TheSamba.com :: View topic

Thu Nov 17, 2005 11:49 pm

I'd like to get some idea of people's experience with reliability and lifespan of the AMC heads, particularly for the type IV engine.

When I bought new AMC heads for my rebuild last winter, I thought I was doing a "good thing" and that my seat-dropping problems were over. Since then I've done a ton of reading on the Samba and have discovered that things aren't quite so cheery. The stock AMC head has earned a reputation for having substandard valves, seats, springs, retainers, guides and keepers, primarily diue to the stellar work that Jake Raby and Len of HAM have done in torture-testing the type IV head.

Now, Len and Jake's work is a highly significant data point, but their main focus is on building high-performance engines, so it's to be expected that they would be stressing the heads past their design limits. I'd like to get feedback from folks who are using AMC heads in their stock busses/vans and find out what their experiences have been, both good and bad.

I've tried to set up the poll to address the common failure modes of these heads that I'm aware of. There may be others that I don't know about, so I included an "Others" category for miscellaneous failures. Please also post details such as how many miles or kilometers you got on the heads before failure, or how many miles the heads have been working well for you.

My own experience with the heads has been good so far, but I've just got a bit over 1000 km on the engine, so it's hardly significant, statistically. I'm hoping to get a better feel for how much life I can expect from these heads. I'm planning to keep them under 400 F. That's easy to accomplish now, but we'll have to see what summer holds in store.

Thanks,
Lyle

Fri Nov 18, 2005 1:11 am

AMC bare castings are imported into the US from the factory in Spain. The company that sells them (drop ships) to various VW parts vendors installs the valves, guides and seats in the US (at least the first two).

The brand and quality of the parts used to complete the heads varies by availability and I assume cost. Because of this AMC heads are probably going to vary from time to time which makes comparison difficult. A head that worked for you in 2004 may contradict a failure someone had in 2002, all other engine conditions being equal.

The importer used to sell bare castings for about $145/ea but the owner only wants to sell complete heads these days. Anyone wanting to improve the head with better parts and sell it for a reasonable price needs to get them straight from the factory it seems.

Fri Nov 18, 2005 1:52 am

Okay, fair enough. So the poll won't reflect any definitive data. There are too many variables. I'd like to hear people's experiences nonetheless. :)

I don't suppose anyone has an inside line to this importer? Perhaps we could find out what quality processes he/she/it follows (I rather suspect they're not ISO-9000 compliant :roll: ) and maybe suggest that the ACVW world might be willing to pay a bit more for more consistent quality.

Or maybe competition is what they really need... :wink:

Fri Nov 18, 2005 4:25 am

This has been discussed on The Shop Talk Forums recently.The castings are fine just pitch the rest.Do the upgrades. I have 3 engines with these heads and I have not seen any problems.But I also install cyl. head temp guages,thermostats that work and all tin and seals.

Fri Nov 18, 2005 9:14 am

The main problem is the valves and other hardware used in the heads from the factory. The valves they provide in the heads are bought for about 2 bucks a piece and the first time they get hot they stretch like mad... Stretched valves are tight valves- tight valves burn and then the heads pop off them and destroy other things in a big way.

I would like to make one thing very clear about the emphesis here and thats the fact that while we do build a LOT of Hi Performance engines my main objective for so many years was for the bus owners. Back before the TIV conversion was our main focus I did a ton of bus testing and found out many things about engines used in buses and what it takes to keep them alive and what breaks first.

Now- Keep in mind first and foremost one thing:

NO OTHER APPLICATION IS HARDER ON A CYLINDER HEAD THAN LIVING IN A BUS!!! All those "Performance" engines we build may make tons of power, but they push 18-2300 pound CARS with great aerodynamics over a bus. The Bus is a 4500+ pounds rolling refrigerator that has no aerodynamics being pushed by an engine that had less than 70 HP! If that Bus was made in the states at the same era it would have a 250HP V-8 and would still be underpowered simply due to its weight.

Due to the huge loads placed on the engine from weight and constant operation @ WOT Bus applications are hard on engines and primarily the failures are aggrevated from combinations that promote heat build up (stock cam, improper engine design when going for more power-etc). The main problem with so many bus engines is the fact that they are never tuned correctly. The load being so high demands the ignition timing and enrichment be dead nuts on to keep temps under control, especially while climbing hills, AND guys that lug the engines increase the chances of failure even more due to loss of fan speed and increased load.

What I am getting at is this: The bus is heavy and hard on engines and has a much better chance of overheating than most any application. The first time the bus engine gets "hot" things will happen that the typical person doesn't think of and until you retorque heads and adust valves after they have been hot you can't understand it.

The marginal quality of the valves, springs and related hardware lowers the threshold where problems go from mnor to severe- 1 degree of excess heat determines what the life of the engine will be!

Most race engines won't see the head temps or EGT that a typical bus engine will see, not even our road race engines that turn 8,500 RPM for 45 minutes at a time! Buying a simple set of instruments will illustrate this easily. Settling for a head that has less valve seat interferance fit than stock, valves that cost 2 bucks each and etc are not what a wise person will accept for a long living bus engine in my professional opinion.

I do not believe in taking any risks with cylinder heads, and I also do not believe in overkill! This is the entire reason that you don't hear horror stiories of my engines breaking- as soon as something bites me in the ass its upgraded. A good example was a Bus customer that snapped off a stock rocker stud in the middle of the Desert, after that hapened EVERY engine I build gets 50 bucks orth of chromoly rocker studs, whether it needs them or not- Guess what, no more broken studs in the Desert!

