Machine shop aggrivations

[IDIBRONCO]

I had my 7.3 heads at the machine shop for a valve job including new guides. When I dropped them off, I spent about 20 minutes talking with the machinist about head thicknesses, valve recession, etc. I even wrote the specs down on a piece of paper and left it with him. He sounded like he understood what I was talking about. I got a call from him yesterday saying that the heads were done. He said there wasn't any problems, everything went smoothly. Then he said that he milled .010" off of one head and .012" off of the other. When I left them with him, he mentioned milling them and I said only the BARE minimum, like a couple of thousandths. He said OK. After this, I'm convinced that he has a "love affair" with milling heads. I was so disgusted. There goes any chance of using my Typ4 cam! I went to pick them up. He got out his caliper and showed me that they are RIGHT at 4.795" for thickness. Of course right at minimum ("love affair" again). I was so tired of talking to him that I paid for them and left. I went down the street and checked the valve recession. One intake valve had .002" and one had .003 too much recession. One exhaust valve had .001" not enough. The rest were all in spec, but the readings were all over the range from high to low. I don't think I'll have a problem with them, but I'm going to check the clearances for sure with some Play-Doh I bought today. I'm waiting for the extra head gaskets that I ordered to come in before I do this. Apparently my idea of being a machinist isn't the same as his. I feel that the measurements should be A LOT closer than that. I guess he works on too many small block Chevys (anyone who wants to dispute that statement has OBVIOUSLY not seen some of the people that I have working on and building them!). Since I need to have my truck running soon, I'm going to have to leave the stock cam in it for now. Maybe next summer, I can pull it back out, tear it completely down and have the pistons shaved .010". Then I (hopefully) should either be able to run my current cam or Russ's new one. It's either that or have the block decked and try Justin's decompression gaskets. To me, that's a last resort since you can't add that material back to the decks when it's gone. At least I'll still be able to install my turbo! Opinions?

 

[chillman88]

Sounds kinda like why I do all my own wrenching. You find a guy that sounds like he knows what he's doing and then find out he charged you 1.5hrs labor to diagnose a bad light bulb

 

[IDIBRONCO]

I know I WILL NOT be going back to him. Also, I forgot to ask, does anyone know exactly what the "cooling" mod to the 7.3 heads is? I think it was to drill some holes to let coolant through. Was this in the soft plugs in the block and heads that are in the same corners as the plastic insert in the 6.9 head gaskets? It also seem like someone said to use the 6.9 head gaskets to let the coolant through. Is this right? I tried for a while to use the search function for this, but wasn't sure what to call it to do the search.

 

[Thewespaul]

Man it's hard to find a good machine shop, I'm lucky my dad was a machinist for years, he can do a lot of the work out of our shop but he still knows the local good shops

 

[shawn deere]

Maybe look into the moose head shims? If you have the cheddar. Might be on par with milling the pistons.

 

[79jasper]

I know I WILL NOT be going back to him. Also, I forgot to ask, does anyone know exactly what the "cooling" mod to the 7.3 heads is? I think it was to drill some holes to let coolant through. Was this in the soft plugs in the block and heads that are in the same corners as the plastic insert in the 6.9 head gaskets? It also seem like someone said to use the 6.9 head gaskets to let the coolant through. Is this right? I tried for a while to use the search function for this, but wasn't sure what to call it to do the search.

That may only work in the 6.9 block. Can't remember.
But Gary @icanfixall knows.

Sent from my SAMSUNG-SM-G890A using Tapatalk

 

[IDIBRONCO]

The 6.9 already has the "extra" coolant holes. They're blocked off on the 7.3 block and heads. The 7.3 head gaskets don't even have the holes in them.

 

[Macrobb]

So... I'd not worry about the milling(head height), as long as the recession is within spec.

If you want to run the Typ4 cam, .001 under spec is... not good enough. I wouldn't even run the stock cam like that!

Get the valve recession fixed to maximum spec at least; a few thou over won't cause issues, a few thou under will.

The lifters will take up a seriously large amount of adjustment; obviously, you'll want to check that they aren't bottoming out or at maximum extension, but there's a lot to play with.

 

[Mulochico]

Sounds kinda like why I do all my own wrenching. You find a guy that sounds like he knows what he's doing and then find out he charged you 1.5hrs labor to diagnose a bad light bulb

Exactly, can't even go into the "fun" I've heard from people just in the last week with getting vehicles back with scratched (gouged) paint, tires that "will fit" and hit the fenders badly, half finished repairs that are "done", etc. I really wouldn't expect this from a shade tree mechanic let alone a "professional" shop.

 

[hce]

What tools did you use to measure your valve recession?

 

[tjsea]

Yep, the mod is to pop out or drill the corner plugs out of the heads and block and then run 6.9 head gaskets. I just did this on my engine, but haven't gotten to run it yet.

 

[icanfixall]

I was the person that measured and researched running the 6.9 head gaskets on the 7.3 block. It fits like it was designed for it.you can remove the plugs or open them up the size of the coolant passage in the 6.9 gaskets. Not sure if you can open up the plugs and... Get all that material out of the block. Check the heads too. I have seen plugs in those too. No idea why the heads AND the block would have plugs but.. Its what I have seen. The Felpro head gaskets are the thickest factory gaskets available. The are about 76 thousands thick and compress to around 72 thousands. So if the pistons raise up out of the cylinders by 31 thousands you end up with around 40 thousands gap between the heads and the piston tops. I still do not know if the valve chases the piston or the piston will chase the valve to the closed position.

 

[IDIBRONCO]

Thanks Gary. That's what I thought I remembered. I looked at one of the inserts from an old 6.9 head gasket yesterday and the hole in it is oval shaped and by just looking at it, I'm guessing that it's about 5/16" long and maybe 3/16" wide. I'm not sure that I'd really need to go very large with the head/block holes if this is all the bigger the hole in the gasket is. The way I see it, any coolant flow is WAY better than none. Hce, I used my Starrett depth mic to check the recession. I sat the base on the head surface straddling the valve and touched the measuring part (not sure what it's called) to the valve face. I know that everything may have not been perfectly clean, but It was as close as I could get it in my situation of being in a parking lot somewhere. I forgot to mention that the machinist (for what it's worth) kept stressing overall valve length. He said that he'd be more worried about that then the recession. Of course it's not HIS engine so I'm worried about it all. He did say that he made sure that the valve length was right. I ordered some Victor Reinz 7.3 head gaskets to do my checking with, but I believe that my 6.9 head gaskets are Fel-Pro. I have to check tomorrow.

 

[Macrobb]

I forgot to mention that the machinist (for what it's worth) kept stressing overall valve length. He said that he'd be more worried about that then the recession.

He doesn't have an IDI, that's for sure. Valve recession is *critical* on an IDI, due to the exhaust valve being chased/chasing the piston.

On my '88 engine, everything should have been in spec - pistons came out of the head by .025".

One head was in spec, recession wise(middle of the spec) = worked perfectly. No marks.
The other head was .006-.010" too shallow... and there were marks on every single piston of each valve.

 

[IDIBRONCO]

That's why I'm going to check the valve clearance with Plat-Doh before I call it "good". I will be measuring with my Mitutoyo mic. I have 4 7.3 head gaskets on the way from Rock Auto.