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Author Topic: Need some engine repair advice  (Read 7601 times)
luvrbus
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« Reply #30 on: December 09, 2010, 07:05:43 PM »

Brandon, give Dale a shot (songman) he sells Interstate/McBee kits made in the USA by Federal  www.thebuspartsstore.com he may have a better price ?
 A bad fit to tight,to loose,to high,to low,cheap liners,loss of piston pin seals, heat, piston seizures several things can cause the liners to pull at the ports on a 71 series 92 series are not as bad as the 71 series for pulling the liner apart.
All diesel engine will pull a liner Cummins,Cat, M/B, S60 when the time comes not just the 2 strokes fwiw 

good luck,
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brando4905
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« Reply #31 on: December 10, 2010, 05:22:48 AM »

Rick,

Wasn't using much oil when I put it in last year, then the consumption went up in the last 3k miles. There was always a pretty good amount coming out of the air box drains. Oil pressure really low at idle. I do have a mechanical gauge in rear, at full throttle It would go up to 50 for about 2 seconds, then drop down to 40 or so still holding throttle. Rod bearings on the busted cylinder were worn down to the other layer of metal. Copper? No piston-valve interference, heads are still good, but going to have them re-worked for a little insurance.

Clifford,

I contacted Songman, just waiting for a reply. I called Nimco as well, and at the moment they are out of 8v71's. Thanks for the info.

Brandon
« Last Edit: December 10, 2010, 05:32:26 AM by brando4905 » Logged

1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
RickB
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« Reply #32 on: December 10, 2010, 07:06:37 AM »

You might want to do an oil analysis as part of your figure out why this happened plan.

I would pull the oil filter and cut it in half as well. See how much stuff was floating around in there the last 3k miles.

Are you doing the cam bearings as well?

Okay I'll quit with the questions....

Rick
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TomC
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« Reply #33 on: December 10, 2010, 03:19:55 PM »

A broken ring could have caused the cylinder liner to break in two.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
brando4905
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« Reply #34 on: December 11, 2010, 07:55:22 AM »

On the phone with a busnut yesterday, and he recommended I order a kit with the 2 piece style pistons. I forgot to ask him why! Can someone explain what the advantages of the 2 piece set-up. Those kits cost more, but if better, than that's what I need.

Rick, do I need to replace cam bearings? They are not part of an in-frame kit.

Thanks,
Brandon
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
luvrbus
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« Reply #35 on: December 11, 2010, 08:03:05 AM »

Brandon, use those only if you have plans to turbo the engine those are 17:1 compression you have 18:1,your guy can check the cam bearing I doubt if you need those they don't wear much, changing those babies it becomes a major job 


good luck
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brando4905
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« Reply #36 on: December 11, 2010, 08:06:15 AM »

Copy that Clifford, thanks. That keeps the kit costs down a little.
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
wildbob24
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« Reply #37 on: December 11, 2010, 01:21:09 PM »

Brandon,

The cross-head pistons are available in both compression ratios. They are better in a number of ways:

The slipper type piston pin bushing provides twice the surface area as the bushings in the trunk piston which eliminates premature bushing wear.

Because the two pieces can react independently to the forces involved, there is less piston slap. So they are quieter and less prone to scuffing and you get reduced ring and groove wear.

There is increased lubrication and cooling of the piston crown.

All of this generally means extended life for the piston and cylinder.

That being said, when we spoke on the phone yesterday, I forgot that in order to make this change, you will have to replace the connecting rods, as well. This will add more cost of the overhaul.

If it was me, I'd spend the extra money for the upgrade, but I wouldn't be paying a mechanic to do the work, which, of course, makes a huge difference to the wallet.

Your mechanic may be able to source some used rods that could be checked by his machine shop and resized if neccessary. He's cutting you a pretty good deal.....in the end I'd go with what he's most comfortable with.

