setting the valves on a 251?

[NiftyFifty]

Hey Gents,

Just wondering if anyone has a base line to set the valves before I install the motor and also the timing cover. I know the book says .010 for the intake and .014 for the exhaust but that's hot and running, and it's not like you can really get in there to adjust the valves very well after you install the intake/exhaust manifold and the exhaust pipe...not to mention just sounds like a great way to burn the heck out of your arms...if I can set them before and they don't tick once running then I'll leave them...or a few minor adjustments..but not all them when it's hot I hope.

Any help would be great...I was thinking maybe .002 off what hot is??

[Don Coatney]

Have you done a forum search for this question? What does your book call for on a cold adjustment? I have installed a lumpy cam in my 251CI long block and the cam grinder recommended .014" for both exhaust and intake cold. But I suggest you look in the book or do a forum search for the correct stock valve lash setting.

[NiftyFifty]

Have you done a forum search for this question? What does your book call for on a cold adjustment? I have installed a lumpy cam in my 251CI long block and the cam grinder recommended .014" for both exhaust and intake cold. But I suggest you look in the book or do a forum search for the correct stock valve lash setting.

I have the book that's PH knowledge site, and it only gives a hot setting, I can't find a cold setting in the book anywhere, except for valve timing it says to set the intake valve on 6 at .014 then nothing else...

Didn;t search the topic, I figured I would get miles of stuff on 230's and 218's vs. a 251

[Dave72dt]

Give it another .003 for the cold setting so for a .014 hot, set it at .017 cold. You should find them very close to .014 when hot. Same thing if spec. required .010 hot, set at .013.

Was common to run 2 different settings on engines back then, intakes were commonly several thousandths closer than exhaust. Exhaust valves tended to grow more than intakes since they got hotter.

[NiftyFifty]

Give it another .003 for the cold setting so for a .014 hot, set it at .017 cold. You should find them very close to .014 when hot. Same thing if spec. required .010 hot, set at .013.

Was common to run 2 different settings on engines back then, intakes were commonly several thousandths closer than exhaust. Exhaust valves tended to grow more than intakes since they got hotter.

So now that I'm thinking about it..doesn't everythkng expand in there, meaning at cold they should be looser? I may be way off...because it might get further apart when hot...but I'm thinking now maybe closer together? Does that make sense?

[Dave72dt]

They all expand but at different rates and different amounts. Block and heads have waterjackets where the heat is transfered. Valves don't have that. Heat is transfered from the valve to the head at the valve seat. Intake gets some cooling from the fuel mioxture coming in. Exhaust has to deal with hot exhaust gases going past it so it will expand more than the intake. Intake is closed and transfering heat through the seat while the exhaust is open and enveloped in hot gases.

Newer cars with iron blocks and aluminum heads use "stretch bolts" to accomdate the diffences in expansion rates between the dissimilar metals. ?Same reason why most of them use a composite or graphite based head gasket.

Sounds logical to me anyway.

[John-T-53]

Set 'em looser as mentioned below. The cold setting doesn't have to be dead on as you'll have to adjust again when the engine comes up to full temp for the first time. In fact, the first hot adjustment might be good to set one or two thousands larger as the gap will naturally get tighter on a new engine (as the valves seat into place).

[NiftyFifty]

Set 'em looser as mentioned below. The cold setting doesn't have to be dead on as you'll have to adjust again when the engine comes up to full temp for the first time. In fact, the first hot adjustment might be good to set one or two thousands larger as the gap will naturally get tighter on a new engine (as the valves seat into place).

I've seen a few old posts where members said they set their valves cold and never looked back....something I would like to do, as setting them hot on a truck seems like a near impossible feat.

Dave..you lost me on your reply....but am I getting that I should set the looser then hot settings to compensate for expansion?, or are you saying everything expands the same and the hot and cold settings should be close?

