In 2007 we stopped servicing used VW T4 bus heads. By that time around half of the castings we saw had severe cracks down in the exhaust ports and/or other evidence of heat related damage. It no longer made sense to put large amounts of time into servicing them when we can buy new, better castings.
As replacements we offer our Blueprint Special’s.
We start with a pair of new AMC 2.0 heads, strip the sub-par valves, seats, guides, springs, and retainers and toss them in the scrap barrel.
The Blueprint Specials are machined to accept new high temp, super durable valve seats that are fitted tight with the proper interference fit. The tungsten carbide exhaust seat material we use is wear rated up to 1800*F.
They’re built with new quality parts proven to be durable and reliable. The valve guides we use are silicon/manganese bronze and are extremely wear resistant.
The valves are tough aftermarket stock 2.0 size (39mm x 33mm) O.E. replacements.
The heads are machined and built with pride to factory specifications. Valve stem ht’s are set to +or- .005” for consistent valve train geometry.
Combustion chamber volumes are stock at ~49.5cc’s.
These heads come equipped with a .8mm raised step in the cylinder registers. This step simulates the O.E. head gaskets thickness and allows them to be deleted per VW instructions without installing spacers under the jugs to restore the unswept volume and deck height lost with the deleted gaskets. This raised step counts as deck ht and is added to the deck ht in the cylinders for determining the total deck.
Example: If you have .25mm deck in the jugs at T.D.C., add that to the .8mm step in the heads for a total deck ht. of 1.05mm. This is the deck value you use for C.R. calculations.
The Blueprint Specials are the best stock specifications heads available, and come with a limited 1 year warranty.
Most 78 models came with Oval Port heads, but some late production year busses came with Square Ports.
We charge $1,425.00/pair for oval ports.
Square ports sell for $1,495.00/pair.
For an additional 25.00 we will machine a notch in the #3 spark plug well for a cht probe to nest under the spark plug. This is popular for guys who want to monitor the temps on that cylinder. This makes plug changes easier without destroying the probe. The plug well on these heads is deep and makes it tough to nest the probe without putting a sharp bend in it. For 50.00 we’ll machine a notch in all four spark plug wells for more comprehensive monitoring.
For serious heat protection we recommend a pair of coatings that have proven themselves in race applications time and again: a heat insulating ceramic coating of the combustion chambers, exhaust ports and tops of the valves as well as the underside of the exhaust valve, and a black exterior coating that aids in the heat shedding process. The most critical of these coatings is the ceramic insulation, which greatly reduces the temperatures of the aluminum. We’ve been using this coating on track/race applications for years and have seen it protect heads from major distortion/warpage caused by elevated exhaust gas temps (EGT’s) as high as 1450F*!
Aside from aiding in the shedding of heat from the fins, the black exterior coating, which is a slippery, Teflon like substance, also aids in preventing oil and debris from clogging the small airways that carry cooling air through the fins.
The added cost of the ceramic insulation alone is 225.00/pair. Add the black exterior coating for an additional 240.00.
These coatings will help protect your investment and improve reliability in heavily loaded highway situations where lengthy, full throttle driving is the norm, like climbing mountain roads or driving into stout headwinds. It is exactly this sort of driving that pushes up EGT’s to dangerous levels and lead to damaging heat soaking and head warpage.