sight-unseen ... roll-of-the-dice
mcditalia said:
I came across an aluminum intake manifold on ebay for sale that I am interested in for my 66. It was repaired with spot welds in the water jackets and has heli coils in the thermostat opening. Not sure what heli coils are (somewhat ignorant with welding terminology). Anybody have any experiences with repaired intake manifiods? Should I just stay away from repaired items or can they be a good deal?
Helicoil looks kinda like a spring and is standard fare for stripped threads in aluminum and iron ... drill out to slightly larger size and spiral in the helicoil ... returns hole to original bolt-thread size. That'll work fine on t'stat ... those holes often are not blind and often do go into the water ... if so, DO use a thread sealer on the t'stat bolts' threads.
At either end of each head is a water port. The intake has either corresponding ports at all four corners ... or ports at two corners & blockoffs at other two. Regardless, the aluminum tends to corrode at those 4 corners. If it gets bad enough that silicone won't stop the leaks, then a bit of welding and flat-filing (IF DONE CORRECTLY) will fix it. Realize the heads' water ports are adjacent to intake charge ports for cylinders 1, 7, 2 and 8. If it leaks water there it will often be sucked into an adjacent intake charge port and into that cylinder.
Just so you know, Aluminum intakes often crack at bolt holes near corners ... often because they're leaking there but the root cause is not addressed ... in an attempt to stop the leaking, the hapless mechanic simply cranks down even harder on the bolts ... and the intake splits right at the bolt hole(s).
Yes, repaired intake may be just fine ... but let the buyer beware.
-edit- If the intake is one that is still in production ... I'd be inclined to buy new rather than repaired ... especially if I could not inspect it before purchase.
JACK:gap
