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I have been looking at Main bearing for a JH 1.8L, and at the same time thinking about rebuilding my 2000 Audi A4 1.8T.......The A4 brg # is 06a 198 491 The 16V 1.8L # 026 198 491...
The main journal size in the 1.8T is 54.00mm the JH is 53.98? So if I use the 1.8T brgs, will I have to run gear oil to have oil pressure?
My reason for trying these is because the 1.8T brgs can handle 180hp+....
2nd reason, I like just wasting time.....
not sure on the specifics of the other criteria of the bearings (most importnatly width). However, you can get a machine shop to cut your block/line bore or turn your crank to run whatever bearings you want to run. However if we are talking a motor for IT this is not legal and woudl typically put your motor out of factory spec, thusly illegal. I know I spec out bearing clearances to the ten thousandths of an inch for both my main and rod clearnaces (among other things) for my machinist, within the factory tollerances, to help me achieve goals that I am trying to achieve.
<- one of the ones that experimented with using acura main bearings on domestic V8's to reduce the amount of surface area=less friction=more power.
<- also runs ford 300 I-6 bearings in his ford SBF 347 stroker motor.
I ordered both bearings, I have seen it in the past were the "BOOK" lies from year to year...The 2000 Audi 1.8T is an old school engine, Non cracked rods, same stroke &bore, It looks just like a 16V 1.8L, witch has the same mains & rods as an old old 1.8L.....I was thinking the Audi 1.8T bearing had a better material than the old 1.8L? Could be exactly the same?
The Audi I drive has 150K on it, Its a turbo, has been beat/ rev-limiter shifting, for the past 30K and its still going strong......Its gotsta have good quality bearings? The evolution of parts is what I am after, TRUTH! technology has come along way since 1975...Its a tough engine to begin with I wanna make it tougher!
The width is the same...
I had a 300-6 once.....I wish it was a 347!
.02mm ~ 8 ten thousandnths of an inch. or (0.00079")
bearing design hasn't really changed that much, from when my father was a machinist int eh 70's through early 90's.
Material and application have defiently improved. But typically the better applciation process is applied to the newer "old" bearings on the market today.
When you tear your motor down, you will have to mic out your crank journals, install the main bearings and use a bore gagues to determine what they meaure. Then do some simmple math and determine if the added 8 ten thousandths keep you within factory spec or more importantly what range you would like to run.
Another thing to think about is are the bearings you replacing a known issue?