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| 1.77" intake valves https://www.slantsix.org/forum/viewtopic.php?t=54840 |
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| Author: | SlantSteve [ Wed Mar 12, 2014 4:54 pm ] |
| Post subject: | 1.77" intake valves |
Hi all, I'm looking at buying a head that is sitting in a machine shop. It's been machined for 1.77 intakes and has hardened exhaust seats fitted. I was curious just how these larger valves flow when run with a 3.445" bore? By the looks of the chamber there would be a lot of shrouding,obviously some can be relieved in the chamber......is it worth considering? It's comes with new valves as well and is a good price. Cheers |
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| Author: | DadTruck [ Wed Mar 12, 2014 6:08 pm ] |
| Post subject: | |
Quote: comes with new valves as well and is a good price.
the question is ?shrouding is always an issue,,along with relieving the chamber, dependent upon rod length and piston compression height,, you can add some additional relief at the top of the bore. |
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| Author: | sandy in BC [ Wed Mar 12, 2014 7:04 pm ] |
| Post subject: | |
I had to relieve around 1.72 valves. ...I dont know if there is even room to radius around 1.77.... Unless this head is stupid cheap...pass on it. It willl cost you more than you can get. |
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| Author: | SlantSteve [ Wed Mar 12, 2014 7:11 pm ] |
| Post subject: | |
Thanks Sandy,I appreciate your reply. It's certainly isn't stupid cheap,I might see if I can take it and do a dry assembly to see what it looks like when fitted to a block... I'm sure I've read guys were running this sized valve,probably on big bore engines I am guessing. The build is a long rod setup,so relieving the bores isn't really an option. Thanks again,it was worth asking! |
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| Author: | slantzilla [ Wed Mar 12, 2014 11:34 pm ] |
| Post subject: | |
1.77's are really more suited to a 3.500" bore, and even then they are marginal unless you are going to use a ton of camshaft. |
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| Author: | Exner Geek [ Thu Mar 13, 2014 2:36 pm ] |
| Post subject: | |
I have used 1.78 valves in 2 engines with bores 3.44 or smaller with good results. They would probably work even better with a larger bore but I don't think anybody has proven that a smaller valve flows better overall. Even though a portion of the valve is shrouded most of it is not and your curtain area goes up fast with valve diameter. Just my 2 cents. |
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| Author: | Reed [ Thu Mar 13, 2014 2:50 pm ] |
| Post subject: | |
It hasn't been mentioned if the exhaust valves are still stock or if there are o/s exhaust valves too. |
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| Author: | SlantSteve [ Fri Mar 14, 2014 1:17 am ] |
| Post subject: | |
Quote: It hasn't been mentioned if the exhaust valves are still stock or if there are o/s exhaust valves too.
Sorry,should have mentioned,they are stock sized ex valves with hardened seats.
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