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I have a 1968 98 that sat in a garage for 42 years prior to last summer. The body is in great shape, as well as the interior, but the 455 is stuck. I've tried every trick I know and have read about but it won't budge. I am trying to decide where to go with this car and part of that is getting an idea of what the cost of a rebuild would be. I contacted a local machine shop and they said around $3500, but they didn't know for sure.
For you all who have a lot more Olds experience that me, what do you think a ballpark number would be for a stock rebuild of a 455? The shop doing the disassembly, machine work, reassembly and paint.
The $3500 was a guess on their part and not an actual quote. They are a great machine shop but mainly do pulling truck engines and such, not usually stock Olds engines. Thanks for the reply, I appreciate it.
I think your first step needs to be to get the engine down to a short block to see why the engine is "stuck". If water or mouse nests have been sitting in the cylinders for years, consider it a loss. If it looks clean inside, at that point take it to your machine shop for an opinion or try getting it apart yourself. Spending thousands to restore the motor will not really pay off in numbers matching value in a 68 98. Different story if the car was a number matching 442 W30 etc. Then I would say do what ever you can to save the original motor. I don't normally have a ton of machine work done, but in 2018 - 2019 I had the heads for my 68 toro machined (Hot tanked, Maged, New stainless valves, Valve job, and light surfacing) final cost was around $700 which I was OK with.
In 2011 I paid $2500 for new pistons, rods, balance and macine work (.030 over bore, balance, crank polishing, block magniflux, and line bore check) on a 427 BBC. I provided the block and crank and assembled the short block. Since then I cannot imagine costs have gone down so I find it hard to believe that a reputable shop will be able to do a complete rebuild on a locked up 455 for only $3500. However, if they have a good reputation and will agree to that price after seing the motor go for it like Costie says.
Last edited by Loaded68W34; Mar 3, 2022 at 05:28 PM.
I just finished up a 425 and it was close to $4800 Parts prices have jumped tremendously in the last year. I just checked the price on a 455 kit and it is about the same. My cost is close to $800 and that does not include any valve train parts like valves, rocker arms, pushrods etc. That is all good name brand parts but also completely stock. With all of the typical labor and complete assembly it looks like your 455 would be about the same as the 425 I just finished. If it is very low mileage and has just be sitting you might not need a lot of the valve train parts but that would only save you maybe $250 ?
I would be a little leery of someone that says they can do it for $3500 unless you are out somewhere where labor rates are dirt cheap. Where are you located ?
First I just put some penetrating oil in the cylinders via the plug holes along with some Marvel Mystery oil and let it sit for days, not expecting to have a problem with it. But it wouldn't move while trying to turn it at the crank bolt. I checked to make sure that the starter wasn't jammed in the ring gear, but it's all clear on that end. So I filled the cylinders with diesel fuel and let it sit for a week. No luck. I then syphoned out the remaining diesel and filled the cylinders with Marvel mystery oil and let it sit. No luck. So I syphoned out the MMO and filled them with ATF. Still no luck even with a fairly 3 foot breakdown handle - the bolt was going to snap if I laid into it much more. Throughout this process, I had the valve covers removed and had soaked the valvetrain with lubricants. The valves are free and not stuck. The carb was also locked up and wouldn't budge and some of the spark plug had rust on the electrodes. I have since gotten the carb freed up. Under the hood, the engine exterior has a lot of surface rust even though it sat inside for all the years. It's like the concrete floor sweated and with the hood being closed it trapped moisture under the hood and made it's way into the engine. It's a very clean engine under the valve covers - there is no sludge buildup as if it was maintained well during the years. But I can't get it to move.
Any other ideas for getting it unstuck would be appreciated, but I've about given up on that.
I just finished up a 425 and it was close to $4800 Parts prices have jumped tremendously in the last year. I just checked the price on a 455 kit and it is about the same. My cost is close to $800 and that does not include any valve train parts like valves, rocker arms, pushrods etc. That is all good name brand parts but also completely stock. With all of the typical labor and complete assembly it looks like your 455 would be about the same as the 425 I just finished. If it is very low mileage and has just be sitting you might not need a lot of the valve train parts but that would only save you maybe $250 ?
I would be a little leery of someone that says they can do it for $3500 unless you are out somewhere where labor rates are dirt cheap. Where are you located ?
Dave,
If you have done all of that to free it up and it still wont move I would probably leave it alone and pull the heads off. The problem with it being stuck is that you will have to pull the engine away from the trans with the converter still bolted to the flexplate because you wont be able to get to all of the bolts. If you pull the heads once you see how the cylinders look you might be able to take a 2x4 and a big hammer and smack all of the pistons a little at a time and get it to start moving. Dont laugh, that actually works pretty good
Not sure what penetrating oil you are using but I found something called Deep Creep and it is the best I have seen in a long time. It is made by the Seafoam people and most parts stores have it. Marvel Mystery Oil is a waste of time. Same with ATF and DSL. But if yours is a s badly stuck as you say none of them will probably work without some shock action.
That engine won't loosen up quickly, maybe never if it has sat that long. Some people use a 50/50 mix of ATF/Acetone. You'll need to turn the crank in both directions when trying to loosen it up. Try that "Deep Creep" stuff to. You're looking at least $5,000 for an engine overhaul.
The idea is to adapt a grease gun hose to the plug threads and pump high pressure grease (slowly) into the cylinder. The resulting torque on the crank will likely rotate the engine.
Obviously valves need to be closed and crank angle needs to be away from TDC or BDC.
I have seen this fail when grease leaks through the ring gaps, but it's worth a shot.
I think 3500 for a rebuild is wishful thinking especially knowing the motor is stuck. I just dealt with a stuck motor and it wasn't pretty . My 455 build came in around 6000 and i did a lot of the work myself. The machine work in my neck of the woods is pricey.whatever your decision i hope it works out well for you.
