Ok, it's a simple problem right? A leaking 67 SB Valve cover.
Originally it wept at the back (as they all do), eventually making its way down the block to the road. I removed both covers and very, very carefully cleaned and prepped both the head and cover gasket surfaces. I then put a small bead of high temp silicone around on the cover and placed a new neoprene gasket in place on it. I then put a very small bead of the rtv on the head flange, lower side and ends only. I placed the covers on, and with little to no fussing to get the bolts to take, I gradually tightened the bolts down using a cross pattern, being sure not to overtighten in any way. They both sealed well...until 2 days ago when the drivers side began to weep. I gave all the bolts on that one a little turn...and it seemed to to leak like crazy. The passenger side cover is still dry.
Funny thing is, it seems to actually pour out under acceleration? It's pooling in the crook of the exhaust manifold and is coming out the firewall end onto the wires and down the block. The bottom of the car got oilsprayed with a litre or so of10-40 yesterday! How could a simple leaking gasket loose so much oil?
The thinking was that the PCV system could be blocked allowing blowby pressure to build and blow out a weak point in a gasket. Last night while driving we stopped and messed with the valve, it seemed to stop leaking oil at that point, at least until I hit the highway to head home! I took a good look at the PCV valve itself today, and it works just fine. Could the baffle at the rear of the block be blocked or restricted in some way? Am I looking at a bigger issue here?
Anyway, any wisdom from you guys on this sort of problem? Any advice on getting these covers to seal once and for all? Todd suggests eliminating the gasket all together and going with a sealer called "The right stuff".
Cheers, Mark
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
Ok, it's a simple problem right? A leaking 67 SB Valve cover.
Originally it wept at the back (as they all do), eventually making its way down the block to the road. I removed both covers and very, very carefully cleaned and prepped both the head and cover gasket surfaces. I then put a small bead of high temp silicone around on the cover and placed a new neoprene gasket in place on it. I then put a very small bead of the rtv on the head flange, lower side and ends only. I placed the covers on, and with little to no fussing to get the bolts to take, I gradually tightened the bolts down using a cross pattern, being sure not to overtighten in any way. They both sealed well...until 2 days ago when the drivers side began to weep. I gave all the bolts on that one a little turn...and it seemed to to leak like crazy. The passenger side cover is still dry.
Funny thing is, it seems to actually pour out under acceleration? It's pooling in the crook of the exhaust manifold and is coming out the firewall end onto the wires and down the block. The bottom of the car got oilsprayed with a litre or so of10-40 yesterday! How could a simple leaking gasket loose so much oil?
The thinking was that the PCV system could be blocked allowing blowby pressure to build and blow out a weak point in a gasket. Last night while driving we stopped and messed with the valve, it seemed to stop leaking oil at that point, at least until I hit the highway to head home! I took a good look at the PCV valve itself today, and it works just fine. Could the baffle at the rear of the block be blocked or restricted in some way? Am I looking at a bigger issue here?
Anyway, any wisdom from you guys on this sort of problem? Any advice on getting these covers to seal once and for all? Todd suggests eliminating the gasket all together and going with a sealer called "The right stuff".
Cheers, Mark
you have got major pressure in the crank case, no amount of sealant will fix that.if its a 67 it still uses a road draft can in the lifter valley, they need to get cleaned or they get sluged up. make sure after you get the pressure thing sorted out your valve cover flange is strait and use those wide load spreader with good quality felpro rubber gasket with metal anti crush ring put on dry
'67s have a PCV? if you've re placed it recently, check if you got the correct valve.
try the fel pro perma seal v/cvr gskts #VS 12869T rubber with a steel center
we all have PCV even the open system, but the 67 still draws the vapour from the back of the block and from the valve cover the can thats in the block might be plugged
I can't check right now but I think the 67 has the valve screwed into a fitting at the base of the carb (rear) and pulls air in through the oil filler cap on the tube at the front.
The valve covers have no filler or breather holes in them before 68.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
thanks, thought '68 was the 1st year they used PCV valves up here.
nope pre 67s used two systems closed and open were the pcv is either mounted in the carb base in the open and in the carb base or the filler tube in the closed system. fresh air comes into the system from a vented filler tube open or from a tap on the aircleaner closed. it can draw either from the filler tube or from the back of the engine. 67 was a inbetween closed system which still drew from the back of the engine but had the pcv in the valve cover. 68 was the last series of engine with casting in place which can be made workable but is not used thats how you can tell a 68 block
This car has a tube coming from a tap at the back of the block, it comes around on the passenger side of the carb and meets a pcv valve thats held in place by a metal bracket. The hose then travels to the carb base. I pulled the hose with the pcv valve off the carb base with the valve still in place. Sucked on the end, it drew, blew in, it stopped...just as it's supposed to do. I then fit a long tube onto the remaining tube back to the block and blew in...it was free, no restriction there. All the return holes in the head are clear, this engine has zero sludge. Pulled the leaking cover off, and low and behold, the lower secton of gasket between the two bolts had pushed off the flange into the head, leaving the cover more or less entirely open there. Probably overtightening a neoprene gasket when hot, what do you think? So again I cleaned and degreased it all, and this time installed it without rtv, carefully and lightly tightening it down.
So far so good!
When I bought the new gaskets I was asked "rubber or cork". Against my better judgement I chose rubber.
Cheers, Mark.
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
Hope you got it sealed up this time. I go for the cork as well, clean everything & a bit of gasket goo on R/C to hold gasket, have even used thread to tie them to R/C through bolt holes. Then as 65 Wagon said, make sure you have the long spreaders on R/C bolts to even out the torgue, & away you go !!!!
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Some times I wake up GRUMPY, but today I let her sleep in !!!!!!!!BLACKSTOCK Ont.
I can make a big issue out of anything Carl! I was going to take pictures, but that would have been just too much for a valve cover leak. God forbid I get a trans problem!
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65 Laurentian post, 67 Grande Parisienne 4 door HT.
