Calling Ol'Ron, calling Ol'Ron...

G.M. said:
You don't just stick .060 shims under warn weak
springs. There is a spring test machine that shows
the spring pressure at a set height. They should
all be close to the same pressure. G.M.
Click to expand...

I'll be using new stock springs from Speedway. Does that sound about right? Ron alluded to using the .060 shims and I was looking for confirmation.
 
George is right. Installed heigth at 45/50lbs for most street cams works quite well I use tgus in the L-100 and it'll turn 5k no problem. But it ain't made for that. It's made for cruising. Now if your going to use the rotators they have a shorter valve and spring and will need a .060a' shim to bring the numbers up to 45/50lbs.
Gramps.
 
As GM alluded to when building engines guessing is never acceptable. Along with any other engine spec you should ALWAYS check valve seat pressure. Guessing is gambling. How much do you have in your engine. Cheers. Tony
 
Okay, I'm getting a little confused here. I was planning on using original Johnson adjustable lifters with original valves that are in good shape along with the advised .060 shims. Are you guys saying that the valves used with the adjustable lifters (which came from a rebuilt C0BA) are different than with the non-adjustable lifters? The engine is a Canadian '49 or '50 Merc (I've forgotten right now,to much thinking!) which was never rebuilt.

In short, are the original, in good shape, valves ok to use with the adjustable lifters with new springs and the .060 shims?
 
Too many unknown variables. How much previously has been cut from valve stems. Exact length of valve. How much valve has by ground. Condition of seats. Installed height of seat. The list goes on of factors that change valve spring tension.
 
Thanks for all those good points. As stated the engine has never been rebuilt. I will discuss more with my machinist when we talk about increasing the over bore. I know the valve seats will need a little tidying up though. So in my mind I'm thinking that valve stems that have never been ground and a tidying up of the valve seats should mean that the valves should be long enough and may need a little trimming. Will measure the length of the valve. Hopefully paying a visit to the machine shop next week.
 
Your machinist should be able to measure your valve springs for you. You need to determine the spring seat pressure at a specific spring height. That height may or may not require shimming. Any good flathead rebuild book should go into detail on how to go about this.

You need to be sure your machinist has experience with flatheads and the required equipment to do the job.
 
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Fortunateson said:
I'll be using new stock springs from Speedway. Does that sound about right? Ron alluded to using the .060 shims and I was looking for confirmation.
Click to expand...

New springs need to be tested and exter shims may be needed
to get the springs to the same pressure at normal spring height.
There is a machine just for this. I have one. If you get to Florida
I will help you do them. G.M.
 
The method of getting the the right tappet clearance in a flathead is by grinding the dtem of the valve. na has nothing to do with the valve spring. The slight amount you'd remove would not change the valve spring pressure a measurable amt. However old springs loos some of their umph and need some help so measuring this is quit easy take a valve and install it witout the spring and measure the distance between the buid and spring retaier, Now get the bathroom scale out and put a valve in the chiuk of your drill press anf force the spring down to the same numbet and read the dial. It should be 45/50lbs. Not exactily rocket science, just flathead science. The adjustable lifter just makes it easire to get the right tappet clearance. Don't forget to drill the hole??
Gramps
 
Ron,

I didn't get to connect with my machinist this week to ask about the .060 overbore versus .030, maybe next week. I will be drilling the holes to lock the Johnsons while they are adjusted. Now do I need the .060 shims if I'm using new springs with my Max1 cam? Sorry for pestering...
 
The only way to know is to measure the installed height of the spring and measures it's tension at that height.
 
Also, when you talk to your machinist find out if you have core shift, casting flaws or other defects that would keep you from putting a decent (.125") overbore in it while you're at it.
 
flatjack9 said:
The only way to know is to measure the installed height of the spring and measures it's tension at that height.
Click to expand...

Will do then. I would think that new springs would be without the variance but then they would be for a stock cam. I was hoping for an "right out of the box" yes or no.
 
Fortunateson said:
Will do then. I would think that new springs would be without the variance but then they would be for a stock cam. I was hoping for an "right out of the box" yes or no.
Click to expand...

All springs need to be measured, just like ring gap, bearing clearance, etc. There really is no such thing as correct or no variance right out of the box. They may or may not be correct, that is why you need to check! You might be able to just install them out of the box, but then you never know what value the spring pressure really is and if it is consistent. You also need to determine the install height before you can determine the spring pressure. The install height varies based on the valve seat and face of the valve.
 
Well I've been well and truely educated! Thanks for all the replies. I just presumed there would be consistency with new parts. I'll see if I can get to the machinist this week...
 
Fortunateson said:
Well I've been well and truely educated! Thanks for all the replies. I just presumed there would be consistency with new parts. I'll see if I can get to the machinist this week...
Click to expand...

There may well be, but there may not be, just no way to knowing without checking.
 
You Just have to measure to see what you need and then supply it, Now, I you plan on running a cam like the 400jr , or any other cam with a high lift rate for extended period's of time ( like circle track or Biville. Your going to need more spring pressure. But why put 60/70 lbs on the cam and lifters, if they will never see 4k.
 
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