?? Valve Lashing 273 ??

-
66 Valiant

66 Valiant

Well-Known Member
Joined
Aug 4, 2010
Messages
66
Reaction score
1
Location
Oshawa ON
Hi All,
66 Valaint 273 engine.
I’m really going to take a shot at getting this engine running as good as I can.
Any info about valve lashing would be a great help.
My questions are, What are the specification for the intake and exhaust?
Can it be done cold?

Jeff.
 
.013" intake, .021" exhaust, hot with the engine running. This is from memory, and I haven't had a running 273 for over 30 years, but I'm pretty sure I'm right. It's not too difficult to do with the enging running at idle. A set of angled feeler gauges helps.
 
My 67 book shows ---- EDIT .013, .021 EDIT---- I disagree that "running" is necessary. I use the "EOIC" method, which means

When EXHAUST (starts to) OPEN, adjust the intake valve on that cylinder

When INTAKE (almost) is CLOSED, adjust the exhaust valve on that cylinder

This works for any 4 stroke engine, no matter how wild or mild the cam
 
Double checked it.

Book I have says .010" intake & .020" exhaust, hot, for a slant six. .013" intake &.021" exhaust, hot, for a 273. Guess you could do it with the engine off but I always did it running.

I'm going hydraulic roller this time!
 
'64 Cuda said:
Double checked it.

Book I have says .010" intake & .020" exhaust, hot, for a slant six. .013" intake &.021" exhaust, hot, for a 273. Guess you could do it with the engine off but I always did it running.

I'm going hydraulic roller this time!
Click to expand...

You're right, I got in the wrong column .013, .021 for 273
 
'64 Cuda said:
.013" intake, .021" exhaust, hot with the engine running. This is from memory, and I haven't had a running 273 for over 30 years, but I'm pretty sure I'm right. It's not too difficult to do with the enging running at idle. A set of angled feeler gauges helps.
Click to expand...

This is the best way for stock 273 mechanical rocker arms. If you do not know how to do it, don't assume it can not be done. Really quite simple and fast.
 
67Dart273 said:
My 67 book shows ---- EDIT .013, .021 EDIT---- I disagree that "running" is necessary. I use the "EOIC" method, which means

When EXHAUST (starts to) OPEN, adjust the intake valve on that cylinder

When INTAKE (almost) is CLOSED, adjust the exhaust valve on that cylinder

This works for any 4 stroke engine, no matter how wild or mild the cam
Click to expand...


You must have better cams than me. I tried it this way, and when I kept turning and checking the gap on the base circle, the gap changed. Is it close enough? Probably... I always, at least, double check everything. I readjust after 5,000 miles and have been good to go. But I only run up to about .500 lift cams anyway. My only point is to keep turning the crank and checking the gap. If the gap gets bigger you need to adjust it to be correct.
 
The service book says to do this running. Sounds messy. I posted this question and I remember someone replied that they used a modified valve cover with the top cut out of it. I have not done my HP motor. Once it is back together in the spring it needs doing for sure.
 
65Vart said:
The service book says to do this running. Sounds messy. I posted this question and I remember someone replied that the used a modified valve cover with the top cut out of it. I have not done my HP motor. Once it is back together in the spring it needs doing for sure.
Click to expand...

Yeah it's messy, but not as much as you would think since it is idling and you only do one side at a time. The cut valve cover works but I have not got around to making one myself. Good luck.
 
67Dart273 said:
My 67 book shows ---- EDIT .013, .021 EDIT---- I disagree that "running" is necessary. I use the "EOIC" method, which means

When EXHAUST (starts to) OPEN, adjust the intake valve on that cylinder

When INTAKE (almost) is CLOSED, adjust the exhaust valve on that cylinder

This works for any 4 stroke engine, no matter how wild or mild the cam
Click to expand...

I've always used this method with no issues.
 
I never bothered to cut a valve cover. I don't remember it being all that messy. I think my engine idled somewhere around 500 to 600 rpm.
 
