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Cal-look/High Performance => Cal-look => Topic started by: rick m on February 03, 2013, 17:23:06 pm



Title: A&A Piston Durability
Post by: rick m on February 03, 2013, 17:23:06 pm
I spent Saturday helping a friend tear down a motor that was smoking badly in a Bay Window bus. It was a 1915cc Type 1 with an Engle 100 cam, dual ports and stock carburetor.  No full flow, no filter on the motor, no additional cooler (just the dog house), no knowledge on why the air/fuel ratio is so critical to heat.  You can see the results.  They had a 34 pict on the 1915 with a 140 main jet but had made no other mods to the carb.

The owner drove the bay window from Reno, Nevada, to Phoenix. He stated that several hours of the trip he had to keep it in 3rd gear with a strong head wind against him. During that time the motor as losing power but he still got it into the Phoenix area. When called over to take a look at it, it still ran when I got to listen to it before tearing it apart.  The motor had all new parts so we were able to salvage the case, cam, lifters and miscellaneous parts.  

The A&A piston #2, literally melted but did not explode, crack, or come apart.  The wrist pin was dark blue from the heat.  The small end of the rod was blued as well. Was running some of the aftermarket "I" beam style 4340 rods (vw length).  

We are in the process of going through and redoing the motor with new 94's.  I am replacing the aftermarket heads with original German heads as the casting is much cleaner as is the airflow that can get through the head. We are also converting it to dual carbs.  Could not talk the owner into allowing us to full flow the motor (which I feel is his mistake) along with another remote cooler and fan. Also suggested adding a deep sump to give the motor some additional capacity while we have it down. May still win that battle before we re-assemble it for him.

All in all, seeing what the A&A Pistons went through in a heavy Bay Window camper bus....I would not hesitate to run them in a properly built street engine of any kind.

Rick M


Title: Re: A&A Piston Durability
Post by: rick m on February 03, 2013, 17:24:13 pm
Here is anothe angle of the A&A Piston after being punished for hundreds of miles.

Rick M


Title: Re: A&A Piston Durability
Post by: Zach Gomulka on February 03, 2013, 17:47:35 pm
Could not talk the owner into allowing us to full flow the motor (which I feel is his mistake)

I wouldn't build the motor then. It's got your name on it, if he blows it (which isn't out of the question, it sounds like he has zero sense of mechanical sympathy), guess who is gonna catch the blame?

I would build an indestructible anvil of an engine. Go thick wall 92's, Kadron's or maybe a single Zenith, something simple carb wise. And over cool it to death, but retain the factory thermostat.


Title: Re: A&A Piston Durability
Post by: Cheesepanzer on February 03, 2013, 18:07:33 pm
^^^   agree 100%.  A full-flow set up doesn't cost much to do and just makes good sense, especially for an engine that will be worked pretty hard across its service life.

I also completely agree with increasing the induction.  The 34 pict set up should be "sunsetted" in that beautiful Arizona sun, and small dual carbs added.  36 DRLA's would be great, or 40 IDF's.  K-dogs are fine as well.

Just my $.02.


Title: Re: A&A Piston Durability
Post by: rick m on February 03, 2013, 18:46:28 pm
We already talked the owner into dual carbs.  Single pict on a 94 bore motor is rediculous. Crazy what some of the bus people try. The motor needs more air. As for the rest, I am not building the motor...just giving input as well as some strong recommendations which I hope the owner heeds or he is headed for repeat trouble. Will post some shots when done helping the friend who is assembling it.

I am a fan of the K-dogs for low end grunt on bus motors too. I have used them on inexpensive builds and they work great!

You can lead a horse to water but you cannot force them to drink.  I have seen VW people repeatedly take the cheap route and they pay for it over and over.

RM


Title: Re: A&A Piston Durability
Post by: Torben Alstrup on February 03, 2013, 23:22:06 pm
We already talked the owner into dual carbs.  Single pict on a 94 bore motor is rediculous. Crazy what some of the bus people try. The motor needs more air. As for the rest, I am not building the motor...just giving input as well as some strong recommendations which I hope the owner heeds or he is headed for repeat trouble. Will post some shots when done helping the friend who is assembling it.

