Oil Leak

[th4neuk]

Hi guys, bit of advice before the spanners come out.

Looks like my car has come fitted with the Bond smoke screen attachment. I've got a leak on the left cam housing (bottom part) which is dripping on to the exhaust manifold. Has anyone fixed this and could give me some instruction on the best way to solve this problem (apart from taking it to the garage).

Thanks all

Alan
89 Turbo

[Chrismsnt]

I've got the same thing going on and I'm in the research phase right now. Check out my pics to see if your's looks like the same spot as mine:

http://curban.dns2go.com/leatherproj.htm

Chris
'91 Midnight Blue

[Lotusguy]

Hi guys, bit of advice before the spanners come out.

Looks like my car has come fitted with the Bond smoke screen attachment. I've got a leak on the left cam housing (bottom part) which is dripping on to the exhaust manifold. Has anyone fixed this and could give me some instruction on the best way to solve this problem (apart from taking it to the garage).

Thanks all

Alan
89 Turbo

Alan,

Sorry to hear of your trouble. By 'left' cam housing, are you referring to the exgaust side or the intake cam? In either case, I would plan on doing both of them as the prospects for the other to start leaking seems fairly high- get it all done at once.
And, if, after investigating that it is the cam housing rather than the valve cover, I'd also plan on checking valve clearances as you have to go through the same procedures whether you check the valve clearances or not.

Since you state that the leak is coming from the bottom part, we'll go on the assumption that it is the cam tower which is leaking. In either case, you'll need to replace the valve cover gaskets as well (Lotus Part #A912E2040), You may also elect to replace the 'O' rings on your cam tower end caps(Lotus part # A907E6027Z) as these are really easy to swap and cheap to buy. You'll also need at least one tube of Hylomar gasket sealer, and some Locktite 504 Gasket Eliminator or preferrably Permatex Aircraft Grade Form-a-Gasket. You'll also need a 12MM allen socket (to remove the access plugs for the cam tower Torx bolts) and an E10 socket (female Torx) socket to remove the cam tower bolts.

The first thing you want to do is put the engine at TDC. To do this, place the car in 5th gear and untighten the spark plugs (be sure to check for any dirt or debris surrounding the plugs before loosening them - you don't want this falling into the engine). Now, you push the car forward until the dots on the rims of your cam timing pulleys line up. If you run out of space, put the car in neutral and back it out, put back into 5th gear and push forward again. Repeat this until you can line up the cam pulley dots. Once the dots are aligned, check the timing pointer on the flywheel at the transmission bell housing to insure that it points to TDC. Once at TDC, get under the car and using a 19mm socket (I think it's 19mm), place it on the crankshaft bolt and turn the bolt 90°, this will insure that the pistons are all drawn halfway down the cylinders to insure that they don't obstruct or hit a valve when you replace the cam towers. With this completed, loosen the timing belt tensioner. This will allow you to slip the belt off the cam timing pulleys (a good time to replace your belt).

Next, remove the valve covers and, turn the cam pulley so that each valve comes 'off cam' in turn and using a feeler gauge, measure the gap between the heel of the cam lobe and the top of the cam follower (tappet). Do this for all 16 valves, using the next higher and lower feeler gauge sizes to insure accuracy. The correct one will be a snug fit, the lower one an easy fit and the upper gauge will not fit at all. Now record the gap values for each of the 16 valves. You are looking for 0.005"-0.007" for the intake valves and 0.010"-0.012" for the exhaust valves, but you will find that almost all of them are smaller than the maximum allowable gap as the valves continually drive themselves further and further into the valve seats. When using Locktite 504 Gasket Eliminator, you must allow an additional 0.001" for the thickness of the sealer, using Aircraft Grade Form-a-Gasket, no clearance need be allowed for as this is what is termed a 'Zero Tolerance' sealer.

Now, using the E10 socket, remove the 8 cam tower bolts securing each cam tower (care should be taken to avoid stripping these bolts- many people replace them with standard 10mm bolts to avoid this in the future). If you have 4 lengths of bar magnet (this is ideal, but not necessary), place them across the tops of the cam followers (tappets) to prevent them falling to the floor when the cam tower is removed, otherwise, loosen the cam tower with a few taps from a rubber mallet or such and quickly invert it with a 'flip'. This will prevent losing any of the tappets or valve clearance shims. These shims will often remain on top of the valve stem set into the collet, but have been known to stick to the underside of the tappets as well.

Now, remove each valve clearance shim, and check it's thickness with a micrometer. Add this dimension to the values you already recorded from checking the gaps earlier. Now, subtract 0.007" for the intake valves and 0.012" for the exhaust valves and the result is the sizes of the new shims you'll need in order to reestablish correct valve clearances(remember to subtract an additional 0.001" if you are using Locktite 504 Gasket Eliminator to allow for it's thickness). Check your list of existing shims as you may be able to shuffle a couple around reducing the number you must buy. Also, if you have a shim that is very close, you can sand it down to size by placing a piece of #600 sandpaper on a mirror and with a drop of oil on the shim, sand it til it's the proper thickness. This method takes about 20 minutes to remove 0.001" of this hardened steel. Some will find it easier and less tedious to simply buy the proper shim.

Now, clean the underside of the cam tower thoroughly using a solvent such as brake cleaner, taking car to keep the tappets in their assigned holes, you don't want to mix these.

Once clean, place each appropriate valve shim in the recess in the collet on top of the valve stem, apply a thin layer of Locktite 504 Gasket Eliminator or Permatex Aircraft Grade Form-a-Gasket around the cam tower and replace it carefully on the top of the head (It uses no gasket, just the Locktite 504 or Permatex Aircraft Grade Form-a-Gasket). Now, run in all the cam tower bolts and torque to a value of 14-16 ft.lbs. Now re-check your valve clearances. If they measure up correctly, you're done, otherwise, you must repeat the procedure. Clean off the valve cover and apply a thin bead of hylomar and replace it on the cam tower w/ new gasket, torqueing the bolts to 3-4 ft.lbs. Replace the cam tower access plugs.

Now, rotate the cam pulleys so that the dots on each align, you may want to take the opportunity to replace the stock 110° intake pulley with a 104° pulley from the aux. shaft, this makes it more driveable and is free.

With the dots lined up correctly, turn the engine back 90° from where you turned it before and check the timing pointer on the flywheel at the bell housing to insure that it points to TDC. Replace the timing belt and retighten the tensioner til you can either: measure 95 lbs. on a Burroughs gauge, measure 50-55 on a Kriket gauge or just turn the belt 45° in both dirctions, do this on the long stretch of belt between the intake pulley and the aux. shaft pulley. This is the proper tension. Retighten the sparkplugs and connect the leads. Voila... You're finished. Hope this helps. Happy Motoring! ..Jim '85TE



>> Edited by Lotusguy on Saturday 25th January 20:11

>> Edited by Lotusguy on Saturday 25th January 20:11

>> Edited by Lotusguy on Saturday 25th January 20:12

>> Edited by Lotusguy on Saturday 25th January 22:22

>> Edited by Lotusguy on Saturday 25th January 22:29

>> Edited by Lotusguy on Saturday 25th January 22:31

>> Edited by lotusguy on Sunday 26th January 15:50

[th4neuk]

Thanks Jim,

I figured you'd be the man for this one.

Appreciate the help v much

Alan

[grungex]

Excellent reply from Jim, but I'd address the end-cap o-rings first, if you're fortunate that will be the end of it. If not, no harm done ;-)

Cheers,
Sanj