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| | | | Joined: Feb 2000 Posts: 69 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 69 | My manual says .006 on the intakes of my 261 Chevy engine. Does anyone have experience with this setting? Seems a little tight; would it be better to set them at .008 - .010?
ron | | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | ron,
I have always used .006" on 261 intake valves, as per the 1954-1960 Shop Manuals (there was no 1961 Truck Shop manual and I cannot find my 1962 manual).
The 261 exhaust valves are set looser than a 235, .018"-.020" (depending on the size of the truck and the year of the Shop Manual or the Owner's Manual).
Tim | | | | | Joined: Aug 2001 Posts: 1,299 'Bolter | | 'Bolter Joined: Aug 2001 Posts: 1,299 | The exhaust have a bigger gap due to more exposure to heat. Also, valve head cooling comes from transferring heat to the valve seat in the head. It is more likely to cause trouble having exhaust valves too tight than the intakes. Too tight an intake will cause a compression loss. Too tight and exhaust valve will cause the exhaust valve and seat to "burn" | | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | I,ve always set trucks at .008 & cars at .006.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Aug 2005 Posts: 1,186 Shop Shark | | Shop Shark Joined: Aug 2005 Posts: 1,186 | I had an old friend who was a mechanic at Downtown Chevrolet in Minneapolis from the '40s-'60's. He told me to always set the valves at .008 and .010. He said you would never burn a valve and their would be no noticible difference in performance. Don't yell at me.....this is what he said. 
Bruce | | | | | Joined: Aug 2001 Posts: 1,299 'Bolter | | 'Bolter Joined: Aug 2001 Posts: 1,299 | I was taught .006 and .016. My Isky cam called for .015 on both but it is pretty noisy at that. | | | | | Joined: Feb 2000 Posts: 69 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 69 | Sounds good, I think I'll reset them to .08. | | | | | Joined: Jul 2004 Posts: 5,708 'Bolter | | 'Bolter Joined: Jul 2004 Posts: 5,708 | uncleb, They're going to be real noisy at .080...better try for .008.  Stuart | | | | | Joined: Feb 2000 Posts: 69 'Bolter | | 'Bolter Joined: Feb 2000 Posts: 69 | .080..........that's about a dime, right.....? Just kidding. | | | | | Joined: Nov 2007 Posts: 131 Certified Bolt Nut | | Certified Bolt Nut Joined: Nov 2007 Posts: 131 | | | | | | Joined: Oct 2001 Posts: 3,458 Extreme Gabster | | Extreme Gabster Joined: Oct 2001 Posts: 3,458 | The clearance is always going to depend on the cam grind. I run my 261 at 0.006 no problem. Its in a half ton truck, though. I'd loosen it up if you are abusing the engine.
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A lone amateur built the Ark. A large group of professionals built the Titanic. | | | | | Joined: Jan 2005 Posts: 1,602 Shop Shark | | Shop Shark Joined: Jan 2005 Posts: 1,602 | What settings should be used with a 261 block with a 235 head?
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | Same settings as for a 261 - Of course, you've drilled the head to match the coolant holes in the block (I seem to recall an older post where you said you had done so) - just checking. | | | | | Joined: Jan 2005 Posts: 1,602 Shop Shark | | Shop Shark Joined: Jan 2005 Posts: 1,602 | Yes. Holes were drilled. Thanks.
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