351C 4V Valve and valvetrain replacement

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Paul of MO

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The picture of the cam bearing that was posted is a 400M not a 351C - I can tell by the casting line. And yes it is set to deep into the block.

Here is a better picture showing how close to thrust face of the block the front cam bearing is in a 351C.

28h1ly1.jpg


Now in real life will this cause a problem? Not really. As long as all of the flat area in the block is covered by the bearing then you are good. If the bearing is farther back into the block exposing some of the flat area then yes - more of that oil passage would be exposed and that would not be good.

For our engineers (even the ones in denial) - if the bearing protruded farther forward and stuck out over the bevel (like in my picture) would more of that oil hole actually be covered or would it just be shrouded a little bit?

I think Ford just wanted to make sure you had it in far enough not to interfere with the thrust plate so they gave a specification to accomplish this goal.

The only real important thing is to have the bearing lined up with the oil passages for the mains and for the rockers. To shallow or to deep or clocked wrong and life will not be good.

As far as cam bearings go they typically can last though 3 or 4 or 10 full life spans of an engine. If there is no signs of damage or wear I typically did not replace them.

351C cam bearings are honed after they are installed and replacements are most often to tight. Again not a big deal - things will clearance themselves most of the time.

I had a used cam that we cut a deep grove in the bearing journals then we would coat them with a very fine cutting compound then spin it with a drill to clearance the new bearings. Seemed to work OK. The new cams went from being almost impossible to turn by hand to spinning like they had been buttered.

I have built and run many 351C's that the cam started off tight without any problems. We only used the tool for the ones that were really stiff.

Like I say the most important thing is to have fun!

(Do not drill a hole in your galley plug - it will cause a leak)

(The photo of the galley plug is a 351M not a 351C not that it matters)

- Paul of MO

 
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barnett468

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I am not sure if it was covered, but make sure the distributor gear material is compatible to the cam gear.
The CRANE gear can be used on any cam material.

 

Paul of MO

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If the engine is only to be a mild build and not see the high side of 6500 rpm's. Just build it with traditional good quality bearings and pay attention to the camshaft thrust clearance.
Thumbs up on this suggestion. You do not need funky grooved bearings for your Cleveland.

Distributor gear problems? - I never had any but there seems to be some buzz on the internet about it in the past few years. Don't really know why.

Get Tom Monroe' book and do what it says.

Paul of MO

 

barnett468

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Distributor gear problems? - I never had any but there seems to be some buzz on the internet about it in the past few years. Don't really know why.
Comp had a bunch of cams with poorly finished gears and they in turn killed a lot of distributor gears, but there has been other probs as well.

I am currently helping a friend of mine in Australia to fix his $18,000.00 aud Dart Windsor engine . The idiot builder didn't check the cam gear and the pad on the block was not machined deep enough so when they tightened the clamp on the MSD PRO BILLET distributor, it put a bind on the distributor making it hard to turn . It had a bronze gear and that wore the pad on the block down by maybe .010" before it lost all its teeth.

This also drove the cam rearward so hard as it was turning that it ground a .050 deep groove in the front of the thrust plate.

He actually got the Howards billet solid roller cam from the US a couple hours ago that I ordered for him.

Burnishing the cam gear and adding the holes in the galley plug is simply free insurance against this happening, even though it's fairly rare these days.

MSD also uses a custom size distributor shaft that is just .001" larger than stock so you have to either buy their gears or get the Crane or other mfg's gears reamed out to fit it.

The bronze gear they use is the best one available but the CRANE steel gear is better than their gear and since you can;t burnish them because they are melonite, I prefer to use the CRANE . It was discontinued for a while as they changed hands but they started making it again and it still has a nice finish on it but it is a slightly different color so the finish process must have changed somewhat.

.

.

 
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Paul of MO

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So distributor gear failure is rare these days - sounds like we do not worry about it then.

Install the distributor and make sure it is centered with the cam and not bottomed out. Sounds easy enough.

Do not drill a hole in your galley plug - it will cause a leak.

Good luck with that Ausie engine - Theo at Pavtek could not help them?

