Oil in intake port

Engine, Trans & Driveline

  1. 62 Dart Convertible

    62 Dart Convertible Well-Known Member

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    I freshened up my '62 413 a few years ago replacing rings and bearings on the previously rebuilt bottom end and changed cam from .557 MP solid to Lunati Voodoo Hyd. Stock heads received valve job, Lunati double springs and retainers and Crane teflon positive seals. When installing intake, was not able to install intake bolts with the felpro gasket/ valleypan/gasket sandwich, so cut my own thinner gaskets from gasket paper. Car is a summer cruiser and has probably done 1000 miles since. I have long suspected it was using a bit of oil, but hard to prove as it is driven so little. It blows oil smoke from exhaust on start up so I suspected something top end. I pulled plugs, 6 looked perfect, 2 were caked with oil residue. Pulled intake, looked into intake port of the 2 oily cylinders and the 1 that had the intake valve closed was holding back a pool of oil (see pic).

    When I saw the oil pool on the valve, my money was on bad valve seals, heads are cracked or I'm sucking oil from intake gasket.

    I dropped heads back at shop that rebuilt them for inspection. They crack tested heads and checked valve guides/seals and say they are perfect.

    That leaves that intake gasket seal.

    Is it really possible that a leaky intake gasket can lead to a teaspoon of oil pooling on an intake valve after shut off?
    20170725_125625.jpg
     
  2. 65-440

    65-440 Well-Known Member

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    It absolutely is. Were you not able to use just the valley pan without any paper gaskets ? Lay the intake on the heads with no gasket And see how it lays. If it fits flush then you should be fine with just the steel pan. You could even put a thin film of rtv on both sides of the valley pan, torque the intake down and let it sit overnight to cure before you run it. On my 383 I ended up using 1 paper gasket on the head side only .....
     
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    • miller

      miller Well-Known Member

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      That could also be blowby, past the rings, in the two holes. Have you done a compression test?
       
    • lewtot184

      lewtot184 FBBO Gold Member FBBO Gold Member

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      I've seen intake ports/valve heads look much, much worse. I've been fighting this for over 20yrs on one of my cars and haven't found the ideal solution. I do know that the gasoline here in the states does contribute to the gummy problem. I cured this problem on one of my cars by going to a fairly lean idle/low speed mix. one thing you can do is check the intake manifold to make sure it's the proper angle. I haven't found the paper gaskets to be ideal; sometimes they are a detriment. there's no substitute for proper alignment at the intake and aftermarket intakes aren't always properly machined.
       
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      • 69Bee

        69Bee Well-Known Member

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        Scrap the Teflon PC seals, and opt for a metal clad positive or band type positive seals. The Teflon seals are not for street use on regular cars. Any valve stem tip from wear will open a channel for oil to get past. Rubber positive seals will move with the valve stem, and wipe most of the oil off. PC Teflon seals are for a race motor with bronze guides and tight clearances.
         
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        • Fran Blacker

          Fran Blacker Well-Known Member

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          Were the heads cut? Might want clean head and intake surfaces and put felt marker covering head surface where intake sits. Set intake on no gasket and move intake back and forth 1/8" to see contact area. Could be sucking oil from valley.
           
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          • Wietse

            Wietse Well-Known Member

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            Which specific cylinders were found with oil contamination?
            2 next to each other, across each other or random ones?
             
          • 62 Dart Convertible

            62 Dart Convertible Well-Known Member

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            I probably could have, but I was under the impression that with gasket would have been better than no gaskets...

            I did a compression test a while ago and it was high and even. Cross-hatch still there on all bores..

            Intake is an uncut '62 factory part. I will certainly be checking alignment more closely this time!

            Whilst I'm confident the seals are not the problem here, I agree I should just replace seals with a better type while I have it apart. What seals you recommend?

            I'm confident it was sucking oil from valley. Block and heads have been cut more than once over it's lifetime. Good idea on felt marker!

            Random cylinders.


