retainer to guide clearance

[siuauto]

Hello all, I just bought a 60403 voodo cam and, I was talking to them before buying the cam about specs for valve springs. I told them I have single springs and gave them the specs and he said they will be fine but I may have to cut the guide down a little. I am assuming he is talking about retainer to guide clearance? Have any of you experienced this? How do I measure this. I am assuming I have to take a measurement from the retainer to the guide but at what what lift point. I think I remember doing this in college and we took a measuremnt and we used max lift plus .030 as a spec but that was a while ago and I haven't do it since. Any help will be great

 

[Guitar Jones]

I like .060 retainer to guide clearance at max lift. I've never experimented with less so I don't know if it works or not. My engine only has .028 piston to head clearance though so common sense would say you can get buy with less on the retainer to guide, but I don't know.

 

[siuauto]

So do you just measure it with the valve closed and the spring off. From the bottom side of the retainer to the top of the valve seal? That number should be .060 above max lift?

 

[moper]

Retainer to guide is the lowest spot on the retaner and the top of the valve seal. You can measure it with the spring and feeler gages or without. I would use a dial indicator and open the valve to the advertised lift with your rocker ratio. I use .050 as the magic figure for most stuff. if your springs are light compared to the recommended Lunati springs you may want more.

 

[fishy68]

So do you just measure it with the valve closed and the spring off. From the bottom side of the retainer to the top of the valve seal? That number should be .060 above max lift?

I haven't done it that way but it sounds like it should work. I've always had the heads off on the ones I've done and I did it with a dial indicator set up on the valve tip. Also remember to do it with the valve seal installed.

BTW: I kinda doubt yours will clear if the heads are stock unless you get real lucky. I've measured a few sets of stock heads and the most lift I've ever seen a stock head be capable of is .490" and some were as low as .450". The Lunati 60403 is .513" lift on the exhaust side. You won't quite get that much lift due to the angle of the lifters to the rocker but it will probably be close to .500".

 

[siuauto]

Thanks for the advice. When I was in collage I built a 225 and I cut the guides for PC seals and I thought that was fun so why not do it again. I finished with one head tonight and I will do the other tomarrow. I used the .050 as my benchmark for my retainer to guide clearance and I have them spot on. It sure saves money when you do it yourself, plus when things break you can only blame yourself.

 

[SpeedThrills]

BTW: I kinda doubt yours will clear if the heads are stock unless you get real lucky. I've measured a few sets of stock heads and the most lift I've ever seen a stock head be capable of is .490" and some were as low as .450". The Lunati 60403 is .513" lift on the exhaust side. You won't quite get that much lift due to the angle of the lifters to the rocker but it will probably be close to .500".

I don't have a lot of experience in this, but my 360 (non-Magnum), has a purple .509 cam. Stock umbrella seals and roller rockers (true lift). Did the engine builder (unknown to me), get a "good" set of heads? I'm disassembling this engine for inspection and freshening. I didn't measure the clearance because it was "a lot". :confused:

Also, don't Magnum heads have a different guide-to-retainer clearance? Siuauto doesn't say what heads he or she has.

 

[fishy68]

I don't have a lot of experience in this, but my 360 (non-Magnum), has a purple .509 cam. Stock umbrella seals and roller rockers (true lift). Did the engine builder (unknown to me), get a "good" set of heads? I'm disassembling this engine for inspection and freshening. I didn't measure the clearance because it was "a lot". :confused:

Also, don't Magnum heads have a different guide-to-retainer clearance? Siuauto doesn't say what heads he or she has.

Sounds like you got real lucky or they were cut down some (and you didn't know) if they truly had "alot" of clearance. I have to say that even with good rockers that provide a true 1.5 ratio, which stock arms don't, you probably still didn't get a full .509 lift because of the lifter to pushrod angle. That angle added to the equation causes a little lift loss. Maybe that's why you got away with it?? Another possibility is if the valves are sunk due to being ground 2 or 3 times over the course of their life. The farther the valves are sunk the more clearance you have. The Magnums seem to accept about the same valve lift (seems every head varies some that's why I gave the range earlier) but the big reason they won't take as much cam lift is they use 1.6 ratio arms. So when you use a .484" lift cam with Magnum heads the actual lift is .516", minus the amount lost due to the pushrod angle. Again these are just my findings. I'm not an expert, just somebody that has measure a few sets.

 

[SpeedThrills]

I just finished cleaning everything. Now, I'm mocking it up to check piston to valve. I'll measure the retainer to valve, and lift at the retainer, too. I are curious. Oh, the valves aren't sunk, but I see your point.
Thanks! (Sorry for the hijack...)

 

[siuauto]

I can't imagine it has umbrella seals and been cut. I don't think I have ever seen cut guides and umbrella seals but I could be wrong. Maybe you just got lucky. I would double check it. The heads I did are a J head not a magnum but they would not clear my 513 lift cam. If you do need to cut them down I would recomend the CompCams tool. I used the 500 PC seals and not the 530 seals. I don't think alot of peole would recomend .500 seals with a 3/8 guide but that was the tool I already had so I just used it. I am going to post some pictures soon but my camera is dead.

 

[SpeedThrills]

I don't think they're cut, either. Looks original. Mine are J's, too. They're ported, they have nice stainless valves, and have worn out stock guides. I guess I should have them flowed to see if they're any good, before I get bronze guides. I'll get 'em cut for the seals then, too. Why would someone get their heads ported and not put guides in? Beats me.

 

[fishy68]

I wonder if those stainless valves are longer than stock (+.050~.100) giving you a little more clearance? Maybe that's why they clear. Just a thought.

I personally don't understand guys even doing a valve job on heads with loose guides. Much less a head that's ported for performance. Guides are extremely important to keep the valve located properly so it seals good.

 

[SpeedThrills]

I didn't think of valve length. Good idea. I'll check when I get out in the garage, hopefully this weekend.

 

[D-mailman]

In mock-up before final assembly, and I have done this on the workbench too. With a light checking spring installed set up dial indicator on retainer with indicator 'zero'd' push down on valve until retainer contacts valve seal and read travel off the dial indicator directly. Then subract your 'as installed actual' lift from that figure. If your not sure as to the actual as installed lift bolt the head to the block and while useing the checking spring crank the engine to max lift and zero the indicator, push open valve until it contacts the seal and read your clearance directly from the indicator. .050 is ok but I like .060 better.

Terry

 

[moper]

The good euipment can't do a valve job on bad guides... So when someone says they can "get a set of heads done for $400" and there isnt a charge for guide replacement... I can already tell the work is not what I would define as good.

 

[SpeedThrills]

The intakes are 5.050, and the exhausts are 5.075. I don't have any known stock valves to measure, but found in a book a number of 4.980. If that number is right, I guess I do have longer valves, and the "mystery" is solved. I'll check the actual retainer-to-seal clearance tomorrow.
As far as getting the work done, I used to live in Philly. Now, I'm 90 miles south. I'll probably take them to the shop in Philly, though. The guy is good.

 

[SpeedThrills]

I got .039 on the exhaust I checked (seal to retainer). The intake I checked is actually making contact. It appears to be squeezing it some. I'll be cutting them for PC's, for sure!