- Paul of MO

 

barnett468

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hes not anywhere near pavtek plus hes paranoid to have anyone work on it now plus he wants to leaarn how to work on engines m. he has never even removed a distributor before but ii told him how to take it apart so the cam is out now and he will have the rest of the parts today and start reassembly today i had him get the double bearing timing set also plus a new distributor with a standard size shaft because they also ground the crap out of the end of the shaft and the body to get it in . . the engine was built by a prominent engine builder too . my guess is that the builder gave the distributor install to a trainee.


even though gear failure is less common these days it still exists and i dont ever want to have one so i preferr to go the extra mile and do the little things i mentioned since they can only help especially making a leak in the galley plugs because in this case a leak is good lol . the size of each hole maybe the equivalent of the clearance between two lifters and the bore or the size of one edm hole in the bottom of a lifter so it is insifinicant in the big scheme of things . unfortunately its just not like the old days where you could just throw the parts in and never have a ggearr prob so in this regard it seems like technology has taken a sttep backwards but who knows . roller cams werent ubiquitous back then either

 
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barnett468

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Will you be installing your own cam bearings?
I was going to have the machine shop install the cam bearings. Looks like we may need to make sure that they are not installed too far.
the front one is the only one you need to worry about .

 
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Ok, so we didn't get to the machine shop quick enough to make sure that the front cam bearing was installed to the correct clearance.

image.jpeg

When asked, the machinist said that "there is a groove in the block and that's where it goes". It is my belief that he is just aggravated at us and didn't want to deal with it,but maybe it is what he believes.

I also already have the book by Tom Monroe, but had not got to chapter 7 where it addresses the cam bearing. I actually had looked through all of the illustrations but assumed that the machine shop would know this little tidbit.

There is also some text in the book addressing the bearing clearance.

image.jpg

The book does mention that the clearance should be .005 - .020 which is a little different than the .003 - .005 mentioned earlier in the post.

Just curious why the book has a different spec than what is advised earlier in the forum.

Is the .003 - .005 clearance specific to higher performance engines?

Second question is regarding how to correct the clearance. I have always relied on machine shops to install cam bearings and have never installed them myself. I want to tell the machinist to set it at my desired spec, but I believe he is ready to tell us to pick up our parts... This may be an exaggeration on my part,but I want to rectify the problem the easiest way possible.

Is there a way for me to correct the bearing myself or will I need to buy new bearings and have the machinist replace it properly?

 
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MeZapU

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The shop could very easily correct the issue bit it would require a new cam bearing galley plug at the rear of the engine. They could try and do the job from the front but it would not guarantee a straight bearing installation.

If you are not building a high revving engine I honestly wouldn't lose any sleep over it. Just ensure that the camahaft thrust clearance is within spec and you'll be fine. So many of these engines were reassembled in this manner over the decades without issue is the reason that this specification is rather difficult to track down and is little known.

One of the other major no-no's in these engines is running a high volume oil pump. They put excess strain on the distributor gear and distributor gear roll pin and almost always cause excessive wear in those areas or breakage. They are just not needed with properly spec'd bearing clearances.

Another unneeded modification is drilling a hole in the oil galley plug for distributor gear oiling. The very hole that is being covered by that bearing is going directly to the base of the distributor gear. The gears already get plenty of oil.

 
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The shop could very easily correct the issue bit it would require a new cam bearing galley plug at the rear of the engine. They could try and do the job from the front but it would not guarantee a straight bearing installation.

If you are not building a high revving engine I honestly wouldn't lose any sleep over it. Just ensure that the camahaft thrust clearance is within spec and you'll be fine. So many of these engines were reassembled in this manner over the decades without issue is the reason that this specification is rather difficult to track down and is little known.

One of the other major no-no's in these engines is running a high volume oil pump. They put excess strain on the distributor gear and distributor gear roll pin and almost always cause excessive wear in those areas or breakage. They are just not needed with properly spec'd bearing clearances.

Another unneeded modification is drilling a hole in the oil galley plug for distributor gear oiling. The very hole that is being covered by that bearing is going directly to the base of the distributor gear. The gears already get plenty of oil.
Thanks, I was hoping for a simple solution.

By the way, how do I get an Air Force insignia to the side like you have. I served from 1980 until 1987. Worked in F-4E's and F-111F models in California and England.

 

MeZapU

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By the way, how do I get an Air Force insignia to the side like you have. I served from 1980 until 1987. Worked in F-4E's and F-111F models in California and England.
Been a while since I got mine. I'd just PM a moderator or admin and ask them nicely. I'm sure they'll hook you up.

 

Paul of MO

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Looking at your pic they have the passage underneath the bearing more than half closed off. I would not expect it to cause any issues but it is just a bit to far back for my comfort.

Cam bearings are cheap - they did it wrong - have them redo it.