I am a fan of the K-dogs for low end grunt on bus motors too. I have used them on inexpensive builds and they work great!

You can lead a horse to water but you cannot force them to drink.  I have seen VW people repeatedly take the cheap route and they pay for it over and over.

RM
Single carbs on a 1914 is absolutely doable, BUT it takes quite abit of carefull selection of parts to make it work. That engine was a disaster even before it hit the roads. I´m sure that on top of it all it ran lean. If the cam and lifters are salvageable, the Kads are a nice and easy solution to the induction problem.

As for the durability of AA pistons. IF those pistons are older than approx. 3 years, the AA pistons were sub quality to Mahle. Today I really dont think there is much of a difference between Mahle as we knew it and AA.

But its a cryin´shame to waste such a bunch of parts due to a low quality build by someone who aparently did not know what he was doing. I see it all the time here too. - Cheap engines from companies with big shiny ads, loaded with ALL the crap parts. In fact I just finshed such a 1914 last week. Had to replace about half of the engine after only 5000 miles. And if I have had free hands I would not have stopped there (!)

T


Title: Re: A&A Piston Durability
Post by: dragvw2180 on February 04, 2013, 02:22:40 am
 I wonder what the compression ratio was ?  Mike McCarthy


Title: Re: A&A Piston Durability
Post by: 65bug on February 04, 2013, 04:37:46 am
Was he by chance running a 009 Distributor with that 34 pict carb?


Title: Re: A&A Piston Durability
Post by: modnrod on February 04, 2013, 06:09:34 am
Nice to know the quality of the AA stuff isn't bad, I agree with what Torben said about the lack of quality in most of the shiny ads. Those pistons had a short and unhappy life for sure.

A quick one though Rick. I'm not disagreeing with you as such, but my observations are with small carbs, especially single barrel carbs, on large motors is that they don't run the motor lean at all, if anything they tend to go really rich when held flat at full revs. The let the motor rev until it gets too rich, not lean, due to the lack of airflow, and this causes a natural rev-limiter function. In the past I have built engines for family (with no mechanical sympathy!), using parts safe to 6000, then used a single Solex or Stromberg so the motor won't rev past 5000/5500. Obviously this one wasn't jetted or tuned well to begin with, but I've used single barrel Solex and Stromberg carbs on everything from 1300 Suzki's up to 3.3L 6 cylinders, and often the only thing I need to check is actually the idle cct, not the mains or power cct. Are you sure the Solex 34 was the cause of the "lean-and-too-hot" blow-up, or could it also be timing/oil quality/dizzy tune?

Perhaps putting the twin Kads on there will merely let him rev the bloody thing 1000rpm higher than before in the same conditions, but without the natural rev-limit function of the single Solex. I'm glad you're not building the thing for him, it will end in tears again probably.


Title: Re: A&A Piston Durability
Post by: rick m on February 04, 2013, 07:12:50 am
The sad thing TORBEN is that it had a lot of good parts in it. New case too. We saved most everything. Turned out to be a bad brass distributor drive gear that went away and kept screwing with the timing on the motor.  Unfortunately the owner kept driving it...which was astonishing it would even run.  I think this was a combination of the brass gear going away and the owner who knew little or nothing about what not to do when the motor starts to run bad.  Anyway, most of the parts are good. We are full flowing the case, modifying the carb and setting it up correctly.

I have never run anything but dual carbs so I am somewhat bias towards more air to begin with.  It will all work out. We will take pictures showing all the stuff we are redoing before re-assembling. One thing I would not do is run the MEXICAN dual ports. These heads almost had no air flowing through them around the intake and exhaust ports due to the really poor casting. We are replacing the heads with original german dual ports and doing some other work on the heads as well. It will run better, have more oil and cooling when we get done.

RM


Title: Re: A&A Piston Durability
Post by: benlawrence on February 04, 2013, 07:57:42 am
the aa pistons are good, after hearing all the horror stories about them failing i was dubious about putting them in my motor, roll on a year and my good freind has run his motor with the non forged stroker 94s for a full season, they have seen 7000-8000 rpm everytime the car is on the track and they have stood up perfectly, needless to say i have no issue with using them for my street car.


