I worked for many years at a boat repair facility. We had a customer with a twin 4-71 powered cruiser who said that both engines were smoking heavily, and had no power. He did not want anything diagnosed. He just wanted modern engines in the boat. When the boss went to the boat to start the process of figuring out what all needed to be ordered for the job, he found that both of the intake dampers had been tripped. When the job was done, the customer had modern 4 stroke engines, and we had a pair of perfectly good 4-71s.
@@bobbybackpain As I said, the owner was not interested in discussing the original engines at all. He wanted no diagnosis, only replaced with modern engines.
@@bobbybackpain no, the Customer wanted a repower with modern engines, and that's exactly what he got; and the customer likely didn't care what was done with his old 4-71s because according to him they were worn out junk.
Put a 471 in a displacement hull with a keel cooler and it will run for 30,000 hours or more. Great engines, they just need a bit of soundproofing on the floor. I've had both 471s and 6V53s in my fishing boats and go out to sea with no auxiliary and they always get you home. I feel like the poor things get abused twinned up in planing hulls.
@@BusGreaseMonkey So they must have changed the blowers design at some point it seems. At least the new blower looks much better and the blades don't look pitted and scraped.
...what continues to amaze me is the memory you have Scott, all these little details about parts... there is more that just your years of knowledge up in that noggin.....
I do continually refer to the manual to double check my memory. Like the perimeter oil seal on the head. It’s got a green stripe on one edge. I said i think it goes outwards away from the cylinders but i double checked. I was correct.
The wizard of Oz, working miracles on Lenny...lookin good..yep never fails on parts, Got to figure for murphys law. Lol..soon you,ll both be on the road, smilin large. ✌️❤️😁
I haven’t been around working on a Detroit in decades and you brought up checking the wrist pains retainer cups with a vacuum gauge. I completely forgotten about doing that. I knew about punching a hole in the center to pop them out but checking the new installation with a vacuum gauge, that was a flash back moment 🤪😂👍
Been a while since I turned wrenches but now I got to find out what you are talking about! Why not just use a c i r c l i p? Vacuum gauge for wrist pins..... I just got to know!!!!
There is oil pressure behind the wrist pins. If you have a leak pressurized oil enters along the piston wall. Very smoky mistake. The piston rods spray oil against the inside of the pistons for cooling.
We had a 6V71 with a roots supercharger in our quarry truck! It was a screaming son of a ######! I read somewhere that the 6V71 stood for V6 with 71CI per cylinder!
which comes to 426 cubic inches. So they made really good power in the late 30s when the 6-71 was first made. For modern standards, they were a tiny engine for a truck or bus. Today they run 14-15 liter engines.
Bus Grease Mountain driveway is Scott's built-in chassis dyno and brake tester. No bus leaves until it can climb to the top and safely stop on the way down.
Wow, that polish sure does a good job. Love the detail on the 6-71 rebuild. Not sure, does Jonathan always talk so much? (Humor). Thanks for the videos
Those 2 stroke diesels don't rev that high. They sound like they do. If its reving at 2g's, it sounds like it's reving 4g's. Two valves are usually sufficient. 😄👍
since they are all exhaust valves they seem to do fine, but, sure a 4-valve head would be nice. This is Scott's old head from when he upgraded to a 4-valve
Making good progress. At 2.18 in the video you seemed to align the ring gaps. Is that a Detroit diesel thing? Also you said the mains were turned 0.030" over. I think it should be under size.
He said it has .030 oversized bearings and those were as big as you can get them these days. The crank has to be .030 undersized to fit .030 oversized bearings.
I have been watching you from the beginning. But I'm curious I was sick for a little while and I missed some episodes where is Tyler. And who is the new guy
Do you have any tips for a crown school bus 530k miles on it? I’m going to build a tool list based on your video from earlier this year. I’m watching and learning how to adjust and maintain the bus. Also I’m thankful you guys make great videos on how to rebuild these engines! Also my bus engine is mounted on its side to fit in the middle of the bus. It’s a 6L71T 275 horse engine with a 4 speed Allison. I’d like to covert this bus to have the fire truck specs and a 6 speed Allison in the future.
@@BusGreaseMonkey Check out "Al Jennings Crown and Gillings Bus Collector" He's driving around a Crown in LA. The video is 2 years old. Great sound of that 6-71. 🚍👍
Do you measure the bore of each cylinder in the block to verify the bore size and check for tapered or out of round cylinders? Do you measure the rod bushings with a pin gauge to check for wear before installing new pistons onto rods? I don't remember seeing either of those procedures in any previous videos on this channel.
when you talk about this being a left hand rotation engine, on the detroits, is that looking at them from the flywheel end of the motor, or the fan end of the engine?
In this gm bus the detroit diesel is a reverse rotation setup. A very small percentage of detroit diesel 671’s are left hand rotation. Most Gm buses and boats are about the only uses for ccw rotation engines
Scott and Tyler did Lenny's inframe in 2019 in front of the house in Indy. Then he's been parked for three years. So yeah his engine is still pretty fresh.
