Rookie modern exhaust valve question

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Model T Ford Forum: Forum 2017: Rookie modern exhaust valve question
Top of pagePrevious messageNext messageBottom of page Link to this message  By Jason Harms - Sacramento County, CA on Wednesday, March 22, 2017 - 07:58 pm:

What specific Chevy 350 exhaust valves should I buy?
Is it ok to buy the cheapest exhaust valves or should I spend money on name brand exhaust valves?

Went to the auto parts store to buy Chevy 350 exhaust valves for T.
They would only look up an exhaust valve if I would tell them year and specifics of Chevy 350.
When I asked if they could just look up 350 exhaust valves they couldn't.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jason Harms - Sacramento County, CA on Wednesday, March 22, 2017 - 08:03 pm:

Is a Chevy exhaust valve face the angle I'll need, or do I need to have the face cut to a 45 degree?
Is the length of the stem good, or will I need to cut the stem shorter?
I have adjustable tappets.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stanley L Brown Drury, MA on Wednesday, March 22, 2017 - 08:23 pm:

Jason in the March/April Vintage Ford Magazine on page 23 Mike Vaughn specifies 1985 Chevy 350 exhaust valves and the spring retainer from Ford 8N tractor part number 8BA6514. His email is TechEditor@mtfca.com


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stanley L Brown Drury, MA on Wednesday, March 22, 2017 - 08:33 pm:

I should add that he says to purchase a .030 oversized reamer from the Model T vendors and grind fresh 45 degree seats and adjustable tappets are needed because the chevy valves are shorter.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Vaughn - Lincoln, NE on Wednesday, March 22, 2017 - 11:24 pm:

Hi Jason

You are correct. The guys in the parts store have to be able to look up a model and Year in their computer. I ask for 1985 Chevrolet Silverado 1500 350 CI exhaust valves. The least expensive valves work great. The Chevy valves are a little shorter so adjustable lifters are required. Original valves are .312" diameter the Chevy valves are .342" so the guides need to be reamed .030 oversized. The Chevy valve face is 45 degrees.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Wednesday, March 22, 2017 - 11:34 pm:

Are they better than the stainless valves sold by the parts dealers?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Pat Kelly Montana on Thursday, March 23, 2017 - 12:44 am:

I just did this job last winter as Stanley explains. Bought a reamer and ground the valves to 45*. I used Chevy keepers also. My son gave me eight used valves I ground and it was a clean install. I also made a guide for the reamer to center it with the valve seat. This info is also on the forum.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Vaughn - Lincoln, NE on Thursday, March 23, 2017 - 12:58 am:

Steve the Chevy valves are stainless.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Thursday, March 23, 2017 - 05:11 am:

Yes. How are they better?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Thursday, March 23, 2017 - 06:07 am:

They have modern style keepers instead of the pins used on standard T valves. That's an improvement, though not really necessary if you have good quality pins.
(There have been bad batches of pins that won't last sold in the past, but the current pins from the vendors seems OK in my experience.)


Top of pagePrevious messageNext messageBottom of page Link to this message  By G.R.Cheshire on Thursday, March 23, 2017 - 07:21 am:

Steve if you are like me I have about 20 or 30 used Exhaust valves I can clean them up and they are Free! also if you have a friend in an engine re-build shop when they do a head they usually replace all of the valves but not all of them are bad!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Wilson - Omaha NE on Thursday, March 23, 2017 - 08:26 am:

Ron's Machine Shop http://www.ronsmachineshop.net/Home.html will sell you a kit with 8 Chevy valves, keepers, retainers and springs for $140. They also have hardened valve seats to go with them for another $35


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Vaughn - Lincoln, NE on Thursday, March 23, 2017 - 08:30 am:

Or you can buy all the parts yourself for around $60.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Vaughn - Lincoln, NE on Thursday, March 23, 2017 - 08:56 am:

A quick search on eBay finds this set of valves for less than $30 shipping included: https://www.ebay.com/itm/151859378211
And here are the 8N tractor retainers for just over $20 including shipping: https://www.ebay.com/itm/331509215970


Top of pagePrevious messageNext messageBottom of page Link to this message  By Paul Vitko on Thursday, March 23, 2017 - 09:29 am:

Had a seven pound box of used ones given to me---been running them in all T engines for years without issues.


Top of pagePrevious messageNext messageBottom of page Link to this message  By keith g barrier Savannah Tn. on Thursday, March 23, 2017 - 03:51 pm:

You also have to use adjustable lifters with the chevy valves which is - in my opinion. There are ford valves(351?) that will work with the standard ford lifters that can also be drilled for the pins if you want to use them. KGB


Top of pagePrevious messageNext messageBottom of page Link to this message  By bob middleton on Thursday, March 23, 2017 - 07:11 pm:

Heads bigger but the keepers seem be better or more secure lock.
Adjustable lifters are required


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Vaughn - Lincoln, NE on Thursday, March 23, 2017 - 07:57 pm:

One of the things I like about using this combination is that the valve springs stay level on the retainers. The pin system causes the retainers to pivot on the pin when compressed this is what causes the retainers to wear through. The tractor retainers fit the Model T spring perfectly and keep the spring level on the retainers. The first picture is of the original style valve system and the second picture is of the system I have described.




Top of pagePrevious messageNext messageBottom of page Link to this message  By Roar Sand on Friday, March 24, 2017 - 08:51 pm:

I see the term "STAINLESS" thrown around a lot when people talk about engine valves. Stainless basically means the material will not rust, but it says nothing about the material properties for use in engine valves. There must be a thousand , or may be more, combinations of alloys that can make steel stainless, but that does not necessarily mean that it is suitable for the use in engine valves.
There are basically two types of stainless steel; martnsitic and austenitic. Martensitics were once used in exhaust valves, but their use shifted to use in heavy duty intake valves, as engine performance and temperatures increased. "Silchrome XB" is an example of such a material. Martensitic stainless steel will stick to a magnet, and it can be heat-treated in similar fashion to carbon steel.
Austenitic stainless steel does not stick to a magnet and does not respond to traditional heat treat. Other such alloys may have been developed since I retired, but as an example, "21-4N" was a popular material in this category a number of years ago. It has good high temperature strength and good lead oxide corrosion resistance, which was very important before they took the tetra-ethyl-lead out of gasoline. The austenitic exhaust valves often had a carbon steel stem inertia welded to the forged stainless head, or a carbon steel disc projection welded to the tip. This would provide heat treatability, for higher hardness and wear resistance, in the lock grooves and tip. The magnet would stick to the stem or tip, but not to the head.
Beyond the austenitic stainless steel alloys are the "superalloys". These are used in extreme heavy duty applications and of no interest in this context. When the list of alloying ingredients end with "remainder Nickel or Chrome", we are talking about superalloys.
f.w.i.w.
Roar


Top of pagePrevious messageNext messageBottom of page Link to this message  By Duey_C on Friday, March 24, 2017 - 09:34 pm:

I procured some 3/8" stainless from work years ago to use for old snowmobile ski wear rods and welded a 1/4" bolt on for holding to the ski. They sucked.
A buddy said "You can't weld on stainless." I told him that "I just did."

My son and I have actually discussed (several times) welding a knob on the end of old Chevy valves for use with stock Ford lifters to reduce the gap so we could grind the stem end to specs. He has a good supply. Bah, it'd prob'y twist the tar out of the stems touching them with a wire feed. Or not.
Better? No. A means to an end? Yep. We're cheap (read frugal). Too cheap to get some adjustable lifters that some guys don't like. :-)
Like days of old, we use what's on hand if it works good.
Back to the shop


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