Need an opinion from experienced engine rebuilders

[Guest]

Hi all,

Can some of you experienced engine rebuilders offer an opinion on the attached pictures?

Here's the story, 16 years ago I got these C90 thru bolts when I had a C90 case overhauled.

I don't recall if they were new or used when I got them from the case overhaul shop. At that time 16 years ago I packed the thru bolts and case away.

Today I started working with them and these look thru bolts look new to me. The threads were totally clean until I ran some old greasy nuts on them.

What is your opinion, are they new?

Thanks, Dave.

[N96337]

Re: Need an opinion from experienced engine rebuilders

Hard to say Dave, but they look like they could be cleaned up and very serviceable!

[Edwin Otha]

Re: Need an opinion from experienced engine rebuilders

Dave,
Check TCM Service Bulletin SB97-6B. It has TCM's view on this. Kind of depends what you want to call the completed engine.
EO

[Guest]

Re: Need an opinion from experienced engine rebuilders

May be some confusion. I am aware of the SB and doing an overhaul that requires new thru bolts.

I think I have new ones that show some signs of shelf wear and wondering if they look new to you guys also or perhaps I am being too optimistic.

Safe thing to do is get two more new ones to be certain but these look new to me, CAD plating is still yellow, worn at the high spots of the bolt due to shelf wear. The dark marks on the threads are from me putting greasy nuts on yesterday.

Part of my dilemma is that I have not seen another actual new bolt or stud to make a comparison too. Have lots of used ones and they sure don't look like these two.

Dave

Dave

[Robert Lees]

Re: Need an opinion from experienced engine rebuilders

Are they to go on a certified engine? And therefore do you have the documents?

That may be a deciding factor.

Rob

[Guest]

Re: Need an opinion from experienced engine rebuilders

Rob I think you are correct. It is my least favorite answer and probably they are fine but I am dumping thousands of $$ into this agonizing over another $100 will not be fun.

I just ordered new thru bolts, cyl. nut sets (required at OH) and case bolts/nuts (many but not all of these are required at OH) from Fresno Airparts, about $230.

Dave

[Guest]

Re: Need an opinion from experienced engine rebuilders

Thanks everyone for your thoughts.

Dave

[astjp2]

Re: Need an opinion from experienced engine rebuilders

Not required for a field overhaul, just call it an IRAN (inspect or repair as necessary) and put it together. The SB is to cover continental liability. You and spend 20K for an overhaul which is worth more than the airplane or 8K and still have a good flyer.

[astjp2]

Re: Need an opinion from experienced engine rebuilders

If you don't buy new hardware also do not sign off a rebuild per the current continental manual, it requires the hardware change because of a note to apply with all service bulletins.... I know a guy who signed off an overhaul per the manual and did not complete every service bulletin and was violated, that is why engine shops have to charge so much for an engine now days if they have a repair station certificate because the faa requires them to use the current manuals and SB's. Tim

[Guest]

Re: Need an opinion from experienced engine rebuilders

Thanks Tim,

I have purchased all new hardware like their SB says.

Expensive yes, bought most of it 15 years ago so it was cheaper by today's standard.

Even got a new crank, $1300 then, more now.

Have not thought about the sign off details will give that some thought.

Dave

Dave

[astjp2]

Re: Need an opinion from experienced engine rebuilders

I have a new gpu crank that I need to get certified, that is going to cost me 1200 and I am providing the crank, I will probably reuse hardware mostly because I am building my next engine on the cheap because it will have a starter and maybe a generator. I will probably buy new cylinders though. I am also thinking of using one of those new lightweight batteries on the firewall, the one from wicks that only weighs 3 lbs, not much bigger than 2 packs of cigarettes either. Its amazing how those small batteries can start an airplane. Tim

[Guest]

Re: Need an opinion from experienced engine rebuilders

I like that battery also. I plan to do the B & C starter and that lightweight Odyssey dry cell battery.

A friend put that battery in a Cub and he got a DER to approve that data.

I am not sure that I believe that adding that battery is even a major alt.

Will likely not install the generator, no need for me.

Dave

[3Dreaming]

Re: Need an opinion from experienced engine rebuilders

If you don't buy new hardware also do not sign off a rebuild per the current continental manual, it requires the hardware change because of a note to apply with all service bulletins.... I know a guy who signed off an overhaul per the manual and did not complete every service bulletin and was violated, that is why engine shops have to charge so much for an engine now days if they have a repair station certificate because the faa requires them to use the current manuals and SB's. Tim

The privilege of rebuilding is only given to the manufacturer. Regardless of what hardware you use you should not be signing it off as rebuilt. That can lead to a violation from the FAA for performing un authorized work.

[astjp2]

Re: Need an opinion from experienced engine rebuilders

The odyssey is heavy compared to the lithium batter, the lithium is only like 4 lbs, I can get a 337 field approval to mount it on the firewall, no need to pay for the DER. Its more than a .5 lb change so its a major due to the weight and balance/equipment list change, along with the structural changes to mount it on the firewall. Tim

http://aircraftproducts.wicksaircraft.com/keyword/all-categories/-electrical-equipment-aircraft-batteries-aerovol-2?&plpver=10&pagesize=50&pagenum=1&filter=1&keyword=battery&key=product&keycateg=100&keyprod=4171&SchType=2&keyType=P

I prefer this battery

http://www.batterymart.com/p-ltx680-earthx-etx680-battery.html?gclid=CMv0lu7a1MoCFQanaQodBmUIZA

and this on is cheaper

http://www.batterymart.com/p-ltx24c-earthx-etx24c-battery.html

I like that battery also. I plan to do the B & C starter and that lightweight Odyssey dry cell battery.

A friend put that battery in a Cub and he got a DER to approve that data.

I am not sure that I believe that adding that battery is even a major alt.

Will likely not install the generator, no need for me.

Dave

[PA1195]

Re: Need an opinion from experienced engine rebuilders

Do you mount forward or aft of the firewall? If mounted forward what temperature environment would a battery experience? I've not measured it but right after flight it gets warm in there and these batteries have a tolerance range. Perhaps the battery case and firewall act as a heat sink and moderate the battery's temperature.

Edit: I see N3572T and N3576T have your firewall forward battery so there's been some use history to support the location with an AGM unit. A lithium iron phosphate unit (LiFePO4)?

Gary