is a stock crank cut to .030 safe???

[TurboBuick86]

hello im new to this site aswell as to the grand national. my dads had the 86 grand national wince 1989 where he bought it used at a dealer in jersey. He's lost interest over the years and the car sees the street less and less so i got him convinced to lemme rebuild it since it had already 115,000 miles and the motor was just begging for a fresh built. To his knowledge this was an UNTOUCHED buick, so i took out the motor last week and even though it has stock heads and the block hasnt been tampered with, the crank had been cut to .010... it has deeper scratches so i think it needs a .030 cut , but im scared if thats dangerous for the car in the future. also are the stock rods good one the cars with all arp hardware or should i just get some scat rods or such??? thanks!

 

[ALVAROG1983]

it all depends on what you want to do you can get away with .030 but that might be pushing it if rods are o.k they shouild be fine to use again stock rods are good.

 

[TurboBuick86]

well since im new to the GN scene i have a lot of questions, and lack of knowledge on the car. But I would say that I will be very happy with a 400hp car, from what I read on this site and others, these cars make 400hp with barely anything. I've spoken to a couple in people that have dealt with Gn's and they all say that the stock rods are great, but to atleast get all arp hardware, which i plan on. thats why I posted here, to hear the facts from the experts like all you guys!

 

[83ttypecooled]

Hi,
Welcome to the club! We Geezers need some fresh ideas,so you are very welcome here!
Pertaining to your issue,a .030 cut in the crank will weaken it,of course, but probably not fatally,with street driving in mind. These cranks are usually good past 500hp. If you want more,see TA Performance, or some such vendor. Your rods are cap in rod style, built tough.Stock bolts are tough,ARP are tougher.Have them resized if you replace them. As a matter of fact, I recommend that you use ARP exclusively.For stock use, ROL gaskets work fine,Felpro is also very good. I am a professional mechanic,and I like the ROL head gaskets;they just look tougher to me.
As far as cams are concerned, I chose Comp's mildest hydraulic flat tappet.
Use a stock replacement timing chain,iron gears,multi link chain.They are stronger than a roller,and are a replacement issue.
That's it for now,keep those emails coming!

 

[87GN_70GS]

Anything more than a .020" cut will remove the rolled fillets GM added for extra strength. The fillets are at 0.025" under, so a .030" cut will do away with them.

 

[TurboBuick86]

will that affect the street performance goals I want??? trust me when I tell you this that this car WILL not see the track for years. The whole suspsension needs work and a fresh paint job will do the body good. I just want a good street running turbo regal...

 

[Grumpy]

we went 9.9 @ 138 with a 20/20 crank with stock rods .. have the machine shop look at the crank..

 

[TurboBuick86]

damn thats an insane time... guess im not feeling to scared anymore about using the crank at 30/30. I took it to the machine shop and they said the scratches are way to deep for a 20/20 so a 30/30 needs to be done, which essentially is the "last" possible cut.

 

[WINDMILL]

crank

where are you from? you might be able to find a crank close where u live.

 

[turbofabricator]

ROL head gaskets!!!!!!!!!!

Do NOT..EVER.....EVER use ROL head gaskets on a Turbo Buick...EVER!!!!!! They do NOT have a wire fire ring inside the gasket. The 'look' like the stock gaskets, but they will NOT withstand any sort of boost!! Let me be clearer.......do NOT use ROL head gaskets. Every other gasket they make is fine for the TR, but NOT the head gaskets. Here is a picture of a ROL that popped at 15psi boost. Yes, it was a strong engine, BUT.....they are NOT made correctly. The picture of the 9441-PT Flepro is the same as a stock head gasket. The ROL does NOT have this wire inside the fire ring. (use FelPro head gaskets (#9441-PT, or the entire gasket set. )

The crank will be fine at .030"/.030" for 550 HP, or maybe even more. A non-turbo (NA) crank will live at over 500 HP, too. Just keep your tune up conservative. Make SURE your machinist has built alot of Turbo Buick V6's, or find someone else!!! These little engines NEED special attention to detail! You MUST keep bearing clearances tight, at .0017". If they grind the crank to typical small block Chevy clearances, you will have very low idle oil pressure. The oil pump/timing cover must be assembled/modified by someone that really knows thier stuff. If they say they will slap it together, run away. It sometimes takes me 4-5 hours to get it right, The thrust clearance on the oil pump gears needs to be set at .0005"- to .0015" for best results. Cam selection is one of the most critical parts in the build, too. Buy a Hydraulic roller cam (somewhere in the 208/210 range) from one of the vendors on this board. (Fullthrottle, Cottons, TA, or others.)
Good luck with yur build. And I will wager to say that if your build goes well, you will not be able to stay away from the track.