rebuilding engine

[pisano]

i pulled my engine out and am rebuilding it and was wondering if i need special pistons or cam or crank my machine shop charged me 1120 for top and bottom gaskets, bore the engine 30 over, new pistons, lifters, rebuild crank, new cam, all new bearings, new timing chain (was ready to go), engine degrease, and oil pump rebuild. i had already rebuild the heads then motor went in like two weeks so those were done.

motor will be done in a couple days.

motor was knocking and crank had spun a bearing.

first car i ever rebuilt the engine in and am excited to see how a fresh engine runs.

oh yea and was wondering with a rebuilt bottom end would i be able to run a bigger turbo and would it be noticeable power increase

 

[pisano]

shop said they had another crank cause mine needed welding and they wanna give me another for cheaper. i asked to make sure if its turbo crank and not a regular one he said no because he gos by casting number so its gonna be the exact same one is it true?

also on my receipt it says cast pistons is that ok?

 

[pisano]

please anyone

 

[turbo nasty]

Turbo Regals and N/A 4.1 had a rolled filet crank for strength. If they put in a standard 3.8 crank then its weaker and not worth it.

WHy dint they reuse your factory pistons?

 

[fmster]

Cast pistons are not turbo pistons!

 

[BRAD_PADGETT]

Turbo Regals and N/A 4.1 had a rolled filet crank for strength. If they put in a standard 3.8 crank then its weaker and not worth it.

WHy dint they reuse your factory pistons?

The engine rebuiler should know the difference between turbo pistons and turbo crank. The block casting number can be deceiving unless you know the history of the motor. Post your casting number. My engine was originally a Jasper 85 rebuilt turbo motor. The block is a 140 which is a nonturbo block. The block casting number is basically irrelevant. This same engine was rebuilt last year and the pistons and crank installed by Jasper are turbo parts. Make sure you have reputable turbo buick rebuiler. Brad

 

[charlief1]

Cast pistons are not turbo pistons!

Would you like to put some money on that.:biggrin:

 

[Nick Micale]

I was looking for a friend for info in this forum and came across this thread.

Not sure where some of these comments originated, but Buick always used cast pistons in their turbo engines.

As far as the crankshaft for a turbo engine, the listing and part number in GM parts for a crankshaft is the same for a turbo and non-turbo engine. The casting numbers are also the same

The crankshaft for the turbo Trans Am was cross drilled, and it did have its own part number.

It is unlikely that Jasper's furnished a turbo rebuild with a "real" rolled fillet crank?

To verify a Buick V-6 turbo crank, you must have rolled fillets on both rod and main journals, and the best way to do this is with a "finger nail test". :smile:

The later factory turbo pistons were made special, and were different structurally and stronger than the NA pistons.

As far as the engine for the OP, it will most likely perform as expected as it should not be subjected to the higher boost and RPM that is seen in the intercooled version, good luck with it and have fun.

 

[charlief1]

Not sure where some of these comments originated, but Buick always used cast pistons in their turbo engines.

The later factory turbo pistons were made special, and were different structurally and stronger than the NA pistons.

Darn it Nick! I was gonna bet him $10K on that. :biggrin:

 

[BRAD_PADGETT]

Hmmm. Time to be quiet and leave the details to the experts. See you later everyone. Brad

 

[Nick Micale]

Hmmm. Time to be quiet and leave the details to the experts. See you later everyone. Brad

Brad, please do NOT be quiet because this is how we all learn and share info among us.

Do not take this personal as we ALL are always learning form each other, and there is info passed around than many of us "assume" is true and correct, but we find the source did not put it out properly.

It is amazing how much valuable information resources are available here and it keeps coming because people ask questions and participate.

And then there are guys like Charlie [and myself] that we have to contend with?

 

[charlief1]

Brad, please do NOT be quiet because this is how we all learn and share info among us.

Do not take this personal as we ALL are always learning form each other, and there is info passed around than many of us "assume" is true and correct, but we find the source did not put it out properly.

It is amazing how much valuable information resources are available here and it keeps coming because people ask questions and participate.

And then there are guys like Charlie [and myself] that we have to contend with?

LOL That's the second time I was gonna win some cash off of a member.:biggrin: I still wish the guy ahd bet me that the first GN was built in 84 though.

Stick around Brad, please. All input is welcome even if it's not exactly right. Learning is a good thing for all of us and I goof just as much as others do, you guys just don't see it that often.:biggrin:

 

[bison]

IMO the stock cast eutectic piston is stronger than any one the aftermarket hyper pistons. Yup mid 80's tech with plenty of r&d done by engineers produced a very strong (but heavy) piston design. I've never had one fail under 750hp and even those hard some hard run time on them. I'd be most concerned about the pistons used and less concerned about the crank and block. I'd run an NA crank if I had to. The 140 casting was used in 1985 and was kind of in between the predecessor and 109 and had the taller deck with steel head gaskets but had the 20 bolt pan. The cam bearing arrangement is the same as the 109 with a groove behind one and im almost positive they used the same od as the 109. I've looked at all these blocks together and the areas that are lacking on one are the same on the others. Weak main webbing with 2 bolt mains. All are almost identical. The machine work done is more critical than the crank or block used.