Going to replace my valve stem seals finally to see if it'll clear up the startup smoke and long idling smoke.
But I have no idea what to order.
Does anyone here know if the '85 duke has 8 valve stem seals? Or do the exhaust valves don't have them? There are also these big stem seals and small orings available at rockauto.
Really don't want to order these twice from the USA since the car will be sitting at a shop for a month longer.
The valve stem seals are sold in sets of 8 and the intake and exhaust seals should be the same. The seals should be the same as used on many GM cars, from the 1960's to 1980's , 1970-1985 Volvos and a few Isuzu' s so they should be able to be easily found in Europe. If you wish to match them up, the valves stems have an 11/32" stem and a .530" guide OD. Using the right tools these valve stem seals can be replaced without removing the head. Replacing the seals may or may not cure the smoking problem, but I would say that it should help.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
The valve stem seals are sold in sets of 8 and the intake and exhaust seals should be the same. The seals should be the same as used on many GM cars, from the 1960's to 1980's , 1970-1985 Volvos and a few Isuzu' s so they should be able to be easily found in Europe. If you wish to match them up, the valves stems have an 11/32" stem and a .530" guide OD. Using the right tools these valve stem seals can be replaced without removing the head. Replacing the seals may or may not cure the smoking problem, but I would say that it should help.
Are you 100% positive on this set of 8? I believe there are 8 orings and 4 cups or 8 cups. So either 12 or 16 seals altogether. Trying to figure this out.
Are you 100% positive on this set of 8? I believe there are 8 orings and 4 cups or 8 cups. So either 12 or 16 seals altogether. Trying to figure this out.
I am just going by the replacement parts manual. They show one piece Viton cup type seals around the valve stem and a simple O ring at the top. Take off the rocker arm cover inspect and verify.
I am just going by the replacement parts manual. They show one piece Viton cup type seals around the valve stem and a simple O ring at the top. Take off the rocker arm cover inspect and verify.
That's exactly what I'm trying to avoid. Don't have the means to look at it myself right now. Wanted to import parts from the USA and take the car to a shop. Not wait for a signal from the shop that something is missing and wait another month for parts. Hope you understand. That's where my thread is coming from.
Stem P/N 450483 (goes on the valve guide) O-Ring P/N 3835333 (goes on the stem under the spring cap)
See figures 1 and 2
Figure 1.
Figure 2.
1986 GM service manual says to replace both seals so you should order both the stem seal and the o-ring. To break this down properly, you would need to order a set of 8 stem seals and a set of 8 o-rings. I don't know what the shipping rates are for your location but ordering both the part(s) sets is good insurance since the part cost is fairly minimal.
As far as your diagnosis, I had a similar problem on a 1978 Toyota 2T-C engine with 89k on it. Smoking at long idle. When I had the engine out of the car to do the engine gaskets and seals, after checking the wear on everything, part of the seal kit was a set of guide seals. After replacing and re-assembly the issue of smoking at long idle was cleared up.
In your case, providing there isn't excessive wear, it should probably do the trick.
As with everything... YMMV
[This message has been edited by Mark_j (edited 05-08-2021).]
I haven't touched a Duke in a long time. But I checked the Fel-Pro head gasket set, and it includes 4 of the cup seals and 8 O-rings. The 4 cup seals go on the intake valves. See link below.
I haven't touched a Duke in a long time. But I checked the Fel-Pro head gasket set, and it includes 4 of the cup seals and 8 O-rings. The 4 cup seals go on the intake valves. See link below.
With all due respect, I'm only going by what the P22 and the FSM state. Neither specifies the count just the part number and the fact that they exist. Considering that the only seals and gaskets needed for this repair are the stem seals and the o-rings plus the valve cover gasket it's cheap insurance to order the set of 8 stem seals as the OP mentioned.
I haven't personally been inside a Duke in over 15 years so I can't say with certainty that the seal arrangement is intake only or all 8 valves. That said, my philosophy is it is better to cover the contingency of all 8 valves than to have the repair get held up due to lack of parts. My assumption from the information given that this repair is going to be done in a shop without removing the head. Since the cost of the parts for this job is relatively inexpensive as compared to the shop time necessary, It would be prudent to have all the seals required on-site.
Originally posted by Mark_j: With all due respect, I'm only going by what the P22 and the FSM state. Neither specifies the count just the part number and the fact that they exist.
I understand where your coming from. But there are 2 issues.
1) You're making assumptions, based on incomplete information. 2) There's a reason why the cup seals don't go on the exhaust side. The exhaust valves get hot enough to melt them!
I understand where your coming from. But there are 2 issues.
1) You're making assumptions, based on incomplete information. 2) There's a reason why the cup seals don't go on the exhaust side. The exhaust valves get hot enough to melt them!
Every engine that I've ever owned and worked on had oil seals on the exhaust valves. The Viton material used for valve seals is rated for up to 400* F use. Water also flows though the head so it never gets hotter than about 190*-220*. Even the older neoprene valve seals held up on the exhaust side.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I understand where your coming from. But there are 2 issues.
1) You're making assumptions, based on incomplete information. 2) There's a reason why the cup seals don't go on the exhaust side. The exhaust valves get hot enough to melt them!
And there is vacuum created under the intake valve to draw oil past the stem. Not so much under the exhaust.
