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Lehman 80 Oil Leak - out of ordinary?

B

bobfar

New member
Happy New Year - as a newbie I ask the following question with no small amount of frustration.
Twin 1976 80 Lehmans in my boat. Port we gave a complete rebuild the starboard an "overhaul" cleanup head valves etc as block and cyl's were perfect.
Both heads were planed and refit with new pistons in port and both honing and overall everything each engine needed.
Twice now we have removed and replaced the head gasket - re set with and without gasket goop - torqued and re-torqued and still there is an oil leak at the rear of the engine. I have used tracer dye and isolated it to the left rear corner of both engines at the head gasket.

The bolts have been checked and the bolt holes cleared. The decks were cleaned only.

Engine removed from the boat twice - re and re both main and tank seals "just to be sure" as oil was showing on the flywheel as well.

As there is no oil pressure to speak of in this area of the engine and setting aside the possibility of a machining error on the same corner of each engine head I wonder if any old timers (like me) here have experienced this oil leak on these Lehmans before?
 
Bobfar, in all my years at lehman i have never seen an oil leak at the head gasket. However i have traced most oil leaks to the rocker cover gasket (cork) which should be sealed with 3m weaterstrip glue on the cover side and rtv on the head side. Try putting a piece of blue masking tape on the back of the head and run underwayfor an hour. If oil shows -- your r/c gasket leaks. Ps the head gaskets are to be fitted dry. Charlie w.
 
Hi Charlie - thank you again. You were right and ... well a tiny leak from the filler cap trailed to the edge of the valve cover and formed a tiny pool appearing to go nowhere. The amount traveled with barely a trace as the oil thinned out to such a degree as to be almost invisible. On the off chance it had something to do with the problem and the engine running and warmed up i dripped oil with the dip stick onto the start of the trace and watched it travel to the edge of the valve cover then go nowhere. But of course it did - "invisibly "under the valve cover along valve cover seal to the edge to bolt number 4 over the edge behind the intake manifold along the head gasket edge and then down the block to pool at the bell housing. Without your clear statement and the dye I would never have taken that route and found the simple solution - now to find a couple of new filler caps.
:)
 
Hi Charlie - I thought an update would be in order as I am approaching the anniversary of my original post. I find some humor in the following albeit black. Tracked down the leaks, as they persisted, on my trip to Alaska etc over the years. Now replacing the head bolts - stretched I'm told, along with two head gasket sets. IN addition the front oil seal has been replaced now three times!! It wont stay in place in the front housing as well as the rear main seals - twice. They wont stay in place either even with adhesive. No huge gulching leaks just enough to be annoying and bilge blackening.
So once again the mechanics are honoring the guarantee to this date and are as frustrated as I. Maybe now - this time - will be different. (What's the definition of insanity again.... ?)
 
Hi bobfar, sorry to hear your having so much trouble!! If front seal is red rubber it should be installed without sealant! After new seal is installed hang front cover and gasket with two bolts so cover can move freely. Add a drop or two of oil on the pulley seal surface. Drive pulley all the way in, install rest of bolts ,tighten, then pull pulley back out enough to put in the bolts covered by the pulley, then tighten the pulley bolt. As to the rear main seal--were the main bearings changed??
Charlie w.
 
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