You probably have burned valves,not good.
running with valves not closing for a year, how bad could it be?
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If the machine shop that did the valve job was reputable, then they should have checked the valve stem height before and after the valve job.
That should have eliminated any change in rocker preload. Also, if a valve was open all the time, your compression would be lousy at best, and the engine probably would poorly all the time.I would tend to agree that you have a burnt valve. A compression test or leakdown check should confirm.
That should have eliminated any change in rocker preload. Also, if a valve was open all the time, your compression would be lousy at best, and the engine probably would poorly all the time.I would tend to agree that you have a burnt valve. A compression test or leakdown check should confirm.
I don't know if you really have a problem, at least a problem related to a lifter preload concern.
I have done a dozen+ 302/351W/351C with milled heads and never had a problem with a valve hanging open, the lifters do have a fair amount of travel left to compensate for things like this. I could foresee trouble if you had a severely milled block deck, in combination with some shaved heads, in combination with some reground valves and seats, maybe. It seriously takes some tolerance stack to bottom a lifter.
If it were mine, I would slap a leakdown tester on it, get my percentage, and then pop the valve cover and loosen the rocker pedestals on that cylinder and see if there is a difference. No difference, then I would look somewhere else for my problem. You will hear a valve leak either in the intake or exhaust if there is a problem.
I have done a dozen+ 302/351W/351C with milled heads and never had a problem with a valve hanging open, the lifters do have a fair amount of travel left to compensate for things like this. I could foresee trouble if you had a severely milled block deck, in combination with some shaved heads, in combination with some reground valves and seats, maybe. It seriously takes some tolerance stack to bottom a lifter.
If it were mine, I would slap a leakdown tester on it, get my percentage, and then pop the valve cover and loosen the rocker pedestals on that cylinder and see if there is a difference. No difference, then I would look somewhere else for my problem. You will hear a valve leak either in the intake or exhaust if there is a problem.
just did some transom work, so the motor was out. It's back in now, all clean and painted. Will have to wire up the starter, and will do the compression check 1st since it's easiest.
So far, with either #5,6, or 7 on port side, I can basically take up all the slack between lifter and rocker arm by tightening down the rocker nut, then if I continue to tighten down the rocker nut all the way I can watch the valve spring depress, at least 0.030". Haven't measured it yet.
not sure wether I should ask questions at the shop. They do a lot of engine machining and I suppose they're reputable, but I've learned a good job always depends on the individual and the type of day they have when they're working on your stuff.
So far, with either #5,6, or 7 on port side, I can basically take up all the slack between lifter and rocker arm by tightening down the rocker nut, then if I continue to tighten down the rocker nut all the way I can watch the valve spring depress, at least 0.030". Haven't measured it yet.
not sure wether I should ask questions at the shop. They do a lot of engine machining and I suppose they're reputable, but I've learned a good job always depends on the individual and the type of day they have when they're working on your stuff.
Get the shims and run it.
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mechtech has it. Shim it and run it. If it doesn't fix it ..where are you at? About $10 and some time behind where you were
Roller rockers will free up some hp. But at $300, if that's the total cost ..hmmm..it may not be a bad bang for the buck.
Roller rockers will free up some hp. But at $300, if that's the total cost ..hmmm..it may not be a bad bang for the buck.
long story short: had valve job done on boat engine, 351w 1993, about a year or two ago. Reinstalled heads and everything ran great for rest of season and the following, maybe around 50 hrs worth.
The valve job that was done caused the oem non-adjustable rockers (pedestal type) to put too much preload on the lifters when tightened down. So the result is the valve is slightly open all the time- other than when it's being opened purposely.
The engine ran like this for quite a while.
This makes sense why I was seeing hotter exhaust manifolds on one side of the engine, and also explains the horrible emissions at idle.
The engine did always run very good, got 4000-4200 rpm, and idled ok down to 800. It used to idle down to 550 no problem (before valve job) but the screwed up valvetrain I'm sure is the problem.
So the big question is, do I pull the heads and inspect the valves for damage, and eat $100 in head gasket cost?
Already found the 0.030 and 0.060 shims at jegs for fixing this situation, and already contacted crane cams about getting there conversion kit to roller rockers, about $300 and is drop in no machining.
a) should I just get the shims for $10 and run it?
b) is $300+ worth it for adjustable roller rockers?
The valve job that was done caused the oem non-adjustable rockers (pedestal type) to put too much preload on the lifters when tightened down. So the result is the valve is slightly open all the time- other than when it's being opened purposely.
The engine ran like this for quite a while.
This makes sense why I was seeing hotter exhaust manifolds on one side of the engine, and also explains the horrible emissions at idle.
The engine did always run very good, got 4000-4200 rpm, and idled ok down to 800. It used to idle down to 550 no problem (before valve job) but the screwed up valvetrain I'm sure is the problem.
So the big question is, do I pull the heads and inspect the valves for damage, and eat $100 in head gasket cost?
Already found the 0.030 and 0.060 shims at jegs for fixing this situation, and already contacted crane cams about getting there conversion kit to roller rockers, about $300 and is drop in no machining.
a) should I just get the shims for $10 and run it?
b) is $300+ worth it for adjustable roller rockers?
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