Machine Shop Torqued my New Rod Bolts to Balance

mtelliott · 12-20-2003, 07:42 PM

Machine Shop tightened my new rod bolts to balance. Did they just waste my brand new rod bolts?

As well, shop couldn't get some of the cylinder studs out of the case. They had the tool and used heat as well. Still couldn't get them out. Should I see if someone else can do it or should I leave them in and pray?

All advice welcome at this point.

makaio · 12-20-2003, 08:15 PM

Sounds like you're going to need to buy some new rod bolts

.

If it was your new rod bolts they used for this, I would buy some more. Just not worth the chance, IMHO. Others may feel different.

Bobboloo · Bobboloo's Garage

Ideally you send the rods to the shop with the old rod bolts and keep the new ones at home.

You might call them and ask how much they torqued them. If it wasn't very much you might be okay but it will still be a gamble.

Chuck Moreland · 12-20-2003, 09:15 PM

They should have used the old rod bolts. And they should have know that. And they should be able to get the studs out.

I think you need a new shop.

mtelliott · 12-21-2003, 10:16 AM

I sent them with the old rod bolts. He wanted the new ones to balance. Not sure why he torqued them down but one of them tested at 40 lbs torque to remove. I'm guessing that I'm buying new ones. Will this effect the balancing that was done?

zotman72 · 12-21-2003, 01:06 PM

Ok I am in Denver area so I am curious which shop would have done this gaffe. If you had purchased Raceware bolts this behavior would be no big deal as Raceware bolts can be retorqued. However I suspect you did not.
As OEM bolts are stretch bolts as you know, you are probably faced with $$ decision. Ask the shop if they were aware of the one torque time rule and if they might co-share the replacement rod bolts because of their error? Yeah right!
Good luck and do tell me who the shop was. Local Porsche pilots need to know who to avoid.
HTH

Wayne 962 · Wayne 962's Garage

Right - you don't want to mess with rod bolts. Sounds like you need to double-check everything they did. If they are not smart enough to avoid a simple mistake like this (detailed in the factory manuals), then who knows what other errors they made.

-Wayne

mtelliott · 12-21-2003, 01:20 PM

I don't want to mention the shop by name and I haven't talked to him about it yet (Monday morning). He is located in Longemont and does work for a rebuilder in Boulder.

I'm going to purchase new and see if he will cover the cost. The rest of his work was spectacular. The valve job was perfect and the block is remarkably clean. I'm not sur what I'm going to do about the block with the fact that he couldn't get the bolts out. I'm thinking I'll leave well enough alone and reuse the one's he couldn't get out. I'll inspect at first valve job and if't it's holding, then I won't worry about. If it's anyways loose, then I'll rebuild again.

Thanks for everyone's advice.

mtelliott · 12-21-2003, 01:21 PM

Wayne, what's your advice on the studs that I couldn't get out?

john walker's workshop · 12-21-2003, 01:32 PM

take the case to a porsche shop for another go at the studs. the machine shop may not know how much heat it takes. does Carquip in boulder do repairs?

jim72911t · 12-21-2003, 01:34 PM

This thread is interesting because I just got my rods back from my machine shop yesterday and assembled my crank assembly last night.

It sounds like the shop screwed you in a couple of ways. First, they should have not torqued the new rod bolts. Their reasoning that they they needed the new ones for balance makes no sense because you would have to use new bolts when you install the rods to the crank, which would be different weights once again (their logic). Second, the torgue value for the rod bolts is 20Nm or 14.7foot-lbs. If he used loctite that might affect the release torque, but it sounds like he didn't use the right torque values.

He also should have been able to get the studs out.

Find a new shop. It may be an expensive lesson if you can't work something out with the shop, but it'll be cheaper thn a motor that handgrenades when you put it together.

Good luck,
Jim

john walker's workshop · 12-21-2003, 01:38 PM

jim 14.7ftlbs is incorrect.

Wayne 962 · Wayne 962's Garage

Wow, a lot of activity on this thread in the last 10 minutes.

I agree - take the case to another shop - these guys don't know what they are doing...

-Wayne

jim72911t · 12-21-2003, 02:24 PM

Quote:

jim 14.7ftlbs is incorrect

John, you've got me scared now. I'm looking at Wayne's book, page 200, and see a spec of "20Nm(14.7 ft-lbs)". I then turned the bolts an additional 90deg as specified in the book.

However, my Haynes manual says 36 ft-lbs. I used the specs in Waynes book.

Am I buying new rod bolts as well, or can my current bolts be torqued to the higher value? (I used Permatex red on the bolts).

Or, does turning the bolts an additional 90deg bring them to the higher value?

Thanks,
Jim

Rot 911 · 12-21-2003, 04:35 PM

Quote:

Originally posted by jim72911t

Or, does turning the bolts an additional 90deg bring them to the higher value?

It does. I just did my cylinder head nuts today. Wayne's book says torque to 23 ft. lbs and the Bently manual says 11 ft. lbs then turn an additional 90 degree. I noticed that turning the addtional 90 degrees got me to 23 ft. lbs.

zotman72 · 12-21-2003, 04:38 PM

When I did my 2.4S motor upgrade from a 2.4T two years ago. The wrenches I trust in Denver told me to send to my case to Competition Engineering in CA as there is no one in the frontal range area qualified. Granted this was a mag case but it was local wisdom. CE was not cheap but the work was done right and I have had not worries. YMMV.
On another story, my Raceware bolts were a bear to get torqued right but I will not hijack your thread.

vash · vash's Garage

mt, someone else, in your situation.

Rod Bolt Problem Help!

cstreit · cstreit's Garage

He should pay for the new rod bolts in my opinion. These are stretch bolts and unless you bought raceware or ARP which can be re-torqued, they must be replaced.

Give him a chance to make it right, you might be suprised.

mtelliott · 12-22-2003, 11:58 PM

Sorry to all. That's my buddy (Bert). Together, we are rebuilding the engine. I didn't realize that he was posting as was I. Bert lives up in ski country and I live in Denver so he probably posted while I was commuting back home. Long story short, I was able to get new bolts locally and get them in.

Rebuild is starting to flow. Just have a rocker question but I started a new thread for that one.

As always, thank you everyone for your comments.

Wayne 962 · Wayne 962's Garage

Quote:

Originally posted by jim72911t
Or, does turning the bolts an additional 90deg bring them to the higher value?

Yes, that's exactly what it does...

-Wayne