Sunyi

Hi guys!

I recently blew my new 383 engine due to oilstarvation. (HV pump, stock pan, hard right turn)

I spun no. 3 rod bearing and damaged the other 7 big ends (not spun).
The mains were hardly damaged at all.

I need your opinion on this one:

The machine shop ground the rod journals 0.20" under and 0.10" under at the mains.

They also alignhoned the rod big ends.

They called me today and told me that the block weren´t true at the mains, that it was 0.005mm (0.0001968503935") out of alignement and it needs alignhoning (cost: 300$! ). Is this true that I need to alignhone my block at these tolerances or is the shop taking me for a ride?

Sunyi

Anyone?

loiq

It's been a while since I've rebuilt an engine, but that seems pretty spendy for align-honing.

xs650

That sounds OK for a production block. You are probably better off spending your money someplace else.

I can't find a tolerance for that in my shop manual. Crank main bearing out of round allowable tolerance is 0.0002 inch, essentially what they found on your block at the mains. Out of round tolerances on those two surfaces should be set about the same. I think it's OK.

I also noticed that other places I found while looking for tolerance numbers charge about $175 for the same job and the one that gave tolerances said they worked to at least 0.0001 inch tolerances. If that's what a good machine shop can give you (sounds about right), don't sweat the 0.0002.

BTW, it gets real hard to measure things accurately on an engine once you get in the 0.0001 range, so don't get to excited about anyone claiming to do a lot better than that.

CFI-EFI

My "Chevrolet Power" book says to check the alignment with a straight edge spanning the main bearing saddles. Nowhere, should a .0015" feeler gauge fit between the straight edge and the block. Your numbers appear to be within that range, if that is how they measured it. The book starts out saying that if a STRAIGHT crankshaft, with .002"-.0025" bearing clearance, turns freely, the block shouldn't need to be bored. The chapter ends, with the sentence,"The block should not be align bored unless it is necessary." That is straight from the horses mouth. Draw your own conclusions.

RACE ON!!!

PS. The "Chevrolet Power" book is by the Chevrolet Division of General Motors.

comp

sounds like it's a little high, price another block

Sunyi

The ting is that when i rebuilt my engine, I had it alignhoned before the assembly due to changing the main bolts to ARP studs. How could it be out of true now the engine wasn´t overheating and the main bearings didn´t spin when it blew?

I live in Sweden, we have 25% taxes on labor
and mashine shops are hard to come by = high prices
To find another block is a tough one. There are very few chevy v8 in this country.

Davemc1963-87conv

If you've got the decimal point in the right place,2/10's of a thou' in my opinion isn't worth bothering about, unless you are after that last 0.0002% of a horsepower. Your crank probably isn't ground that accurately, never mind your block and to be truthful many 'run of the mill' machine shops would probably only work to that as a finished tolerence. Those tolerences look to me more like jet engine tolerences rather than internal combustion tolerences. They must have very accurate digital measuring devices, which is good, but can they improve it that much? Maybe someone else will comment, but I would say 0.0002" is OK, but maybe you're spinning 10000rpm, and need that reassurance. Your shout.

Sunyi

No way I am spinning that many rpm´s
I am putting out about ~400hp at the crank @ 6800rpm´s. Not a big deal, it´s just a regular street engine.

I´m sure I got the decimals right. The shop said that it were 0.005mm out of true.

Looks like the shop want´s to take me for a BIG ride.
Better of spending my hard earned $ on a canton road race pan

Thanks for the advice guys.

comp

may not have been done correctly before.. 25% on labor man!
have them write it up as parts

Sunyi

You have a good point there, I did´nt have any means to check the block before the faliure, the shop put it together for me. I took their word for it that it was ok the last time. I don´t have the right measuring tools to check it this time either.

I know, this country sucks. 25% tax on labor and there is 25% tax on parts as well

Not to mention the 30% income tax that is drawn from my sallary.......

comp

a "good" straight edge and feeler gauges is what i do first

Davemc1963-87conv

[QUOTE=Sunyi]
Looks like the shop want´s to take me for a BIG ride.

I suppose it depends on the quality of the work that the shop puts out. You often get what you pay for and being in Europe like myself, you will also most likely be charged extra for setting up an unfamiliar (American)engine and not the run of the mill 'Euro/Asian' I4's & I6's that the shop will be used to! The engine bearing sizes will more than likely be totally different than what they have in there on a regular basis and they may charge you extra set up time to ensure they are not out of pocket for something expected. Working on a familiar set up is always quicker and easier than something unfamiliar, especially if they want to send out a quality job. For what its worth,I would expect similar prices to yours over in the UK too!