Despre Blocul Motor

[MishuL]

Daca tot s-a facut vorbire, care e shpilul cu AS 21 si AS 41? Am observat si eu ca scrie din turnare pe bloc, in spatele volantului....

[MikeRG]

cifrele indica cum sunt combinate A(luminiul) si S(iliciul) in compozitia blocului

ref serie - nu e cea originala asa ca identificarea motorului e mai greu de facut, doar masurand setul, identificand tipul axului cu came, a pompei de ulei samd

[MishuL]

Aia banuiam eu, dar difera calitatea materialului? Pe ale mele scrie AS21 (un bloc de T3 acasa, blocul meu de duba de la scarbiciu....) E de bine, de rau sau indiferent?

[MikeRG]

I would like to share some information about the stock case. The first thing practically every shop will tell you is to line bore your case if it is worn. Have you ever asked, "Is this rebuilding the case?" Not so, according to a document on the applications and effects of magnesium when used for engine and transaxle housings that are heated and cooled many times. The document was written by the Quality Control Department of a major German car builder. It disclosed that the engine cases made with the AS41 material (no longer used for VW parts, now all cases are AS21) are designed as non-rebuildable items. In other words, when it needs to be reconditioned, replace it with a brand-new case. Naturally, this will depend on how bad and how much more use you think you can get for the money you will spend patching it up. Remember, you are only patching it up to run a little longer, not reconditioning it.

Why does the case pound out and get bad in the first place? Why does it have over-heating and low oil pressure after it is rebuilt? What are the facts about all this?

AS41 magnesium is a very lightweight material. When used in ideal circumstances, it will give 100,000, maybe even 150,000 miles of trouble-free service in the VW engine when never overheated or ran over 4400 RPM. When I read available documentation about the AS41 and AS21 material used in the VW cases, I was shocked when I saw how weak the AS41 is when subjected to conditions beyond the normal VW temperatures and stress. This, however, substantiated many evaluations I made from my own years of research and development and answered some questions previously unanswered regarding the memory, rigidity, resistance to elongation and strength which was reduced drastically.

The higher the temperature, the faster the case is reduced to junk! A new material called AS21 was available, however, it required slower, expensive production procedures and was not introduced until the FI engines in 1975. The Volkswagen factory of Brazil has informed us that the AS21 case containing 2% aluminum and 1% of silicon have not been available since 10/25/95. They have been replaced with the new AS41 case. The new AS41 case has been upgraded with a new alloy composition consisting of 4% aluminum and 1% of silicon, giving the new AS41 case 2% more aluminum and the same amount of silicon than the AS21 cases had. This gives the new AS41 case better flexibility and durability than the previously desired AS21. AS21 is stronger and resists problems of the old AS41. The AS21 markings can be found at the side of the case and often in large letters in the bell-housing area.

Most engine builders have noticed these cases show a considerable decrease in pounding or distortion as compared with the old AS41. When any of the cases are overheated (AS41 old material being the worst) they are stretched, pushed out of shape and the center main bearing area starts to wear. The materials are subject to stress beyond their design limits. This overheating is more apt to happen to the smog controlled engines (1968-on) that are run very lean, which causes overheated heads that come loose or head studs to pull out. The more times this happens the worse it gets. This is irreversible damage. It soon pounds out the center main saddle enough so oil leaks between the case and the main bearing.

This loss robs the engine bearings of needed oil. More heat is produced due to less lubrication and more damage occurs. Soon the number one bearing starts to do the same thing. By now the case has lost most of its resistance to elongation and the center main saddle is pounded so badly that the cam tunnel has moved over and is wearing the center cam bearing. A non-counterweighted crank only aggravates this condition especially when the engine is often turned to its upper limits. Even if a properly counterweighted crank is used under the conditions I spoke of, some of this damage may still occur. Some of this stress can be dealt with by stress-relieving the case 3 or 4 times, removing the case studs, machining both halves flat, re-install the studs, torque everything, and remachining every surface to the proper size. This is still not a guarantee of being 100% like new and at today's labor prices it is out of the question.

A new case is far cheaper and will assure 100% life ahead. That's one of the reasons Volkswagen cast new cases for their factory rebuilt engines from the mid 60's and on.

I tested 100 line bored cases in stock 1600cc engines. Over 80% had low oil pressure when normal temperature was reached. This often occurred in less than 5,000 miles. Most of them never performed well and got poor mileage. FAT Performance line bored the case on one of their 1600cc off-road race engines. The dyno revealed that it was down 17 HP from previous tests.

