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A Few Things For The Experts...


Benjamin A.R.

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Hey all,

 

   I'm looking for a second opinion on a few things. I just got done with a 5 speed swap, took it out for some highway driving, and noticed a sizable oil puddle under the car later on. So far as I can work out it was coming from the place where the lower and upper timing covers meet. The last big job I did recently other than the 5 speed was replacing all of the front seals and gaskets, so as you could Imagine, this was very annoying. That little piece of head gasket was broken off already when I took everything apart the first time. I assumed I could bridge the gap with quality rtv (Permatex Ultra Black) It seemed to work for a little while while running non synthetic. Anyway, I took it apart again, resealed it with the same stuff again but this time I gave it more time to cure. I also adjusted the valves while I was at it and then sealed the valve cover in the same manner.

 

   I started it up this evening and after warming up a bit, the oil began to seep from the same general vicinity. Very frustrating again as you can imagine. So knowing that, I took it for a spin and was rather surprised... I put it in first and when I let out the clutch the engine shook pretty violently. (There was no indication from the idle or anything else to tell me that something was wrong up until then.) I got it going after some feathering of the throttle (in 2nd too) out onto the highway and it went through the other gears above 2nd just fine. I highly doubt it's clutch therefore. I turned it around and the same thing happened in the lower gears coming into my neighborhood then driveway. I stopped and went a couple times and It was intermittent. I opened the hood and checked for loose wires, saw that the oil leak was definitely unsolved to my dismay, reattached the tach which vibrated off it's connection at the coil, scratched my head and drove the same route again. This time with no problems except that god damned oil leak. Fender has been a moody fella lately.

 

   So here's what I'm thinking:

 

-I've been messing around with wiring lately trying to get all of my lights to function properly, I'm wondering if that would have caused the ignition to act up under load if wires bumped into things. (Not the tach connection though right?) hmmm...probably not.

 

-I'm generous with rtv, so maybe a(several) little chunk(s) of the stuff broke off in the head and caused a little chaos before getting spat down into the pan. Unlikely? Yup, even more so.

 

-I tightened the adjuster nuts on the eccentrics as much as I dared so I don't think one of those came off.

(Also I think that this would have caused a much more significant catastrophe than what has befallen me yes?) And engines typically don't misbehave under load after a valve adjustment and then act fine...?

 

-As for the leak, I hope that I slowed it down a little bit, but is it possible that the head gasket in this same area could seep? I doubt it but I'm not sure. Dang, I thought I had that cover sealed well this time... I'm tempted but also hesitant to tighten on the cover bolts more, stripping one out is a lot worse than a moderate leak.

 

   I'm going to do some more driving tomorrow. Hopefully this thing really has worked itself out (yeah right, that'd be a world first) but in the mean time I'd love to hear from the engine/ignition experts (like I said, I really doubt it was in the clutch, it didn't feel that way) about what It may have been on the first drive. More info the better. And do you guys just live with that notoriously hard to cure leak? Or do you battle with it over and over. (or cave in and just replace the whole head gasket to cover that one tiny spot between the covers?) I'm curious because it does make a mess.

 

   Finally, how much torque can those upper cover bolts take? I'd love to force that little f*cker down hard, but I'd hate to break one off. Unless it's indeed possible that the head gasket in that sameish area could seep oil. (I guess that little area between the timing covers COULD be considered a head gasket leak, but not in my case because that piece is gone.) In any case, I'm referring to a section of head gasket directly towards the firewall from the crotch of the block and cover for about 2-3 inches in that direction. Happy Sunday morning!

 

-Ben

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A lot of vibration while letting out the clutch on first speaks to an imbalanced or poorly supported driveshaft. If you mounted your transmission too low in the rear there will be excessive flex in the guibo from misalignment between the driveshaft to transmission, and a resulting vibration under heave driveline loading (ie: 1st gear acceleration). Additionally and otherwise, you could have a bad center support bearing, your driveshaft could be too long, improperly balanced, or have bad universal joints. Basically, it sounds like a driveshaft issue.

To confirm it being driveshaft, stomp the gas at low rpms in 2nd gear. If you feel a vibration from the middle of the car, it's driveshaft.

Oil leaks are completely unrelated.

Valve cover nuts are somewhere between 72 -90in/lbs. Moderate to light pressure with a 5-6" 1/4 drive rachet. Not much at all.