Title: Re: A&A Piston Durability
Post by: BeetleBug on February 04, 2013, 09:19:57 am
As for the durability of AA pistons. IF those pistons are older than approx. 3 years, the AA pistons were sub quality to Mahle. Today I really dont think there is much of a difference between Mahle as we knew it and AA.
T

Is not AA and some other brands just re-labeled Chinese parts easily available for those considering to import parts themselves? Some guys in Norway bought a pallet of cylindersets from China and got the following info:

Offset wrist pin:                                          Off set as original
Forging, alloy type /                                     T6 aluminum
Production process/                                     Hypereutectic Casting
Tolerances                                                  +/- .02mm
Quality of rings ,                                           Chrome top ring/ Cast iron, USA brand
Maximum RPM range                                     7,000rpm

Same piston and barrels is delievered to several US dealers.


Price is 289 USD including freight and Norwegian VAT of 25%. They offer the following sets:

P/N          OEM #   Description
VW9000T4E   029-37-90   90x66 mm   1700cc  Dome Top
VW9000T4F   021-198-075   90x66 mm   1700cc  Flat Top
VW9300T4   021-198-075A    93x66 mm   1800cc    
VW9400T4   021-198-200     94x71mm    2000cc Dish Top
VW9400T4E   021-198-200 FT   94x71mm    2000cc Flat top Piston
VW9500T4S71   021-198-200 95   95x71mm    Big Bore Slip-in
VW9600T4S71   021-198-200 96   96x71mm    For 2.0 Case
VW9600T4S66   021-198-075 96   96x66mm    For 1.7 & 1.8 Case
VW9600T4B66       96mm    For 1.7 / 1.8  Aluminum Biral P&C Kit
VW9600T4B71       96mm    For 2.0  Aluminum Biral P&C Kit
VW9800T4BL       98mm    For 2.0  Aluminum Biral Cylinder Set


(http://www.raceinfo.no/temp/China%201_1.jpg)


Title: Re: A&A Piston Durability
Post by: Torben Alstrup on February 04, 2013, 13:05:22 pm
AA pistons ARE made in China.

AA claims that they do the final honing on the cylinders in the US. Wheteher that is correct or not, I do not know. What I do know is that at least for the last approx 2 years the piston quality has been good, and the quality of the hone and roundness of the cylinders better than Mahle. It is about over now, but out of the last approx 11 set of 94 Mahle´s I dealt with, I was only able to make 8½ set with perfect cylinders. The last 6 cylinders went on the shelf for rehone to JE pistons.

Rick. OK. I may have painted the ugly one on the wall a little too early. Good to hear that most of it is salvageable. I agree that dual carb engines are way easier to set up. Its the maintenance part that make them a PITA for some people. Like I wrote earlier, the large cc. single carb engines are much more difficult to get to run perfect than most would expect. you simply have to think different.

´nuf said. Getit running again  ;)

T



Title: Re: A&A Piston Durability
Post by: 65bug on February 05, 2013, 00:34:03 am
The 34 pict carb was a major problem when paired with a 009 distributor. After changing the timing for the 009, you had to back down the idle screw on the carb so low, it shut the idle circuit down. This would let the engine get so little fuel, it would not idle correctly. If you can get it to idle, it would not transition to the next circuit properly. Even with a good accelerator pump.
     I went through that crap years ago on a 1600. Of course, dual carbs solves that problem alltogether! Motor ran nice and cool then. No big flat spot either..........


Title: Re: A&A Piston Durability
Post by: modnrod on February 05, 2013, 03:57:03 am
The 34 pict carb was a major problem when paired with a 009 distributor. After changing the timing for the 009, you had to back down the idle screw on the carb so low, it shut the idle circuit down. This would let the engine get so little fuel, it would not idle correctly. If you can get it to idle, it would not transition to the next circuit properly. Even with a good accelerator pump.
     I went through that crap years ago on a 1600. Of course, dual carbs solves that problem alltogether! Motor ran nice and cool then. No big flat spot either..........

To get them to idle and also transition properly with a 009, drill a 2 to 3mm hole in the throttle blade next to the idle slot.

To jet them on a big motor, tune the air bleeds, and keep the main jet as small as possible.

The best thing is a completely stock-looking motor (it's the street-racer in me..........), with amazing throttle response and excellent economy. You can easily double the HP and still use a Solex 34pict.

But dual carbs are the preferred option for most, and make more power.
 ;D


Title: Re: A&A Piston Durability
Post by: 65bug on February 05, 2013, 04:02:57 am
modnrod,
        I hear ya! I did all that crap too. Then when I scraped up the bucks, I graduated to dual kads. I was in heaven! Now I much more prefer my 2165 with dual 48's..........HA!


Title: Re: A&A Piston Durability
Post by: modnrod on February 05, 2013, 04:11:20 am
Yep, been there myself too! Webers at full noise can be addictive.

But it's really easy for someone to put down $100, not knowing that a single Solex and stock air cleaner can push a standard-looking Bug to 100kph in under 6secs........

Or at least, so I've heard.  ;D ;D ;D


Title: Re: A&A Piston Durability
Post by: 65bug on February 05, 2013, 04:34:27 am
I just know ALOT of motors have been fried that way!!!!! I think it was part of the reason the Holley Bug Spray got so popular! LOL.
       I must admit, I have never owned 48 IDA's. I have Dell's...................but I love em nonetheless! Great carbs! Dial em in and your done!


Title: Re: A&A Piston Durability
Post by: modnrod on February 05, 2013, 06:47:21 am
Yeah probably. Twins make the power, and the jetting knowledge is plentiful and easy to access.

But I just realised I didn't explain myself properly above.

What I meant is that it is very easy to get someone to put up $100 against you if all you have under the lid is a stock Solex, twin Webers makes them think twice.
Aaahh, the bad old days, how I miss them sometimes!  :D


Title: Re: A&A Piston Durability
Post by: andy198712 on February 05, 2013, 13:08:25 pm
As for the durability of AA pistons. IF those pistons are older than approx. 3 years, the AA pistons were sub quality to Mahle. Today I really dont think there is much of a difference between Mahle as we knew it and AA.
T

Is not AA and some other brands just re-labeled Chinese parts easily available for those considering to import parts themselves? Some guys in Norway bought a pallet of cylindersets from China and got the following info:

Offset wrist pin:                                          Off set as original
Forging, alloy type /                                     T6 aluminum
Production process/                                     Hypereutectic Casting
Tolerances                                                  +/- .02mm
Quality of rings ,                                           Chrome top ring/ Cast iron, USA brand
Maximum RPM range                                     7,000rpm

Same piston and barrels is delievered to several US dealers.


Price is 289 USD including freight and Norwegian VAT of 25%. They offer the following sets:

P/N          OEM #   Description
VW9000T4E   029-37-90   90x66 mm   1700cc  Dome Top
VW9000T4F   021-198-075   90x66 mm   1700cc  Flat Top
VW9300T4   021-198-075A    93x66 mm   1800cc    
VW9400T4   021-198-200     94x71mm    2000cc Dish Top
VW9400T4E   021-198-200 FT   94x71mm    2000cc Flat top Piston
VW9500T4S71   021-198-200 95   95x71mm    Big Bore Slip-in
VW9600T4S71   021-198-200 96   96x71mm    For 2.0 Case
VW9600T4S66   021-198-075 96   96x66mm    For 1.7 & 1.8 Case
VW9600T4B66       96mm    For 1.7 / 1.8  Aluminum Biral P&C Kit
VW9600T4B71       96mm    For 2.0  Aluminum Biral P&C Kit
VW9800T4BL       98mm    For 2.0  Aluminum Biral Cylinder Set


(http://www.raceinfo.no/temp/China%20_1.jpg)

blimey, that'll make a few engines! how many kits in a pallet?


