351c 4v valve spring shim question |
Post Reply |
Author | ||
SeattleJay
Member Joined: 07-October-2012 Location: Seattle, WA Status: Offline Points: 134 |
Post Options
Thanks(0)
Posted: 24-January-2022 at 2:47PM |
|
Hello all,
I was trying to figure out on stock 4v heads what would be the maximum thickness of a valve spring shim that could be used to dial in spring installed heights? This would be a drop in on a stock head 1.5 OD and 1.031 ID shim. I was guessing a .060 would be the max while still having enough shoulder on the valve guide step to keep the spring from walking. Anyone have any idea that has done this? Also not sure of exact height of the valve guide step in relation to the spring seat face. Thanks Jay
|
||
Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
Post Options
Thanks(0)
|
|
i forget what they said was the max recommended shim thickness but if you shim too thick you'll lose the locating register of the spring seat and the spring will get out of shape. you can also use - (minus) valve locks to achieve your target valve spring installed height / pressure. they come in several different amounts of -. these are supposed to be some high quality pieces, locks are on pages 10-11 in the online catalog http://www.pppcenter.com/ if you can't get your height / pressure you may need to choose a different spring? you said stock heads, are you using stock valves, springs retainers & locks? what cam are you setting up for?
|
||
72 GT Ute
|
||
SeattleJay
Member Joined: 07-October-2012 Location: Seattle, WA Status: Offline Points: 134 |
Post Options
Thanks(0)
|
|
The valve spring installed height is .060 off so I just ordered some hardened shims to bring me up to spec. The headwork was done by PO years ago. The replacement cam has 227 duration intake and 233 exhaust about .556 lift hydraulic flat tap. Seated without the shim I was under 100# seat and knew it would be when I put it together but decided to give it a go, worked out for a lighter break in and really wondered if i really needed 120# that was spec. Now I'm getting some float around 4000rpm . This is a "what can you get away with?" type of deal. Hind sight when I bought this stuff I had no idea the can of worms I would open up from the last owners work and the nuances of the Clevelands valve train. I decided to give it a shot to see if I could put this train wreck together and have some fun with it. I've watched too many episodes of Roadkill I guess. So, stock type valves, new locks and retainers. Yep, the kiss of death! Scorpion adjustable rockers bolt down, Lunati Voodoo cam, lifters, timing set, and springs. I was just really hoping to get confirmation about the locating register before I ordered the shims. I guess when I do crazy stuff like this the only way to know is when the shims get here this week and install them. Heck, I have driven this car more the last month than the 13+ years I've owned it so I consider that a win. Thanks for responding I appreciate your experience! |
||
72 RS 351
Senior Member Joined: 04-September-2014 Location: Knoxville TN Status: Offline Points: 2765 |
Post Options
Thanks(0)
|
|
I wish I wasn't so far behind on many things. I too am planning a rebuild of my 4V. I expect to find some good and some bad things. I have a set of used heads I could build from scratch, if those on the engine were okay with new valves etc(to sell as is). They may be fine for a typical mild build. I will have the heads reworked and put in custom cam springs(they are unlike common springs(usually beehive and stronger)). The oiling system is what you have to deal with if the rpm goes above 5k. Usually for a better engine you have spring seats installed, so the machine shop does what it takes so the spring seats fit right. Then the spring height ends up being very close, or else you have the seats that have plenty of ledge to accept any shims.
|
||
Don
73 Ranchero "Sport 72 front end", floor shift/console, planning EFI 7000+ rpm 351-4V &4R70W 73 Ranchero GT 351C-4V &4R70W for sale later. 92 Lincoln Mark VII SE GTC, OBDII 347/4R70W |
||
SeattleJay
Member Joined: 07-October-2012 Location: Seattle, WA Status: Offline Points: 134 |
Post Options
Thanks(0)
|
|
These heads have had guides and seats. The work though is questionable. Installed valve height is off valve height variance. That was the main reason I put the scorpions on.
|
||
Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
Post Options
Thanks(0)
|
|
you'll want to check the springs for bind height and make sure your .060" shim doesn't eat up all the bind clearance. IDK if i posted this vid before but it covers a lot of info. dude mentions locators, you can use a locator as a shim and the ID step prevents the spring from dancing on the bottom end |
||
72 GT Ute
|
||
SeattleJay
Member Joined: 07-October-2012 Location: Seattle, WA Status: Offline Points: 134 |
Post Options
Thanks(1)
|
|
Thanks for the video. I just got my shims. Springs were made to be installed at 1.82 and I am at 1.88. I will double check the bind but should be okay with the .060 shim that will put me right at installed height. The Cleveland head having that 1 inch shoulder gives you little option if you need to shim. The size is not available when it comes to locators with that inside diameter that I could find. I also looked at spring cups but ID is not a common size. The OD on the drop in springs is usually 1.5 for the stock head and spring cups did not look like they would clear without work to the seat. Smaller OD springs tend to be dual spring and the ID and rate is a no go for stock. There was one spring I found that had an iinstalled height that was closer but, the rate was not up to what Lunati speced for the cam.
I hope this info helps others that think about using stock heads for a cam upgrade that is beyond what stock springs can handle. Hind sight, I should have but had no idea... 1. Verify the current valve spring installed height to make sure I would be in spec with new springs. 2. Using stock heads has a very narrow window when it comes to spring rates ,rockers and part options. I will report back when I install the shims. I will give before and after measurements on things.
|
||
SeattleJay
Member Joined: 07-October-2012 Location: Seattle, WA Status: Offline Points: 134 |
Post Options
Thanks(0)
|
|
Shims arrived from Alex's parts. Took some time and measured all of them before installing. Nice quality, hardened and they dropped right in. For the stock head this would be the limit for thickness at .060. It gives enough for the spring to locate on the valve guide shoulder.
|
||
Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6059 |
Post Options
Thanks(0)
|
|
it's always something, each component further restricts your options on the next. i used Isky 8005A springs on this last set of heads i just had done, the spring seats needed to be cut for the inner spring ID so shop dude took that opportunity to cut an ID locator right into the spring seat or so i'm told. i haven't had the chance to have a look-see for myself yet. it's not easy selecting parts that all work together, it takes some time & still depends upon availability. makes me want to do the Sam Kinison yell sometimes
Edited by Rockatansky - 29-January-2022 at 12:25PM |
||
72 GT Ute
|
||
SeattleJay
Member Joined: 07-October-2012 Location: Seattle, WA Status: Offline Points: 134 |
Post Options
Thanks(0)
|
|
I believe they take the original locator and grind it to the point for the new type seals and should be around .530 to .500 instead of the stock diameter of 1.025 or so. You then can drop on a locator or use spring cups to help locate. You will find tons of options. I would think any stock cleveland head will need to be machined for anyone considering running higher spring rates like on bigger solid lifter and roller applications. Live and learn.
|
||
Post Reply | |
Tweet |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |