Head gasket... when to replace... - Page 2 - PeachParts Mercedes-Benz Forum

Hit Man X · #16 12-07-2013, 10:42 AM

$550 seems decent for a stripped No 17 that is a known good head. Make sure the camshaft bearing caps are true. You may have to line hone that. Prechambers, glow plugs, injectors, and injector lines are all different between the 14 and 17+...but you probably know that by now.

I swear the two front allen bolts in that timing cavity are longer when using a late head. If I am wrong, someone cast me down with aspersions.

Consider going with the most updated timing cover too. Early crack where that big tensioner bolt threads into it. I forgot what I used to know on this swap, I put my SDL on the back burner and I am tired of it sitting which is why I am reading/posting on the top end threads.

On this topic, what head gasket is needed for the 17+ swap? Is the Victor Reinz fine or was the Goetz a better unit? I forget.

Hit Man X · #17 12-07-2013, 10:54 AM

Here is more info from my old threads:

Per Sir Sixto -

You need longer bolts from the head into the front cover. #14 takes 50mm bolts, #17-up take 80mm bolts.

You can turn down #14 prechambers [edit] to work in #17-up heads. Dave's website has pictures that were good enough for my machine shop. I don't recall paying for different lock rings going this route

If you look at straight and angled injectors side-by-side you'll see the difference - one has threads near the tip, the other has threads near the hex. Dave would know if the innards can be swapped.

You can probably persuade #14 injector lines to attach to angled injectors.

Angled prechambers take a different thread pattern injector so note that you need a different compresstion tester adapter if it comes to that.

US 3.5 cars came with #17 heads. #18-up are replacements but might be original on crate engines.

If you're pulling the head, consider swapping in a Euro or 140 exhaust manifold that doesn't have that goofy reverse layup feed pipe arrangement. You might need to rework the downpipe.

uhh... use a 3.0 head gasket on a 3.0 block

LATE 603.xx head questions

My 603 head gasket finally failed...

Lots of interesting bits there on head gasket brands.

87tdwagen · #18 12-07-2013, 01:02 PM

HitManX,
Always appreciate the great info you provide! Thanks

I'm confused regarding the timing cover to head bolts. I understand that you will need longer bolts from the #14 to the #17, but I have conflicting details as to the measurements:

One set is M8 x 30mm (#14) vs M8 x 50mm (#17)
Next set is M8 x 50MM (#14) VS m8 X 80MM (#17)

Any idea of which is correct?

Head gasket sets seem that Reinz is most often listed. Somewhat torn on using a OM606 MLS gasket, namely to permanently end the risk of this type of failure again, and also for future power upgrades. Just not sure of the sealing quality, there are posts and info that argue both sides equally,

either the require perfectly mated/polished surfaces in order to work, or...
They dont, and are commonly installed on "normal" mating surfaces and seal just fine.

Does anyone have experience going this route? What pros cons can you share?

Hit Man X · #19 12-07-2013, 01:19 PM

I would check the EPC for exact details on the fasteners.

The 300SEL now has a Victor Reinz and is doing its job well, as is one of my E23 BMW 745i cars. MLS is a better design, but you better make damned well sure the surfaces are basically spotless so it can seal. It has something to do with the RA, being in the 50s. The VR is what I am going to order on my next parts go around, I have no desire to crank the power up on the SDL anymore than high end of factory. I have stuff that will blow its doors off, the ALDA delete, gutted cat, proper boost, high side of IP flow will be plenty adequate for the thing for me. It is an economy car after all.

When I last drove mine, it drove plenty well...quicker to about 50mph than the 300SEL. I was taken from there so meh, but the 560 with true duals and a throttle that actually goes 100% WOT will eat it alive...then my 745i is quicker yet. And my 6.4 will shoot past that like it is standing still. See where this is going?

Well, the 17 can still have the No 1 cylinder oil passage failure as I understand. If you can find a picture of the deck surface on a 22 head (right by the timing chain cavity), you can see how the area is different at the very front. That long, skinny earthworm looking section is gone on the 22s. 17 and 18s still have the long section.

Another thing that popped in my head, is you may want to consider new chain sprockets if yours are worn severely.

Hit Man X · #20 12-07-2013, 01:49 PM

http://www.cometic.com/technical.aspx

Check that out, a bit of info on the RA.

87tdwagen · #21 12-07-2013, 02:08 PM

Quote:

Originally Posted by Hit Man X

Another thing that popped in my head, is you may want to consider new chain sprockets if yours are worn severely.

Good call, I was hoping to not have to mess with the timing cover. I understand that the older design has its flaws but also believe in "if it ain't broke, don't break it"

I measured my chain stretch a couple of years back and was in the 0.5-0.75 degree territory so was hoping that based on such little stretch on the factory chain, the other components "should" be in fine working order...

About the only thing I was thinking of changing was the belt tensioner, although seemingly fine (I've two belt change-outs in the last week) it has not been replaced in 10+ years and is probably due.

In the end I'm prepping for the eventual work. As much as I would have liked to simply raise the head, throw on a new HG and rebolt the head...alas this ain't GM iron, and while it may work with a OM617, not the best approach for a OM603. The "while I'm at it" syndrome takes hold quick, and then you are practically rebuilding the engine .

I was hoping to capitalize on the car being down to do some other upgrades, like the later exhaust header and downpipe, possibly a 7mm IP and whatnot. Still need to determine if I will use the old prechambers although I have the slanted style in hand, I do not have the newer injectors or shorter glow plugs, so money will be spent, for either new parts or machine shop time.

Any real advantage to the slanted prechamber design?

sixto · #22 12-07-2013, 03:05 PM

There's nothing special about the front cover bolts, though my memory is obviously less special still. If your #14 head is off, measure how much of the original bolt extends into the front cover. Then drop the bolt into the #17 head to determine how much longer the bolt has to be. It'll need to be at least 20mm longer. You can get what fits from Home Depot.

The critical spec when milling the head is prechamber protrusion. Check the FSM for the spec. I don't know if a thicker head ga$ket is the only answer but I read a list price of $300-500 for the beast. It might be possible to shim prechambers. I don't know if there's a point the valve seats have to be cut deeper.

What lock ring tool are you using? I found one on Amazon for $15. It works but it has to be hammered into the lock ring to engage the splines.

Sixto
87 300D

87tdwagen · #23 12-07-2013, 03:55 PM

Quote:

Originally Posted by sixto

There's nothing special about the front cover bolts, though my memory is obviously less special still. If your #14 head is off, measure how much of the original bolt extends into the front cover. Then drop the bolt into the #17 head to determine how much longer the bolt has to be. It'll need to be at least 20mm longer. You can get what fits from Home Depot.

The critical spec when milling the head is prechamber protrusion. Check the FSM for the spec. I don't know if a thicker head ga$ket is the only answer but I read a list price of $300-500 for the beast. It might be possible to shim prechambers. I don't know if there's a point the valve seats have to be cut deeper.

What lock ring tool are you using? I found one on Amazon for $15. It works but it has to be hammered into the lock ring to engage the splines.

Sixto
87 300D

Thanks Sixto,

Need to look up the prechamber protrusion specs in the FSM and see what's up. Was I reading right...$300-500 for a thicker HG!? Wow, hope it's made of titanium

I dont have the lock tool, either one, which suck because I have to buy two of them one for the slotted old style and then a spline tool, but heck for $15 bucks, that's awesome, mind PM'in me that one?