[1965 Pontiac Parisienne]

I have a 389 YF engine that I just dissemble because the engine was looked ..after a lot of WD40 and weapon oil I got the engine turning by hand after removing the heads ..okay one cylinder has a rust issue at top cylinder area ..

I was thinking about letting the engine hone ..but during dissembling the engine I saw a 60 printed on the pistons ..after some search I found out : the engine was rebuilded around 2005? and only runs a short time and was sitting the last 12-15 years .. inside everything is looking very good .. bearings are nice ..what can I do now? Already bored to 0.060” ..
my machine shop said : they can hone and coat the pistons for extra material .. what do you think about ?
Some pics of the current situation :

[geeteeohguy]

I don't like the look of the scratch in the first cylinder in the first photo. Looks like it could be a crack?
I would disassemble the engine and have the block sonic checked for cyl. wall thickness and cracks. I would check the cylinders for taper and out of round. If not too bad, you can have pistons made at .065 or .070 oversize, and even have dished pistons to run on pump fuel. Some 389's can go as much as .090" oversize if they are thick enough, but you need to have it checked.
Another solution is to sleeve the cylinders, which is expensive and IMO, not as nice as a regular block that is properly refinished oversize.

[hurryinhoosier62]

Originally Posted by geeteeohguy

I don't like the look of the scratch in the first cylinder in the first photo. Looks like it could be a crack?
I would disassemble the engine and have the block sonic checked for cyl. wall thickness and cracks. I would check the cylinders for taper and out of round. If not too bad, you can have pistons made at .065 or .070 oversize, and even have dished pistons to run on pump fuel. Some 389's can go as much as .090" oversize if they are thick enough, but you need to have it checked.
Another solution is to sleeve the cylinders, which is expensive and IMO, not as nice as a regular block that is properly refinished oversize.

X 2. ‘66 389s can be a crap shoot. I know of two blocks that had to be scrapped due to incredibly thin( like .090) cylinder walls in standard bore engines. I would have the block ultrasonic tested before going further.

[25stevem]

Those look like 400 pistons since the centered valve notches do not line up with valve chamfer in the top of the bore, which correct for the early heads valve inclination angle.

Before you cart it off to the machine shop check the fit of a lifter in each bore once free from oil.

I would be surprised if that one bore with the bad rust cleaned up even at .010” .

That cylinder may be a candidate for a sleeve!

[Dragncar]

66 blocks had problems overheating and warranty issues. Thin cylinder walls. Its one of the reasons the 67 400s had thick cylinder walls. Bad experiences from 1966 389s.
I had one crack myself.

[Sirrotica]

In 1972 I bought a .060 over 65 GTO 389 that I owned for a whole week before the cylinder wall collapsed into the water jacket. I had bought the car mostly because the guy needed money, and had all the receipts for the engine parts and labor.

The engine stalled when the cylinder collapsed dumping coolant into the #3 cylinder. That hydrauliced it, so I popped the clutch out while I was still moving, ignorant of what had happened inside of the engine. The crank broke in 5 pieces, one for each main bearing, the engine was completely destroyed internally. 4 pistons weren't broken, the cam surprisingly didn't get nicked, and the cylinder heads survived. Everything else was scrap metal.

After it happened I pulled over to the side of the road and tried to crank it with the starter, it was locked up. Further investigation shows oil, and coolant running out of a gapping hole in the pan, and block....... I had another stock 389 2 bbl engine from a 65 Catalina that went into it so I could get back and forth to work that went in that weekend. We then did a post mortem on the blown engine.

Expensive lesson learned about 65, and 66, 389s, with thin wall castings, they don't like to be bored .060 over, 64 and earlier, usually have enough meat to go .060 over. 64 is also the only thick wall casting that has a provision for block mounted starter though. After that debacle I was pretty much going for 67, and later blocks for all my builds.

Some 65-66 389s were okay for .060 over, but some weren't, and this was before sonic testing was common, so I just avoided those blocks. A standard bore 400 will accept your .060 pistons, but it would be a challenge to find one with minimal taper after decades of use.

[1965 Pontiac Parisienne]

Thx for the feedback ..yes ..finally 2 machine shops said ..sorry this engine block is at the end. The rust issue is to bad to bore & hone ..and hone and coating the pistons won’t work in this case ..and put sleeves in and new standard size pistons is an option but a risk to do and finally a lot of bucks ..better to look now for a better complete standard 389 engine around ..
thx a lot
Bjoern

[geeteeohguy]

Originally Posted by 1965 Pontiac Parisienne

Thx for the feedback ..yes ..finally 2 machine shops said ..sorry this engine block is at the end. The rust issue is to bad to bore & hone ..and hone and coating the pistons won’t work in this case ..and put sleeves in and new standard size pistons is an option but a risk to do and finally a lot of bucks ..better to look now for a better complete standard 389 engine around ..
thx a lot
Bjoern

Your location is the big issue. Likely the shipping of a replacement will cost more than the part itself. Good luck in your quest. Lots of good guys here, a post in the wanted section may help.

[racegto65]

Originally Posted by 1965 Pontiac Parisienne

Thx for the feedback ..yes ..finally 2 machine shops said ..sorry this engine block is at the end. The rust issue is to bad to bore & hone ..and hone and coating the pistons won’t work in this case ..and put sleeves in and new standard size pistons is an option but a risk to do and finally a lot of bucks ..better to look now for a better complete standard 389 engine around ..
thx a lot
Bjoern

I've got a 1965 389 block currently .090 over that has been street driven and bracket raced since it was built in 2007 with no issues. And no I didn't sonic check this one.

But the rust in Number 8 cylinder looks more than .030 deep. If you have a machine shop you trust have them bore the worst hole and then decide. Good luck