A Little Off The Top

D

Dan Sarandrea (Phila)

Waitin' On Parts...
Been replacing the head gasket on my car, and while the head was off my machine shop buddy rebuilt it (new guides, reground the valves and seats, bead blast, two .002" passes on the Storm-Vulcan to resurface it, paint, etc.

Reinstallation onto the block is a bit tricky.

My car (10 bolt '86) came with stretch head bolts, which you are not supposed to re-use. Apparently, there are no OEM replacement 17mm hex head stretch head bolts (sometimes called torque-to-yield) available from any vendors, so the next best thing are the stretch head bolts used on other FIATs contemporary to the X and later.

Unfortunately these bolts are slightly shorter, so the cast-in bolt bosses in the head have to be "lowered" so that the bolts can be threaded into the block at least as far as the originals. Taking this little (4.5mm) off the bosses does not affect the strength of the head or its ability to properly and evenly clamp the head gasket in any way.

Here's a short vid of my machine shop buddy doing that:



Conventional non-stretch head bolts are available from our vendors, but using them means they have to be retorqued (stretch bolts do not get retorqued) and that means you have to find or borrow the head bolt tools, not an easy task.
 
Those are the exact ones I got, and from EuroSport, too.

Note in their comments they talk about them being 4mm shorter, but they say that they are functionally equivalent since the new ones are the same length under the integrated washer as are the old ones under the separate (and 4mm thick) washer.

Well, OK for the web site copy writers, except my concern was that means the integrated washer is bearing directly on the aluminum head material without the benefit of a "free floating" washer, and such an arrangement with its attendant extra friction might result in the wrong clamping force being applied and would most certainly result in galling of the bolt head to cylinder head pressure surface.
 
Original appearance is important but not paramount.

I suppose this would be a pretty good analysis.....


ARP studs are:

1. Expensive
2. Lengths are all over the map
3. Gotta put them in upside down
4. Gotta retorque
5. Good for a performance build, but this is not a performance build
6. In stock maybe today, out of stock for months tomorrow
7. Still studs, and we have seen some nightmare head removal scenarios with studs.

OTOH, my method was:

1. Much cheaper (admittedly a machine shop labor charge is not factored in)
2. Quick
3. In stock
4. Does not need retorquing with those pretzel tools :)
5. Consistent with a stock rebuild level of performance
 
Yep in the real world you have to account for the shop charge, but I'm lucky to have a good friend who owns and runs his own automotive machine shop and does the work for a medium Dunkin Donuts black coffee :):shh::whistle:
 
Head Bolt TOOLS for re-torquing...

Can be BORROWED from a GOOD guy by GOOD guys for the price of postage and a cup of Java...

Shout out to Mike Moisa here...
 
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