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Valve seat replacement #498537
07/21/13 9:08 pm
07/21/13 9:08 pm
Joined: Aug 2012
Posts: 107
British Columbia Canada
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kootbiker Offline OP
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Anyone have a recommended place in North America for valve seat replacement on a T150 cylinder head.

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Re: Valve seat replacement [Re: kootbiker] #498539
07/21/13 9:16 pm
07/21/13 9:16 pm
Joined: Mar 2005
Posts: 10,083
Boston, Massachusetts
J
John Healy Online content
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John Healy  Online Content
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Posts: 10,083
Boston, Massachusetts
May I ask why you are replacing the valve seats?


Re: Valve seat replacement [Re: John Healy] #498541
07/21/13 9:25 pm
07/21/13 9:25 pm
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Posts: 107
British Columbia Canada
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kootbiker Offline OP
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British Columbia Canada
Because they are worn in to deep to cut. When cutting the 30 and the 45 degree angle the cutter will be cutting into the aluminum surrounding the seat and the valve will sit to deep into the head.

Re: Valve seat replacement [Re: kootbiker] #498559
07/21/13 11:56 pm
07/21/13 11:56 pm
Joined: Mar 2005
Posts: 10,083
Boston, Massachusetts
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John Healy Online content
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Posts: 10,083
Boston, Massachusetts
In that case, it would be a lot cheaper to find a donor head!!


Re: Valve seat replacement [Re: kootbiker] #498588
07/22/13 7:39 am
07/22/13 7:39 am
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Posts: 3,646
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DMadigan Offline
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I have used Martin Wells hardened seats to replace them. You do not have to remove all the old seat (they are reverse taper and cast in).

Re: Valve seat replacement [Re: DMadigan] #498636
07/22/13 4:16 pm
07/22/13 4:16 pm
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Posts: 107
British Columbia Canada
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kootbiker Offline OP
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Great link on the valve seats but I need someone capable of changing them out.

Re: Valve seat replacement [Re: kootbiker] #498639
07/22/13 4:44 pm
07/22/13 4:44 pm
Joined: Mar 2005
Posts: 10,083
Boston, Massachusetts
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John Healy Online content
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Boston, Massachusetts
kootbiker:

Unless you can do this yourself, setting up a Trident head with new valve seats and getting all of the seats cut, so you have the proper valve stem and fitted valve spring height correct, is a lot of work! Putting in the new seats is only half the job. Then you have to cut the seats so that you get the proper fitted spring height and rocker arm geometry.

Then there is the problems with these cast in iron seats where the original seats are not centered. Then when you cut the head for the new seat, you will have the new seat, half in the original cast iron seat and half in the aluminum head. This isn't going to be something you want. This means you will have to machine out what's left of the seat and weld up the head and cut a new hole for the new seat. $$$$$$$

As I said above, and it is good advice, unless your rolling in money, it would be cheaper, and you will get a better head in the end, to buy a good used head.

Call Keith Martin at Big D. He has heads 214 339-2285.


Re: Valve seat replacement [Re: kootbiker] #498647
07/22/13 5:37 pm
07/22/13 5:37 pm
Joined: Mar 2005
Posts: 10,083
Boston, Massachusetts
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John Healy Online content
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Kootbiker:

I have all the kit, including a dedicated fixture to mount the head in a Bridgeport and cut out the old seats to put new seats in Triumphs here from the days when we did service work.
I have done hundreds of these heads over the past 40 years.
I have all the kit to remove the old seats, and weld the head if required.
I have all the dimensions required to cut the seats so the the valve stem tip is properly located so the rocker arm geometry and fitted spring length is correct.
But if I could find a used Trident head that only needed a valve job, I would be hard pressed to refurbish a head that needed new seats. Even doing the job for myself it would be cheaper to find a donor head.


Re: Valve seat replacement [Re: John Healy] #498664
07/22/13 7:09 pm
07/22/13 7:09 pm
Joined: Aug 2012
Posts: 107
British Columbia Canada
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kootbiker Offline OP
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British Columbia Canada
Thanks for the info, I will try to find another head.

Re: Valve seat replacement [Re: kootbiker] #498707
07/23/13 1:12 am
07/23/13 1:12 am
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DMadigan Offline
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Unless, of course, you want larger valves and/or hardened seats. Finding a 40 year old head that has not been hacked by someone is not always easy. There is one for $385 on eBay with a dinged up chamber from a dropped valve, another for $320 but cannot see the seats and another for $230 that is nicely corroded with original copper based valve guides that you would probably want to replace.

