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Discussion Starter · #1 · (Edited)
OK, a question for the guru's on valve guide seals. I have two heads being done right now (they are at the machine shop, I should have snapped some photos when I was communing with them this afternoon). One is a '71 head, which uses the "positive" rubber seal, with wire retainer rings, that slip over the exhaust guides (like a hat). I understand that they are "good" (or maybe "best"?).

The same head appears to use a Viton (I think that was the material) O-ring that sits in the lower groove in the intake valve stem, just below the keeper and retainer. I presume that is "ok", but not as good as the positive seal.

Now the other head (a '69 three bearing head) seems to use the Viton O-ring on the exhaust stems, but I CAN'T figure out what to use for seals. The intake valves don't have a second groove on their stems, and the boss' around the guides are far too large for a positive seal. The gasket sets I have bought all have the two aforementioned seals, and also a rubber washer style (a light-brown colour) that I found on my '71 intake stems when I disassembled it.

My machinist and I discussed this, and (tentatively) have decided to leave the '71 head with the positive seals on the exhausts, and the Viton O-rings on the intakes. He will machine the '69 guide bosses to accept the positive seals. We discussed machining ALL the guide bosses for the positive seals, but he thought that there must be a reason the factory didn't already do that (although I have a recollection that the latest Opel CIH heads use the positive seals on all valves).

So, what seals are normally used on the '69 heads, and should I reconsider machining all the guide bosses for the positive seals. And what the heck are the rubber washer seals for?
 

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That is interesting so I had to look. I have a 69 here that the valves have never been removed and I don't find a seal of any kind on the intakes. Very curious.
 

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Keith,

Are you replacing the valve guides on either head? I know if you are/will be using bronze guide material, positive seals on both int and ext will be no problem.

Keep in mind Viton has high heat capabilities, 500-600 F. Nitrile or Buna N is only good for 300 F or so. The exhaust valve itself gets very hot, expecially # 2 & 3. I don't know if its a good idea to use the standard SBC positive intake seal, that most shops carry, on the Opel's exhaust. I'd try to find Viton positive seals. Teflon seals are high temp also, but require accurate machining for proper operation and longevity.
 

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Discussion Starter · #4 ·
Paul said:
Are you replacing the valve guides on either head? I know if you are/will be using bronze guide material, positive seals on both int and ext will be no problem.
Yes, all the guides on both heads have been repaired with bronze guides. And I have enough of the Opel positive seals (which I believe are Viton, same as the O-Rings) to do all the guides, intake and exhaust, on both heads. So is that the issue? The cast iron guides may do better without as much oil sealing, but the bronze allows less oiling, so the positive seals are the ticket.
 

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Keith,

That's the way I understand it. I was trying to relay info I had received from RBob when I was having a head done. I dont know for sure what the implications are if positive seals are used on the exhaust side if the factory iron guides haven't been replaced, scuffing of valve stems, etc. He had stated to me that since I would be using bronze guides, then positive seals on both would be no problem. Also, the Viton seals will out last the other seals by a long time.
 

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Valve component Questions

Since my questions are probably related to this thread that Keith started, I will ask them here. But first a bit of background on the situation.

Well, it has been a long time coming but I finally began dissassembling one of the remaining spare engines I have in my possession. This engine once was a runner but has been in storage since around the mid-eighties. I know what you're thinking, that it is probably seized and in pretty bad shape inside. Well quite to the contrary. Being an amateur and first timer rebuilding an engine, I asked a co-worker who used to build engines for dragsters in his younger days, to give me a hand. He was totally surprised and impressed at finding everything in very good shape (mopar guy!). The Crank, crank bearings, connecting rod bearings, all clean and no markings. As for the pistons and the cylinder walls, there was no scoring or damage to any of the items. The cylinders will require rehoning and the pistons require the carbon deposits removed from the tops. The block is now waiting to be taken to the local machine shop to be dipped, checked for cracks and rehoned.