Title: Re: A&A Piston Durability
Post by: BeetleBug on February 05, 2013, 13:16:55 pm
blimey, that'll make a few engines! how many kits in a pallet?

Just enough for one engine and one season on high boost  :D

I believe  they sold every kit and is now taking new orders.


Title: Re: A&A Piston Durability
Post by: 65bug on February 06, 2013, 03:58:00 am
And very possibly ONE PASS TOO............................


Title: Re: A&A Piston Durability
Post by: RhoadsVW on February 06, 2013, 08:21:57 am
I was putting a new set of 90.5 Mahle's and one piston had no wrist pin grove.  Guess that one some how made it through Mahle's tite quality control.    Dave Rhoads


Title: Re: A&A Piston Durability
Post by: Fast Bug on February 07, 2013, 12:59:27 pm
(http://cal-look.no/lounge/index.php?action=dlattach;topic=20136.0;attach=64040;image)

Wrong mixture, ignition and oil issues could cause the fried piston but what about ring gap?
Too tight ring gap could help heat up the piston. It’s not normally necessary to check ring gap on the Mahle stuff but maybe you have to check everything on the Chinese.  ::)


Title: Re: A&A Piston Durability
Post by: RhoadsVW on February 07, 2013, 19:34:00 pm
I am not trying to knock Mahle piston sets but when running new engines there is less crank case pressure from AA's than Mahle's. I have checked ring gap on AA's and never a problem. Not trying to sell AA's but I think the quality on Mahle's has dropped. Mahle are good but a little pricey for what they are now. Mahle's don't seam to be a true forged pistons like they used to be. The cylinder quality I think is better than AA but the piston's are lacking.  Also you better balance the Mahle's. Out of the box they are as much as 4-5 grams off. One set I did was 8 grams off.  The most I have seen from AA's are 2 grams. Most all are within 1 gram.  Just some information I have personally found while working with both sets.  Dave Rhoads


Title: Re: A&A Piston Durability
Post by: rick m on February 07, 2013, 20:19:00 pm
Dave....Your feedback is very true. I have found the same with weight and ring gap when comparing between MAHLE and A&A.  I have several different sets of the A&A pistons I will be using.  Preparing a set of thick wall 92's right now for my wife"s 1835 buggy motor.  Will be running a set of their slipper skirt style 90.5s in an 84x90.5 motor I am building for another project.

RM


Title: Re: A&A Piston Durability
Post by: Fast Bug on February 07, 2013, 21:38:23 pm
I am not trying to knock Mahle piston sets but when running new engines there is less crank case pressure from AA's than Mahle's. I have checked ring gap on AA's and never a problem. Not trying to sell AA's but I think the quality on Mahle's has dropped. Mahle are good but a little pricey for what they are now. Mahle's don't seam to be a true forged pistons like they used to be. The cylinder quality I think is better than AA but the piston's are lacking.  Also you better balance the Mahle's. Out of the box they are as much as 4-5 grams off. One set I did was 8 grams off.  The most I have seen from AA's are 2 grams. Most all are within 1 gram.  Just some information I have personally found while working with both sets.  Dave Rhoads

Dave....Your feedback is very true. I have found the same with weight and ring gap when comparing between MAHLE and A&A.  I have several different sets of the A&A pistons I will be using.  Preparing a set of thick wall 92's right now for my wife"s 1835 buggy motor.  Will be running a set of their slipper skirt style 90.5s in an 84x90.5 motor I am building for another project.

RM

Good to hear the positive feedback on the AA pistons. I’m now not so worried about using AA pistons next time. I have never held an AA piston I my hand, but on the pictures I have seen they look thicker and heavier than Mahle pistons, are that the reality? Do you guys know how much an AA 94 mm B piston weight?

FB


Title: Re: A&A Piston Durability
Post by: rick m on March 14, 2013, 03:10:41 am
We just got the 1915 bus motor back together! In the bus and now on the road.  Open chamber heads. Slight exhaust port work. Stock cam with 1.25 rockers. Modified 34 Pict with 10% more air flow. Merged exhaust, full flowed and boy does it pull and run smooth. Will post some shots later when we download the pictures and video on the engine stand.