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^ ^ ^ ^ ^. That

Oil leak should be easily solved

While head gasket, per say, gets no sealant applied,

it is ok to use some at portion over lower timing cover

I've always used the sticky/tacky sealant for timing covers

-Indian head or similar - has the "glue" applicator brush thingy

No sealant on valve cover gasket

Neither bolts or nuts at timing/valve cover very tight, I've always just hand tightened, snugged them

Timing cover bolts take advantage of gasket sealant as well. Never had a leak or problem after install

Good luck

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You mentioned your wiring and tach...

A few months ago, I was troubleshooting an inop tach on my car.  I finally got the tach working and took it for a spin.  Did exactly as you described. Pretty bad shuddering off the line in first and a little bit more in 2nd.  Turns out, some dumbass left a live wire going to the coil hanging in the enginebay and it was shorting out.....

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An unbalanced driveshaft won't show up at low rpms.

 

But a misaligned one might.

 

In a different direction-

if your engine's unusually free to move in the engine bay, and you use the

standard linkage, you can get an uncomfortable 'self- throttlng'

effect from engine rotation.  It's normally not a problem, but very floppy

(or broken) engine mounts can make it pretty bad. 

 

As the engine

rolls over to the right in reaction to driveline torque, it opens the throttle a

bit.  This makes it roll over more.  Which adds throttle a bit more.  If the

engine's free to move, and you have a twitchy carb (like a 38) you can

get quite a boost from it, let off, and then it starts oscillating.

 

Not usual, but possible

 

t

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I found a loose wire hiding under the coil, this may have been shorting it out intermittently. I aligned the transmission output flange and the diff input flange buy sticking a very small narrow beam light in the trans side. I used washers until they were in a straight line. I then used a level to make sure that the center bearing wasn't throwing anything off. I'm totally confident that the driveshaft is not the issue, if it was, the symptoms wouldn't just go away. I'm taking it on a long drive today to investigate further. I'm suspecting that loose coil wire could have been responsible. Interesting diagnosis Toby, I never thought of that. I don't think my engine mounts are bad, but I am running stock linkage to a 38. I'll report back this evening. Thanks for the thoughts.

 

-Ben

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I snugged up the cover bolts as tight as I dared, and the leak appeared to slow down a bit more. Mechanically everything was a-ok, musta been that coil wire. My dad spotted a beautiful inka tii roundie on the way up to Estes Park today. Sundays are great in the canyon because everyone has their classics out to play. I also saw an olive Pontiac GTO sport coupe and a midnight blue convertible Alfa Romeo GTV with gold stripes.  

 

Fender and my sister's 1275 mini, Ruby did some hanging out in the nice weather too. 

post-41166-0-56164500-1411357261_thumb.j

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Oil leak:  remove valve cover, and check mating surface in all directions with a steel straightedge.  Chances are a PO (or even you!) may have warped the cover by over enthusiastic bolt tightening.  You can have the cover milled back to flat by a machine shop if it's warped.  Always tighten  in a criss-cross pattern starting with the middle two nuts and ending with #7 on the front edge.

 

While the valve cover is off, lay that straightedge along the top edge of the head so that it extends over that upper timing cover casting and see if there's any daylight on either side of the joint.  I suspect the timing cover casting is sitting exactly one head gasket's thickness below the head where the valve cover mates with the head and timing cover.  If that's the case, you can make a paper gasket to compensate for the missing piece of head gasket to even up the two mating surfaces.

 

cheers

mike

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When I put my head together, it leaked at the timing cover too due to milling.  There was only probably a 1/32 gap, but it was enough.  What I did was take a razor and cut the paper side gaskets flush with the head and the top of the timing cover.  Then clean everything really good with alcohol or acetone.  Then take some permetex instagasket and lay a small bead from the front of the side of the timing cover back to the head.  None on the front of the cover.  Then take a straight edge and scrape any excess going sidesways along the timing cover and the block, this will leave you a nice smooth fillet of gasket material that is enough for the main gasket to seal onto.  There should be little to no sealant at the front of the cover, building up to flush at the head. Be sure to let the sealant dry completely before putting the cover back on.  I did this 4 months ago and no leaks yet, when it leaked immediately before.

 

Kind of a cheesy pic, but you get the idea (side view)

post-32031-0-17223600-1411397214_thumb.p

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