351C c.c. deburring??

674 Views 4 Replies 3 Participants Last post by adamg69, Apr 13, 2001

whales

Discussion Starter · Apr 13, 2001

Got my block and heads back today. Things look good. Engine is bored .30 over, heads are fresh and resurfaced. I was checking over the combustion chamber edges on my 4V heads, they have sharp edges with a little roughness around the intake valves (just where the combustion chamber meet the head surface) . It appears on all intake valve areas. I was reading over Tom Monroes book on rebuiling the Cleveland and i notice the same thing on some pictures. Would it be wise to lightly file these burrs and sharp edges down?

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camachinist

· #2 · Apr 13, 2001

As a rule of thumb, I do all chamber work prior to doing a valve job and surfacing the head....the last machine the head goes on is the Storm Vulcan...don't want any slips to screw up the gasket surface.

Sharp edges where the chambers meet the deck surface are fine...roughness within the chamber should be taken care of when porting and polishing...IMO, it's not that important on a street engine, especially with the clean, unleaded fuels being used today..

I'd suggest calling the shop which did your work...I'll defer to their opinion.

BTW, are these open or quench chamber heads?

Pat
http://www.jps.net/binay/webdocs/strtmstng002_sml.JPG

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whales

Discussion Starter · #3 · Apr 13, 2001

thx Pat
The heads are the closed chamber type. Tomorrow I'm going to thoroughly clean the block and plastiguage the crank which was turned .10 under. Have clevite 77 bearings should i clean them with a scotchbrite pad. I read that somewhere on how it improved the surface of a new bearing shell.

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camachinist

· #4 · Apr 13, 2001

If you promise to be careful about running too rich a fuel mixture, I'll give you a reprieve on the combustion chambers..*G*

Reason is carbon deposits stick easier to rough surfaces and glowing carbon is a leading cause of pre-ignition...much less so these days with modern fuels...

I suspect you'll be running close to detonation with those close-chambered heads....

In the past I've used Scotchbrite on bearings but recently have omitted that step with no adverse effects...
Being sure of correct bearing oil clearance is much more important, IMO....

Good luck with the assembly....post any Q's you have during the process...

Got the oil restrictors in?? *G* Ok, keep the rev limiter set at 7....

Pat
http://www.jps.net/binay/webdocs/strtmstng002_sml.JPG

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adamg69

· #5 · Apr 13, 2001

If you get detoantion problems (like I did with the same heads) one thing I did that really helped was dropping down a couple grades in the temperature range of the spark plugs, I called NGK and their tech recomended UR6 plugs. Made all the difference.

69 Sportsroof, 351C, 4spd toploader, Restomod BOSS 429 clone - the one and only (?) 1969 BOSS 351

http://home.swbell.net/boss351/mustang/boss1.jpg
http://stangnet.cardomain.com/user/adamg69

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