Now to the head and the valves. I removed the camshaft and it too is clean and unblemished indicating (I assume) that the camshaft bearings are also good, so no need to replace'em (will get my expert over to have a look). I dissassembled and removed the valves,springs, retainers and caps, placing them into separate bags and ensuring to identify where they came from. (note: I started from the rear of the head and numbered each valve 1 thru 8). Here are the questions I noted while doing so:

1. Valves 2,3,6 & 7 (intake valve? one groove) had NO rubber o-rings on the stem, where as the remaining four (exhaust valve? two grooves) did have a brown/red rubber o-ring. It appears the valves 2,3,6&7 are utilizing seals like Keith discribed "positive rubber seal, with wire retainer rings, that slip over the intake guides (like a hat). Are they available, where do I get them and can I install them myself? What about the Viton O-ring, does Gil stock these?
2. The afore mentioned valve's springs have two colored markings on them. Is this just to identify them as intake valve springs or is there another reason?
3. At the base of valve springs 1,4,5 & 8 there was a seat that appears to be a bearing. What is it called and what do you look for to determine whether it is serviceable or requires replacement?
4. Along the top of the head, between the hydraulic lifters are 5 what appear to be threaded "plugs". What are their purpose and is it detremental if they become scored?
Anyone?
I will try to get hold of a digital camera early this week to post some pics of the valve guides.
 

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Seals

1) The brown/red "O" ring on the exhaust valve is a Viton one. It is positioned just below the valve spring cap to stop oil that is collected on top of the cap "running" down the valve stem and flooding the guide. The "Hat" type seals used on the intakes restrict the amount of oil that is "sucked" in through the guide by the lower pressure the intake manifold. (The oil is of course "pushed" down the intake guide by the higher pressure in the rocker cover ...). Viton "O" rings can be bought at Engineering supply houses.
If you are using the stock 9mm stem valves ten you will have to get some Opel seals. If using 11/32" Chevy valves then a ice set of after-market "Teflon" valve stem seals can be used. Just cutt he top of the guide with an SB Chevy seal tool and use SB Chevy seals .....

2)The coloured markings ("paint") is an identifier for the springs. If you are using standard springs note that there is a mafor difference in the free lengths of the intake and the exhaust spring.

3)That bearing is and exhaust valve rotator and is the reason that exhaust valve springs are shorter - to make room for it.
Intake valve springs can be used on both intake and exhaust as long as a spacer is used to replace the rotator to make the installed height of the springs the same on both types of valve. However the rotator is there to extend exhaust valve seat life and a hardened exhaust valve seat should be fitted if it is removed, as a precaution to reduce e-valve seat recession due to unleaded gas ..... a whole 'nother story......

4)The plugs are the ends of the oil transfer pasages from/to the cam bearings - one is the end of the oil passage up through the head from the block. As long as they seal what the outside looks like is not going to affect them - if they are replaced then just use screw-in plugs .....
 

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I'm reviving this thread as I have to figure out what to do with the valve seals on the reconditioned head I'm working on.

I tried to post pictures to this thread, but they won't upload. The upload screen just sits there. Anyway, what the picture would have shown is:

  1. The intake seal that came with Felpro set doesn't look like it has much of a chance of fitting over the valve guide in my '69 head. The valve guide bosses are larger than the entire seal.
  2. These are Chevy valves and the 1.5" exhaust valve doesn't have a second groove - no place for the o-ring seal.

When I took this head apart, I don't remember there being any of the intake type seals installed. Both intake and exhaust valves has second grooves and may have had the o-rings.

Are there any solutions to this other than machining the guides down to fit the seals over?

Has anyone ever used the valve seal cutter available from Crane and others?
 

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68, 69 and 70 heads that will work on a 1.9 had only the O ring seals on both intake and exhaust. Some of the 1.5 exhaust valves have the second groove and some don't, just depends on the manufacturer. I don't know where your at in this project but most shops that do head work can grind in the second groove or fit a seal to the head. Personally on early heads I use a valve with the second groove and on later heads no worries with whatever you choose to do later on with the same valve. Oh the joy of mixing and matching parts is a fun process. HTH and have fun. If you want I can ask the shop that does heads for me on monday about brands and things. I'll PM you the info if you want. I'll be there anyway

Did you resize the pics you wanted to load? if they are too large it does just sit there.
 

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Thanks that's helpful info on the early heads. If I understand you correctly, I can just use the o-rings on both the intake and exhaust if I get the groove cut in the exhaust stems.

I would like to get get going on this but I'm still waiting for the Getrag to arrive and I've got engine compartment work to do so there is really no rush. I can take the head and get the bosses resized to use the umbrella type seals is that is really the superior way to go.

The question is, will I get significantly more oil leakage if I just go with the o-rings?

(and yes, the pic is only 113kb and should upload. even photos I've already posted don't work)
 

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On one motor I left out the seals completely by my inexperience. the guides were so correct that it never leaked. Pick a good machine shop and let them go with it is my best recommendation. I won't tell you which is better because it is up to you and your expextations of what you want vs what you want to spend.

