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Discussion Starter · #1 ·
I've been hearing for years that these are weak and unreliable.
Does anyone have definitive proof that Ford used 2 piece valves in their 351C, 351M/400s?
 

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I have one as a paper weight and it has a big ridge where it is. I'm not 100% sure, but ask C.Kelly, as i think its on his site where he has some bad times with new std valves.
 

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well yeah the proof from what i understand is when you take apart any number of 351c 351m or 400 and it had 2 piece valves proof enough? I know BOSS 351 had one piece valves but that is the only one that i know of
 

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I don't know personally of the "two piece" valve, but from what I've heard the weak point is the multi groove keepers.

They have a tendency to fail.
 

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I have personally had a head break off of a 351C exhaust valve, and also the tip break off where the grooves are.

Re-using the OEM valves is a poor way to save $200.00 in a performance engine.

Greg
 

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Well, unless you want to re-rebuild your engine, get a new block, and get a new head; put NEW stainless ONE-PIECE valves in it.
I wish I could rebember where I found it, but there is a pic on the internet of one separating on a cleveland, thus making a big, gaping hole in the cylinder wall, and destroying the piston and cylinder head. So, I say if you go into it to do head gaskets, rebuild, bigger cam swap, etc.; be safe and put new guides, springs, keepers, retainers, and one piece valves. It may cost more now, but it will be worth it in the long run.
Just my opinion, Chris.
P.S. I just rebuilt my engine, and I spared no expenses especially on the heads. I got some Ferrea 5000 valves, new springs, keepers, retainers, valve stem seals; also along with that, I had the machine shop deck the heads, drill & tap for screw-in studs, guideplates, new seats, and new BRONZE guides. With all that and the block work I had done(quite a bit) I spent $1,600, but it would have cost me about $4,000 if I didn't know some people.
 

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On 2006-11-22 16:30, MontegoMan351 wrote:

I wish I could rebember where I found it, but there is a pic on the internet of one separating on a cleveland, thus making a big, gaping hole in the cylinder wall, and destroying the piston and cylinder head.
Here is the destruction. Its on Chris Kelly's site.
http://raceabilene.com/kelly/hotrod/wreck.html
 

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Thank you, that is sure to ruin your day!
 

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Discussion Starter · #9 ·
Thanks everyone. I'm having a tough time convincing people of this on a particular forum. I posted a link to Chris' site originally but they said he was just blaming it on the valve for nothing.

I pulled 27 posts from the N54 forum about warnings of the 2 piece valves but I haven't posted them yet because these guys wouldn't be impressed by anything less than an engineer's report from Ford.

More carnage pics: Destroyed 73 351cj
http://www.network54.com/Forum/119419/thread/1141697214/

Hot Valve Materials for Hot Engines
http://www.automotiverebuilder.com/ar/eb120524.htm

This site does talk about some of the problems with 2 piece valves. I dug out a couple valves that came from a 351C 2V head I had on the shelf. The intake tip, stem and head were all magnetic. The exhaust however had a light magnetic pull from the head, a heavy pull from the tip and nothing from the stem. It seems consistent with the automotive rebuilder article and to the best of my memory, all the valve head failures seem to be from the exhaust valves. So the intakes may all be one piece? There was one post from a guy who said the 2 piece valves were friction welded. If I find any else I'll keep everyone updated.
 

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I can't remember the magizine, but they built a 400-some hp 302 and were proud of it untill the stock 2 piece valve broke, they didn't spend the money on new valves and I think they learned their lesson.
 

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On 2006-11-22 18:11, BrianS wrote:
I'm having a tough time convincing people of this on a particular forum. I posted a link to Chris' site originally but they said he was just blaming it on the valve for nothing.

I pulled 27 posts from the N54 forum about warnings of the 2 piece valves but I haven't posted them yet because these guys wouldn't be impressed by anything less than an engineer's report from Ford.
maybe when they end up with a hole in THERE engine block thatll convince them-
theres just no telling some people,suppose they prefer learning the hard way that valves arent something you should cheapout on in a performance build
 

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On 2006-11-22 18:11, BrianS wrote:
Thanks everyone. I'm having a tough time convincing people of this on a particular forum. I posted a link to Chris' site originally but they said he was just blaming it on the valve for nothing.
And these experts say it should be blamed on...?
 

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Discussion Starter · #13 ·
I should have said he rather than they. He being Woodz428, resident Ford know-it-all on the HotRodders forum. Blaming your workmanship, or lack there of.

http://www.hotrodders.com/forum/windsor-cleveland-head-compatibility-302-blocks-78105-4.html
About a third of the way down the page

"You can e-mail the guy and tell him he's a fool. He strikes me as one of those guys that would rather blame something other than his workmanship, or lack there of.I blasted the valves in the shop and also looked through several old Manley catalogs, including their current website one. Guess what,ALL are one piece.
Last edited by woodz428 : 11-20-2006 at 06:49 PM. "

<font size=-1>[ This Message was edited by: BrianS on 11/23/06 3:15pm ]</font>
 

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Why risk it and listen to the so called "experts", just because they have been lucky and not had a valve break? One piece stainless valves are cheap enough, it may not seem that way at first, but in the long run you will be glad you did. New valves, springs, keepers, and retainers are a lot cheaper that finding a new block, and they give you the peace of mind that the heads or stems won't break off. After I saw Chris Kelley's site, that was enough for me to buy 1 piece valves, because I didn't want to be driving alone and that happen, or in front of a bunch of people.
Chris
 

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If you're going to spend $500 for a set of pistons, why not spend a couple $$$$$ more for the things that can put holes in them when(not if) they fail.


BTW after spending $300 for an oil pan, $150 for valves and keepers is a bargain.
 

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Discussion Starter · #16 ·
This was the statement I made on the other forum that started the whole debate.

"I've never seen a multigroove valvestem fail at the keeper but I wouldn't trust them much beyond 5500rpm or .550 lift. It's more common to see the valve fail near the head where Ford welded them together."

I was talking about both Cleveland and 351M/400 and used a link to Chris' site to show where they separate. The guy assumed I meant M engines and stated Clevelands all use 1 piece valves. I've read at least 30,000 posts in the last 5 years on a dozen Cleveland/M forums and have seen pictures of, or heard about, valve heads coming off more often than the multigrooves themselves causing problems.

I can't recall the percentage but it's more likely been a problem with Clevelands, If you think about it, how many 351M/400 owners rev past 5500? And yes, the pictures on Chris' site should have been enough to warn everyone about 2 piece valves.

All the rhetoric on that other forum is just an attempt from a petty person to prove me wrong about what type valves Clevelands used as OE. All I have to work with so far is a general consensus. I'm going to respond at some point because I have a couple of my own corrections to make.
 
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