I'm considering making an offer on a MCSS and the engine smokes every startup for 15 secs. What would be a reasonable shop repair cost for just the seal replacement? I'd like to deduct that amount off the offer.
SBC Valve Guide Seals - repair cost
- Thread starter ed1948
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The valves seals are not that hard to change especially if the engine is out of the car. The tools are not expensive and it may be a good time to replace the tired valve springs
If the valve seals are going to be replaced while the engine is in the car, then the usual procedure is to remove the spark plugs, one at a time, install an air fitting adapter from a compression testing tool into the spark plug hole, then connect an air hose, which is connected to a source of pressurized air, to put air pressure into the cylinder, to allow the valve springs and retainers to be removed, in order to allow the valve seals to be replaced, without removing the cylinder heads, and without dropping the valves into the cylinder during the seal replacement. Also, in order to do this, the valve covers and rocker arms will have to be removed, then the valves will have to be re-adjusted after the springs and rocker arms are reinstalled. If the car that you're looking at is completely stock and original, then a couple of the plugs will be hard to reach, and there will be some wiring and plumbing that will have to be moved, in order to get the valve covers off the engine. Most likely, you'll be looking at replacing the valve cover gaskets, once the valve covers have been removed.
What I'm getting at here, is that without knowing exactly how original the car is, how well its been looked after, or how long some of the parts have been there, its going to be difficult to give you an accurate idea of the amount of time that its going to take to do the valve seal replacement. If everything comes apart easily, and goes back together OK, and the person working on it is familiar with the job, then it might only be a matter of several hours. If the plugs have been in there for a long time, or the rocker covers are hard to remove, or if you run into other issues during the job, then it could possibly take much longer to do the job.
Chances are, that the seller will tell you that everything is good, and that its an easy job to do, regardless of the actual condition of the car, and without knowing more about the specific condition of the car that you're looking at, then it could be hard for anyone here to give you any kind of accurate estimate either.
These cars are going on 30 years old now, and there probably aren't too many mechanics out there currently, who are going to be familiar, or comfortable with doing this job.
I'm not trying to rain on your parade here-I'm just trying to be realistic, and to give you an idea of how things might go.
I hope I'm wrong. Let us know how it works out.
What I'm getting at here, is that without knowing exactly how original the car is, how well its been looked after, or how long some of the parts have been there, its going to be difficult to give you an accurate idea of the amount of time that its going to take to do the valve seal replacement. If everything comes apart easily, and goes back together OK, and the person working on it is familiar with the job, then it might only be a matter of several hours. If the plugs have been in there for a long time, or the rocker covers are hard to remove, or if you run into other issues during the job, then it could possibly take much longer to do the job.
Chances are, that the seller will tell you that everything is good, and that its an easy job to do, regardless of the actual condition of the car, and without knowing more about the specific condition of the car that you're looking at, then it could be hard for anyone here to give you any kind of accurate estimate either.
These cars are going on 30 years old now, and there probably aren't too many mechanics out there currently, who are going to be familiar, or comfortable with doing this job.
I'm not trying to rain on your parade here-I'm just trying to be realistic, and to give you an idea of how things might go.
I hope I'm wrong. Let us know how it works out.
Thanks for the answers Mr Clean. I guess the procedure could range from $200 to $400. I would deduct maybe up to $400 from my offer.
From your description I would believe the valve seals should be replaced. The issue is that the chances of the seals being the root cause of the problem is slim. If the smoke is severe (fog of blue smoke) then there will be more than valve seals needed. Most likely the valves are loose in the guides which implies a valve job is needed. Heads need to be removed if that is performed. Most likely disassembly will identify valves and guides that need to be replaced. Someone else mentioned about the springs. If these are original springs, then the springs will undoubtedly be need of replacement as well if any spirited driving is in this motor's future.
I'd guess the motor runs smoothly, but that does not mean that it is good. If you want to know the status of the motor then get a manual compression test done and/or a leak down test. If either of these tests yield good results - all cylinders within 10psi of each other on a compression test or all cylinder leakage rates below 25% (engine cold) - then getting with a set of valve seals is possible, but still not a guarantee.
If you could get an accurate and honest answer from the seller of an oil consumption rate, then that is where the real proof is.
Getting to your original question, $300-400 is a fair price and it could easily be $6-700. But keep this in mind, a SBC is about the cheapest V engine there is to buy parts for due to the shear numbers of them out there. You could pickup a set of aftermarket aluminum heads, head bolts and required gaskets for $1000 give or take $100. A new set of heads implies new valves, guides, valve springs, valve seals and fresh valve job. Speedway FloTek's, Promaxx, Brodix 170 street heads, etc. Or a set of iron GM Performance can save a $100 or so. Of course this doesn't include labor, but from the intial layout of $400 it's only another $600ish to have a solid repair. Swapping a set of heads is not as major of a job as many think. Basic tools, a torque wrench and timing light needed.
In my opinion, the valve seal replacement has less than a 25% chance of resolving the problem permanantly.
Good luck - Jim
I'd guess the motor runs smoothly, but that does not mean that it is good. If you want to know the status of the motor then get a manual compression test done and/or a leak down test. If either of these tests yield good results - all cylinders within 10psi of each other on a compression test or all cylinder leakage rates below 25% (engine cold) - then getting with a set of valve seals is possible, but still not a guarantee.
If you could get an accurate and honest answer from the seller of an oil consumption rate, then that is where the real proof is.
Getting to your original question, $300-400 is a fair price and it could easily be $6-700. But keep this in mind, a SBC is about the cheapest V engine there is to buy parts for due to the shear numbers of them out there. You could pickup a set of aftermarket aluminum heads, head bolts and required gaskets for $1000 give or take $100. A new set of heads implies new valves, guides, valve springs, valve seals and fresh valve job. Speedway FloTek's, Promaxx, Brodix 170 street heads, etc. Or a set of iron GM Performance can save a $100 or so. Of course this doesn't include labor, but from the intial layout of $400 it's only another $600ish to have a solid repair. Swapping a set of heads is not as major of a job as many think. Basic tools, a torque wrench and timing light needed.
In my opinion, the valve seal replacement has less than a 25% chance of resolving the problem permanantly.
Good luck - Jim
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