00 now for the studs and i can get this baby back on the road for the 07 rally!!!!!:Sly
sle2115
NRA LIFE MEMBER
Personally, I would have rather it been a press in seat, then it could be fixed. In many heads, the crack isn't an issue, in others, it will eventually get to water, your guess as to which you have!