Bob
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luvrbus
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« Reply #38 on: December 11, 2010, 01:33:19 PM »

Do what ever you choose Brandon but Cross/Heads are a waste in a 71 600 bucks for rods and bolts rebuilt with out the core.
Talk to your guy if your engine has cross/heads go back the same just be sure and gauge the dome for the right compression no telling what a aftermarket kit will have.
You need to wait to order anyway till he gets the engine tore down to make sure you don't need oversized bearings and liners


good luck
« Last Edit: December 11, 2010, 02:38:58 PM by luvrbus » Logged

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brando4905
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« Reply #39 on: December 18, 2010, 05:46:30 AM »

Here's an update,

After thinking really hard about which pistons to use, I decided to just go back with trunk style, wanted to use the cross-head pistons but just couldn't justify the extra expense right now. My mechanic had the correct rods, but they were in another engine. He would have pulled them for me, but that would have been more labor, and the 2-piece kit cost a good deal more. If I was rebuilding a truck engine to make money with, I would have gone with the new technology. I think the original set-up is going to be fine in my bus used as a motorhome.

Received all my parts yesterday, picking up my rebuilt heads on Monday and dropping them off with my mechanic. Can't wait to get it all put back together!

Brandon
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
luvrbus
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« Reply #40 on: December 18, 2010, 06:00:31 AM »

Brandon, tough to throw old smiling Ben into those old engines you will be fine with the standard setup it worked for 40 years ,me I do not like that rubber o-ring between the the dome and skirt 


good luck
« Last Edit: December 18, 2010, 06:05:02 AM by luvrbus » Logged

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brando4905
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« Reply #41 on: December 18, 2010, 06:13:59 AM »

Clifford, yeah, the way my "bus luck" has gone, I might as well have had the sliders open and and let the Franklins fly! Shocked

Oh, and for what it's worth, all my new parts are Interstate-McBee. Good 'ole American company, but the part boxes say "Made in Korea". Huh But that's ok, I drive a Subaru, and own a Toyota truck, and the one vehicle that has been in the shop is the F550 Ford!

Brandon
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
Gary LaBombard
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« Reply #42 on: December 18, 2010, 07:17:01 AM »

Brandon,
I am just now following this thread, it is probably a late reply of any kind to you now but knowing that you live in NC, the suggestion that Kyle gave you to look up or call Gene Russel who lives in Mill springs, NC is about a solid advise as I can suggest also.  This guy is phenomenal, he can assemble a bicycle with a turbo and be a two stroke at that!!  No kidding, I love this guy and his mechanical knowledge.  When you talk to Gene, he is soooo laid back, you are  probably thinking, (wow, I wonder how much Sour Mash this guy made) but man are you in for a surprise as to what a nice guy he is and how much knowledge he as as soon as he speaks.

Anyhow, if you got your engine rebuilt and finished and want a tune up etc. at any time, consider contacting Gene and be prepared for a pleasureful visit and receive great workmanship from him.  I only hope when I am finally ready to crank up my Eagle, after 8 years on blocks, to try and have Gene come here for a weekend to visit and also check over my two stroke before firing her up. 

Good Luck Brandon on your decisions, everyone is trying to help you out up and down the coast and between two coast at that.  Let us know of your final work that has been completed and hopefully it will make your travels much more pleasant and hopefully not at the cost of what I am seeing above.  WOW!!  $25K to replace my engine, I would contact 4 Illegal Aliens with torches if that happens to me!!  Only kidding, only kidding.

"Gary lee"
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Gary
brando4905
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« Reply #43 on: December 18, 2010, 07:31:45 AM »

Gary,

I keep hearing that Gene is a really good mech, and a good guy. Can't wait to meet him one day, his shop is about the same distance away as David's from me. I feel pretty comfortable with the mechanic I have, but good to now I have choices around here.



Good Luck Brandon on your decisions, everyone is trying to help you out up and down the coast and between two coast at that.  Let us know of your final work that has been completed and hopefully it will make your travels much more pleasant and hopefully not at the cost of what I am seeing above.  WOW!!  $25K to replace my engine, I would contact 4 Illegal Aliens with torches if that happens to me!!  Only kidding, only kidding.

"Gary lee"

Yeah, the folks and help offered on this board is amazing! I hope one day we can make it to a rally to meet you awesome busnuts.

As for the inframe rebuild costs, I'll have right at $5k in it.

Brandon
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1980 GMC H8H-649  8V71/V730 Marion,NC

"The highway is for gamblers, better use your sense" -Dylan
Gary LaBombard
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« Reply #44 on: December 18, 2010, 07:49:59 AM »

Brandon,
It is good to know you are happy with your mechanic and trust him as well.  Good luck again, the price on your rebuild is pretty good to me, safe traveling to you and family, have a Merry Christmas and Happy Holiday season.

"Gary Lee"
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Gary
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