At 2:18/2:19 the top compression ring have their gaps aligned. Time to fix that. Tell me you fixed that before putting the cylinder sleeves in the block!
I worked for many years at a boat repair facility. We had a customer with a twin 4-71 powered cruiser who said that both engines were smoking heavily, and had no power. He did not want anything diagnosed. He just wanted modern engines in the boat. When the boss went to the boat to start the process of figuring out what all needed to be ordered for the job, he found that both of the intake dampers had been tripped. When the job was done, the customer had modern 4 stroke engines, and we had a pair of perfectly good 4-71s.
Sounds dishonest to me
@@bobbybackpain As I said, the owner was not interested in discussing the original engines at all. He wanted no diagnosis, only replaced with modern engines.
@@bobbybackpain no, the Customer wanted a repower with modern engines, and that's exactly what he got; and the customer likely didn't care what was done with his old 4-71s because according to him they were worn out junk.
That´s perfect, exactly what I would have done!
Put a 471 in a displacement hull with a keel cooler and it will run for 30,000 hours or more. Great engines, they just need a bit of soundproofing on the floor. I've had both 471s and 6V53s in my fishing boats and go out to sea with no auxiliary and they always get you home. I feel like the poor things get abused twinned up in planing hulls.
The blower end plate being totally different was a total surprise. Lenny is looking really nice. Not long until we hear the 6-71 run like new.
Lenny has the same plate as the new blower.
@@BusGreaseMonkey So they must have changed the blowers design at some point it seems. At least the new blower looks much better and the blades don't look pitted and scraped.
...what continues to amaze me is the memory you have Scott, all these little details about parts... there is more that just your years of knowledge up in that noggin.....
I do continually refer to the manual to double check my memory. Like the perimeter oil seal on the head. It’s got a green stripe on one edge. I said i think it goes outwards away from the cylinders but i double checked. I was correct.
Lenny looks AMAZING! That old boy is going to turn some heads.
Great mentoring for the young man, he's been learning a lot.
BTW where's his son? Open his own shop?
Tyler moved back to Indianapolis for a different career path and isn't wrenching anymore.
Even with setbacks you are still the Detroit Diesel master and 2 Stroke whisperer.
Lenny is looking nice too!
With noticing the end of the blower being wrong that late, thats like a "hey lance" moment? Lol.
That's hilarious.
The wizard of Oz, working miracles on Lenny...lookin good..yep never fails on parts,
Got to figure for murphys law.
Lol..soon you,ll both be on the road, smilin large.
✌️❤️😁
I allways replace the main bearings with the cylinder kits out as you can check it spins free after replacement 👍🙂
Lenny is looking amazing! Gosh darn on the blower cap but it’s a fixable issue and Lenny gets a bit of extra lovin’ in the meantime. 👍🏻 👍🏻
Nice to see the young feller learning the trade without us old goats passing on stuff so much will be lost
I'm chomping at the bit, cant wait to hear it run.
Scott, you are a patient teacher. Johnathan is getting a college degree from you. Great job.
Quality work ! Wish there were more mechanics shops for any vehicle like yours, that puts quality of workmanship first !
Have a Blessed Day
That is why Jonathan's services will be in high demand for years to come by people with fat wallets.
Very lucky young man. Getting all that training 🦘
Love me some of that new Detroit Diesel green paint.
Lenny is looking so good
A professional is someone who makes something hard look easy. You sir are a professional.
👍🏻👍🏻 Lenny looks great
Wonderful job on both busses! Congrats.
I was just wondering about Leroy your Saint Bernard. Did I miss something. I always enjoyed the videos he was in. Beautiful dog.
Great job on both these buses👍
I haven’t been around working on a Detroit in decades and you brought up checking the wrist pains retainer cups with a vacuum gauge. I completely forgotten about doing that. I knew about punching a hole in the center to pop them out but checking the new installation with a vacuum gauge, that was a flash back moment 🤪😂👍
Been a while since I turned wrenches but now I got to find out what you are talking about! Why not just use a c i r c l i p? Vacuum gauge for wrist pins..... I just got to know!!!!
There is oil pressure behind the wrist pins. If you have a leak pressurized oil enters along the piston wall. Very smoky mistake. The piston rods spray oil against the inside of the pistons for cooling.
Can’t wait to see it make it up the hill
We had a 6V71 with a roots supercharger in our quarry truck! It was a screaming son of a ######! I read somewhere that the 6V71 stood for V6 with 71CI per cylinder!
which comes to 426 cubic inches. So they made really good power in the late 30s when the 6-71 was first made. For modern standards, they were a tiny engine for a truck or bus. Today they run 14-15 liter engines.
Scott fixing it Right..
👍😎💯
Is your first test going to be pulling the hill it couldn't get up before? I can't wait to see that if you do Scott.