They need to worry about getting the passages under the cam bearing centered in the grove more than being concerned about the exact clearance behind the thrust plate. This is the reason for such a wide window for the official specification.

If they knife edged the leading edge of the cam bearing to make it install smoother then they will have a problem knocking it back out just a hair.

If it were me I would just replace it. 20 minutes and 20 dollars. Not a big deal.

If they bitch then offer to pay for the part - not exactly fair but for 20 bucks the lack of worry would definitely be worth it.

Also -

Yes on the standard pressure oil pump and it does not need to "modified" for higher pressure.

Do not drill a hole in your galley plug - it will cause a leak

- Paul of Mo

 
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Looking at your pic they have the passage underneath the bearing more than half closed off. I would not expect it to cause any issues but it is just a bit to far back for my comfort.

Cam bearings are cheap - they did it wrong - have them redo it.

They need to worry about getting the passages under the cam bearing centered in the grove more than being concerned about the exact clearance behind the thrust plate. This is the reason for such a wide window for the official specification.

If they knife edged the leading edge of the cam bearing to make it install smoother then they will have a problem knocking it back out just a hair.

If it were me I would just replace it. 20 minutes and 20 dollars. Not a big deal.

If they bitch then offer to pay for the part - not exactly fair but for 20 bucks the lack of worry would definitely be worth it.

Also -

Yes on the standard pressure oil pump and it does not need to "modified" for higher pressure.

Do not drill a hole in your galley plug - it will cause a leak

- Paul of Mo
Thanks Paul, I think that we are going to leave it as is to keep from pissing off the machine shop.

We already had to return the wrong pistons and the wrong camshaft to his supplier. And since he is a well respected local (and older guy) machinist I would rather just leave it alone. The rebuild is basically stock anyway with original intake & exhaust manifolds and carb.

And we also have no intention of drilling any oil passages...

Jeff-

 

Paul of MO

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Looking at your pic they have the passage underneath the bearing more than half closed off. I would not expect it to cause any issues but it is just a bit to far back for my comfort.

Cam bearings are cheap - they did it wrong - have them redo it.

They need to worry about getting the passages under the cam bearing centered in the grove more than being concerned about the exact clearance behind the thrust plate. This is the reason for such a wide window for the official specification.

If they knife edged the leading edge of the cam bearing to make it install smoother then they will have a problem knocking it back out just a hair.

If it were me I would just replace it. 20 minutes and 20 dollars. Not a big deal.

If they bitch then offer to pay for the part - not exactly fair but for 20 bucks the lack of worry would definitely be worth it.

Also -

Yes on the standard pressure oil pump and it does not need to "modified" for higher pressure.

Do not drill a hole in your galley plug - it will cause a leak

- Paul of Mo
Thanks Paul, I think that we are going to leave it as is to keep from pissing off the machine shop.

We already had to return the wrong pistons and the wrong camshaft to his supplier. And since he is a well respected local (and older guy) machinist I would rather just leave it alone. The rebuild is basically stock anyway with original intake & exhaust manifolds and carb.

And we also have no intention of drilling any oil passages...

Jeff-
Jeff,

Not a problem. I am certain that you will not have any long term issues. In later years I would grab a cheap 351C engine here and there just to have some on hand.

I would bet nearly all that had been opened up at sometime in their lives had the front cam bearing in to deep like yours is.

Have fun putting everything together!

- Paul of MO

 

barnett468

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The book does mention that the clearance should be .005 - .020 which is a little different than the .003 - .005 mentioned earlier in the post.

Just curious why the book has a different spec than what is advised earlier in the forum.

Is the .003 - .005 clearance specific to higher performance engines?
Exactly which book do you have?

No there is no spec for high perf, however, you seem to be missing the point, which is not that there is a difference between the spec I posted and the one in your book, but that the bearing is supposed to cover the hole . If it was mine I would fix it . Some box stock Clevelands had early crank or rod bearing failure from the factory, so I see no reason to vary from Fords recommendation in this particular area since they are the ones that designed the engine and I'm sure their engineers know more than I do about doing that . Even at .020, the bearing would cover most, if not all of that hole in many Cleveland blocks . Your bearing is more than .150" deep, I guarantee it . Even with a .020" spec, that is still a whopping .130" [more than 1/8"] too deep.

