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I think I have been running my valves too tight
https://slantsix.org/forum/viewtopic.php?t=58190		 Page 1 of 2
Author:  Sam Powell [ Thu Aug 06, 2015 8:27 am ]
Post subject:  I think I have been running my valves too tight
My slants have always idled poorly when coming off a long highway drive, regardless of the engine, and the induction system. It popped into my head last night that maybe in an attempt to quiet the engine down I have always adjusted them too tightly. I have a cam of unknown specs in there now. (Somewhere along the line I lost the cam card.). I think I was adjusting them at 15 and 20, but will open them up a bit and see if that helps. I know this has been addressed many times in the past, but wondered if there was advice out there?

While I am at it, let me ask a question that may make some laugh, but would it work to put hydraulic lifters and valve train on this solid lifter cam? Will it damage the cam? How will performance be effected? Will the push rods from the truck work in this motor? I think I have milled the head and block minimally to straighten. If I recall correctly, the compression is just about 8:1 now. Should I buy new lifters, or use the old ones that are in the 80's truck engine I have in my garage? Is this a completely stupid idea? Long range plan is to build the truck engine as a hydraulic engine.

Thanks for any thoughts, and thanks for not laughing too hard. :oops:

Sam
Author:  coconuteater64 [ Thu Aug 06, 2015 12:23 pm ]
Post subject: 
First of all, I think the hydraulic lifters with a solid cam would make the cam seem more aggressive, since the ramp shape it different. The lifter would start moving a bit earlier. Also, the ramp profile on a solid cam is not really flat as viewed front to rear. I don't know if it would bust stuff up or not.
Author:  SlantSixDan [ Thu Aug 06, 2015 2:32 pm ]
Post subject:  Re: I think I have been running my valves too tight
Quote:
I have a cam of unknown specs in there now. (Somewhere along the line I lost the cam card.). I think I was adjusting them at 15 and 20, but will open them up a bit and see if that helps.
That's the way to do it—try it and see if it helps. If you like quiet, pick out a nice valve cover and have it powder-coated (I recommend Leanne at Phoenix Specialty Coatings, who makes powder walk, talk, sing, and dance). A powder-coated valve cover cuts way down on valve noise audible with the cover installed. If it's powder-coated inside and out, even more so. If it's cast aluminum (Offy), even more so. This trick also works on the oil pan.

Note that 0.010" and 0.020" is the lash recommendation for the stock cams. It doesn't necessarily apply to aftermarket cams, some of which want looser and some of which want tighter.
Quote:
would it work to put hydraulic lifters and valve train on this solid lifter cam?
The engine might start and run, but it will be very far from optimal. Solid lifters : solid cam :: hydro lifters : hydro cam. Different lobe profiles for any given desired valve motion schedule.
Author:  '67 Dart 270 [ Thu Aug 06, 2015 3:10 pm ]
Post subject:  similar question
Sam,

I adjust my valves with the engine warmed up and running as the manufacturer specifies.

But, last time I did this, I had come straight off a long drive and the engine was really, fully, warmed up, so to speak. I noticed that my feeler gauges lash settings from the previous adjustment (a week earlier) didn't fit, the gap was too snug to fit the feelers. Which means to me the last time I'd set them, the engine wasn't fully warmed up yet. So, did I set them right this time or last time (or not right either time)?

I don't have the idle issue that you have, or any performance issues that I can discern. I'm only mentioning this because there appears to be quite a bit of expansion between a cold engine and when the system is fully warmed up. Those push rods are pretty long....

I don't mean to usurp your thread, but my question was also around adjusting them properly and optimally to minimize the clickety-clack when at idle. I have a powder coated offy cover and Dan is correct, it is quieter than a standard tin for sure. Still, I haven't mastered the art of adjusting them to be quiet; mine seem to sound the same no matter what adjustment. Though I've never tried gaps smaller than spec's. I have tried looser to exactly on spec at both "warm" and "hot" engine temps.

I've seen videos posted on youtube that show "before" and "after" valve lash adjustment and some appear to have really mastered quieting down their valve train.

Anyone out there have particular tips on the "feel" of the feeler gauge for optimal sound reduction and/or particulars on engine temp when adjusting valves while running?

Fun stuff.

Brian
Author:  Rick Covalt [ Thu Aug 06, 2015 5:38 pm ]
Post subject: 
If a solid lifter engines is not making some noise then I am pretty sure the valves are not adjusted right. :lol: :lol:

I run my engine until fully hot, and adjust the valves with the engine off. I see no reason to throw oil everywhere and shake my arm off. :lol: :lol: Many will say that this method is wrong (as will the factory manuals) but many of us have done this and it works fine for me. I adjust until I have just a little drag on the feeler gauge and call it a day.

I have done it running many times and I prefer the easy, non running method.

Do a search and I am sure you will find plenty of debates about this subject. :lol: :lol:
Author:  '67 Dart 270 [ Thu Aug 06, 2015 5:46 pm ]
Post subject:  Thanks Rick...
I don't want to stir up the running/non-running debate for sure. To each his own.

Your comment on the drag on the feeler gauge was helpful.

Do you pull the plugs so you can turn the crank easier when moving from adjustment to adjustment, or how exactly do you do this? It would be great to get the non-running adjustment perspective.

thanks,

Brian
Author:  slantzilla [ Thu Aug 06, 2015 6:05 pm ]
Post subject: 
Turn the radio up and call it a day. :D
Author:  Rick Covalt [ Thu Aug 06, 2015 6:22 pm ]
Post subject: 
I start at the front and go to the back. I have a bolt in the crank and wind it over with a wrench. I don't pull any plugs and I am done in 10 minutes, 15 tops.

Rick
Author:  Sam Powell [ Thu Aug 06, 2015 8:19 pm ]
Post subject: 
Thanks for the thoughts. I am wondering how much too tight Brian's adjustments got when really warmed up, and what setting he used initially. In other words, how much looser than initial adjstment would you need to go to compensate for the later extra expansion?

Sam
Author:  Rick Covalt [ Fri Aug 07, 2015 3:43 am ]
Post subject: 
I seem to recall someone setting their valves cold and then checking them when the engine was hot. And they were something like .001 to .002 tighter when hot.

Rick
Author:  Sam Powell [ Fri Aug 07, 2015 4:47 am ]
Post subject: 
Hmm. Thats not much. You would not think .001 would not change the idle much. Maybe I am barking up the wrong tree here. What else would make the engine idle poorly when arriving at the first stop light after an extended 70 mph run? I thought for years it was somehow temp related, but this always happened with all my slants regardless of induction or fuel routing. So I got to wondering what else could temp effect besides fueling. That was when valve adjustment came to mind.

Sam
Author:  mopardean [ Fri Aug 07, 2015 6:05 am ]
Post subject: 
many would disagree but I like the sound of solid lifters in an old slant

its kinda vaguely agricultural and gives the old beast character

:wink:
Author:  Nicademas [ Fri Aug 07, 2015 6:16 am ]
Post subject: 
Quote:
I seem to recall someone setting their valves cold and then checking them when the engine was hot. And they were something like .001 to .002 tighter when hot.

Rick
Yep that was me :P
Author:  Nicademas [ Fri Aug 07, 2015 6:29 am ]
Post subject: 
Also here is the link to my valve adjustment problem in case it helps you. Go to the bottom of page 2 to skip the chatter :3
Author:  Nicademas [ Fri Aug 07, 2015 6:30 am ]
Post subject: 
Also here is the link to my valve adjustment problem in case it helps you. Go to the bottom of page 2 to skip the chatter :3

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