Author Topic: Re-use Head? (Read 4696 times)

Harry · « **on:** February 05, 2006, 06:41:37 pm »

I had a blown, or actually seeping, head gasket on my '81 Dasher wagon. It would still start up on glow plugs after a couple of cycles, but it was pumping oil into the coolant and the compression was down, obviously, also it would pressure up the cooling system just by spinning the starter. I removed the head and cleaned it, carefully, and then feeler gaged it with a straight edge. There are three spots, toward the middle of the head, that will pass a 0.004" feeler, but will not pass a 0.005" feeler. This is at the limits according to the Bentley. Should I try it, or should I not, using a new gasket of course. The old gasket is a 3-notch, the engine is a 1.6l n/a, solid lifters. Would like to not spend too much on this, as we want to buy a '98 Jetta TDI and 2 expenses at once we don't need, but we need both cars.

vwmike · « **Reply #1 on:** February 05, 2006, 07:19:37 pm »

The head gasket is actually sort of a wear item on these cars. They do periodically need to be replaced regardless of damage. If the surface of the head is a gradual bow and within spec I wouldn't worry too much about it. If the surface is at all wavy (this makes me wonder since you said there were 3 spots) I would have it milled.

Harry · « **Reply #2 on:** February 05, 2006, 08:09:04 pm »

vwmike, thank you,
If I get the head milled about how much do you suppose they will take off? Will this then put the valves too close to the pistons? This engine already had a 3-notch gasket, which I'm told is the thickest, so....? Is there a thicker gasket, composition or steel, available that would work? Maybe when they gring the valves the valves set deeper in the head and there's no problem?
Thanks, Harry

Master ACiD · « **Reply #3 on:** February 06, 2006, 10:38:59 am »

just clamp the head in a vise upside down. grab a 12 inch square plate of relatively thick glass and use some 3m adhesive aresol to glue down a sheet of 150 grit wet-dry metal sandpaper onto the glass. use some wd40 for lubrication and work on the head back and fourth untill the low areas are gone.

i have done this to a relatively large number of engines, from vw to mazda, kia, a big old ford 400cid all iron motor, lawnmowers, chainsaws etc.

its awalys worked out great.

note that this only works on heads with flat spots. if you head is warped or has high spots then this wont work. you cant remove warping with sandpaper and glass. also high spots cant be removed because its impossible to hold the glass straight on the high spot and not effect the edges of the head.

vwmike · « **Reply #4 on:** February 06, 2006, 10:55:34 am »

In a perfect world they wouldn't take much off...but it depends on the machinist. A lot of times they like to take a lot off but if they really understand the job they've been given they would be careful about it. If you already have a 3 notch gasket that may also be because the head gasket has been replaced. Frequently a mechanic will just default to the 3 notch gasket when it is replaced. You can check the piston protrusion if you want to verify which gasket you should have. As for the valve clearance, I can't really be sure when that will become a problem. Stay away from head spacers and such...especially copper head gaskets. They are nothing but trouble and ALWAYS leak.

Harry · « **Reply #5 on:** February 06, 2006, 03:52:32 pm »

Master Acid and vwmike,
Thanks guys, I appreciate the help. Got a better straight edge today and am only getting about 0.002", toward middle of head(between #2 & #3), measured diagonally. Firend of mine is a machinist at Los Alamos and is coming down here tomorrow to get some stuff for his own 1.6n/a from me and is bringing his gizmos to check as a favor. He has done something similar to your technique M. A., says lots of cases it can work within the parameters you mentioned, as a matter of fact, just not enough warp to bind the cam, he said, or somehting like that. Again, thanks. Harry