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Topic: center-bolt valve cover issue

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center-bolt valve cover issue (1/25)
 4/29/12 10:10pm
daveo76
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Vancouver, WA - USA

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1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


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While installing my valve covers (stock for Vortec trucks) last night I noticed something odd.  The valve covers only go on the heads one way, but when installed that way the PCV hole on the drivers side is in back and the breather hole on passenger side is in front -- opposite of our cars' stock positions.  Again, I can't just install the other way (breather apparatus interferes with a rocker) and swapping them between heads does not solve the issue, it would just move the oil fill over to the passenger side.   Is this an expected scenario?  I think the PCV should not be a big problem - just need to run a longer hose - and perhaps the same thing with the breather.  (I'm using my stock air cleaner base so I had hoped to use the original breather pipe, but I'll have to re-engineer that, I guess)   Any thoughts?  I'm guessing most folks with Vortecs don't use the original air cleaner base so they don't worry about that.  But the PCV I'm wondering how others do it - longer hose or can you run PCV from a port on the back of a Q-Jet?  Thanks guys....I'm making some progress.

|UPDATED|4/29/2012 7:10:32 PM (AZT)|/UPDATED|


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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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Re: center-bolt valve cover issue (2/25)
 4/29/12 9:16pm
Ron 78Lifetime Member
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why is this thread so HUGE ?

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Re: center-bolt valve cover issue (3/25)
 4/29/12 10:11pm
daveo76
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Vancouver, WA - USA

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1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


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Posts: 857

Is this better?  I thought using a cell phone pic would automatically be small - no such luck.  Still had to convert to smaller size.  Sorry.

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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: center-bolt valve cover issue (4/25)
 4/29/12 10:23pm
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Ideally, the PCV valve and the breather would be at the front of the engine on both sides. That just ain't always how it works out, tho. I don't understand why the breather baffle on the one valve cover would hit with it on one head, but not on the other head. I guess it's one of those things you'd just have to see.
You'll just need to reroute the hoses, apparently. May not look "stock", but then again...neither will the center bolt valve covers. Thumbs Up


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Re: center-bolt valve cover issue (5/25)
 4/30/12 1:25am
daveo76
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


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Joel, just to clarify - the valve covers are identical except that one has the oil fill and the other has a round flat spot (where I mounted the emblem) in the same location.  So both fit on either head, but neither of them can be inverted (front to back).  This is kind of a hard one to explain with words.  But anyway, the short description is they can only be installed one way and that puts both small holes in the opposite location of where I was expecting.  What did you mean about how it is preferred to have the breather in the front?  I just checked my air cleaner (had to make sure my memory wasn't going) and with the stock pipe it definitely hooks in to the pass side valve cover at the back.  

Yep, my goal is a "stock" look, but it will only apply to folks who don't know that center-bolt valve covers (and the associated heads) didn't show up until well into the 80's.  I think I'll still be able to keep that look if I have to re-route the breather pipe and PCV.  


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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: center-bolt valve cover issue (6/25)
 4/30/12 7:36am
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What I said was "Ideally"....in the real world, it rarely happens! Having the breather and the PCV at the front keeps either of them from sucking up as much oil vapor. I unnerstand now what you said aboot them not flipping. I thought you said they would only fit on ONE head each. Thumbs Up

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Re: center-bolt valve cover issue (7/25)
 4/30/12 10:01am
DaveMLifetime Member
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Be carefull with those center bolt pressed steel covers, if you overtighten them they deform just enough to leak at the gaskets. I had problems with mine and changed them out for cast alumimum ones, no more leaks. Good luck.
Dave


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Re: center-bolt valve cover issue (8/25)
 5/1/12 2:02am
daveo76
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
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Thanks Dave - I'll be sure not to over-tighten 'em.   They're just on there loose now - I was thinking 10-12 ft-lbs.  I'm using the thick fel-pros that you put on completely dry - maybe that will help.  

