2.8 which valve stem seals with pics

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brooky
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2.8 which valve stem seals with pics

Post by brooky »

Just taking heads off to replace valve stem seals, wanted to check if i need to fit new head bolts as various forums say use new and others say you can reuse so what do you recommend from your experience.

Also want to check which valve seals to fit as old ones are spring ring type on inlets and rubber cap with no spring on exhaust, these are the new ones supplied by motomobil which are like the ones took off (Spring type on right, rubber cap type on left}

https://flic.kr/p/VuYpV4

According to Motomobil the spring ones go on inlet and rubber ones on exhaust, done some translating from Google :cool:

https://flic.kr/p/VuYpVz

As you can see, both my seal seats are the same

https://flic.kr/p/Vw7m8c


Haynes also states that the spring ones go on inlet, rubber caps on exhaust

https://flic.kr/p/VuYpVp


My query is that my head has all the seal seats as shown on the left of the motomobil picture so I assume I need to fit all spring type seals and not the rubber caps which need the deeper seating arrangement shown by motomobil, even though I had rubber cap type fitted to exhaust valves when heads were refurbed by tickover - could this be why the engine is smoking on start up after just 6000 miles, rubber cap seals not right for configuration of the seats?

The rubber seals on the exhaust valves at the moment do not fit onto the seal seats as the seats are smaller diameter, you can see here the seal just sliding up the valve stem

https://flic.kr/p/Vw7m8H

can i fit spring type on all the valves. The rubber cap type are in the new head sets sold by burton but surely the spring seal type provide a better seal but i am sure there is a reason Mr ford didnt use them on the exhaust valves.

Here you can clearly see that the current seals have worn compared to the hole size of the new ones on the right hand side so definitely think this is the smoking problem,
https://flic.kr/p/WG1P7E

the spring seal will be the best fit on the exhaust valve but will this be okay or does the valve stem need to get some oil through which the spring seal will not let through. Here you can see my seal seats with inlet on right (well spotted neil in later post so updated here)

https://flic.kr/p/Vw7m8c
Mark
Last edited by brooky on Sun Jul 16, 2017 8:19 am, edited 7 times in total.
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Peter-S
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Re: 2.8 cylinder head bolts and valve stem seals

Post by Peter-S »

Hi Mark,
From the three sets of heads that I have experience of you won't be able to use spring seal on all stems, they won't fit. Inlet and outlet are different as you say but the exhaust seals that I have used are an off white plastic as in your third picture. Seems strange that your heads are different.

On the bolts I've reused them without any problem.

Peter
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brooky
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Re: 2.8 cylinder head bolts and valve stem seals

Post by brooky »

Looking at the 3rd picture you can see a difference in diameter of the 2 seals/ valve stems diameters but on mine the exhaust and inlet shafts are same diameter as are the base on the heads that he seals go onto so i can get the spring seals to fit as the configuration of inlet and exhaust are the same apart from the actual valves being different sizes

You can see on the 2nd picture that the base on the heads is physically different when fitting the 2 types of seals recommended but i have the same base on all positions.
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sheff
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Re: 2.8 cylinder head bolts and valve stem seals explanation

Post by sheff »

Hi Mark,

All other engines that I have replaced stem seals on have had the spring type on exhaust and inlet valves. However the cologne engine seems different possibly to provide a little lubrication to the exhaust valve and guide, not needed on the inlet as it would be lubricated by the fuel.
Knowing that your heads have been refurbished then I think you might have phosphor bronze guides fitted which in the machining process has changed the shape at the top. The change of shape now allows the seal to move up the valve as its no longer a tight fit on the head. Check this with Burton but I think they may suggest not fitting the seals on the exhaust valves if bronze guides are fitted.

In my experience its the inlet valves that tend to cause smoking when they leak. And you'll see evidence of this when you remove the valve as it will look blackened with oil. A good exhaust valve will have a light coloured crust similar colour to the spark plug.

Remove the valves and post some pictures of what they are like.

