|
Valve guide wear? And valve job with new valves?
#1175799
02/10/12 04:16 AM
02/10/12 04:16 AM
|
Joined: Jun 2006
Posts: 5,161 CT
GTX MATT
OP
master
|
OP
master
Joined: Jun 2006
Posts: 5,161
CT
|
How do I determine if I need to have the guides done on my 906 heads? I assume there is a measurement to check the play? The play in the valves seems pretty equal in all directions, with the exhaust valves seeming a bit loose compared to the intakes. When I cover the guide at the top and pull the valve out the intakes generate a very loud pop when they come out of the guide, the exhausts aren't as loud but still make a pop. I would think the exhausts might have a looser tolerance.
Also, the seats and original valves look to be in very nice shape. I want to replace them with one piece stainless valves though. What is the opinion on new valves on an old seat? Obviously a valve job would be better but is it necessary? I have hand lapped new valves into old seats before on a late model turbo application(~20 psi) with 115k miles and the car ran flawlessly. I would think if it could hold up on a boosted application it shouldn't be a problem naturally aspirated.
Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street
|
|
|
Re: Valve guide wear? And valve job with new valves?
[Re: GTX MATT]
#1175800
02/10/12 05:28 AM
02/10/12 05:28 AM
|
Joined: Jan 2003
Posts: 1,996 s. e. pa.
calrobb2000
top fuel
|
top fuel
Joined: Jan 2003
Posts: 1,996
s. e. pa.
|
hi almost always is a good idea to install new guides in ex side and check the intakes for play . you got away with the laping on the turbo cars as they were newer and had hard valve seats for unleaded fuel which wear much slower than 906 soft cast seats . get new hardened seats installed in the 906 and do a 5 angle valve job and they will hold up way longer !
|
|
|
Re: Valve guide wear? And valve job with new valves?
[Re: calrobb2000]
#1175801
02/10/12 10:43 AM
02/10/12 10:43 AM
|
Joined: Aug 2005
Posts: 4,799 ILL
MLR426
master
|
master
Joined: Aug 2005
Posts: 4,799
ILL
|
Are you planning on keeping the engine your installing the heads on ?? If you are planning on keeping it wouldn't you be much happier knowing you have a great set of rebuilt heads on the engine rather than just a lap job to get you through ? Do it right and have a good valve job done that correctly locates the valve seat wigth on the valve face for better seating and performance. If your changing out the valves they will vary in diameter compared to your existing valves, so valve guide I.D.'s will need to be checked. Intake stem to guide clearance should be .0015 and exhaust .0015-.002. Your saying you hear a loud pop when you remove the valve ? Is that being done with oil on the stem or a dry valve ? With oil on any stem it will pop but that isn't a good test of valve guide condition. With experience over time a rebuilder can judge the condition by feel.
logan426
Last edited by Logan426; 02/10/12 10:58 AM.
|
|
|
Re: Valve guide wear? And valve job with new valves?
[Re: dogdays]
#1175804
02/10/12 04:12 PM
02/10/12 04:12 PM
|
Joined: Aug 2005
Posts: 4,799 ILL
MLR426
master
|
master
Joined: Aug 2005
Posts: 4,799
ILL
|
Take your heads to a good shop near you and have the guides checked out or replaced before putting in new valves and have a valve job done. I also have the replacement bronze guide liner tooling in my Radiac Abrasive catalog and web-site under Automotive aftermarket at www.radiac.com but you need to have experience when boring, installing and sizing valve guides. logan426
|
|
|
Re: Valve guide wear? And valve job with new valves?
[Re: MLR426]
#1175805
02/10/12 08:56 PM
02/10/12 08:56 PM
|
Joined: Jun 2006
Posts: 5,161 CT
GTX MATT
OP
master
|
OP
master
Joined: Jun 2006
Posts: 5,161
CT
|
The heads would be getting replaced not too far down the road, so I'm just trying to keep investment in them minimum. If I have to sink much into them I will be much too tempted to buy aluminum, but at this point I'm just trying to get the engine back together and running if you get my drift.
Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street
|
|
|
|
|
|