Joel, thanks for the explanation about the desire to put the breather in the front - I see now that it's a desire at the "design stage".   Hopefully having my PCV in back won't cause any problems.  


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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: center-bolt valve cover issue (9/25)
 5/1/12 7:38am
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You'll usually find that the PCV valve will be at the front on one side, and the breather in the rear on the other, but they could be either way. The idea is to get the oil vapor/blowby completely out of the crankcase. The PCV and breather in the same valve cover only clears the one valve cover area, so that isn't done by any manufacturer, but I've seen folks do that themselves, for whatever reason. By putting the two components on opposite sides, it draws the blowby thru the entire crankcase, doing a much better job of clearing the vapors. Thumbs Up

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Re: center-bolt valve cover issue (10/25)
 5/1/12 11:24am
VikingVette
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I have a ZZR in my '78. This spring I swapped outthe valve covers (again...I wanted something else).  I went with some polished billet aluminum and of course they are center-bolt (by the way, chevy does make an adapter to use on center-bolt situations where you can use the standard vavle covers instead of center-bolt).  The Breather/oil fill is on the passenger side towards the rear and the breather/PCV is on the drivers side towards the front.  It has been so long ago that I removed the L-82, that I do not remember the stock position.

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Warning: The surgeon general has declared that it is NOT unhealthy to smoke your competition AND I just discovered that my corvette is a hybred.  It burns gas and rubber! 
Re: center-bolt valve cover issue (11/25)
 5/1/12 12:40pm
VikingVette
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Stupid keyboard.....I have a ZZ4 NOT a ZZR in my '78Embarrassed
 
Life is tough enough without having to live it dumb like I am!!!!!!!!


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Warning: The surgeon general has declared that it is NOT unhealthy to smoke your competition AND I just discovered that my corvette is a hybred.  It burns gas and rubber! 
Re: center-bolt valve cover issue (12/25)
 5/1/12 1:00pm
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Normal positions for most small blocks have the PCV valve at the front on the driver side, and the breather(tube to air cleaner) at the rear on the pass side, with the oil fill at the rear of the driver side.


Ermm˙˙˙˙spɹɐoqʎǝʞ pıdooʇs ʇooqɐ uɐǝɯ ɐʎ ʇɐɥʍ ʍouʞ ı˙˙˙ʍʇq

|UPDATED|5/1/2012 10:00:52 AM (AZT)|/UPDATED|


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Re: center-bolt valve cover issue (13/25)
 5/1/12 1:55pm
VikingVette
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thanks Joel, I needed that.  15 hour day yesterday...looks like a 14 hour day today...AAARRRGGGGHHHWacko.    So my breather on the passenger side (towards the rear) is also the oil fill hole.....that just doesn't sound right does it..."the oil fill hole" (especially towards the rear...can you tell I have been putting in long hours)...ewwww!



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Warning: The surgeon general has declared that it is NOT unhealthy to smoke your competition AND I just discovered that my corvette is a hybred.  It burns gas and rubber! 
Re: center-bolt valve cover issue (14/25)
 5/1/12 6:15pm
Ron 78Lifetime Member
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Here's a dumb question,why did the General change from the old style 4 bolt system to the top bolt valve covers,I think they are ugly .why mess with somethin that worked for years Thumbs Down

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Re: center-bolt valve cover issue (15/25)
 5/1/12 10:19pm
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What happened, from my unnerstanding, is the castings on the newer style heads were designed to be thinner/smaller. There really was no room for the casting to support the perimeter style covers. That, and the newer heads had raised, and machined rails for the cover gaskets to seal against. With the sides if the castings raised, and machined, they could get a good seal with the center bolt design without leaks(yeah right...how's that workin out, GM?)...
The really good thing aboot them is you don't have to worry aboot dropping one of the friggin bolts down behind the exhaust manifold anymore....LOL


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Re: center-bolt valve cover issue (16/25)
 5/2/12 2:08am
daveo76
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
Posts: 857

VikingVette: thanks for the input.  I knew about the adapters, but I didn't think they were worth it for my L-48 orange jobs.  If I had a set of the finned aluminum ones that would be a different story, but....

