[robconner]

It started off as an enjoyable day off that I could spend some time on the vette. That has change and I need some assistance.

I dropped the tranny to send my clutch and pressure plate off to mcleod to be resurfaced. That went fine. I decided to pull the flywheel and get that machined. That went fine. I have a new milodon oil pan that I have been meaning to put on so I decided to do that. My old pan did not have the built in windage scraper, it was bolted to the block. So I took off the old scraper and took out the five main bolts, cut the windage studs off and put them back in at 80 ft pounds. All went in except one would not tighten so I pulled it out and it looks as if the treads are pulling. This is where I don't know how bad I have messed things up? I figured I would just put in some arp bolts in place of the old ones. So I called arp. Where I was told that I should use all arp or all stock. Which I understand, different materials different clamping forces. But the guy in tech said I have to line hone the block again. I am only changing five bolts is it that important? Or did I just do something so stupid I am going to have to pull the block? Please Help....

 

[1 MN MCN]

No ones gonna answer this so I figured I would. Well, what i know about engines can fill any decent sized bottle cap,, so what I would do is get one "Arp" bolt and replace only the one, look the other way when i put the oil pan back on, and drive it like I just rebuilt it.

 

[69MyWay]

I would call a local production (not high performance) machine shop to see how they deal with this. My guess is if the entire engine were to be rebuilt with this problem they would drill out and replace the threads with a repair kit.

If that is true, I would assume you could pull the main cap back off and from underneath drill, tap, and insert a heli-coil thread kit in place, then reassemble the cap and replace the bolt.

Otherwise, the only other option I think you might have is to install a stud in place of the bolt. A stud can be finger tightened in place, then you can torque the nut. This works in a lot of damaged thread applications.

I can't imagine why you would need to line bore it. That is insane - unless you replace the main caps, or some how get them mixed up or something.

 

[kwplot34]

Wow i don't understand that one, maybe they mis-understood you? i wouldn't think that new bolts would move the cap's off center :huh: you might try to get TimAT opinion on this one.


Kevin

 

[TimAT]

If the main caps still register in the block properly changing the main bolts to studs, ARP's or even just different stock bolts should not make any difference. I can see ARP saying a line hone may be needed- their bolts may not stretch as much as others and cause the bores to go out of round. Just 1 bolt? Try another bolt in the spot that's pulling. It may be that bolt is failing and stretching. Torque is another way of measuring stretch of a fastener.

The stud idea is good IMHO, it will be a little longer than the bolt and may get to good threads in the block. Heli-Coil is not a bad idea either, but it'd be a bear to do without a tear-down.

I've never heard of a SBC losing threads on a main bolt hole. I'd be very suspicous of another problem in the block. Not saying that it's not happened, just after 30+ years it's a rare thing.

Let us know what you decide/find out. Inquiring minds and all that.

 

[robconner]

Thanks for the replys. I must not of been clear. The threads on the one bolt were stretching, that is why it would not torque properly. I just hope that I did not screw up the threads in the block. I don't think I have because I took my time and did the five bolts 5 pounds at a time and when I went from 75 to 80 and that one did not click like the rest I backed it out and checked it and said S*@#. Called arp and started to sweat. Yesterday I took my flywheel up to the machine shop that built my motor and talked to the guy who built mine and he gave me five oem main bolts and told me I would be fine. He said as long as you didn't take off a main cap or rotate the assembly while you had the bolts out you should be fine. So that was good news. Now I just need to find some time to put them back in.

Right now the car is in my parents garage with the pan off. How long can it sit open before you have to worry about rust?

 

[big2bird]

Anything critical is covered. Worry about dust/dirt.

 

[robconner]

:thumbsup: