Endurance motor

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TOOF
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Endurance motor

Post by TOOF » Fri Jan 06, 2017 6:49 pm

All other things being equal, is a 1641 going to be less reliable than a 1600 just due to the thickness of the cylinder walls? Even in the Texas heat? I am going to run a true full flow oil system with a 12 row cooler and fan.


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Kyle

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Marc
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Re: Endurance motor

Post by Marc » Fri Jan 06, 2017 8:02 pm

The thinner walls are the issue. Bear in mind that 87mm is .060"-over, and VW used to sell factory-exchange engines that were bored .040" with a full warranty - also that the walls of 87s are only ~.006" thinner than those of 94s, which don't have a particularly bad reputation.
What's key is making sure that it's never, ever, overheated - so no power pulley, and make sure that the engine compartment is well-sealed and the freshair hoses & fanbelt checked regularly. Not a good idea for a heavy vehicle, but probably will be fine in a well-maintained Beetle.

Is the 3½% increase in displacement worth the risk? Probably not. That said, I am using 87s in my daily driver ;) but only because I had a set on the shelf when I had to pull the heads to install new pushrod tubes - plus, I live in the Northwest where it rarely gets over the high 80s in the summer.

AA makes some "slip-in thickwall" 88s which require no machinework to the case (the heads have to be opened up to the 98mm diameter used for late 90.5s and classic 92s). For a stockish engine they'd probably be my first choice. Cylinderwalls are >.030" thicker than stock except at the bottom spigot - it's scary-thin, but that's not a stressed area...handle with care until assembled and don't cut your fingers on the bottom edge :) 1679cc will still work fine with a stock carb but the ~6% displacement increase makes a noticeable difference.

The stock doghouse oil-cooler setup is hard to beat; I'd recommend retaining that and only adding a (smaller) additional cooler in series with the filter if it proved necessary. It's also possible to "stretch" the doghouse to make room for the larger Type IV cooler; do NOT overlook the "Hoover Bit" that prevents cooling air from escaping around the bottom of the cooler.

The later 11.3x912La belt is mandatory with an alternator and not a bad idea even for a generator with the larger "doghouse" cooling fan. A 9.5x905La should only be used as a spare IMO.
Last edited by Marc on Fri Jan 06, 2017 8:20 pm, edited 1 time in total.

dragvw2180
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Re: Endurance motor

Post by dragvw2180 » Fri Jan 06, 2017 8:19 pm

Great job Marc , covered it pretty well. I agree with most everything you said. If you install ALL the original tin and engine seals then the stock oil cooler is up to the task of cooling your engine. On my 2387 turbo engine I am running just the stock dual port oil cooler and it has never overheated ( 8.2 compression ) here in NC . Keep the compression ratio reasonable for the best longevity . A 1600 or 1650 with a small cam and dual carbs is a blast to drive on the street .

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Re: Endurance motor

Post by Marc » Fri Jan 06, 2017 8:27 pm

We've got a big hill nearby, about ¾mi ~12% grade, that I've used as a performance gauge since I was a kid. My DD engine is completely stock other than dual Weber 34ICT 1-bbls, and starting at 45 MPH at the bottom as a 1585 it couldn't quite make the top without falling below 30MPH and downshifting to 2nd. With the used 87s (and some new cheap Grant rings) it now makes it over at 35MPH. Under most other conditions you might not even notice the difference.

"all other things being equal":
I threw .020" barrel spacers under to maintain the same C.R. so I could continue to run 87 (R+M)/2 E10 gas with impunity - at the same deck there'd be a slight increase in C.R. that might increase the power almost as much as the displacement increase alone.

One other point I forgot to mention above - use a louvered engine lid or provide some other way to allow more air into the engine (such as cutting out a big hole behind the license plate). The factory felt this was necessary even on the `70 which still had the smaller cooling fan at 1600cc - with the doghouse fan it's absolutely needed. Note that when the rear window size was increased in `72, even more louver area was added to the decklid to make up for the loss under the window. Why would they have bothered if it wasn't an issue?

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Re: Endurance motor

Post by TOOF » Sat Jan 07, 2017 10:41 am

So right now this is what I have in my garage for engine parts (not yet assembled):

-All fresh machined parts: crank, case, rods, and flywheel (also lightened and 8 hole).
-SVDA Pertronix I installed distributor (new)
-W110

I keep thinking about the guys running 5/1600 class in baja with 1600c motors and 30PICT carbs in high compression. Those motors are lasting 250-1000 high stress miles and making 75+hp.

I know they are high dollar engine builders with custom ground cams and other tricks but I still think I should able to do pretty well with a single 34PICT 1641cc W110 with a static CR of 9.0:1 on 93 octane?

My concern is, at sustained 3-4k RPMs, will the 87mm jug walls be more likely to fail than the 85.5mm?

