A Visit with Len Hoffman.
Posted: Mon Jun 26, 2017 10:26 am
My wife, Janet, planned an itinerary for a trip north for us, and we were to be in Watkinsville, Georgia, at a B and B. This rang a bell, and I realized that Len Hoffman had his shop in this town. As it turned out, he was less than a mile away from where we were staying. I dropped him a line, and he invited me to stop by when we were up there. We arrived on a rainy day, and I called him.
Len's shop is tucked away, behind a Shell gas station, by a motorcycle shop. It's difficult to locate, from his address, so I called him from my car, and he came outside and waved at me. I drove over, and he invited me inside. I walked into a very clean environment, filled with the tools of the modern machinists trade. Len and another fellow were busy, working in some racing car heads. I knew that he had a lot of work to do, but he graciously offered me "the nickel tour".
Of course, I was interested in his air cooled work, so he told me about his Blueprint Special head work, and brought out a modified AMC head to show me. Here, in his own words, is what he does:
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.
Here Len showed me how they peen the head area to strengthen it.
An example of the ceramic coating he offers as an option for better heat handling qualities. He also has the black exterior coating, but told me that if you can afford but one, this is the one to get. He also showed me the Manley valves, which is one if his valve suppliers.
A closer view. The coating looks really good, and consistent.
He showed me a Chinese made copy of a head, that he was experimenting with, but I got the impression that he felt the AMC product was superior, because it is beefier. The Chinese copied the Porsche design exactly, while the Spanish one is heavier.
I could have spent a lot more time speaking to Len, as he is really open about his work, and passionate about what he does. I knew he was busy, so I took my leave. I enjoyed meeting him very much, and the quality of his work looks really good. His shop is clean, air conditioned and well lighted, and well organized. He is expecting a shipment of AMC heads in several weeks, and will be making a run of his Blueprint Specials. He is a real interesting guy, and it's good we have some folks like this around for a resource, in my opinion. If you're ever around Athens, Ga., he is worth a visit. Jimbear, sorry I
missed you on this go around, and you as well, Hobug. Maybe on the return trip, and I'll give more notice, for a bite at that Chops and Hops!
Len's shop is tucked away, behind a Shell gas station, by a motorcycle shop. It's difficult to locate, from his address, so I called him from my car, and he came outside and waved at me. I drove over, and he invited me inside. I walked into a very clean environment, filled with the tools of the modern machinists trade. Len and another fellow were busy, working in some racing car heads. I knew that he had a lot of work to do, but he graciously offered me "the nickel tour".
Of course, I was interested in his air cooled work, so he told me about his Blueprint Special head work, and brought out a modified AMC head to show me. Here, in his own words, is what he does:
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.
Here Len showed me how they peen the head area to strengthen it.
An example of the ceramic coating he offers as an option for better heat handling qualities. He also has the black exterior coating, but told me that if you can afford but one, this is the one to get. He also showed me the Manley valves, which is one if his valve suppliers.
A closer view. The coating looks really good, and consistent.
He showed me a Chinese made copy of a head, that he was experimenting with, but I got the impression that he felt the AMC product was superior, because it is beefier. The Chinese copied the Porsche design exactly, while the Spanish one is heavier.
I could have spent a lot more time speaking to Len, as he is really open about his work, and passionate about what he does. I knew he was busy, so I took my leave. I enjoyed meeting him very much, and the quality of his work looks really good. His shop is clean, air conditioned and well lighted, and well organized. He is expecting a shipment of AMC heads in several weeks, and will be making a run of his Blueprint Specials. He is a real interesting guy, and it's good we have some folks like this around for a resource, in my opinion. If you're ever around Athens, Ga., he is worth a visit. Jimbear, sorry I
missed you on this go around, and you as well, Hobug. Maybe on the return trip, and I'll give more notice, for a bite at that Chops and Hops!