Maximum Block and Head Distortion - B5234T Topic is solved

Hoytster · Post by **Hoytster** » 04 Dec 2016, 18:08

I apologize if this has been covered but I haven't been able to find anything by searching. I bought a 95' 850 Wagon (88k, 5 speed swapped) for $200 that needed a head gasket (due to overheating). I tore it down and measured the head at .024 out lengthwise. From what I have found on this site, that is way beyond spec as to what can be machined, so I believe the head is junk. I measured the block at being .003 out lengthwise, but haven't been able to find a spec for how much distortion is allowed on the block. Does anybody have this information?

Post by **rspi** » 04 Dec 2016, 19:29

Was fluids mixed?

Post by **polskamafia mjl** » 04 Dec 2016, 21:34

rspi wrote:Was fluids mixed?

OP said he bought it so I imagine he doesn't know the history. Besides that's not what he asked about.

Hoytster · Post by **Hoytster** » 05 Dec 2016, 06:29

polskamafia mjl wrote:
rspi wrote:Was fluids mixed?
OP said he bought it so I imagine he doesn't know the history. Besides that's not what he asked about.

You are correct, i dont know much about the history other than it overheated and was taken to a garage. There was no coolant in the oil when i bought it, but there was plenty of oil in the coolant. Exhaust gas in the coolant resevoir and it would push coolant out when started.

Post by **polskamafia mjl** » 05 Dec 2016, 23:47

My Haynes manual only lists specs for the cylinder head. Is it possible that there's no range for the block and instead it should just be decked? I've never rebuilt a motor so I don't know.

Hoytster · Post by **Hoytster** » 08 Dec 2016, 16:28

I know most motors have a range. General rule of thumb I've heard is no more than .003 on a v8. And no more than .005 on a inline 6. I've never heard anything about an aluminum block inline 5....

Post by **JDS60R** » 08 Dec 2016, 22:21

Block is normally a thousandth per cylinder. The block is much harder to warp. So normally on a 5 cylinder I'll see 2-3 thousandths max if any.

The head is normally out 6 thou unless its been overheated. There are machining notches in the head- recessed areas that you should not cut past. If the head hasn't been cut there should be more than .024 in there. Take it to your machinist and have him measure. Sometimes they will heat the head and straighten it to within 8 thou or less and then cut.

I had a couple of 95 850's and loved them. The piston rings could use a little help. Technology has increased since then quite a bit. I like to put on a set of new Total Seal piston rings while the engine is apart. It gives me a chance to inspect and replace the bearings while I'm in there. A few hundred on rings and a hundred or so on bearings and you have really brought that car back to life.

Keep in mind with the head being out .024 it probably saw some heat so I would check the block for out of round cylinders and consider all the aspects of the motor before fixing anything . Plenty of good used engines that you can put in there. Lucky even did a video on putting a newer model engine in there.

Hoytster · Post by **Hoytster** » 11 Dec 2016, 05:43

JDS60R wrote:Block is normally a thousandth per cylinder. The block is much harder to warp. So normally on a 5 cylinder I'll see 2-3 thousandths max if any.

The head is normally out 6 thou unless its been overheated. There are machining notches in the head- recessed areas that you should not cut past. If the head hasn't been cut there should be more than .024 in there. Take it to your machinist and have him measure. Sometimes they will heat the head and straighten it to within 8 thou or less and then cut.

I had a couple of 95 850's and loved them. The piston rings could use a little help. Technology has increased since then quite a bit. I like to put on a set of new Total Seal piston rings while the engine is apart. It gives me a chance to inspect and replace the bearings while I'm in there. A few hundred on rings and a hundred or so on bearings and you have really brought that car back to life.

Keep in mind with the head being out .024 it probably saw some heat so I would check the block for out of round cylinders and consider all the aspects of the motor before fixing anything . Plenty of good used engines that you can put in there. Lucky even did a video on putting a newer model engine in there.

Thanks for the information. That is exactly what I need!