Oversized exhaust valves

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dartjack

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Seems a clumsy uncoordinated dummy let the carbide burr slide across an exhaust seat:( It probably needs new valves anyway. Does anyone have a source for oversized valves? I can find .017 oversized but a teeny bit more would be nice. By the way, it's a 360 head(s) with .375 stems. Thanks guys.
 
You don't have to replace the valves. You can have new hardened seats put in and machined.
 
Doesn't sound like a ton. See if the shop will work with you on a little grind to see where the cleanup is. I assume you're talking 1 seat? If it doesn't sink too much, you may be able to shorten that valve and get a decent height as far as the other's. Best case scenario, nope, but it might work out for you on this particular build.
 
It will have to be sunk in ar least. 010 to clear. I do have access to a Neway cutter setup for free. I am going to try that first. I do like to have a plan B just in case. Same subject; has anyone ever cut down an intake valve and used it as an exhaust? Got plenty of 318room intakes lying around. I want to do this build on the cheap just to see how little can be spent to get decent dependable power. Most of us don't have the resources/deep pockets to do a "magazine" build. I'm not great on the computer so a build post will be a pain. I am planning to start one for the engine and overdrive install early next year. If there are any members nearby it would be great go have an "eyes on" sounding board. I already know I'm half backed and loony so lets stick to the facts. Thanks.
 
Intake valves aren't designed to take the heat of a exh valve.
 
Kinda knew that. Just wondering if anyone else was thinking waaaaayyyy out of the box also.
 
1.65 or new seat.

or you can take a 1.74 and cut it down and machine keeper grooves.lol

otherwise if its really bad, a valve job would sink the valve and kill the flow on the exh port. In that instance just have a new hard seat pressed in and valve job that one port.
 
10 thou you think?. I think your being quite pedantic here. Just cut the seat. I wouldn't be too worried about a little sinking on the exhaust valve on what sounds like a set of home ported heads with well used valves.
 
I wouldn't recommend doing this at home. Take it to an experienced head guy, they can machine out the old seat and install a new one without having to "readjust" any other valves.


I use a head guy out of Detroit for all of my work, he is good. (he's done heads on cars that do 5 sec. quarter mile). He can fix that cheap, it would probably cost more in shipping than to fix the heads with a new seat. If you need his number contact me.
 
holy crap, take it to the machine shop, have them do ONE seat, and move on... tally what the f up cost you and * it so you can go, hey that's the way it goes... no reason to spend a week trying to turn down a bigger valve just to have the seat screwed with anyways...
 
Bakerlite said:
10 thou you think?. I think your being quite pedantic here. Just cut the seat. I wouldn't be too worried about a little sinking on the exhaust valve on what sounds like a set of home ported heads with well used valves.
Click to expand...

It's .050 thousanths with a 1.65 , and actually .025 being that we're talking about a circle.
I wouldn't mess with a 1.62 because its too close.

And home ported doesn't mean the heads flow for squat, so I'm not sure where you are going with this other than to say the op can't port correctly and he ruined his heads, is that what you are saying?
I'm not trying to teach people how to half *** stuff, I treat it like its mine.

My first set of home ported heads I did when I was 19 flowed 187 on the exhaust and 236 on the int., so u'd be surprised what a beginner can do.
Op, buy the 12-15 dollar 1.65 valve and go have the machine shop grind the seat for it and be done. It migh take a whole 2 minutes to blend it.
 
Hebrews10:26 said:
And home ported doesn't mean the heads flow for squat, so I'm not sure where you are going with this other than to say the op can't port correctly and he ruined his heads, is that what you are saying?
I'm not trying to teach people how to half *** stuff, I treat it like its mine.
Click to expand...

I ported heads when I was 19 blah, blah, blah..they flowed *** CFM blah, blah blah.. I want to let everyone on this sight know this and how great I am... blah, blah, blah. Yeah I saw you sticking it to Ramm in the other thread... I'm not a fan...
Read this one, Proverbs 27:2 since you like that sort of stuff.
Are you done with the trumpet blowing yet again??? OK good.

My point is oh man of 25 years head porting experience, that you don't even know what the rest of the seats are like in these heads do you?. Fact is the OP said he probably needs new valves anyway, which to me sounds like seat valves even the guides are well worn. Who's to say even if he cuts this seat, that this will be the most sunken valve in the head? Maybe these heads have been serviced in the past and other exhaust seats are even worse than the one we are talking about?? Maybe in reality, once checked, it may be found that ALL the exhausts need overhauling?If the heads are done at home without the aid of a bench, who's to say the one with the sunken valve will flow the worst?. Who's to say how much it will effect the flow and if that will have any real effect on the HP of his engine?

Please don't go trying to put words in my mouth.
I didn't say he ruined his heads, what I'm saying is that there is a greater chance of uneven flow from port to port on home done heads so the one with the sunken valve may not necessarily be the one with the worst flow.
But being an expert, then you would already know that. :)
 
Break out the fire extinguishers! Yes they are well used heads. Yes the valves are used also. I do have 3 or 4 other sets to choose from. Yes they are home ported. No they won't be flow checked. No it won't have a new seat installed. Yes the installed height will be checked. Yes they are 596 castings. Yes the castings around the ex guides was plum ugly. Yes they will go on a 318. No they won't be milled. No I'm not concerned about the compression ratio. It will have more than enough. No to boost also. No I don't build an engine from Jegs or Summit catalogs. Yes I do have the factory manual on the shelf-collecting dust.

Bet you guys are scratching your heads now. I really DO think outside the box. If my memory is correct that is where the foundation of hot rodding came from. Call me a nonconformist or a relic if you want. I can embrace that. Oh, and no I won't be paying big bucks for MP oversize valves.

I'll let you know how it turns out.
 
I'm assuming you tried lapping it in before you started this thread?
 
Not yet. I've done enough to know it will take more cutting than I would like. I was exploring options just in case Plan A didn't work. I always try to have Plan B even before it's really needed.
 
Debate is good. We are never going to all agree. We can express our opinions and hope that we can all gain a little perspective from others input. I helped rebuild a 312 Ford 50 years ago. That was my first. You never forget your first. It was far from clean and a manual?! It was a complete hodge podge of parts. 312 short block with 272 heads. Ran like a raped ape. Never did figure out why. But I was hooked. Now my biggest disappointment is not having anyone to pass on what I've learned over the last 50 years. I do think outside the box but where would we be if everything was in a pretty box with a bow on it? Let's all learn from each other and not be afraid of "what if."
 
well you've been exploring your options for 3 days.

Here's the summary.

Try to lap it in and if that doesn't fix it...
Replace the seat

Or

Buy the expensive 1.65" and hope like hell you don't have to replace the seat anyhow.

Or

spend a week trying to ****-hack it with whatever mismatched leftover parts you might have and hope like hell you don't have to replace the seat anyhow.
 
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