Retainer/Seal Clearance & Valve Springs

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White Lightening

White Lightening

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Fairbanks Alaska
So my question is straight forward,

I want to know how much can say, stock 318 heads take before the retainers start knocking on the stem seals.

How can I increase the retainer/seal clearance?

What's a good rule of thumb for camshaft lift in relation to valve spring open pressure/closed pressure? (Particularly with mechanical flat tappet camshafts)

How do I know if the machining die is the right size for resizing spring cup diameter?

I'm asking a lot of questions, but I hope that if any one does a quick google search and they come across this thread it can help guide them in the right direction; either to their engine room, or to a professional machine shop
(which is in lacking supply in Alaska)
 
White Lightening said:
So my question is straight forward,

I want to know how much can say, stock 318 heads take before the retainers start knocking on the stem seals.

How can I increase the retainer/seal clearance?

What's a good rule of thumb for camshaft lift in relation to valve spring open pressure/closed pressure? (Particularly with mechanical flat tappet camshafts)

How do I know if the machining die is the right size for resizing spring cup diameter?

I'm asking a lot of questions, but I hope that if any one does a quick google search and they come across this thread it can help guide them in the right direction; either to their engine room, or to a professional machine shop
(which is in lacking supply in Alaska)
Click to expand...

Google search the questions.:D
Bet they are already out there.
 
usually, 318 , can use .480 lift max. to make more clearance, you shorten the guides. there's cutters made for that. usually, from .060 to .100 removed will provide room. also, use a shorter seal. like a K line style. camshaft will determine spring pressures needed. most cam companies list correct springs required. you have to measure installed height and max lift to know how much to remove.
 
i ran the 284/484 mp with no issues.according to hughes there are no clearance issues(usually).that was there reply when i inquired about the 318 whiplash. i didnt care for the usually part so stuck with what i had
 
I did a little research in to the guide cutters and watched some videos of them in operation. It seems like a simple job of calculating the amount of max lift+ .050" for safe clearance for the retainer/seal clearance. Then scribing a mark on the guide to cut down to with the guide cutting tool. Once done cutting and cleaning its as easy as installing the new aftermarket guide seals and making sure everything is geometrically sound.

As for camshaft + springs and finding answers, the only manufacturer I've found so far that lists recommend springs is comp cams. Dealers like Summit, Jegs, and some cam manufacturers fail to provide spring rate pressures. Or I'm missing it some how. Even comp cam's recommend springs don't delve in to detail about closed/open seat pressures and if they do, then they make it difficult to find that information.
 
the information is in their catalog. spring rates and pressures. it's under springs. their book shows spring number, then you look in spring section, gives you information.
 
Thanks for the help guys, I found the pressures and compcams recommendations.


I'll have to make a photo by photo "how-to" to measure valve guide to retainer clearance, and how to scribe and calculate how much of the valve guide will need to be cut.
 
it's very simple, measure open height of retainer. open valve to that measure between guide and bottom of retainer. you'll know how much room you have. it's not rocket science.
 
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