lucasstarfire00

I'm very aware that since the 425 is a motor that wasn't built in many numbers it is harder to find parts and sometimes more expensive. For the future, how much should I expect for a full rebuild of a '66 starfire spec high compression 425? I know it always is more than planned but would like a rough number to reach for once the time comes. I'm at 80,000 miles but it sat since '84 and I just got it running good. Thanks guys...

Oldsmaniac

The 425 was produced in 65 66 and 67 and there are plenty around. Parts are expensive for all Oldsmobile engines and there would be little difference in price for a stock rebuild of the 330, 350, 400, 425 or 455. If you had a machine shop do the build and heads I would guess you would be in the 4000 dollar range for parts labor and machine work.

lucasstarfire00

Also have a very generous neighbor who rebuilds lots of motors. I'm not experienced enough build a motor myself yet so I'd hope to rebuild it with him, and am sure I'd get a very reasonable price.

lucasstarfire00

What would I expect for much less or no labor costs, like my neighbor and I doing most of the build and then the machining work at a shop?

Oldsmaniac

I would say knock 1500 off the 4000. It gets expensive when you need to buy new pistons. Valves too are not cheap but most other parts are reasonable such as a cam, bearings rings oil pump gaskets and seals. You will be saving a lot if you are not paying for labor to disassemble and put back together costs.

Sugar Bear

Consider replacing the timing chain and both gears before using it much whether rebuilding it or not. Good luck!!!

jaunty75

Just out of curiosity, if you just got it "running good," why are you even thinking about rebuilding it? I have a 425 in my '67 Delta 88. It has 131,000 miles on it, and it runs like a top. I wouldn't think of opening it up until and unless there is a reason to.

I do not know the full history of the car as I've only owned it since 2009, and the engine may very well have been rebuilt in the past. Regardless, I see no reason to fix what ain't broken.

lucasstarfire00

I just wanted to know what to expect because I'm that guy who is always thinking of the future. Sh*t happens and just want to know what to prepare for. I don't have a whole lot of info other than that it has 80,000 miles and it sat since 84 but I'm very happy with how it runs. Just curious as well that's all

jaunty75

If I were you, I would take the money you'd spend on a rebuild and put it towards other things the car needs, such as a new paint job if that's on the list. The 425 is a solid piece of machinery (by some measures, it's a better motor than the 455 that replaced it), and, at 80,000 miles, it's barely broken in.

lucasstarfire00

I think you're taking my high school curiosity the wrong way... A motor rebuild isn't something that I'm just gonna jump at for fun. I'm not gonna rebuild it for as long that it won't need to be rebuilt. Nothing more than wondering.

jaunty75

Unless you're planning to use this car as a daily driver and put 100,000 miles on it in the next 10 years, it is unlikely to ever need rebuilding in the time you'll own it.

And your series of questions DID sound like a little more than simple idle curiosity.

lucasstarfire00

Well it's hard to tell talking through a computer. Thanks for the info though

rocketraider

Timing set is a good and fairly simple project that a reasonably bright high-schooler can handle, with a little help and armed with a shop manual. You can rent the pullers to get the crank gear off. Count on replacing water pump while you're into it since it has to come off anyway.

Sometimes the timing cover's front oil pan seal can be a bitch to put back. The solution is to grind off a tad amount of the inner side of the seal retainer, to where you can wedge the timing cover back in. Use plenty of sealer.

If you're really curious about engine's internal condition- pull the intake and see what kind of crap is built up in the lifter valley. But if it runs smoothly and doesn't use an excessive amount of oil, you should be OK.

lucasstarfire00

Thanks a lot that's something that hasn't entered my mind but incredibly important. Thanks a lot for the tip!

lucasstarfire00

I didn't even see this comment from you until right now for some reason... You have to take off all the accessories right? I'm pretty sure my dad could guide me through it pretty well. I've watched videos and it seems straight forward.

rocketraider

Taking them off makes it easier to work around front of engine, but you may not have to take all of them.

Lucas- if you get as deep as replacing a cam, you need to know that 65-67 non-Toronado 425s use a 45 degree lifter bank angle. Most Olds cams are for the later 39 degree cam bank engines and they do not interchange. Keep some GOOD oil in it with ZDDP additive to preserve your cam and lifters.