Maybe my pistons will be in tomorrow and then the rest of this beast can go back together

[MBF]

To set them accurately you're going to have to set them hot after the engine has run awhile and has heat soaked. Like a previous poster said-the valves will seat in. You'll need a set of valve adjusting wrenches (makes the job easier along with a set of mechanic's gloves) and to remove the inner fender housing, but it is do able. A pain for a contortionist, but it is doable. Better to go through the process of adjusting them hot than to burn a valve. Mike

[Merle Coggins]

The valves aren't that bad to adjust in the truck. Jack it up and remove the right front wheel, pull out the inner fender, and you have fairly good access to them. And as mentioned, mechanics gloves and long tappet wrenches help a bunch. I also used long bent feeler gauges to stay away from the manifold.

Here's a couple of videos I did about removing the inner fender panel and adjusting the vavles with the engine running.

[Don Coatney]

Excellent film clip Merle. Thanks for posting..

[Dave72dt]

I've seen a few old posts where members said they set their valves cold and never looked back....something I would like to do, as setting them hot on a truck seems like a near impossible feat.

Dave..you lost me on your reply....but am I getting that I should set the looser then hot settings to compensate for expansion?, or are you saying everything expands the same and the hot and cold settings should be close?

Maybe my pistons will be in tomorrow and then the rest of this beast can go back together

You had it right the first time. Set them looser than your hor spec says. .002 or.003 looser. Everything expands from heat but at different rates and the amount of heat also affects how much it expands,. You still need to go through them again to get them just right. Some won't need any further adjustment. If you set them at .010 and .014 respectively cold, you'll find them all to be tight when they're hot and you'll spend a lot of time working around hot parts.

Edited July 25, 2011 by Dave72dt
puntuation,spelling.

[Todd B]

I think you missed your calling. You should have been an info commercial guy. Great job Merle.

[NiftyFifty]

Thanks guys, a lot of great info! Now if only I knew the exact specs for my 251 engine...the book is a little vauge and when your engine came from a combine that you don't know the year or exact make of it makes everything a bit more difficult

[Dave72dt]

Here you go:

Intake lash - .008 hot

Exhaust lash - .010 hot

Conn rods clear- .0005 - .0015

end play - .006 -.011

torque - 45-50 lbs.ft

Mains clear - .001 -.015

crank end play (thrust clear ) -.003 -.007

torque - 80 -85 lbs.ft

Head torque -70 lbs.ft

Initial timing at 2 deg BTDC on a '47 and 0 deg on a '51 engine.

[NiftyFifty]

Here you go:

Intake lash - .008 hot

Exhaust lash - .010 hot

Conn rods clear- .0005 - .0015

end play - .006 -.011

torque - 45-50 lbs.ft

Mains clear - .001 -.015

crank end play (thrust clear ) -.003 -.007

torque - 80 -85 lbs.ft

Head torque -70 lbs.ft

Initial timing at 2 deg BTDC on a '47 and 0 deg on a '51 engine.

Great!! I was just into the old shop I used to work at and found an old Chiltons manual and it had those numbers as well...Good thing I didn't use the Dodge numbers...would have been a bit to loose

[Merle Coggins]

My Dodge shop manual shows the 250.6 CID engines used in the "J" and "K" models. The specs for those is listed as; Intake (Hot) .010" Exhaust (Hot) .018" To check timing (Cold) .014". The "to check timing" would just be an initial setting to get the engine running and then the hot setting could be done when it warms up.

Todd,

If I were to do Infomercials I'd first have to fumble around trying to do it the "hard" way. Then do it the "right" way with the proper handy-dandy gadget to "show how much quicker and easier it is this way."

"And if you call right now you can get this $200 dollar value for JUST $9.95, plus shipping and handling."

Merle

[Dave72dt]

The numbers I posted would have been for a Chrysler car engine. Merle's numbers will also work but may not be as quiet. If you can find an old Massey tractor dealer, he may have a book specific to your engine.

[HanksB3B]

it make me wish Wisconsin was a hoot and a holler over the hill. Trouble is the hill is the Rocky Mountains!

Hank

[48Dodger]

I think you missed your calling. You should have been an info commercial guy. Great job Merle.

These are great videos...I posted them to my youtube acct last year and they are the most watched out of them all!

48D

http://www.youtube.com/user/194853DodgeTrucks#p/u/11/8G3MJGuKIQ8