            Things will get more interesting with intake alignment as I am installing 0.1" cometic head gaskets to drop the 11:1 CR..

            So are most folks in consensus that installing a valley pan without gaskets is preferable to using gaskets, and that it's OK to use RTV around intake ports too?
             
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            • 65-440

              65-440 Well-Known Member

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              It's not that it's preferable, sometimes there is no room for the paper gaskets. Especially when stock heads and intake are being used. Yes RTV is ok around the ports, I like a thin film under the ports the whole length of the head preventing oil from seeping up outside the valley. Just don't go crazy, a little bit goes a long way !
               
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              • moper

                moper Well-Known Member

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                Two comments...
                1. The valve job that was done - did they replace the guides, install liners, or knurl them? If they didn't - what was done as part of the first rebuild? They should be able to tell you.
                Positive seals are required for dual valve springs. But - they require perfect guides. because it the valve moves around instead of up and down, the seal gets damaged and they will leak. IMO - that's your oil leak. Especially if it's two holes all the time which is what your plugs are telling you. The oil on the retainer and rocker will run down due to gravity over night.
                2. The intake not fitting - was that because the holes were so far off? By how much? If you used thin paper and the bolts just barely cleared, the intake still didn't fit right. It can cause oil use - but not puddling. Once the vacuum's gone the oil won't get pulled in. So ports are oily and the valve is wet. No puddles. I don;t ever use the paper. Never have. Never had an issue either. But - the intake has to fit right. Put the gasket on dry and don;t tighten fully the end rails. Then set the intake on the heads. The hole in the head has to be centered in the hole of the intake on all 8 bolts. If not - have the intake milled to get them centered.
                 
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                • 62 Dart Convertible

                  62 Dart Convertible Well-Known Member

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                  Ok, I get it, thanks 65-440!!

                  1. Heads had bronze thin walls installed previously and were still perfect when valve job was done by very competent shop. When I saw the oil puddled on the valve, I concluded the same thing - that it must be residual oil from rocker gear running down the leaky seal after shut off. Builder swears that the seals on those valves are perfect and that it can't be the cause.
                  2. When I assembled, the intake holes were not perfectly centred. Now I understand that this is what I have to aim for.

                  Thanks moper!
                   
                • moper

                  moper Well-Known Member

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                  I respectfully disagree with you shop.. If it's two cylinders with the problem - there are either bad seals on those two (it is VERY easy to damage them during installation - been there, done that) and the liners may be worn too, although I kind of doubt it... I've never had any issues using bronze liners.
                   
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                  • 62 Dart Convertible

                    62 Dart Convertible Well-Known Member

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                    Thanks for your point of view moper, much appreciated!

                    I concur with your earlier view that a leaky intake gasket could not cause puddling of oil at the valve - it was my first conclusion when I saw it too. Though I'd like to trust my machine shop know what they are talking about, I will hedge my bets and replace the seals with viton - would these be OK? -https://www.summitracing.com/int/parts/cca-514-16/overview/
                    So it looks like I will be stripping/cleaning and re-assembling the heads - yay!:rolleyes:
                     
                  • moper

                    moper Well-Known Member

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                    You need to know what the guides were cut down to. Personally I've not had an issue with Teflon beyond being in a hurry and breaking a few installing. Make sure you know the OD of the guide before you order, and that the tips of the stems are smoothed at the edge. I use assembly lube on the stems of the valves.
                     
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                    • lewtot184

                      lewtot184 FBBO Gold Member FBBO Gold Member

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                      i agree with this. generally if it's an intake problem the whole bank of cylinders are affected. I have installed some edelbrock intakes where one side fits good and the other side will have a taper towards the rear of the engine leaving a gap at the rear. I only use papers if there is a gap between the intake surface of the head and the block or the intake is properly milled to allow for them. papers can be a nuisance. I've found factory intakes to have a more consistent good fit than aftermarkets. the old edelbrocks fit much better than the new stuff.

                      on another note here; I've been using big block chevy umbrellas vs the factory. I've found the longer chevy's (seems to be two versions of them) to give a little more coverage over the valve guide boss.
                       
