Chevy 250 Valve Cover Help

I have a 1970 250 straight 6 in my wagon with a cheap ass speedway chrome valve cover that will not stop leaking out the firewall end... I found an Offy cover on Egay for a good price but the pic shows 5 bolt holes on the carb side and mine only has 4? Will this work? Anybody know where I can get a good valve cover that wont warp and leak? I would prefer the finned cast offy but am open for options. Help a rookie out, Thanks!

 

Your 70s head should have 7 holes that hold it down NOT 4 Nore 5. And just about every aftermarket Cheap A** chrome cover/s Leak Because most for them do not have enough lip on the edge to seal the gaskets Or to hold them in place. What I had done with one i had was fold the lip a little more and to Take the chrome off the under side edge,Then add a bead of RTV.

I have seen many guys take a stock cover with the script and have them chromed. (To copy what GM did with some of them.)

 

Correct, mine has 7 and the one on ebay looks like it has 8? I am messing with folding it under and looking for a stocker as well. Doe the offy covers seal up good?

 

Got it handled...thanks

 

There's a guy on "hotrodders.com", strummin67 I think, that has a Chevy II wagon also. He's gone through HELL with his Offenhauser valve cover; won't stop leaking no matter what he did. He finally put the stock one back on. You may search that site/poster.

 

get a Clifford v/c and be done with it, plus it clears roller rockers!

 

I ordered the Offy cover. Anyone running one? Looks like I will need to drill it for the PCV. It has no baffles..... Any thoughts on not running a PCV ???

 

Btt.....................

 

What is that intake manifold?!!

 

It is a PES intake that was made for the Roundy round guys

 

When using an aluminum valve cover, be sure to check it for straightness. I had to have the Offy on my 261 surfaced because it was warped. Hasn't leaked since.
I also bought a piece of Buna-N rubber from McMaster-Carr and made my own gasket. No sealant needed, and it is completely reuseable.

 

Don't forget the Mercruiser boat valve covers. They're aluminum and can be polished. But the Clifford looks better.

 

YES, A bit O.T. on the thread, but I'd like more information on that intake manifold also. PES? This company still around and making this intake?

 

You need to run a PCV. There is a boss cast in on the drivers side to drill and tap.

I have been messing around with my Offy cover for awhile and still can not get it to fit good enough to get all the bolts in. One bolt hole is way off. That is after I had it polished as the factory, partial, polish job is real poor. Should have fit it first. Still grinding on it. The front fins and lip need to be clearenced to miss the thermostat housing. I ground on the housing as well. The gasket surface at one end needs excess material removed for the gasket to lay flat. The casting looks like the mold has been broke and patched a couple times which shows on the inside. I have cleaned this up but as I get it closer to fitting I believe I might have to clearence the inside some more.

After all this I still might end up with a Clifford valve cover.

 

Mine is on and sealed up fine. The holes lined up perfect. Sorry you did not have such luck. I am just running a breather oil cap today but have an oil cap that takes a elbow pcv out the top. That and a side breather and I should be good to go.

 

You can make or buy a spacer for the thermostat housing, so you don't need to butcher the cover. I believe Tom Langdon sells them, maybe Larrowwe & Sons also...

 

With an Offy you can never go to a bigger spring or roller rockers...I just received my Clifford to day, just have to polish it and it'll look great !

 

Just a side note for you guys that may have valve cover clearance issues. I to have the thermo housing (billet spacers) also Have a 3/4 billet valve cover spacer which will raise the cover.I have also been working on a taller valve cover Which may have a remove able top. But this is still in the works.

 

Got a Clifford, off eGay, and when I went to mount it the cover holes didn't match up. Was the correct pattern, but no matter how you tried some holes would be off. Sat it on the welding table and noticed a wobble. Checked it on a flat plate and when you held one end flat the other was about 3/8" off the plate. How does cast aluminum get warped.

 

Dropped? over heated? Or just plain and simply a Pour mold/casting

 

I have the same offenhauser valve cover, and I have had the same issues as MilesM. Three bolt holes had to be drilled oversize to line up, and I had to grind the front lip for thermostat housing clearance. Yet, it still leaks in the back no matter the gasket type, or the presence or lack of sealant. Even a careful 2-4 foot pounds torquing with a torque wrench makes no difference.

 

https://www.12bolt.com/ i bought one of the valve covers from this place , it is well made , but not cheap , also bought the side cover s in finned aluminum

 

I have a offy finned aluminum valve cover on my 250 six. I plumbed the PCV valve into the oil filler cap. Mine doesn't leak

 

I did the same form 12bolt.com.
I have had a little trouble with the side covers leaking when using stock cork gaskets, and 2-4 ft-lbs of torque.
Should I use just Right Stuff gasket maker from Permatex? No combination of gasket/sealer seems to stop a leak from the bottom of the side cover.
Thank you

 

A lot of the same problem as the valve covers that leak, the sealing surface on the head for the valve cover is not a machined surface, and is not flat, so it contributes to leaks. Same for the side cover surface on the block, it's also "as cast" and not machined. Many other inlines like Ford's have those surfaces machined and helps seal. The only fix for the Chevy block and head is to mill those areas flat before installing. Unfortunately, that is one of those "tricks of the trade" you have to know beforehand instead of afterwards.

 

See above post. Also, the bosses for the side cover bolts extends beyond the gasket surface, and depending on how good or bad the part is designed to compensate for that feature, the cover(s) can be bottoming out on those bosses before the gasket is tightened enough to seal.

 

Thank you CNC-Dude. I am going to try Right Stuff gasket maker without a cork gasket. That product is advertised to be used on older vehicles with imperfect mating surfaces between parts.

 

Great! Hope this info was useful to you.

 

Right stuff will seal it up! Just have every surface clean and dry and get all your work done under the cover because once the Right Stuff drys, you will not get it back off.

 

Just to let you know the result of my endeavor, with the chevy 250 side covers. I spoke to to Tom Lowe at 12bolt.com, and he reccomended a few things I could try. I ended up torquing the side cover bolts to 15 foot-pounds, and that stopped the leaks. Thanks Tom!