Rick M


Title: Re: A&A Piston Durability
Post by: Speed-demon on March 14, 2013, 11:55:05 am
Can you please describe the carb mods?


Title: Re: A&A Piston Durability
Post by: ALB on March 14, 2013, 14:42:52 pm
Can you please describe the carb mods?

I would like to hear what you did to improve the air flow as well. And thanks in advance. Al


Title: Re: A&A Piston Durability
Post by: rick m on March 15, 2013, 05:46:07 am
Larger venturi was the first mod.

RM


Title: Re: A&A Piston Durability
Post by: rick m on March 15, 2013, 08:52:31 am
Here is a short video of us breaking in the 1915 bus motor cam. It has oiling mods that ensure 45+ lbs of continuous oil pressure. The motor never got over 175 degrees during the break in. The 34 Pict is modified for 10% better air flow to work better with the modified dual port heads. Heads are open chamber hemi design with un-schrouded valves, modified exhaust ports, stock cam modified to use a bolt on cam gear, 1.25 rockers, aluminum push rods, EMPI I Beam rods, electronic distributor, and aftermarket exhaust. The motor is now in it's Bay Window bus home doing some road trips to get 500 miles of break in on the motor.  It will be leaving with the owner back to Reno, Nevada, later in the month.

 http://youtu.be/icR41tdK2co

Rick Mortensen


Title: Re: A&A Piston Durability
Post by: Zach Gomulka on March 15, 2013, 15:50:57 pm
Good news Rick. Should be a great motor. What did you settle on for CR?


Title: Re: A&A Piston Durability
Post by: Frenchy Dehoux on March 15, 2013, 16:47:53 pm
 
    Rick what size main jet did you have in the carb. And idle jet. And where did you have the total timing set at.

Thank
Frenchy


Title: Re: A&A Piston Durability
Post by: Cheesepanzer on March 15, 2013, 23:11:18 pm
Can you please describe the carb mods?

I can't recall which month/year exactly, but I believe it was Hot VW's that had a feature in the 1979-1981 time frame that showed how to modify your solex carb for more flow.  (It might have been Trends, but I thought it was Hot VW's.)  I fooled around with a PICT 30 carb using the tips in the article and definitely noticed improved performance.  As I recall, basically think "porting" and smoothing out of the rough edges where air flow occurs from top to bottom.  One mod was removing the choke.  The other was filling in an aluminum "botton" with JB Weld.  Smooth out the screws on the butterfly.  And if you choose, open the venturi up.  You'll need to adjust jetting (I went up a couple of sized in the main jet as I recall).

Hope that helps.


Title: Re: A&A Piston Durability
Post by: rick m on March 16, 2013, 02:10:48 am
Frenchy,

Enlarged the venturi to 1.10 from the stock 1.0".  We tried different jets but landed on 150 main, 85 Air Correction and 85 idle.  It liked the bigger idle jet and really smoothed it out from the idle circut to the main jet circut  We used the stock settings on the two adjustments on the left of the carb....about 2 1/2" turns on the small adjustment screw and 2 1/2 to 3 turns on the larger screw.  Idles nice, runs incredibly smooth through the whole rpm range.  We did not have to adjust the throttle plate way out to get it to run well.  I left the butterfly in the carb with the holes to give it a little air on the idle which helped not having to screw open the throttle arm for the air at idle.  Compression ended up at 7.4 to 1 with the open chamber heads.  I think we ended up at 64cc.  I had Mike Fischer flycut them and we started at 59cc ending up at 64cc after my chamber modifications.

We set the timing at 5 degrees before TDC at idle.  It is about 34 degrees at full advance (around 3200-3400 rpms).  Just a note.  The owner supplied CHINESE 009's with unknown electronic module went away before 100 miles on the road.  We pulled it out and put in an older 009 and pertronix.  This is one of my first rounds with the CHINESE crap (ignitions) and I would NEVER run one on my own personal car.

