mokicruz
Senior Member
Posts: 815
Loc: Montana
Reg: 12-11-04
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06-29-12 05:29 PM - Post#2242760
I have ported Gen VI heads worn out valve guides. I want to install press 11/32 in Manganese Bronze Guides for a set of Stainless 1.88 x 11/32 stem diameter +.100 length I have. Local parts houses don't have Manganese Bronze universal Valve guides .620 O.D. x .344 I.D. x 2.6+ so they try to sell .344 x 2.75 K-Line bronze bullets and new press in cast iron guides to install smaller stem valves. The .3685 max bore size 11/32 liners are to smallfor .375 cast guide bores. They can order .502 x .344 I.D. x 2.60 Manganese Bronze Guides but boring the original guides to .500 will only leave .0575 wall because the 3/8 Cast Iron Guides are .615 O.D x 2.65 long. Does anyone know where to find Universal Manganese Bronze Valve Guides .620 O.D. x .344 I.D. x 2.6+ Long? Will the Manganese Bronze Valve Guide need more interference than .002 like cast iron guides have due to the lower expansion value from heat of Manganese Bronze.
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Allan In NE
Contributor
Posts: 904
Reg: 12-27-11
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06-30-12 03:49 AM - Post#2242855
In response to mokicruz
I really like the bronze guides because they are tough, but like you say, the machinist really has to watch what he's doing when he cut's 'em to size.
.002" is a Gwad's plenty on the oil clearance.
Allan
| Lifelong GM automatic transmission specialist |
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motorman
Super Senior Member
Posts: 5023
Loc: south western pa.
Reg: 01-25-00
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06-30-12 08:44 AM - Post#2242921
In response to mokicruz
I have ported Gen VI heads worn out valve guides. I want to install press 11/32 in Manganese Bronze Guides for a set of Stainless 1.88 x 11/32 stem diameter +.100 length I have. Local parts houses don't have Manganese Bronze universal Valve guides .620 O.D. x .344 I.D. x 2.6+ so they try to sell .344 x 2.75 K-Line bronze bullets and new press in cast iron guides to install smaller stem valves. The .3685 max bore size 11/32 liners are to smallfor .375 cast guide bores. They can order .502 x .344 I.D. x 2.60 Manganese Bronze Guides but boring the original guides to .500 will only leave .0575 wall because the 3/8 Cast Iron Guides are .615 O.D x 2.65 long. Does anyone know where to find Universal Manganese Bronze Valve Guides .620 O.D. x .344 I.D. x 2.6+ Long? Will the Manganese Bronze Valve Guide need more interference than .002 like cast iron guides have due to the lower expansion value from heat of Manganese Bronze.
you have to be careful doing this because the stock GM BBC heads had the bore put in the guides after the guides were installed. this means that if you install new guides with the bore concentric with the outside diameter you can be off center to the valve seat and need a lot of grinding to make it work. i went thru this with GM aluminum beads and after that is just use guide liners.
| retired race engine builder,former NASCAR tech inspector. new corvettes owned 1959,1962,1963,1964,1965, 1966,1997,1999,2002,2005, 2008 plus 30+ other chevy cars and trucks along the way |
Edited by motorman on 06-30-12 08:45 AM. Reason for edit: No reason given.
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mokicruz
Senior Member
Posts: 815
Loc: Montana
Reg: 12-11-04
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07-01-12 12:35 AM - Post#2243195
In response to motorman
I realize the aluminum heads aren't concentric so we used to add liners with a for jaw chuck on the lathe. after installing micing an unfinished seat was necessary to make sure it was close to the original Valve Center to center. I cut two of the guides in half that I pushed out of my heads. They are concentric even though they are oval shaped a little even in the center. With all the BBC Propane engines in Trucks it's odd there isn't a parts supplier selling better Valve Guides. Cast guides live extremely well with Stallite valves but with stainless valves they don't last. Eve Phosphorus Bronze Guides can wear out in 10,000 miles leaving off the oil seals. I can't be the only one who wants a faster and easier way to install Guides than boring guides out.
