New guy with question
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Tuned
Joined: Sep 2001
Posts: 279
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From: Western PA
New guy with question
Long story.. I got 1966 F-100 in 2002 with 352 that was rebuilt for street in 1992. Truck had a wild cam and I couldnt drive/emjoy it. Paid mechanic to install Edlebrock stock cam. Upon startup had smoke coming from driver side exhaust and out of oil fill cap (never had smoke before!) Did compression test and two clyinders were way low (spuirted oil in and it came up 20 psi). Pulled those two and everything looks o.k. machine shop says valves & guides are bad and wants to install unleaded valve seats.
1. can I reuse the old rings since I checked ring gap and it .018 and top and bottom of cylinder?
2. Does this head work sound reasonable?
3. Prior owner had super valve seals installed, could this have made my guides go bad (no oil) and should I just use the stock FelPro valve seals?
4. Forgot last question
1. can I reuse the old rings since I checked ring gap and it .018 and top and bottom of cylinder?
2. Does this head work sound reasonable?
3. Prior owner had super valve seals installed, could this have made my guides go bad (no oil) and should I just use the stock FelPro valve seals?
4. Forgot last question
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 423
From: Long Island USA
What do you mean "pulled those two" - just the plugs?
If you have smoke out the oil cap, sounds like the MECHANIC cracked a piston or ruined the rings. If you have smoke out the exhaust, again, sounds like they ruined at least those two cylinders.
If they did something stupid like cranked over the motor with the wrong valve timing, chances are they cracked a piston when it hit the valves (or dropped a bolt/washer/nut into the intake and didn't notice it). Probably bent the valves in those two cylinders too.
Or, another possibility is that they left water in one of the cylinders (even a little big will do it) and cranked it over. Hydro-lock is not good for pistons or rings.
Oh, and coolant will cause the rings to stick to the piston, which will also cause your symptoms.
I would bring it back to the mechanic and tell them they broke it - no smoke in crankcase (out oil filler) before, smoke after? They screwed something up big-time.
If you have smoke out the oil cap, sounds like the MECHANIC cracked a piston or ruined the rings. If you have smoke out the exhaust, again, sounds like they ruined at least those two cylinders.
If they did something stupid like cranked over the motor with the wrong valve timing, chances are they cracked a piston when it hit the valves (or dropped a bolt/washer/nut into the intake and didn't notice it). Probably bent the valves in those two cylinders too.
Or, another possibility is that they left water in one of the cylinders (even a little big will do it) and cranked it over. Hydro-lock is not good for pistons or rings.
Oh, and coolant will cause the rings to stick to the piston, which will also cause your symptoms.
I would bring it back to the mechanic and tell them they broke it - no smoke in crankcase (out oil filler) before, smoke after? They screwed something up big-time.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 423
From: Long Island USA
Oops... aparrently, you have the motor apart already.
If the motor was rebuilt, and they used those "super seals" chances are they did the right thing and put in silicon/bronze guides. They don't really need oil. And it probably had seats put in already. If they were rebuilt, that is.
Did the machine shop inspect the heads yet? It should be easy to see if the exhaust seats were already done... and you checked the pistons for obvious damage?
Never re-use rings, especially when you already have a compression problem. And make sure to hone the cylinders (and not with a home drill and "dingleberry" honer
If the motor was rebuilt, and they used those "super seals" chances are they did the right thing and put in silicon/bronze guides. They don't really need oil. And it probably had seats put in already. If they were rebuilt, that is.
Did the machine shop inspect the heads yet? It should be easy to see if the exhaust seats were already done... and you checked the pistons for obvious damage?
Never re-use rings, especially when you already have a compression problem. And make sure to hone the cylinders (and not with a home drill and "dingleberry" honer
FE "Freakin Expensive"
Joined: Dec 2003
Posts: 6,461
Likes: 4
From: Smith Mountain Lake, VA
Just my 2 cents...
There is know reason why an engine should start smoking just from a cam change!
If it wasnt puffing before it shouldnt be puffing now!! Somebody screwed up
Somewhere!!-Russ
PS..and I agree with Krewat...If you have the motor down..dont ever use old rings..
its like having the pan off and not going to a new oilpump..Cheap insurance..
There is know reason why an engine should start smoking just from a cam change!
If it wasnt puffing before it shouldnt be puffing now!! Somebody screwed up
Somewhere!!-Russ
PS..and I agree with Krewat...If you have the motor down..dont ever use old rings..
its like having the pan off and not going to a new oilpump..Cheap insurance..
Senior User
Joined: Dec 2003
Posts: 337
Likes: 0
not to chage the subject but you mentioned the unleaded gas today chews up valves.
in my old nissan mule I have for a few yrs religiously been using marvel mystery oil, and it raised the compression and makes it run overall, better. I notce it when after a few tanks of huntreated gas it starts running different and the mpgs go down.
slightly back on subject....
now I have this old 390. will using MMM in it too prolong the life of the valves? (acting like the lead in the old gas, as I read MMM is chocked full of molybdinum and other good stuff)
if it is healthy for the valves I'll start giving it a few shot glasses in each tankfull.
when I can afford to get gas that is.
in my old nissan mule I have for a few yrs religiously been using marvel mystery oil, and it raised the compression and makes it run overall, better. I notce it when after a few tanks of huntreated gas it starts running different and the mpgs go down.
slightly back on subject....
now I have this old 390. will using MMM in it too prolong the life of the valves? (acting like the lead in the old gas, as I read MMM is chocked full of molybdinum and other good stuff)
if it is healthy for the valves I'll start giving it a few shot glasses in each tankfull.
when I can afford to get gas that is.
Tuned
Joined: Aug 2003
Posts: 346
Likes: 0
From: Eastern Virginia
I heard unleaded gas only hurts older valves and seats under extreme circumstances. Such as tractors, racing, heavy trucks, ect. My '71 390 has had a steady diet of unleaded for 15 years now. At 180K still purs like a kitten. I do give it a dose of Marvel's before I put it away for winter.
