Valve cover bolt size

[AFT1973]

Hi All. Chasing down the dreaded / usual valve cover oil leak in 73 Roadrunner 400 / 6.6L. Come to find that the valve cover has been cracked due to too many “uga ugas” in the past. I’d curse out my brother in law / prior owner but he’s passed on. It isn’t as much fun without getting a reaction tbh.

At some point the bolts were placed with stainless 1/4 x 20 x 3/4 hex bolts and washers. Got new basic aftermarket Edelbrock Chrome covers on the way for time being.

To avoid other issues. Are the bolts supposed to be 3/4 long? Washers or spreaders? Cork or newer style gaskets?

Much obliged Mopar gurus.

 

[MoparLeo]

How about short studs or cut some 1/4" threaded rod to length and use nuts/flat washers. Even acorns even for a clean look..

 

[AFT1973]

TBH. Didn’t give studs or the like any thought. It may be an option. Acorns too. Think threaded rod can handle engine use / temps?

 

[Black_Sheep]

It depends on your choice of valve cover and gaskets, or you could use studs and length won’t be as critical. I used ARP 12 point stainless studs and nuts when installing the cast aluminum valve covers on my BBC, they look trick and were super easy to use.

 

[Lefty71]

If you want OEM look.... I was getting those from Mancini..they still had original Mopar sets. I havent looked for them in a while tho. They are pretty short with captured flat washers... same ones go on the oil pan for BB.

 

[Black_Sheep]

If you want OEM look.... I was getting those from Mancini..they still had original Mopar sets. I havent looked for them in a while tho. They are pretty short with captured flat washers... same ones go on the oil pan for BB.

Pan bolts are 5/16” and much longer…

 

[AFT1973]

Studs maybe the way to go. I haven’t used them often. OEM would be nice too. If they exist in new condition.

 

[Black_Sheep]

Mega Parts has stock valve cover hardware kits. Big blocks used studs on each end of the bottom row and bolts with captive washers in the remaining locations.

 

[Lefty71]

Mancini Racing Valve Cover Bolt Package

Black_sheep is right. Oil pan is bigger... those sets are available from classic ind for $15 a set...oem

 

[AFT1973]

That explains part of the issue. There are no studs on the bottom ends. And definitely no captive washers. Its a mess.

 

[MoparLeo]

Food for thought

 

[71Beeper]

I use a long stainless set screw with a stainless ny-lock nut and a valve cover reinforcement.

 

[gtx6970]

You can get a double end stud at most any good hardware store . Pick your length based on valve cover and type of gasket choice

OEM was 1/4-20 on the end where it threads into the head.
1/4-28 on the exposed end

 

[fourgearsavoy]

Go here and cut out the middle man
Bulk & Wholesale Auto Fasteners & Parts - AMK Products, Inc.

 

[Black_Sheep]

Go here and cut out the middle man
Bulk & Wholesale Auto Fasteners & Parts - AMK Products, Inc.

I’ve purchased direct from AMK, but I believe they have a minimum purchase. I don’t think a valve cover hardware kit will get you there…

 

[gtx6970]

I’ve purchased direct from AMK, but I believe they have a minimum purchase. I don’t think a valve cover hardware kit will get you there…

Agreed, I believe they have a $35 minimum order

 

[33 IMP]

Hardware store 1/4-20 set screws (in the proper length, for covers chosen), bottomed into head, nuts, washers, and home made spreaders.
Paper thin moroso covers, with a coat of turquoise, rubber gaskets, glued to the cover. No leaks.
These are grade eight steel. Doing it over, I might buy stainless, but these were on the shelf waiting for me.

 

[AFT1973]

Next stop is see what’s waiting on the shelf to pick up.

 

[fourgearsavoy]

Not really my flavor but I don't judge.

 

[AFT1973]

Not really my flavor but I don't judge.

View attachment 1585252

Not mine either. But happy shopping.