The fact is that if you leave it, it will Hurl more oil out there than old Faithful Geyser . Also, it is a 100% guarantee that if you cover the hole by installing the bearing to the factory recommended spec, it is impossible for it to ever affect oil pressure which means that there is one less thing to worry about . Most people have absolutely no idea how much oil will come out of that hole at just 20 psi and you will probably have around 45 psi with a standard oil pump.

At the 30 second mark in this video, you can see just how much oil gushes out of a tiny .020" hole in the lifter bore of this Cleveland with just a hand pump . The size of the hole in your block is probably at least 8 times bigger.



imo, it is illogical not to do this, in fact, it is recommended by most high perf engine builders and no professional engine buider will tell you it is a bad idea, I guarantee it . There is absolutely do direct oil feed to these gears, and although in stock form with factory parts, there is no problem with them, there has been with aftermarket parts and one of the things that has been done by many, many people to correct it is drill the holes I suggested . Advising you not to do it is contradictory to what is standard known protocol by many builders and it also goes against proven results . I suggest you do yourself a favor and simply do a bit more research on the net on this subject before you take just one persons word as gospel.

From professional Ford engine builder and NMRA National champ Ed Curtis, owner of FTI whom is the same person that mezapo got his cam from and whom he suggested you to get a cam from.

"The use of this small hole in the lifter gallery plug is to spray oil into the "cavity"..."

http://diyford.com/small-block-ford-lubrication-parts-interchange/

"Marvin McAfee of MCE Engines uses a timing set oil spray via a .020-inch oil hole drilled in the front oil galley plug. The oil spray provides additional lubrication and cooling for both small-block and Cleveland engines."

You also say you don't want the engine to fail yet you are willing to leave a gaping oil galley open just because you don't want to piss off the builder that clearly is illiterate and NOT a professional because he can't even read, otherwise he would have known what the spec was for the bearing and installed it to the proper depth.

So in summary, you want to leave a big gaping hole in an oil galley which will be a detriment to the engine but you don't want to improve oiling to a critical area of the engine that in fact has failed in countless engines and had the problem cured at least in some part by the addition of a tiny hole in a galley plug which would take all of 10 minutes to do.

Here's several pages of links to Ford distributor gear failure.

https://www.google.com/?gws_rd=ssl#q=ford+distributor+gear+failure

.................................. I for one prefer this...

........
101.jpg


......................................... ...to this

campressgear.jpg


 
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MeZapU

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With the bevel at the edge of the cam bearing hole and on the bearing itself, there is no way to completely cover that hole even if the bearing is installed completely flush with the front of the block. Once the camshaft is installed as well as the retainer plate and timing gear, all of the areas where the oil can go are minimized negating the need for the forgotten spec.

Mr Curtis recommends the oiling hole mod on 351w/302 blocks as they do not have the same distributor base oiling provisions as the 351c.

Running billet or austemper roller camshafts and high volume/pressure pumps can inject distributor/cam gear wear issues if not addressed. The camshaft pictured above is a billet steel unit and likely in a very high performance application. It is extremely uncommon for the gear teeth to be that worn without some other circumstances at play. 99% of the time with a billet cam the gear takes the brunt of the wear.

If you are staying with a cast iron flat tappet cam, a stock cast iron distributor gear, and a standard oil pump, and good quality oil, you should never have an issue.

 

barnett468

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Mystic Fish, Ed Curtis certainy can build engines, however, he mainly designs cams and maybe 99% of his business is Windsors, and irregardless of any oil any cam gear gets from the factory system, there is absolutely no downside to giving it more but there is definitely the possibility of an upside, therefore, it simply baffles my why two people are so vehemently resistant to making a small mod that can in fact reap huge benefits, especially since I have never seen anyone ese opposed to it in my entire life.

Also, unfortunately, the fact is that nothing will completely "negate" the need for the forgotten cam bearing spec because the cam has no affect on the hole like the bearing does because it is above the hole, plus, the cam retainer is not designed to act as an oil seal against the block and can allow some oil to flow between it and the block, however, the biggest leak will be between the timing chain gear and the retainer plate because there is no seal there and there is a fair amount of clearance between the od of the gear and id of the plate, plus there is clearance between the thrust surface of the gear and the plate.

As for leaving the hole exposed as much as it is instead of relocating it to the correct position because in your case there will in fact be some of it still exposed, moving it to the correct location will still in fact cover at least 90% of the hole, therefore I don't see the "logic" behind that approach.

If you had got a leak in your oil pan or your gas tank while you were driving, would you rather have one that is 1/32" in size or one that is 1/4" in size?

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