First, I would just like to thank everyone on this forum for their help. You guys are awesome. Well, last night I got the intake manifold off my ’95 Burb. Now I only have the A/C Compressor and fuel lines to go, and then I can pull the head. What is the best way to prep the mating surfaces for a new gasket? I was thinking, shop vac, engine degreaser, wire brush, and then wiz wheel. What techniques did you guys use?<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Thanks,John

Carb cleaner to loosen the residue





cup brush or wire wheel on a die grinder to finish it out

paint scraper and a wire brush, die grinder might be a little much

napa sells these little discs and a little arbor for them made by 3M. the discs are about 2"dia. and the arbor fits into your drill. they are made of something like a scotch-brite pad on crank but it absolutely will not remove any metal or scratch any metal. with the help of some acetone (nail polish remover) it will remove all traces of gasket material. doing my heads last summer i used 4 of those pads but i was changing them for each new surface.

Those cute little 3M 'scotchbrite' or whatever pads WILL do more than remove gasket material, even on cast iron blocks. ask me how i know. oh, i was using them as intended - on a 10,000 rpm air angle die ginder. and - fortunately i didn't hose the engine at the time.


if you're careful and use a lower-rpm drill to power the pad you may see different results. wire wheels and the like are nice and don't resurface cast iron like those 3M doohickies . . .


Good Luck !!

wha'chu talking 'bout willis? when i used them they wore down to almost smooth and wouldn't remove anything if i pushed too hard on them. i'm assuming that we're talking about the same pads. i guess different strokes.http://www.dieselplace.com/forum/smileys/smiley2.gif

Thanks everyone for your advice. So how have then new head gaskets held up so far? Also, did you guys use gaskets or RTV to re-seal the valve covers? How did you set the intake gaskets? I was thinking about using just a little bit of RTV on each corner just the hold the intake gasket in place. Is this a good idea?

I would make a thin rtv smear around all intake ports to help hold pressure.

valve covers-i used the cork gaskets with rtv on the valve cover side


intake- gaskets came with little plastic studs to hold them in place for assembly so no rtv was used


USE LOCTITE (the red stuff)on all bolts on valve covers and intake or your bolts won't stay torqued down. even if you use a torque wrench the diesel will shake 'em loose and your valve covers will leak like you didn't even put a gasket in there. try to re-torque them later and the cork splits, the covers warp, and more leakie.

Silicone for the Cork Valve Cover Gaskets yes, but your best not putting Silicone anywhere else, or Loc-Tite.

i don't mean the blue heavy duty break off before coming out loc-tite. i mean the red medium stuff. i did my valve covers about a year before my heads went and i cleaned the bolts even ran a tap down the holes, torqued them in sequence to the specs even added a couple of pounds to be sure. about 4 months later they were leaking and a year later when i went to take them off again they were barely hand tight and the intake bolts weren't too much better. when i put it back together i was damned if they were going to loosen up on me again so i used the red loc-tite on valve covers, intake, and upper intake. over a year since the new heads and still bone dry and tight.

lupey and bob t. you guys were probably using different grades of those scotch brite pads kind of like different grade sand papers. I use these pads all the time different ones for different jobs some of them will eat anything including cast iron.

Regarding the loctite issue, the blue #242 is the removable stuff, the red #262 is the heavy duty need heat to break loose stuff. I don't think the red would be good to use on anything you might need to take apart again, especially with old bolts, you'd be sure to cause some headaches.

Regarding the loctite issue, the blue #242 is the removable stuff, the red #262 is the heavy duty need heat to break loose stuff. I don't think the red would be good to use on anything you might need to take apart again, especially with old bolts, you'd be sure to cause some headaches.


Yeapper That's ture with the "loctite" brand but there are other good brands out there that use different colors. best advice would be to read the package to see which one you want to use, but for sure use something.

My bad. http://dieselplace.com/forum/smileys/smiley5.gifI DID re-machine a VW 16-valve aluminum head. I DID NOT do any damage to the block. was using the nasty red 3M pad on said air die grinder . . .

Hey Everyone,<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />


Well, I finally got my passenger side head off this weekend. I removed the bigger pieces of gasket with a paint scraper, and then cleaned the mating surfaces to a nice polish with a wire brush attachment on my drill. Worked surprisingly well.


The fire ring on #4 was completely toast, but I didn’t find any obvious signs of coolant leak, either on the cylinders or the gasket. I also noticed that the gasket had been replaced before, because it was an after market Fel-Pro. Anyhow, there was a blemish on the head running right where the fire ring failed on #4. I carefully filled the small nick with JB Weld and sanded smooth. I am just hoping this helps the head gasket last a little longer this. At least long enough for me to drive this heap to the used car lot.


Anyhow, this is a huge job, and I am not entirely convinced that it is worth it. Since I couldn’t find any obvious signs of coolant leak on the passenger side, and I found a lot of coolant in the cross-over pipe, I have decided to pull the drivers side head as well, but I will keep that wonderful job for another day. For now, I need to take a break from this POS.

Both heads is the way to go.


Isn't it likely the gasket was bad around the #4 cylinder and leaking coolant into the cylinder and out the exhaust valve?


