Anyone else surface heads the hard way?

[FriendOfYours]

Our bridgeport has been out of comission for the last few weeks

This is the third set of heads I've done this week

The slab is flat to .001



I feel buff

 

[Jbizzle]

Can you explain the process of doing it the hard way? Just curious how it's done and if it can be a DIY project?

 

[PT Doc]

Big flat surface with 120 grit and lots of figure eights until your arms fall off? Witness marks left.

 

[FriendOfYours]

You need a surfacing plate. Granite slab that is flat at least to .001

Can buy one already flat for $150+ or go measure one out at Home Depot til you find a good one.

You need a REAL machinist straight edge, not a ruler or something and a set of feeler gauges

180 --> 220 --> 320 grit sandpaper laid down with contact cement. I use brake fluid to wet the surface. Go to town until it's flat. 320 is enough for MLS gaskets

 

[G1K]

What kind of fixturing do you use on the Bp?

Ryan

 

[57c]

I've done that many times on small engines, and once on a quad 4 motor that I ran way too hot.. didn't need a straight edge to see where it was warped.

I don't have a surface plate but I have a big 1.5" thick aluminum plate that was machined flat that I found at scrap yard, it is flat enough. taped some sandpaper down, wet it, and start running the head back and forth, in circles. on aluminum heads it's not to bad to do. sometimes I put some dye on them to see the high spots, but basically you just keep checking it with straight edge until it's flat. I'd rather take it to a machine shop, but when there's no time or no money I do it this way. I guess doing a big v8 cast iron head is possible, but I wouldn't want to try it.

 

[FriendOfYours]

What kind of fixturing do you use on the Bp?

Ryan

Three slotted angle plates, a 6" flycutter, lots of shims, and patience lol

I'll usually go over to the surface plate with 320 afterward. It's really hard to get a good cut on a pass that long. It has to be trammed freaking balls on

Maybe one day we'll get a resurfacer but I don't see it happening. Times are tough right now so we are doing more repair than custom

 

[Technicality]

learn something new every day. I never knew about resurfacing the hard way

 

[Hafen_Kafer]

I think that slab is flexing on you as you put pressure on it. Its too thin. Get one from ENCO. They're cheap

 

[FriendOfYours]

It's not. Never had a head come out further than .0015

That head started at .008

Stopped when it was in spec. No need to go completely flat

 

[gungatim]

I did a warped head off a overheated taurus v6 the hard way...used a file and then sandpaper wrapped around a flat piece of metal stock. checked with a straight edge when done, it worked like a charm. Wouldn't want to do it like this all the time, but in a pinch, it can be done manually if not too bad.

 

[Nortonscustom]

I use cast iron lapping plates. Have 2, both are about 16"x16". Have done goodness knows how many Shovel and Iron head motors with them. Lapped the heads and rockerboxes on every motor I did. Works good on case halves, oil pump faces and cam covers too. Little extra time goes a long way towards building an oil tight motor.

That being said, it would **** to do set of heads off a car! That's a lot of work!

Actual lap plates look like theses.

 

[stratman977]

I did an old subaru 4cyl boxer using a piece of glass set on top of my table saw. Neither side was warped but it had an impression where the fire ring was. More of a PIA than its worth if you ask me.

My lower back was in bad shape for at least a day after doing that.

 

[sberry]

My guy does our golf cart heads on the drill press table. Sticks DA paper on it.

 

[sberry]

I use cast iron lapping plates. Have 2, both are about 16"x16". Have done goodness knows how many Shovel and Iron head motors with them. Lapped the heads and rockerboxes on every motor I did. Works good on case halves, oil pump faces and cam covers too. Little extra time goes a long way towards building an oil tight motor.

That being said, it would **** to do set of heads off a car! That's a lot of work!

Actual lap plates look like theses.

I can see for sure cleaning and straighten bike parts could go a long way.

Even car engines, especially old shitt V8 stuff. They had ruff castings and poor machining etc. We got a few we own a long time, when we do or did reman I would go over them and do clean up while its up on the stand, cleaning castings lets them paint nice and last a long time.

 

[1969]

I think that slab is flexing on you as you put pressure on it. Its too thin. Get one from ENCO. They're cheap

Question......... How would you know that just looking at the picture and the info provided?

 

[2oolhound]

I think he's talking about the machined aluminum plate.

 

[colin39]

1/2"plte glass and 1200 yes on more than one occasion

 

[compaddict]

Yup. Suburu heads back in the day!