I'll go have a peak at the 70 delta head and see how it was sealed.....it has a valve with a second seal point. The 1.5 heads will be the same and I'll ask him about the manufacturer on Monday. ... I'm already on black ice to respond but I will find the manufacturer for you.

Go with the new guides at factory tolerance and keep with the year specific seal type is my best recommendation.

Fully built heads are like lawn ornaments here! No late model years any more but they all are ported with big valves.
 

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Guide Lube ...

Cast Iron guides can get by with very little lubricant as the carbon/graphite in the cast iron itself acts as a solid lubricant. So teflon seals can be used on both in and ex guides. These seals tend to be a little tight for a street motor which does need some lube in the guides - I usually 'rattle' a valve guide reamer around inside the teflon seals before fitting them.

Bronze guides, on the other hand, MUST have some lubricant or they get sticky. In this case a teflon seal that has had a valve guide reamer run through it can be used on the intake valve but it is best to just use the 'o'-ring and umbrella set up on the exhaust valve to ensure a bit of lube for this, the hottest valve.

I use K-Line ali-bronze liners for Chevy valves (and Holden ones!) - with the intake use the spiral swaging tool to make a groove down inside the guide to within 6 to 8mm of the inner end and the exhaust right through - this helps with oiling the guide. Without oil these liners just DIE!

When Chevy valves are being used it is real simple as there is a vast range of valve seals available - with Opel valves you are pretty much stuck with the standard seals.

When fitting teflon seals the guides have to be cut so they will fit (there are several Chevy tools available to do this job). Make sure the guide is cut down far enough so that when the seal is fitted there is at least ).040" clearance between the top of the seal and the bottom of the valve spring retainer.
 

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Thanks Jim. The picture uploaded fine this morning so I'll attach it even though the discssion is well under way.

As you can see, this head has chevy valves and bronze guides installed. The exhaust springs will no longer have the umbrella type retainer on them which I gather helped with oil control so it seems to me that something additional will need to be done.

I will go today and see if I can source the cutter. Would it cause a problem to cut the guides on both EX and IN to use the teflon seals on both?
 

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Discussion Starter · #14 ·
I had "hat" seals fitted to all the valve guides (only the '71 head had the proper guide boss size on the exhaust originally), albeit I stayed with the stock Opel valves with 9 mm stems (I had extra hat seals from a multitude of gasket kits I had acquired over the years). The machinist suggested that the bronze guide was actually better than the OEM cast iron for "lubricity", but I suspect that is related to his experience with SBC's (although RB apparently agrees). The machinist just cut down the guide bosses for the umbrella seal to fit over. He did John Warga's head (going on his 2.4 conversion) which uses the Chevy 11/32" valves at the same time, which of course used Chevy seals. They looked exactly the same, but both the ID AND OD of the hat seals are a different size (makes sense).

I just looked at the invoice (I had pulled them out earlier when CDN OpelNut PM's me about cam bearings) and the cost to cut the guide bosses down were only $5 each (and $CAD at that!). The Viton "hat" seems like a better seal than any old O-ring, and the machinist concurred, and the cost was only $60 extra for two heads.

HTH
 

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As You Are ....

I will go today and see if I can source the cutter. Would it cause a problem to cut the guides on both EX and IN to use the teflon seals on both?
The seal you have pictured looks like a Viton seal - with the bronze guide liners you have I would use that seal on the intakes and (because the ex valve is cut for them) the 'o'-ring and umberella on the exhaust valves.
The 'o'-ring stops oil running dow the stems by sealing under the retainer and the umberella directs oil out over the spring - leaving a bit of splash lubrication for the valve stem.

With due deference to what anyone else thinks/says - my experience with bronze liners leads me to believe that they DO need a wee bit of lubrication - more so than cast iron guides. :confused:
 

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The seal you have pictured looks like a Viton seal - with the bronze guide liners you have I would use that seal on the intakes and (because the ex valve is cut for them) the 'o'-ring and umberella on the exhaust valves.
Sounds reasonable except the exhaust valves I have don't have the grooves in them for the o-rings, and I don't think I can use the stock umbrellas on the Chev valves. (valves in the photo are not in front of their respective guides)

Leaves me with 3 options on the exhaust side - 1. go with o-rings alone and get the grooves cut, 2. go with seals on the machined guide bosses, or, 3. both.
 

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Ummm ...

Best to leave cutting grooves in valve stems to the manufacturers - they have found a way to do it that does not weaken the valve stem by trial and error.
Just go with the seals on both in & ex - check that the groove on the in does not get tangled up with the seal at full lift though ....
BTW Chevys do have umbrellas too
 
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