I have not heard of a failure of this type but then again, not a lot of guys racing with 1641cc motors.


*im not springing for Mahle, so they will be AA or Euro. Its Lemons, not LeMons! haha

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Re: Endurance motor

Post by 66brm » Sat Jan 07, 2017 4:52 pm

The W110 will give you grief when trying to tune idle with a single carb, I fought it for years in my 1600, eventually a set of 40 idf's made life easier

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Re: Endurance motor

Post by TOOF » Sat Jan 07, 2017 6:18 pm

66brm wrote:The W110 will give you grief when trying to tune idle with a single carb, I fought it for years in my 1600, eventually a set of 40 idf's made life easier
So when you stopped at a light it would die, or just run rough?

Not much idling during a 24 hour race.

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Re: Endurance motor

Post by TOOF » Sat Jan 07, 2017 6:19 pm

66brm wrote:The W110 will give you grief when trying to tune idle with a single carb, I fought it for years in my 1600, eventually a set of 40 idf's made life easier
Were you running 93 octane?
Also, what compression were you running?

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Re: Endurance motor

Post by Marc » Sat Jan 07, 2017 6:31 pm

TOOF wrote:...Not much idling during a 24 hour race.
I presumed from your original post that you were concerned with longevity on the street, not just a long Lemons flog. If you already have the 87s, I wouldn't expect them to be a liability compared to 85.5s unless you toss a fanbelt and don't notice right away.
I'd still go with the AA 88s and have the heads opened up though. They were on sale a few days ago for less than the price of 87s, but it looks like that deal's over.
https://aapistons.com/collections/vw-pi ... -90-5-head

Just stay away from the full-slip-in 88s, those jugs are like tin cans with fins on 'em and will cut right into the heads - I can almost guarantee compression leaks if run hard for a day without a retorque.

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Re: Endurance motor

Post by TOOF » Sat Jan 07, 2017 6:44 pm

Marc wrote:
TOOF wrote:...Not much idling during a 24 hour race.
I presumed from your original post that you were concerned with longevity on the street, not just a long Lemons flog. If you already have the 87s, I wouldn't expect them to be a liability compared to 85.5s unless you toss a fanbelt and don't notice right away.
I'd still go with the AA 88s and have the heads opened up though. They were on sale a few days ago for less than the price of 87s, but it looks like that deal's over.
https://aapistons.com/collections/vw-pi ... -90-5-head

Just stay away from the full-slip-in 88s, those jugs are like tin cans with fins on 'em and will cut right into the heads - I can almost guarantee compression leaks if run hard for a day without a retorque.
Thats good to hear. I don't have P&Cs yet.

dragvw2180
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Re: Endurance motor

Post by dragvw2180 » Sun Jan 08, 2017 11:10 am

Heck I would rather run 85.5 P/Cs to save money and buy at least a set of dual 1 barrel carbs than run a stock carb. A stock carb to me is only good for driving around with a stock engine. To me it is like having a long distance runner start to breath through a straw and trying to run the same as normal , a waste of time.

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A pic of my engine in my Speedster , Dual Baby Dells , was a blast to drive with basically same engine you are talking about. Afterwards I upgraded the carbs to dual 44 Webers and loved it even more. When the new owner flew in to pick it up he drove it home to Florida from my house in North Carolina without any problems and it is still going.

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Re: Endurance motor

Post by Marc » Sun Jan 08, 2017 12:52 pm

I realize enforcement is a joke, but isn't it one of the precepts of Lemons that entrants are supposed to be limited to $500 cars? ...or $500 not including safety equipment, anyway.

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Re: Endurance motor

Post by TOOF » Sun Jan 08, 2017 6:14 pm

Enforcement is not a joke, sir! haha

yeah, there are penalties but the "judges" are often (but not easily) bribed.

Bribing is in the rules. Beer and cheap wine work best.

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Re: Endurance motor

Post by TOOF » Sun Jan 08, 2017 6:16 pm

wheels, tires, brakes, and safety are excluded from the $500.

Also, your theme materials are not included in the $500.

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Re: Endurance motor

Post by Marc » Sun Jan 08, 2017 7:52 pm

If I were assembling a motor for Lemons that wouldn't have the benefit of any break-in time beforehand, I'd basically be shooting for the equivalent of an engine with 30K+ miles on it with a fresh valve job. Polish the coating off of all the bearings with 000 steel wool, used cylinders honed out....and cheap cast-iron rings that'll stand a chance of breaking in quickly. If dual carbs won't raise any eyebrows at tech, by all means run 'em - but do make sure your linkage won't fall apart before the race is over ;)

I'd also vent the valvecovers and glue them on well, so you don't have to waste any time in the pits fixing oil leaks. And a 1½ qt sump for a little reserve just in case there is one that you don't get black-flagged for ;)
Last edited by Marc on Mon Jan 09, 2017 2:49 am, edited 1 time in total.

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