Another engine that made the correct HP was disassembled and every part, piece by piece (except the case) was swapped, still down 17 HP. I was called in as a consultant. My only comment, "Replace the case." This advice was not taken at first. In fact, a newly designed head was tried first. Better, but still not up to normal. Finally, Ron went for the new case. "Voila!" a magical 19 HP appeared. Ron said, he has heard me saying this for years and never paid much attention, but now had the actual experience of what I have been seeing for years.

If nothing else, use your common sense. When you use up 75, 80, 90% of the life of the part why put it back into service and ask it to take more stress and strain than it did when it was new? Don't spend a bundle for machine work on an old worn out case and expect it to give the service of a new one? It is your gamble. What is it worth to you to know it is good for 100% of its life rather than 10% or 20%?

http://www.geneberg.com/cat.php?cPath=22_503_2984

[MishuL]

Am splituit topicul, discutam aici in continuare.

Sincer, eu am maaaari dubii ca AS 21 inseamna 2% Al, 1% Si si... restul... ce? Magneziu? Nu cred! sunt sigur ca materialul de baza e Al, aliat cu siliciu si magneziu. Ia sa ma uit in :frigbaitata:

[MishuL]

Vad pe Paruzzi blocuri VW si AutoLinea, ambele la 475 euro. Cred ca reduc inghetzata la copii si iau unul......

[bogdan_bus]

date mai detaliate despre materialul blocului are cineva???.... eu am un bloc motor tip1 pe care vreau sa il tin pentru experimente... ma gindeam la incarcarea palierelor cu un aliaj al-si cu tig-ul si dupa alezarea palierelor....

jan spunea ca blocurile de tip 1 contin magneziu in cantitate mai mare si atunci nu se poate incarca

[jan]

Blocul de broasca nu se sudeaza, ca ia foc, din cite stiu io. Acelasi lucru se poate intimpla cu carterul cutiei de viteze. Am taiat unul de-asta, e extraordinar ce flama grozava face.

Misule, blocul tau AS21 de-aia n-a avut asa uzura la paliere, probabil, e un aliaj mai bun ca AS41.

Blocul de T3 nu poate fi din aliaj AS decit daca-i motor CT/CZ. Ar trebui sa scrie ceva de genul Si 12 sau Si 21 pe el. Doar daca nu te gindesti la tip 3 in loc de T3.

Modificat 13 Februarie, 2008 de jan

[bogdan_bus]

de exemplu pe chiulasa pe care am incarcat-o aliajul de al-si cu care am facut incarcarea a prins foarte bine... chiulasele sint din alt aliaj???........as21 are 21% siliciu in compozitie.. iar as41 are 41% siliciu in compozitia aliajului ...cu cit este mai mult siliciu in compozitie creste duritatea si temperatura de topire..caut sa vad cam cit magneziu este in compozitie.... spun asta ca jantele din aliaj de aluminiu contin si ele siliciu si magneziu.. si se sudeaza .. sint jante facute din doua bucati si sudate ...

[bogdan_bus]

am gresit la compozitie... as41 are 4,1% si si as21 are 2,1 si ...... am gasit cu gugalu ca se pot suda si aliajele de al-mg-si doar cu sudura cu puls pozitiv in mediu protejat.. deci tig....

[MishuL]

O sa ma uit diseara mai atent la blocul de T3 sa vad seria si materialul.

Oricum e clar ca nu poate fi bagneziul elementul preponderent. Din cate shtiu, este chiar instabil, ia foc f ushor si arde violent.

Am taiat aseara seria de la un bloc spart si nu facea scantei deloc, a facut doar de 2 ori cand s-a incotzopenit discu'flexu'

[bogdan_bus]

..... iaca http://www.springerlink.com/content/wu4458l21461xmj3/

[bogdan_bus]

.... cred ca scinteile nu le facea magneziul ci mai degraba sodiul din compozitia aliajului..

[Bugtuner]

Chiulasele sunt din complect alt aliaj decat blocul motor. Confirm ce sa zis despre faptul ca ia foc. Arde, exact ca o flacara de sudura, (magneziu) sau ca stelutele vechi de craciun. Am gaurit un capac de cutie de viteza sa pun sonda de marsarier. La gaurire a iesit span de curgere lung. Am strans spanul in pumn, l-am pus pe masa si si i-am dat foc cu o bricheta. A ars ca artificile tot spanul transformand-se in praf alb. .