I wasn't talking about valve stem to guide clearance of .002 I was referring to the size to press a guide into being smaller than the Valve Guide .002 . I'll set the stem clearance at .0015 with a reamer. A .344 Guide has only .001 stem clearance. After pressing Guides in they usually distort a small amount and reaming .0005 trues up any tight spots
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motorman
Super Senior Member
Posts: 5023
Loc: south western pa.
Reg: 01-25-00
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07-01-12 11:44 AM - Post#2243334
In response to mokicruz
I realize the aluminum heads aren't concentric so we used to add liners with a for jaw chuck on the lathe. after installing micing an unfinished seat was necessary to make sure it was close to the original Valve Center to center. I cut two of the guides in half that I pushed out of my heads. They are concentric even though they are oval shaped a little even in the center. With all the BBC Propane engines in Trucks it's odd there isn't a parts supplier selling better Valve Guides. Cast guides live extremely well with Stallite valves but with stainless valves they don't last. Eve Phosphorus Bronze Guides can wear out in 10,000 miles leaving off the oil seals. I can't be the only one who wants a faster and easier way to install Guides than boring guides out.
I wasn't talking about valve stem to guide clearance of .002 I was referring to the size to press a guide into being smaller than the Valve Guide .002 . I'll set the stem clearance at .0015 with a reamer. A .344 Guide has only .001 stem clearance. After pressing Guides in they usually distort a small amount and reaming .0005 trues up any tight spots
i have found what wears the guides is not replacing the valves when replacing the guides or guide liners as the surface of the stem get rough that can only be seen with a microscrope. once guide show wear i never use the valves over. i have found spiral wound guide liners last the longest because the grooves hold the oil for lube.
| retired race engine builder,former NASCAR tech inspector. new corvettes owned 1959,1962,1963,1964,1965, 1966,1997,1999,2002,2005, 2008 plus 30+ other chevy cars and trucks along the way |
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 Rick_L
Honored Member
Posts: 24731
Loc: Katy, Tx, USA
Reg: 07-06-00
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07-01-12 12:45 PM - Post#2243351
In response to motorman
Is there enough valve guide left to just use a spriral wound insert to renew the guide? Seems to me that's the most straightforward way to do this, and it should have decent life.
Goodson in Minnesota sells lots of different valve guides as well as the installation tools. They have a website, you might want to google it.
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mokicruz
Senior Member
Posts: 815
Loc: Montana
Reg: 12-11-04
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07-02-12 06:01 AM - Post#2243586
In response to Rick_L
After pushing them all out and cutting two in half to mic spending twenty bucks on new Cast Iron Guides then doing the work on them in the lathe would be the most economic way to go.
Valve Train Manufacturing makes Manganese Bronze Replacement Guides but the head and Guide will need to be reamed to fit .341 I.D. X .6210 O.D. 2.565 Long. I just have to find a vendor for them. They are part number VG 11830/00. The /00 stands for .6210 so /30 would be .030 over since they can be ordered in multiples of .010 over sized. Now I guess call Eclers to see were to start looking if they don't carry them.
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mokicruz
Senior Member
Posts: 815
Loc: Montana
Reg: 12-11-04
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07-02-12 07:08 AM - Post#2243594
In response to motorman
Thanks. I have an SZ Stereo Olympus microscope with objective lenses 10x, 20 and, 40x to measure Cut depths and wear patterns. Stainless and Bronze won't polish to a degree as high as Cast Iron. Stallite is extremely hard so working in a Cast Iron Guide with the soft but highly polished sufface and controlable heat will avoid wear longer than Stainless against Manganese Bronze. Since side pressure is the main culprit in Guide wear geometery of the rockers covering as much of the center of the valve stem through a cycle and a seat being true to the guide bore. With high lift cams and 1.8 rockers the stems load surface is wider than stock valve train. Not all valve surface machines center the valve head to the stem so the valve when seated with compound corrects that issue. Valves seated with a hammer presses against the Guides till they wear in to the same orbit as the guide bore. I don't run seals on the Exhaust valves for added lubrication.
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mokicruz
Senior Member
Posts: 815
Loc: Montana
Reg: 12-11-04
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07-06-12 08:43 PM - Post#2245311
In response to mokicruz
The guides are $5.99 each and UPS is about $14.00 .
http://www.sivalves.com/ocdomestic_vguides_ch evv8....
This saved a lot of time and money.
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