even Chevy motors need to be line bored/honed from time to time.
it's not the fact that he was a "Chevy specialist"- it's the fact that he cut a corner that shouldn't have been cut.
That is a common problem with engine shops, and especially not good for those doing performance engines.
Here is what I have personally found over the many years I have done and supplied Buick engines.
The shop and/or owner must have 3 characteristics present in the operation of engine building - capability, ability and desireability.
Capability - the shop must have the proper equipment and machine tools to perform the necessary machining and assembly functions. They must be up to date with latest technology and be fit to the specific job.
For example, an alum block with ductile iron or steel liners must have different tooling and methods for cylinder finishing. The other shop equipment must be able to give the desired results, and do jobs on a consistant basis.
Ability - the person or persons doing the work from dis-assembly, cleaning, machining, fit and finish, etc. must have the experience to do each individual step of the process exceeding industry standards. They must be experts in all aspects machine work, assembly, cylinder head prep and flow and all other processes.
This "ability" comes from training, personal knowledge and experience. listening to customers, past, present and future is important. Lots of this knowledge comes from experience, but also feedback and hands-on experience in the field is also needed.
Desireability - this is what most shops lack, primarily because they are a production shop, and do not have the time or inclination to spend on "minor" items during the engine building process. Additional dollars are not always the answer here. Some shops have production schedules to keep, and will not vary.
If a minor "problem" is found in final assembly, will a production shop completely dis-assemble the engine to rectify it? Probably not as as removing a girdle, or whatever, is not in their plan or budget. This "minor" item could be an issue at 7000 RPM.
So how to find a shop to fit your specific needs? First, be able to specify your needs, wants and budget. Talk with the person in charge and see if they can, and want, to fill your requirements. Then check with customers that have had work done by them to see if they were satisified.
To comment on the original post, and specifically about bearing clearances, most of the bearing problems we see are from detonation, and the next most common is too tight bearing clearances, especially on the rods.
The Buick factory specs for the turbo motors are the same as for an economy 2 barrel V-6. Looking at the Buick Power Source manual and you will see much difference in their bearing specs - and we ARE talking performance builds here.
Not far from SBC specs.
To freshen or rebuild any motor without doing a crank line bore is not smart. We have seen many problems because of lack this too. If you are saying no. 2 main bearing spun, something was way out of spec.
Hope you find a good shop to get it done right.
and when the pan came off
3 sets of head gaskets and now this....