[soryn]

de exemplu pe chiulasa pe care am incarcat-o aliajul de al-si cu care am facut incarcarea a prins foarte bine... chiulasele sint din alt aliaj???........as21 are 21% siliciu in compozitie.. iar as41 are 41% siliciu in compozitia aliajului ...cu cit este mai mult siliciu in compozitie creste duritatea si temperatura de topire..caut sa vad cam cit magneziu este in compozitie.... spun asta ca jantele din aliaj de aluminiu contin si ele siliciu si magneziu.. si se sudeaza .. sint jante facute din doua bucati si sudate ...

Chiuloasele sunt AL in proportie ff mare, blocu motor are in schimb fff mult magneziu. Sa nu va puna draku sa puneti flama pe bloc ca arde ca "Blitzu" din alte vremi ( cutiutza cu magneziu) !!. Am dat io foc la spanu care a rezultat din alezarea blocului meu ( acu 6 ani) si a ars instant !!

[bogdan_bus]

....eu vorbeam de TIG WIG.. nu de electrod sau oxiacetilenica........la TIG WIG exista suflaiul de argon corgon sau heliu care creeaza un clopot de mediu inert, lipsit de oxigen .. iar curentul nu vine continuu ci pulsatoriu....cutiile cu magneziu le-am vazut si eu numai ca acolo compozitia e alta

inca o data ... jantele din aliaj Al-Mg-Si se SUDEAZA

[mircea_cotiga]

Blocul de broasca nu se sudeaza, ca ia foc, din cite stiu io..

Se sudeaza si aliajele DE magneziu...cu W.I.G. DAR trebuie sa ai material de adaos din acelasi material...cam greu!

[bogdan_bus]

.... nu am aprofundat problema .....dar daca materialul de adaos are siliciu mai mult??? si mai putin mg.... de ce nu ar prinde????...e vorba de o suprafata pe care s-ar depune cel mult 1mm de adaos.. care este solicitata la forte de compresiune .. nu la tractiune si nici la torsiune... ar fi ca un bailagar...ideea ca materialul de adaos la care ma gindesc eu are o duritate un pic mai mare si nu este asa friabil ca materialul blocului ......hai nea mirecea ajuta-ma te rog ..

[mircea_cotiga]

Pai ideea cu sudura e sa faci ceva care sa reziste...la solicitari!

Daca trebuie doar un mm de ce sa nu faci ceva mai putin complicat, costisitor si fara riscuri.

Exista adezivi care fac fata la o tablitza de 1 mm lipita la locul faptei solicitata la compresiune, si care atunci poate sa fie si din alceva(ma rog, sa-ti indeplineasca cerintele)...exemplu: temperatura!

Modificat 13 Februarie, 2008 de mircea_cotiga

[bogdan_bus]

ideea cu adezivul e buna .. dar sint unii care nu le place sa stie ca au ceva subt cuzinet...

[mircea_cotiga]

E treaba lor

[jan]

Pentru toata lumea, care le place sau nu sa aiba ceva sub cuzinet, vw nu recomanda alezarea blocului motor. Scrie undeva sa-l alezezi?

Iei unul nou si gata.

[bogdan_bus]

Iei unul nou si gata.

daca as fi shashiu si m-as uita numai la bloc motor....asa am un ochi la bloc si unul la buzunar .. deh sintem romini... daca ar fi ieftine ar merge, dar sint cam 711$ la cip cu transport si cu bir ...

[jan]

daca as fi shashiu si m-as uita numai la bloc motor....asa am un ochi la bloc si unul la buzunar .. deh sintem romini... daca ar fi ieftine ar merge, dar sint cam 711$ la cip cu transport si cu bir ...

Aoleo, iar ajungem la discutia asta, aci nu ne gindim la bani, eram intr-o lume mai buna.

Nu stiu daca-i relevant ca sintem romani, uite, cautam set(uri) de garnituri pentru carburatoare. De-alea de bus, sa zicem, nu de Messerschmitt. Bine, o sa zici ca ala n-avea carburatoare, dar nu conteaza. Omul zice 2 milioane sau asa ceva. Io zic: cum, mai, un plic cu niste hirtii, atita costa? Pai da, zice el. Si se uita la mine parca eram o babuta de-aia care nu stia ca nu mai exista Ceausescu. Deci exista oameni care platesc 4 milioane pe niste hirtioare si oringuri (pe care le poti pune de la brichete, de altfel).

Ia-ti blocul motor si gata.

[bogdan_bus]

jane .. exista in ecuatie niste "if-uri"... as trece peste ele .. la banii aia ar trebui sa faca si perveriuni sexuale...asa ca revenim la baialagare sau cutiute cu magneziu