When you say fire ring, do you mean compression ring on the piston?Edited by: quantum mechanic

QM,<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><O:P></O:P>


Yes, the compression ring. I was very careful to use the smallest amount of JB Weld to fill in the small nick. I rubbed all the excess off before the JB Weld had time to harden, leaving only trace amounts behind to fill in the defect. I then very gently hand sanded smooth with fine grit sand paper. <O:P></O:P>


Not sure how well it will work, but I bet it will help the head gasket last longer, than if I just put a new one on without doing anything to the nick. Only time will tell.


Man this is a big job though. I can see why it is so expensive for a shop to do it. Actually the biggest pain so far has been the 17 head bolts. That's a lot of bolt to first undo, and then replace with new ones. The head was stuck on pretty good to, so I finally had a mechanic friend of mine come by and he used a screwdriver on the very outer most corner to wedge the head free. What a pain. <O:P></O:P>


My only biggest concern, is that I have spent all this time and money to fix something that I know will run for a short time, before I have to fix something else. Edited by: Juancho

Nature of this beast, John, but it doesn't get much worse. Stay organized and goal oriented and it will come together.


It's a big job for a first job. sorry, about the baptism by diesel oil but you're already the a better man for having jumped into it. It's your sweat and bllod that are going to make that truck run again. ill it be so easy to part with it?


It looks like you'll be pulling the oil pan to loosen the #4 cap bolts. Put a piece of fuel line on the bolt threads and push it up and out. You can measure the wear on it's racer with a micrometer.Edited by: quantum mechanic

What or are the #4 cap bolts?

The bolts that hold the cap on the rod end. When you take them off you can remove the piston.

Why would I want to remove the piston? Hey, do you know where I can get a socket for the injectors?





Thanks,


John

QM,


I think he means the small metal circle in the headgasket around the cylinder opening when he says "fire ring".

Bobt250






You are correct sir. That is exactly what I mean. Thanks for the clarification.

What about the valves on the #4? Did they get burnt?

Valves looked great along withthe pistons and rings. In fact the inside of the engine, (ie pistons, cam, pushrods, cylinder walls etc.) looked almost new.


Any idea where I can find a socket for the fuel injectors?

Oh... sorry bout that question. I use a 30mm deepsocket 1/2"drive iirc costs about $10 at the parts store

What about teh fuel return nubs? It doesn't hurt them to just use a regular 30mm deep socket?

No. it doesn't seem to matter.

Jauncho,


Do you have a digital camera, so you can document for others that might not know what it looks like, you can inform at same time you are learning. I think the fire rings you are referring are the pre-combustion chamber "cups", I sort of remember a thread over at the page, about it being "normal" for them to be loose after they get some miles on them.


I'll have to dig around to see if I can find the info, in mean time anybody remember this article I'm referring to; also both heads need to come off.

Actually, the fire rings I am referring too probably have a completely different name so I will do my best to explain. If you look at the head it is obvious were the cylinders match up because there are four machined circles. The fire ring I am referring to is the border of the circles where the compression ring on the head gasket mates up.<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

On the head of the #2 cylinder there was a little pitting along the border, which caused the compression ring on the head gasket to fail. I filled the pitting with the smallest amount of JB weld and rubbed the excess. I am hoping that this will help extend the life of new head gasket I installed. I knew that if I did nothing, then the new head gasket would fail again prematurely.

Personally, I am not a huge fan of JB Weld, mainly because I have been using it wrong for years. It is terrible glue, and doesn't work at all if you are trying to say glue two pieces of metal together. However, I have heard many people have great success using it to fill small crack or pits in engine blocks, so I decided to try it out.

I copied this from 6.2L forum





"One of the Tech books from GM I have it says to torque them to 20 ft/lbs in sequence and then to 50 ft/lbs in sequence and then a ¼ turn in sequence. It is a rough drawing but you'll get the idea."


14 10 6 2 3 7 11 15


17 9 1 8 16


13 5 4 12


JB works if you get the mix right.



But it can't hold up o combustion tempatures.


The damage is on the head? If the head's damaged turn them in for a remanufactred head for ~$450
Edited by: quantum mechanic

Thanks QM. I have a manual, which outlines the correct tightening sequence, and I found the 20lbs, 50lbs and 1/4 turn procedure on the gm-diesel forum. The combination of the manual, and the wealth of knowledge from you guys make this job a lot more manageable. Thanks for all your help everyone. I could not of done it without all of you.Edited by: Juancho

do the torque to 50 twice in sequence because when you go from 20 to 50 by the time you get to the end of the sequence the bolts in the middle are not at 50 anymore. if you go over them again then the 1/4 turn they will all truely have the same torque. the haynes book tells you that if you clean the threads on the head bolts you can reuse them, this is not true. these bolts are tty (torque to yield) hence the 1/4 turn at the end and not an acctual torque value. these bolts stretch ever so slightly and never return to where they began after being torqued down.gud luk man, been there.

When I torque this many bolts I like to "stage torque" them 20 then 40 then 50 would be what I do here, then go back and recheck for 50 final a second time, length of bolt, and thread pitch will have a lot of drag and stretch that can skew your torque sequence, this is how we torque jet engine case flanges, using body bound "fitted" bolts to get consistent torques in critical areas subjected to heat.