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[email protected] Samba Member
Joined: June 24, 2015 Posts: 718 Location: Rialto. CA
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Posted: Fri Sep 24, 2021 2:46 pm Post subject: Valve guides |
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Would cast iron valve guides be a good thing or a bad idea ... |
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petrol punk Samba Member
Joined: August 21, 2007 Posts: 974 Location: Las Vegas, NV
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Posted: Fri Sep 24, 2021 2:49 pm Post subject: Re: Valve guides |
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Aluminum has a thermal expansion coefficient of ~13, bronze roughly ~10, and cast iron about ~6. So I think there would be cause for concern that the valve guides might loosen up at high head temps. _________________ 36hp '56 European DeLuxe oval, '70 bug 1835cc dual 36DRLA, and a '98 4x4 5spd single cab Tacoma |
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[email protected] Samba Member
Joined: June 24, 2015 Posts: 718 Location: Rialto. CA
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Posted: Fri Sep 24, 2021 3:12 pm Post subject: Re: Valve guides |
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I notice on my honda 400t cylinder heads had 3 valves per cylinder and used cast iron valve guides...so I was just curious if they could be done to a 36hp head ...it was just a thought ...bored in life right now ..to much thinking you can say lol ... |
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AirCooledClassics Samba Member
Joined: August 20, 2004 Posts: 294 Location: Saskatoon, Sk Canada
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[email protected] Samba Member
Joined: June 24, 2015 Posts: 718 Location: Rialto. CA
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Posted: Sun Sep 26, 2021 8:23 pm Post subject: Re: Valve guides |
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I heard they last way way longer than a bronze ones for street use but not so good for racing motors .... |
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RWK Samba Member
Joined: June 24, 2009 Posts: 1347 Location: S.W. MI
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Posted: Mon Sep 27, 2021 5:13 am Post subject: Re: Valve guides |
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Your Honda guides are most likely powdered or sintered metal, all kinds of thing are made this way now, very accurate and needs little machining after it is made (pressed).
I would stick with a good alum. or tin bronze for valve guides. _________________ 73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
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RWK Samba Member
Joined: June 24, 2009 Posts: 1347 Location: S.W. MI
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Posted: Mon Sep 27, 2021 5:41 am Post subject: Re: Valve guides |
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Also on a side note, IMHO some after market heads have brass valve guides, I assume because of cost and ease of machining, see pic, about 90% certain these heads have brass guides, see also stock replacement guide and good grade of bronze bar stock I make guides from. Brass has a machinability rating of over a 100% compared with the steel standard, bronze's range from 20% to 80%.
Point is that most anything will work, just how long it last's is the key.
_________________ 73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
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gears Samba Member
Joined: October 28, 2002 Posts: 4391 Location: Tamarack, Bend, Kailua
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Posted: Tue Oct 19, 2021 4:17 pm Post subject: Re: Valve guides |
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VW cast iron guides were distributed to shops in the early '70s (EMPI), both 36hp and 40hp style. I still have a few 36 somewhere. _________________ aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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RWK Samba Member
Joined: June 24, 2009 Posts: 1347 Location: S.W. MI
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Posted: Wed Oct 20, 2021 5:35 am Post subject: Re: Valve guides |
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Here's some pics of some cast iron guides, 10mm OD 7mm ID, the drawer they are in is marked
111-101-417-B-C1 I didn't mark them so not sure of accuracy.
_________________ 73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
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[email protected] Samba Member
Joined: June 24, 2015 Posts: 718 Location: Rialto. CA
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Posted: Wed Oct 20, 2021 1:16 pm Post subject: Re: Valve guides |
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RWK wrote: |
Here's some pics of some cast iron guides, 10mm OD 7mm ID, the drawer they are in is marked
111-101-417-B-C1 I didn't mark them so not sure of accuracy.
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Nice ....yeah I knew I seen some heads with them in the past but thought my eyes were playing with me ...and was thinking what would be the down side of them ..all I know by what I've read is that cast iron valve guides last longer for a street engine/use but not good for racing engines and bronze ones are good for racing so they have there up and downs .... |
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