Re: Valve seat replacement [Re: kootbiker] #498745
07/23/13 1:40 pm
07/23/13 1:40 pm
Joined: Mar 2005
Posts: 10,083
Boston, Massachusetts
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John Healy Online content
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Beryllium based valve guides.

A lot of the time your problem can be cured by cutting the existing seat to take an oversize valve. If possible, this is the least expensive course of action. Plus .060" valves are readily available for this head. If you are using stock pistons and camshafts there should be no clearance problems, but one should always check.

I did a little searching around and the going price for seat replacement seems to be $75.00 a seat. It was more for people who have experience with these types of heads. This didn't include replacing guides or additional welding or head work required. After all of the heating involved you will want to check and have the head straighten necessary. You don't want to just fly cut the head gasket surface to flatten it.

So with shipping you are approaching $500. Add labor to assemble, new valves, guides, springs and seals and you are getting close to $900.


Re: Valve seat replacement [Re: kootbiker] #498761
07/23/13 4:05 pm
07/23/13 4:05 pm
Joined: Nov 2009
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bon Offline
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Good info on cylinderheads on this site.

http://cylinderheadshop.com/

Re: Valve seat replacement [Re: bon] #498770
07/23/13 5:02 pm
07/23/13 5:02 pm
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Posts: 107
British Columbia Canada
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kootbiker Offline OP
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Thanks again for all the info. I'm considering kibblewhite oversized valves and guides which I have used in Honda 4 stroke motocross engines with good results. The seats in the T150 heads use only two angles 45 and 60. The way the valve seats are in the head doesn't allow for a 30 degree cut. I'm thinking I can save the head after cutting a couple of the worst seats.

Re: Valve seat replacement [Re: John Healy] #498966
07/25/13 8:44 am
07/25/13 8:44 am
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Posts: 591
Oregon
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Dana_twin Offline
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I have a question on this. I had the exhaust seats re-cut subsequent to a valve guide change. The re-cut caused the valves to "sink" or recess slightly deeper into the head. So the manual states the fitted length of the outer valve spring should be 1.229" however my actual outer spring (fitted) reading is 1.265". So the re-cut has added about .035" thou to the fitted spring length.... I assume that is acceptable?

Re: Valve seat replacement [Re: kootbiker] #498984
07/25/13 2:05 pm
07/25/13 2:05 pm
Joined: Mar 2005
Posts: 10,083
Boston, Massachusetts
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John Healy Online content
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Shim spring cup.


Re: Valve seat replacement [Re: kootbiker] #499122
07/26/13 3:47 pm
07/26/13 3:47 pm
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DMadigan Offline
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You should ckeck your springs for sag. Or you could use a spring gauge to measure the the required spring pack for the correct seat pressure. I made a simple one this way:

Re: Valve seat replacement [Re: kootbiker] #501181
08/10/13 7:29 pm
08/10/13 7:29 pm
Joined: Aug 2012
Posts: 591
Oregon
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Dana_twin Offline
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John thanks for the advice the shims are easily available and did the trick.

Dmadigan I see the spring pressure deal in your pic but guess I'm thick as don't see how that works.

Anyway with correct color code on the springs my main concern is the free length, and then the fitted length. I'd imagine for a racing bike to know the actual poundage pressure would be of interest.

Re: Valve seat replacement [Re: John Healy] #501201
08/10/13 9:18 pm
08/10/13 9:18 pm
Joined: Oct 2008
Posts: 4,934
Gnashville
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Originally Posted By: John Healy
You don't want to just fly cut the head gasket surface to flatten it.

Good advice there. Some moron "shaved" my head during a valve job once. I had to double up on the base gasket to get valve- to-piston clearance after that.


Stepping on others doesn't make you stand tall.

71 A65L "Zelda"
92 BMW K100rs "Gustav"
72 T120V cafe project "Mr. Jim"
Re: Valve seat replacement [Re: kootbiker] #501244
08/11/13 5:07 am
08/11/13 5:07 am
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DMadigan Offline
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Put the spring on the gauge piston and the whole thing in the vice jaws. Compress the spring to the desired force (piston is 1 sq in so the gauge reads direct) and measure the length of the spring. Make this the pack height when installing the springs.

Re: Valve seat replacement [Re: DMadigan] #516433
11/27/13 4:19 pm
11/27/13 4:19 pm
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Posts: 107
British Columbia Canada
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kootbiker Offline OP
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Jerry at TripleTecs reconditioned my Trident head with freshly ground seats,Kibblewhite valves and guides. Very nice job!



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