GEP 6.5NA replacement

[erasedhammer]

GEP 6.5NA replacement?

I was thinking about dropping in a GEP 6.5NA in place of my current 6.2. I was wondering if anyone had any experience with super high mileage gep engines and if they lasted significantly longer than thier GM counterparts?

This will probably be down the road a bit because my 6.2 only has 14k on it right now.

I'm trying to build my cucv up to a more reliable state, which would involve a stronger engine, just not with a turbo. Using the KISS method here.

 

[NDT]

My 2 cents: lots of GM 6.5s run 100’s of thousands of miles in pickups etc. But they are 2000 or older. The GEPs are 2001 and newer and have beefier castings. That alone is peace of mind. I doubt you will find a GEP in a HMMWV with over 60,000 miles.

 

[erasedhammer]

My 2 cents: lots of GM 6.5s run 100’s of thousands of miles in pickups etc. But they are 2000 or older. The GEPs are 2001 and newer and have beefier castings. That alone is peace of mind. I doubt you will find a GEP in a HMMWV with over 60,000 miles.

Yeah I was comparing GEP 6.5 to more modern engines that can go 400k+ without opening them up.
I saw somewhere that the 6.2s need to be opened up around 250k, so I would assume a GEP could go a lot longer than that?

 

[ken]

I have owned GM 6.2's and 6.5's since the late 1980's. I have gotten over 200K on more than one 6.2. There are a few things to keep in mind on keeping them around a long time. First never overheat one. Install a 180deg thermostat. The originally came with 180's when first introduced. This prevents block cracking at the rear cylinders. The coolant can't get hot enough to bubble. Next never over speed one, along with making sure your harmonic balancer is in good shape. The owners manual for my 1982 model GMS with a 6.2 states to change the oil and filter every 2500 miles. I can see where one would think this is ecessive but if GM wanted it that way back then there must be a reason. It has worked well for me for decades. IMHO oil is cheaper than engines anyway.

 

[nyoffroad]

I'm trying to build my cucv up to a more reliable state, which would involve a stronger engine, just not with a turbo. Using the KISS method here.

Your really not going get any simpler than a NA mechanical injected engine than a 6.2 and it's reliable, I have one sitting on a shelf in my garage that has a tad over 400,000 miles! I bought the truck from the original owner with aprox. 155,000 and it was never opened up. I'd still be driving it if the body and frame hadn't rusted away.

 

[erasedhammer]

Your really not going get any simpler than a NA mechanical injected engine than a 6.2 and it's reliable, I have one sitting on a shelf in my garage that has a tad over 400,000 miles! I bought the truck from the original owner with aprox. 155,000 and it was never opened up. I'd still be driving it if the body and frame hadn't rusted away.

Yeah that's my plan, na, all mechanical engine. GEP block would just add life to the truck. 6.2 is great and all, and I'll be keeping it for a while, but the base design flaws aren't very reassuring. I'll be doing cooling upgrades and such to keep it working well

Unfortunately even though my truck is very low miles is rusted bad.

 

[Sharecropper]

In my opinion, the 6.2 can be a dependable, long lasting engine IF it is kept clean and cool. The engine was not designed to handle the increased pressures and heat of a turbo charger. Keep your air filter clean and change oil & oil filter regularly. And don't red-line it. Cruise, don't cram.

Probably one of the best things you can do is to replace your harmonic balancer. And like Ken said, install a 180 degree thermostat.

If mega horsepower is your goal, you will need to change engines. But for reliability, the 6.2 is excellent.

Just my 2 cents. Hope this helps.

 

[erasedhammer]

In my opinion, the 6.2 can be a dependable, long lasting engine IF it is kept clean and cool. The engine was not designed to handle the increased pressures and heat of a turbo charger. Keep your air filter clean and change oil & oil filter regularly. And don't red-line it. Cruise, don't cram.

Probably one of the best things you can do is to replace your harmonic balancer. And like Ken said, install a 180 degree thermostat.

If mega horsepower is your goal, you will need to change engines. But for reliability, the 6.2 is excellent.

Just my 2 cents. Hope this helps.

I definitely didn't get a cucv to go fast. I bought as a project to make a reliable all mechanical vehicle.

I know the 6.2 had its head cracking issues, were those solely limited to overheating?
I suppose a radiator upgrade couldn't hurt either in addition to a 180 thermostat.

 

[cucvmule]

The radiators are big to start with. As long as they are Clean and the coolant changed on maintenance schedule as for usage, then radiator will last a very long time, unless overheating happens, then stress issues may happen.

Cylinder heads, at least on civi trucks that I have seen after teardown or viewed in salvage yards, have had cracks between the valves. Not every set of valves but at least one pair on every cylinder head that I have seen. I am talking hairline and I am looking close for them. Would I use with small hairline crack? No I wouldn't but have seen them used with years of service given.