Never read the HVW article.  Just did what makes sense to get the carb to run well with a larger motor.  I will shoot some shots of it running in the bus next time it is over.  It sounds really healthy for a stock carb being used. We had it up to 80mph on a road trip up to Wickenburg. Did not even slow down on the little grades.  Ran smooth as glass throughout all rpm ranges and gears.  Made me want to duplicate the motor for my wifes play buggy.

The next motor build will be my wife's 1915cc engine with ported heads, mild cam, typical off road exhaust and goodies.  Will post shots when we get it done and on the engine stand for cam break in and miscellaneous jetting & tuning adjustments.

Rick M


Title: Re: A&A Piston Durability
Post by: modnrod on March 16, 2013, 04:22:24 am
I just love these engines Rick, they are a ripper little mild streeter engine set up, and I think the modded Solex carbs suit them best. They start first pop, great economy, heaps of grunt off idle, really SMOOTH and about 30%+ more power from stock (with stock capacity). I call them Superstockers, coz there's no way something that looks and idles stock should have anywhere near that much stick!  :D
Definately not for everyone though, they won't run mid-14s for sure.

Just one question, about your heads (and no, it won't lead to the usual crap about semi-hemi's........). What deck height did you use with this set-up? I assume you used the AA stock flat tops?

Are there any "special" tricks or guidelines (like % of squish band left or distance to cylinder wall remnant, concave/convex/flat machining angles, etc) when you do your heads?
(apart from what's in your thread).


Title: Re: A&A Piston Durability
Post by: rick m on March 16, 2013, 06:14:53 am
ModnRod,

Nothing real special on this set of heads. Deck ended up .058 .  Ran flat tops in this motor since we ran a stock cam and the total lift is around .360 with the 1.25s.  Besides the open chamber and unschrouded valves I did some exhaust port work since that is primarily where the stock dual port needs help. Polished the chambers (not a shiny polish) to eliminate all sharp edges and potential detonation spots.  When I get a short video of the motor in the bus, I will post it. The 1915 with the combo we used is very responsive and has great bottom end and cruising power.  Runs smooth as silk!

I am building a couple more motors with some different mods on the heads.

My next personal motor is a 90.5 x 84.  I am using REVMASTER heads (best castings I have ever seen). Great mods to the heads to ensure the torque stays true the way they casted the combustion chamber support and upper (outer) stud bosses.  Will do a host of mods to these heads and run an even tighter and true "0" deck to the head/combustion chamber. Piston mods done for clearance and squish. Will not run a big cam in this combo either but will have some very nice heads but only 40mm x 35.5 valves.  Will post progress shots and engine stand time when we do that motor too.

Rick M


Title: Re: A&A Piston Durability
Post by: modnrod on March 16, 2013, 07:38:46 am
Thanks Rick, looking forward to the write-ups.
Regards,
Dave


Title: Re: A&A Piston Durability
Post by: j-f on March 16, 2013, 10:46:58 am
There is a tech article in a French VW tech magazine about modifying the stock 34PICT. They remove the venturi and add a "fuel centering tube", manifold is an Hi flo from CB. They even modified them for turbo application with very good results.




Title: Re: A&A Piston Durability
Post by: andy198712 on March 16, 2013, 17:54:04 pm
whats the oil mod you mentioned in the video description if you dont mind sharing?


Title: Re: A&A Piston Durability
Post by: Cheesepanzer on March 31, 2013, 23:31:33 pm
Can you please describe the carb mods?

I can't recall which month/year exactly, but I believe it was Hot VW's that had a feature in the 1979-1981 time frame that showed how to modify your solex carb for more flow.  (It might have been Trends, but I thought it was Hot VW's.)  I fooled around with a PICT 30 carb using the tips in the article and definitely noticed improved performance.  As I recall, basically think "porting" and smoothing out of the rough edges where air flow occurs from top to bottom.  One mod was removing the choke.  The other was filling in an aluminum "botton" with JB Weld.  Smooth out the screws on the butterfly.  And if you choose, open the venturi up.  You'll need to adjust jetting (I went up a couple of sized in the main jet as I recall).

Hope that helps.


Found it!  In case anyone wanted to check out the carb mods article:  Hot VW's - May 1980