Bus Grease Mountain driveway is Scott's built-in chassis dyno and brake tester. No bus leaves until it can climb to the top and safely stop on the way down.
Lenny looks gooooood!!!
Great Scott ! 😅
I've never seen so many buses/schoolies in one location. Quartzsite AZ
I see your now using graphics on your thumbnail pics like lots of folks do. Looks good and professional!
The design of these engines are so bizarre but very interesting to me
Mr Kettering was a pretty amazing fellow.
Wow, that polish sure does a good job. Love the detail on the 6-71 rebuild. Not sure, does Jonathan always talk so much? (Humor). Thanks for the videos
A four valve head would be nice. I am surprised the valves are so small on these engines.
Those 2 stroke diesels don't rev that high. They sound like they do. If its reving at 2g's, it sounds like it's reving 4g's. Two valves are usually sufficient. 😄👍
since they are all exhaust valves they seem to do fine, but, sure a 4-valve head would be nice. This is Scott's old head from when he upgraded to a 4-valve
keep the clips coming
great Video !
Good job
NSK, nice!
Making good progress.
At 2.18 in the video you seemed to align the ring gaps. Is that a Detroit diesel thing? Also you said the mains were turned 0.030" over. I think it should be under size.
He said it has .030 oversized bearings and those were as big as you can get them these days. The crank has to be .030 undersized to fit .030 oversized bearings.
I have been watching you from the beginning. But I'm curious I was sick for a little while and I missed some episodes where is Tyler. And who is the new guy
You replace lots of cylinders but I don't recall you pulling a cam or lifters. Do those not go bad?
If they wear out over time but most engines are murdered vs dying of natural causes. Heat doesn’t take out the cams.
Wow nice work ! Is Tyler still with you. ?
Did you just put a little grease on both sides of the coolant O rings to keep them in place? Getting ready to re assemble my 3-71.
Jif peanut butter is my favorite brand.
Do you have any tips for a crown school bus 530k miles on it? I’m going to build a tool list based on your video from earlier this year. I’m watching and learning how to adjust and maintain the bus. Also I’m thankful you guys make great videos on how to rebuild these engines! Also my bus engine is mounted on its side to fit in the middle of the bus. It’s a 6L71T 275 horse engine with a 4 speed Allison. I’d like to covert this bus to have the fire truck specs and a 6 speed Allison in the future.
Don’t over heat the engine 180° is normal operating temperature. Watch oil pressure and water temp gauges continuously.
th-cam.com/video/MZdfIaPlxKg/w-d-xo.htmlsi=vSVU8_ZCtjflTq_e
@@BusGreaseMonkey can I also get invited to your website? I submitted a form but still haven’t received a link yet.
@@BusGreaseMonkey
Check out "Al Jennings Crown and Gillings Bus Collector" He's driving around a Crown in LA. The video is 2 years old. Great sound of that 6-71. 🚍👍
@@henrys.6864 I do follow him fb and TH-cam. He doesn’t have any building and tune up guides. Lots of driving videos though
Do you measure the bore of each cylinder in the block to verify the bore size and check for tapered or out of round cylinders?
Do you measure the rod bushings with a pin gauge to check for wear before installing new pistons onto rods?
I don't remember seeing either of those procedures in any previous videos on this channel.
when you talk about this being a left hand rotation engine, on the detroits, is that looking at them from the flywheel end of the motor, or the fan end of the engine?
In this gm bus the detroit diesel is a reverse rotation setup. A very small percentage of detroit diesel 671’s are left hand rotation. Most Gm buses and boats are about the only uses for ccw rotation engines
A convenient problem 🤣😂
Why would anyone not use you for their drive train work is beyond me!
Both classic buses getting a different extended lease on life . They both will be around for many more years
Scott and Tyler did Lenny's inframe in 2019 in front of the house in Indy. Then he's been parked for three years. So yeah his engine is still pretty fresh.
Just wondering, why weren’t the wrist pin bushings changed ???
Because they were very low miles and wear. The engine died of murder not old age
Is that a reman blower ?
Yes
Is everything ok with Tyler ? have not seen him in any videos.
Where’s Tyler?
Where is Tyler these days?
At 2:18/2:19 the top compression ring have their gaps aligned. Time to fix that. Tell me you fixed that before putting the cylinder sleeves in the block!
Thanks for playing but there are 4 rings on top.
"Connecting rod"
At min 4:10 it is a fine crack in the block or just look like?
Casting mark
👍 Nice work !
👍👍👍🇨🇭
Where is Tyler??
Where's Tyler
Dod you bore the block & put oversize liners ??
Be kinda hard to bore the block since it was an in frame rebuild.
What happened to the Dog
True we have not seen him for months
What happened to the audio, on the video
Works for me
@@BusGreaseMonkey I did find the problem.thought it was the video..
Do you not have to measure cylinder protrusion on these engines...
Did you not watch the video ??? It showed him using a mic to check protrusion.
favorite peanut butter GM special lubricant 12345879
5198563 is international compound #2