All the best
Neil
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sheff
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Re: 2.8 which valve stem seals with pics

Post by sheff »

brooky wrote:
the spring seal will be the best fit on the exhaust valve but will this be okay or does the valve stem need to get some oil through which the spring seal will not let through, I suspect this is also why the exhaust guide has the oilway you can see on the right hand side which obviously wont be fed if spring seal is fitted?

https://flic.kr/p/Vw7m8c
Mark
Hi Mark,

Its not easy to see in the photo but the left hand side looks a bronze guide to me. Just the top 1/4" is visible the rest is pressed into the head, which would have been bored out to accept it http://www.burtonpower.com/valve-guide- ... fp381.html.
And are you sure the right hand side is the exhaust valve? Was it the valve with 3 grooves for the collets? The inlet valve is 1 groove.

All the best
Neil
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Re: 2.8 which valve stem seals with pics

Post by brooky »

Well spotted neill, just checked and it is the inlet with the oilway as the photo taken is number 2 cylinder and front one on this cylinder is inlet. Now back to square one as exhaust has no oilway groove so can i fit spring seal or do i stick with cap seal and let it float.

Regarding bronze inserts i have tried the magnet again and definitely steel. going to drop a note to tickover to see if this size of seal base is normal because maybe it is meant to be that way and the non spring seal does just slide on the valve stem, the only indication it should be different is the motomobil picture I found when looking for the seals
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sheff
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Re: 2.8 which valve stem seals with pics

Post by sheff »

brooky wrote:Well spotted neill, just checked and it is the inlet with the oilway as the photo taken is number 2 cylinder and front one on this cylinder is inlet. Now back to square one as exhaust has no oilway groove so can i fit spring seal or do i stick with cap seal and let it float.

Regarding bronze inserts i have tried the magnet again and definitely steel. going to drop a note to tickover to see if this size of seal base is normal because maybe it is meant to be that way and the non spring seal does just slide on the valve stem, the only indication it should be different is the motomobil picture I found when looking for the seals
Hi Mark,
I'm not an expert, so you need to ask advise from Tickover and I would suggest Burton will probably be better as they didn't supply the heads. But my thoughts are and now I'm a little worried what I have on mine :? the exhaust valves should be plastic with what almost looks like oil ways to lube the valve like the white ones in this set http://www.ebay.co.uk/itm/FULL-ENGINE-H ... xyNDhSZX-b. I think the rubber ones you have might prevent lubrication and you'd be better off fitting your old ones.

Secondly I'm not sure if thats an oil way in the inlet valve stem guide! My concerns are that you have wear in that guide which could be the reason for the smoke. It will be interesting to hear what Tickover or Burton have to say about that? Give me a shout when you get the heads off and we can meet up to get a better assessment of what needs doing.

All the best
Neil
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Re: 2.8 which valve stem seals with pics

Post by brooky »

Just got both heads off and removed all the valves, the groove in the photo of mine is on all the inlet guides at the top 10mm on one of the heads, other head which was a replacement when engine was refurbed has slightly different shaped guides (slightly chamfered at the top rather than square edged) the ones with the grooves look like machined grooves rather than wear, etc so will check with tickover if I can fit spring seals to all positions.
Last edited by brooky on Mon Jul 17, 2017 6:17 pm, edited 1 time in total.
brooky
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Re: 2.8 which valve stem seals with pics

Post by brooky »

I have had some interesting clarifications back from tickover

From the factory the exhausts had the umbrella type seals and the inlets have the push on spring types. Reason is that there is suction around the inlet stem that draws oil in, so a positive seal is needed. The exhaust doesn’t have suction and so simple umbrella type works fine. When the heads are reconditioned, they fit a liner in the exhaust guide, because the exhaust guides wear badly. This liner is shaped and fitted in such a way that you can use the same style of seal that the inlets use if you want. It still works fine with the umbrella type though, and generally no benefit is found by fitting the other type. Umbrella type floats up and down with the valve
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