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                      • 69Bee

                        69Bee Well-Known Member

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                        If the guides were not touched (original OD), umbrellas will work as long as the wear is not too much. If the guides have been replaced, and the original guides have been cut down on top (0.502" replacement guide), then the comp cam 514-16 will work. If the original guides were not cut down on top, the guides can be cut for Comp Cams seals 515-16 which fit a 0.530" guide top. Basically, you tell your machine shop what you want, and he can advise with the best solution to use a Viton positive valve seal.

                        As far as the intake gasket goes, when the block and heads are milled, the intake or intake side of the heads need to be milled to re-establish alignment of the intake to heads. This allows the ports and bolt holes to align up properly. When I seal a BB Mopar, I like to use Ultra Grey Permatex on the end rails, and spray Copper Coat on both sides of the intake ports of the pan.
                         
                        Last edited: Aug 17, 2017
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                        • 62 Dart Convertible

                          62 Dart Convertible Well-Known Member

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                          Cheers moper. I have not stripped them down yet to measure OD, but will B4 ordering. Do seal sets not always come with thin installation sleeve to protect seal from sharp edges on grooves (like every fel-pro umbrella set I ever used?)

                          Cheers lewtot. I have milled small block intakes for this reason in the past (though now I realise it preferable to mill head intake face). On this, my first RB, I jiggled gasket thicknesses to improve alignment, but likely not enough as I know bolt holes were not perfectly centred. Also, the original cast iron 2 x 4 intake has some cast in bumps underneath adjacent to port face that slightly interfere with the fel-pro valley pan, and that I had to dent the pan slightly to clear. This may have distorted the pan gasket face and attributed to leakage. I will be grinding these bumps off the intake.

                          Cheers 69Bee. I'm using double springs so umbrellas are no option. Guide OD was cut for the Crane teflon seal, I'm just not sure what OD until I strip and measure.
                          I will definitely be using sealant when I re-assemble (which up until now would have thought was a big no-no...)

                          As I said earlier, things will be more interesting due to the thick cometic head gaskets going on. I imagine that intake gaskets will be required!
                           
                          Last edited: Aug 17, 2017
                        • Wietse

                          Wietse Well-Known Member

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                          Not providing any solutions, but i am wondering how it would be possible to get oil sucked out of the valley through a leaking valley pan. I understand that engine vacuum will suck on a potential leak there.
                          Oil is not really flying about there, i would expect some oil mist/vapor there but what is throwing oil that far up against the corners?
                          With that quantity of oil in the inlet that must be coming from leaking valve guide seals indeed, that drips down once the engine is shut down and accidentally is visible because the valve is in the closed position.
                           
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                          • miller

                            miller Well-Known Member

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                            Though the years, I had always used teflon seals, with no problems. But, on my current build, bought teflon seals, and they didn't seem as well made. Proved it, trying to put them on, almost half tearing.
                            Broke down, listened to the guys, especially since the guides were already cut, and got a set of iron-clad. Think that's the name, the blue ones. Went on a heck of alot easier!
                            Also want to see if the valve spring caps are hitting the guide seals. Won't last long like that...guide tops need to be cut, with the diameter...but, sure your machine shop knows that.
                             
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                            • 62 Dart Convertible

                              62 Dart Convertible Well-Known Member

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                              I have wondered the same thing mate. I'd imagine potentially it is just the odd droplet or oil mist that could be ingested, but I have read of cases on this forum where an engine with a severely leaking intake gasket used a quart of oil in a few hundred miles. It has to be the seals, doesn't it?! (Or a hole/crack in 2 intake ports to top of head - unlikely.) I will be spending the weekend in the shed to find out.

                              Though I'd like to hope that the shop considered this already when they cut guides and installed seals first time, I will assume nothing and check that retainer won't hit seal for my cams valve lift.