Well I finally had a chance to do the valve lashing. I did it cold at .010 and .018. I read some where if you do them cold on you have to do them hot later. I may have to do hot sometime but there much better, one bank turned out fantastic and the other is still a little noisy.
Thanks , I wouldn't of tried to do them without your help.
 
The clearances should close up as the valves warm up because the valves get longer as they get hot. Usually better to set them a bit loose if you set them cold.
 
66 Valiant said:
Well I finally had a chance to do the valve lashing. I did it cold at .010 and .018. I read some where if you do them cold on you have to do them hot later. I may have to do hot sometime but there much better, one bank turned out fantastic and the other is still a little noisy.
Thanks , I wouldn't of tried to do them without your help.
Click to expand...

Thank you for letting us know how you made out, I for one greatly appreciate it when folks give a follow up on their question, sometimes we are left wondering...
 
Babyblue66 said:
Gap actually grow as it gets hot.
Click to expand...

If the gap grows as they get hot then you would be able to set them at zero, or near zero, cold.

Here is what my auto mechanics text says about valve clearance....

"This is necessary as engine heat will expand and lengthen the valve stem to such a degree that the valve would not close, with the further result that the combustible charge in the cylinder would not be compressed."

As to hydraulic lifters, it says....

"When valve linkage expands due to engine temperature increases, the plunger must move to a slightly lower position in the lifter body to assure full closing of the engine valve. Similarly, when engine temperature drops, the plunger must move to a slightly higher position."
 
I have a very smart Mopar friend that has a slant 6 in his Dodge coupe. He slipps the alternator belt off and runs the engine till the temp gauge just hits the red zone. He then sets the valves at 0 lash and hasn't readjusted them since he built the car years ago. (and no burnt valve problems) The theory behind this is that if the engine ever gets this hot he will shut it off anyway. The valve clearance will never get tight enough to keep valves open. It works for him. I set mine at spec. (.013-.021 warm {not hot} and always have a little rattle. I like the noise because it's a character sound of HP 273's and solid lifter cams. toolmanmike
 
toolmanmike said:
I have a very smart Mopar friend
Click to expand...

Well, maybe

toolmanmike said:
He then sets the valves at 0 lash and hasn't readjusted them since he built the car years ago.
Click to expand...

This is one guy, one car. I can guarantee you that if enough people do this enough times, burned valves will ensue.

There is a REASON why, after all these years, factories and shop manuals recommend certain things be done -- certain ways.

What your "smart friend" is doing saves no time and has no advantage whatsoever.
 
I just wanted to describe a different idea. A different way. My buddy built a beautiful car. It runs good, gets great mileage and is a blast to drive. He may be no expert but he bleeds Mopar and does cast iron head work for R&J Performance here in Iowa. They have done heads for John Force and heads for Chrysler Corp. He's no dummy.
 
toolmanmike said:
I just wanted to describe a different idea. A different way. My buddy built a beautiful car. It runs good, gets great mileage and is a blast to drive. He may be no expert but he bleeds Mopar and does cast iron head work for R&J Performance here in Iowa. They have done heads for John Force and heads for Chrysler Corp. He's no dummy.
Click to expand...

I have heard this being done also. The guy I knew would tighten the adjuster hot and running till the pushrod wouldn't turn by hand then back it off just a bit??? He only did it on slant sixes also. The problem is, if it ever gets hotter than where the valves were adjusted things will expand to the point that the valves will not close. I like a little margin myself and set to factory specs or cam munufacturers specs.
 
You guys sure these weren't anti pump up hydraulics?
 
67Dart273 said:
You guys sure these weren't anti pump up hydraulics?
Click to expand...

Yes, it was a stock solid lifter slant six. I would not do it myself for the reasons you mentioned. I just thought it was interesting at the time. How hard will most people be able to push a stock slant six? Probably safe unless it seriously overheats. I also think you get more lubrication with a solid cam because of the gap, but that is just me thinking out loud...
 
You must log in or register to reply here.
-

Back
Top