Joel: thanks for the explanation about why they went this way.  I was hoping it was to improve the leaking situation, but it sounds like the improvements may not have worked.... I'm going to hope it works out for me.  These guys came with the heads I bought - I was going to toss them but I decided to clean them up, paint, and see what they looked like.  They turned out OK and I actually like the look of the center-bolts.  I'm going to look for some stainless or black replacement bolts for 'em. 

I'm going to do my best to make these leak free, but if that doesn't work out I'll go with a set of finned aluminum covers.  We'll see!


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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: center-bolt valve cover issue (17/25)
 5/2/12 5:39am
VikingVette
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Dave,
If you have an ACE hardware store near you, they carry a huge selection of chrome and stainless bolt, nuts, washers and caps..  If you do not want the shine, then definately black to make them disappear


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Warning: The surgeon general has declared that it is NOT unhealthy to smoke your competition AND I just discovered that my corvette is a hybred.  It burns gas and rubber! 
Re: center-bolt valve cover issue (18/25)
 5/2/12 10:33am
daveo76
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Vancouver, WA - USA

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1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
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Yep, I do have an Ace very close to where I live and, believe me, I use that awesome selection of hardware all the time!  Way better than Home Depot.  I'm going to go look at their stainless selection and see if they have anything, but I'm not sure they'll have bolts that long.  I went online last night and found a set of ARP stainless last night for about $22 - that may end up being my best bet.  

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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: center-bolt valve cover issue (19/25)
 5/2/12 6:05pm
annicorvetteLifetime Member
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can't help with the problem just need to know where you obtained the valve covers? at present i want a set like that for a 327 im almost finished with.

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Re: center-bolt valve cover issue (20/25)
 5/2/12 7:27pm
DaveMLifetime Member
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annicorvette said: can't help with the problem just need to know where you obtained the valve covers? at present i want a set like that for a 327 im almost finished with.

 

I have a pair (same as the first picture, black) They are from a ZZ4 and I did not use them. Don't know if they will work for you or not.

Dave




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Re: center-bolt valve cover issue (21/25)
 5/2/12 7:43pm
annicorvetteLifetime Member
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dave do the covers come with the bolts-- how much you want for the covers and can you e-mail pic to  annicorvette@hotmail.com

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Re: center-bolt valve cover issue (22/25)
 5/2/12 8:36pm
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Dave -- some pics of the engine i want to put the covers on are at

 
and before you ask yes that is my homemade teststand the engine is on at the present time.


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Re: center-bolt valve cover issue (23/25)
 5/2/12 9:22pm
DaveMLifetime Member
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I'll try to get pictures of them tomorrow after work.
Dave


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Re: center-bolt valve cover issue (24/25)
 5/2/12 9:25pm
daveo76
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Vancouver, WA - USA

Vette(s):
1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
Posts: 857

They'd also be available at most any wrecking yard, I'd guess.  '96 and later trucks (subs and tahoes, pickups, etc.) with a Vortec 350.  And lots of cars and trucks ('87 and later) had center-bolts, too.  

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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Re: center-bolt valve cover issue (25/25)
 5/4/12 2:30am
daveo76
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Vancouver, WA - USA

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1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.


Joined: 8/25/2005
Posts: 857

VikingVette:  the Ace plan worked.  $10 bought me (8) 1/4-20 x 3 1/2 stainless bolts and washers. They're just regular hex head, not Allens, but I think they still look pretty good.  (they did have allen cap screws, but they didn't have the half inch sizes and they cost 3 times as much). 

Middle bolt is original, other two are the new ones:



Pic also demonstrates the use of Calyx exhaust manifold dressing.  I'm pretty impressed with that stuff so far, but my camera flash highlighted some areas I missed!  


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1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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