The Forestry Forum

General Forestry => Forestry and Logging => Topic started by: LeeB on June 03, 2015, 06:13:47 AM

Title: Ring gear on 8V-71 Detroit flywheel
Post by: LeeB on June 03, 2015, 06:13:47 AM
Just a question for you guys. How does a body change the ring gear on an 8V-71 Detroit flywheel? The engine is on an offshore crane. The diesel shop that my company uses says we need to send in the motor for them to do it. I'm calling BS.
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: snowstorm on June 03, 2015, 08:10:43 AM
take the flywheel off. usually its a shrink fit. heat it to take it off the same to put the new one on
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: scsmith42 on June 03, 2015, 08:35:27 AM
What Snowstorm said.  I've never done a Detroit, but from what I've seen of their flywheels they use the same press-fit design as everybody else.

I use an air hammer with a blunt nosed bit to press the old ring gear off, and use a cutting torch to heat the new one to expand it before dropping it in place.  Final adjustments into position can be made with a flat nosed punch and a hammer.  Usually the gear is heated to a dull red (it doesn't take much).

In a pinch you can usually remove the old ring gear, turn it around and reinstall it.
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: LeeB on June 03, 2015, 08:45:18 AM
I suspected as much. I certainly couldn't see any reason to send in the whole engine just to change the ring gear. I have no idea how much they want to charge us to do the job. Several thousands I'm sure. Just had the engine overhauled and it was 93 grand. I about crapped myself when I heard that. Could have bought a new one for that price. Finding one and getting it here is a whole other story and we couldn't be down that long. The cranes are an integral part of the operation.
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: starmac on June 03, 2015, 10:36:54 AM
93 grand to rebuild a 318 detroit??? Something is bad wrong with that picture.
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: ga jones on June 03, 2015, 10:52:18 AM
8v71na are a dime a dozen around here.
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: LeeB on June 03, 2015, 10:53:49 AM
Welcome to oilfield prices in Saudi. I asked my boss today if I could sell the company a few rebuilts. I can sell them 5 with a years warranty for that price. Not quite sure what it would cost me to get them over here and through customs.

Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: BW_Williams on June 04, 2015, 10:04:49 AM
Lee, can you use a propane torch on site?   Send me a plane ticket! 
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: coxy on June 04, 2015, 12:45:11 PM
holly bat doo doo robin :o :o back in the day I think my dad only paid 8-9k for one from GM cant remember if it was new or remand  but that was back in 80-81
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: LeeB on June 04, 2015, 01:04:08 PM
I was quite shocked myself when I found out how much they paid. I only found out by chance when I asked for the quote on the flywheel and the materials man sent me the overhaul quote by mistake. I really freaked then thinking it was $93k for the flywheel and started digging deeper. Trying to convince my boss that we can do this out here ourselves and save a ton. More money the company has the more than can pay me.
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: BW_Williams on June 04, 2015, 01:37:33 PM
How much is a round trip ticket from Pangborne International to whereever you are!  But i got a Dr appt on next Tuesday:)
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: BW_Williams on June 04, 2015, 02:06:56 PM
Better yet Lee, i have a 471 4 stroke id swap ya for a 2 stroke!   I could just swim it to ya!  Which way is closer, East or West?  :)
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: LeeB on June 04, 2015, 03:11:55 PM
you don't want to come here.
Title: Re: Ring gear on 8V-71 Detroit flywheel
Post by: WH_Conley on June 04, 2015, 04:08:05 PM
Last press fit I did was on a John Deere. Layed the ring on the wood stove about 10 minutes. Slid right on. Had to peck it for final adjustment. Same thing works for bearings. Take torch and heat a piece of steel, preferably thick, and lay the bearing on it. If on a shaft where it can be moved put the shaft in the freezer a couple of hours first. Dry ice works great. Have to work fast though.