Cylinder heads are the weak point of the aircooled engine, settling for heads that are marginal is not a wise decision and if you build enough engines and drive them far enough you'll see the same things I did. I feel it is a must to update these heads off the shelf to increase that threshold where failure becomes a reality (temperature wise) therefore reducing your chances of ending up as a statistic and a tow bill.

BTW- I just sold a HUGE BOX of AMC valves, springs and retainers all brand new on ebay for 42 bucks, enough to do dozens of pairs of heads thats how much I think of those components off the shelf.

Do as you wish, believe as you may but when the day comes know you could have prevented it. Buy and install a CHT gauge and slap the sender under the #3 spark plug- when the temp gets past 410F close your eyes and begin to pray unless these heads have been upgraded. 410 is the magic number where things go south very quick.... After the engine cools down retorque the heads and readjust the valves and the chances of having a failure are reduced.. Guaranteed you'll find tight valves and loose head nuts!

(Oh yeah, Volcano has one set of upgraded heads on his RAT Powerstroke!)

Fri Nov 18, 2005 11:33 am

SlowLane wrote: Okay, fair enough. So the poll won't reflect any definitive data. There are too many variables. I'd like to hear people's experiences nonetheless.
Me too. Certainly someone is going to buy a used bus with AMC heads.

In fact I've seen AVP engines with rebuilt AMC heads so even they are making the rounds as rebuilt heads these days.

Fri Nov 18, 2005 10:18 pm

this year i made a trip in a 71 bus up to the jerome jamboree in Arizona. the engine needed attention, but if there was a problem I knew that there would be parts and help to get me 250 miles back home.

the 79 westy is another story. it routinely goes places where there is no one else. somewhere up in the mountains and a moderate load for the weekend. the only thing i want to worry about is running out of beer or gas.

bought some new AMC heads and then started reading. needless to say i did not want to be a statistic at 8,000 ft and 30 miles from anyone. sent my new heads off to Jake this week for the 'treatment'.

in my opinion, vw's have gotten a reputation for being easy to work on and also cheap to fix. that is true to a point. a type 1 engine is much different than a type 4. these late buses with fuel injection and catalytic converters are very much like 'newer' cars. no longer are there $3.00 fixes for running problems. a new resistor unit for the injectors cost me close to $100. that's almost the price of a new carb for a type 1! how much is a cylinder head for a watercooled 1.8 golf/jetta? much more than we are paying for 2 properly done type 4 heads. i work on expensive auto's all day. i know how much things cost. it makes me sick.
spending more on heads for the bus than i did for the beetle is ok. it is still cheaper than a new car payment or breakdowns.

thanks for all the work you've done Jake. i'm sure i won't be disappointed.

Sat Nov 19, 2005 9:21 am

Its great that Jake and Len offer these redone AMC heads, I have a set ready to go in my winter rebuild of the Westy.

If you guys really want to cry about head prices, a few of new 914 2.0 heads are available from Porsche at $1375 each without valves!

Geoff

Sat Nov 19, 2005 11:46 am

What's your opinion on re-torquing the heads ? Should one add this to maintanance?Thanks

Sat Nov 19, 2005 11:49 am

Bleyseng wrote: If you guys really want to cry about head prices, a few of new 914 2.0 heads are available from Porsche at $1375 each without valves!
And 911 heads from Porcshe cost $1500 and you need six of them. Porsche prices don't really have meaning in the VW world especially when you can compare the price of identical items with the same part number and two different prices. Even VW dealer pricing was shocking compared to what vendors like Bus Depot charge for the same parts.

Sun Nov 20, 2005 3:26 pm

Those Porsche heads LISt for that, but they are NLA and have been for years..

BUT I can still get BRAND NEW TIV bus or 914 longblocks if anyone wants one!

I have bought a couple just to get the new parts from them to go big with.

Mon Nov 21, 2005 9:23 am

Quote: And 911 heads from Porcshe cost $1500 and you need six of them

2 of them no?

Mon Nov 21, 2005 12:27 pm

Jake Raby wrote: BUT I can still get BRAND NEW TIV bus or 914 longblocks if anyone wants one!
Which engine codes?

I know of a longblock at a dealer on the east coast. I'm not sure if it's 100% in tact but I can give you the info and you can take a look.

jberger wrote: 2 of them no?
Two heads? No. The 911 is unlike any other aircooled VW/Porsche motor.

Mon Nov 21, 2005 9:14 pm

jberger wrote: Quote: And 911 heads from Porcshe cost $1500 and you need six of them

2 of them no?

Six little individual heads with two big cam-carrying rocker boxes that tie the three-per-side together. Beautiful engines.
Colin

Tue Nov 22, 2005 8:46 am

Amskeptic wrote: jberger wrote: Quote: And 911 heads from Porcshe cost $1500 and you need six of them

2 of them no?

Six little individual heads with two big cam-carrying rocker boxes that tie the three-per-side together. Beautiful engines.
Colin

yeah and spendy

Tue Nov 22, 2005 2:24 pm

Jake Raby wrote: BUT I can still get BRAND NEW TIV bus or 914 longblocks if anyone wants one!
Okay Jake, I'll bite: brand new?? :shock: Where from?
I'm thinking a new factory longblock with HAM-improved heads would be the next best thing to a Camper Special. :)