6CTA8.3 engine rebuild for Sur Móvil

[Mos68x]

Thanks for the info, I’ll have to see what the options are before I do anything then.

 

[98G]

Thanks for the info, I’ll have to see what the options are before I do anything then.

One option is a full refund.

Although I'd find it instructive to compare them side by side with what's currently in the truck.

98G

 

[Jbulach]

Pull the head, hopefully you wont even need to mess with the lower end.

 

[Mos68x]

One option is a full refund.

Although I'd find it instructive to compare them side by side with what's currently in the truck.

98G

Don’t worry, I’ll be doing a side by side comparison before I make any decisions.

Pull the head, hopefully you wont even need to mess with the lower end.

I can only hope, but my luck is never like that unfortunately.

 

[Jbulach]

Yeh, lot less chance of needing the parts if you have them paid for sitting there.

 

[Mos68x]

Yeh, lot less chance of needing the parts if you have them paid for sitting there.

That’s my thoughts too. Although I did look and I found a full set of the correct piston kits for $300 so I’ll probably go that route instead. Rather be safe than sorry.

 

[Mos68x]

Finally got the hood off, now starts the real work.

 

[Buffalobwana]

Considering how much trouble she has on a small incline at my property from a stop I reckon it’s possible that it could only be a turbo issue.

I didn't read through all the pages, but I can tell you that I have taken my truck from sea level up to 10,000' and there is a HUGE difference. HUGE!!!

The biggest benefit is to turn up your fuel. The screw that gives you more fuel at low RPM's. It also gives you more smoke, but, it will get that big boy moving in those first moments from idle rpm until the turbo kicks in.

When I was at 10,000' I felt as if I was trying to pull a train! There is a thread here somewhere on how to do it. It's simple. Pop the cap off the fuel pump, loosen the jam nut, leave the socket in there, put the screwdriver through the socket, and loosen the screw. Start small, maybe one turn it's an easy adjustment. It works. Might consider a pyrometer or two and a boost gauge while you are at it since you are messing with fuel.

 

[Mos68x]

I didn't read through all the pages, but I can tell you that I have taken my truck from sea level up to 10,000' and there is a HUGE difference. HUGE!!!

The biggest benefit is to turn up your fuel. The screw that gives you more fuel at low RPM's. It also gives you more smoke, but, it will get that big boy moving in those first moments from idle rpm until the turbo kicks in.

When I was at 10,000' I felt as if I was trying to pull a train! There is a thread here somewhere on how to do it. It's simple. Pop the cap off the fuel pump, loosen the jam nut, leave the socket in there, put the screwdriver through the socket, and loosen the screw. Start small, maybe one turn it's an easy adjustment. It works. Might consider a pyrometer or two and a boost gauge while you are at it since you are messing with fuel.

My issue was twofold, my governor was set too low (basically just at the shift point) and my fuel trim screw was also set low. I’m fairly certain it had never been touched before I did it. I adjusted both (probably too much) and it woke the motor up like a big beast. I have a hill on the interstate right by my house that would drop me down to 3rd gear (about 35-40) before I did the fuel adjustment and the governor adjustment, afterwards I was able to climb the same hill at about 55-60. I did buy the pyro and boost gauges from TMG but hadn’t installed them yet before I started having issues with the motor.

 

[Mos68x]

Got to work on the engine today, pulled a few parts off. I’m almost down to the head, but it started getting too hot and I was baking on top of the truck. When it cools off I’ll do a little more after I eat some dinner.

 

[Mos68x]

Head is finally off, wasn’t too hard, just had to fit with the exhaust pipe.


Cylinders #5 & #6 are the worst, there is moderate damage on #3 piston, and none on any of the others.


Two valve seats are destroyed, both are on #5 & #6.


Every single cylinder is cracked between the valve seats.


Does look like the new pistons are identical, but I’ll find out for sure when I pull the old ones out. I’ll use my calipers and measure the burn chamber size, as well as wrist pin to piston top to see if compression ratio is different. If everything is the same then it may be an alloy, ring placement, minor design, or an oiling change in design.

 

[74M35A2]

Wow, that motor is lunched.

 

[Mos68x]

Wow, that motor is lunched.

Sad thing is, there’s only 15k on the odometer. I’m half tempted to get the rest of the stuff to do a full rebuild.

 

[74M35A2]

You're doing a great job. Looks like you'll need a replacement used head, cylinder kits, gasket set, and may as well do rod bearings since you will have them apart. It is not too hard to sneak crank main bearings in also if you want, or pull one main cap and see what one lower main bearing half looks like and make a decision.


I have a few leads to acquire a used 8.3L cylinder head from individuals and core suppliers if you want their contact or me to reach out to them. I don't think there are many 8.3's in parts status on this board, they generally stay together pretty well, and are not as old as the 250's. I just scrapped an entire 300hp 8.3L motor last fall (over-heated, non-running), got like $17 for it. Tried selling it here but no interest at the time, but kept the Bosch P-7100 14mm injection pump off of it. Also, http://www.heavytruckparts.net is a fabulous use parts resource, specific to medium and heavy duty.

 

[Mos68x]

Why don’t we trade phone #’s since I know it’s hard to get you through PMs lol

text/call me at 928 350 9048 (Leon)

 

[Mos68x]

Does anyone have personal experience pulling the radiator or camshaft? It looks like there’s only three bolts holding the radiator in place but im sure that's not right. How hard is it to pull the cam with tappets still in place? I want to inspect the cam and tappets to be sure I don’t have to replace anything there as well.

 

[WillWagner]

Cam is easy. Go to the local hardware store, get 12, 1/2 in od pine dowels. radius one end and then use a hacksaw to make a split in-line with the dowel. Forgot, you also need rubber bands. remove the push rods, drop the dowels into the pushrod hole split/radius end first, use a bit of force to push the split dowel into the tappet. Gently pull the two dowels on the same cylinder up until they stop. Use rubber bands to pinch the tops together so they don't fall down. You need to remove the lift pump, remove the 2, 8mm bolts that hold the cam thrust in place, and slide the cam out, rotating as you come out. Take a pic of the lobes after you get the cam out if you are unsure of reuse, and post them/txt them to me and i'll give you an opinion. If cam is junk, tappets must be replaced as well as the pushrods, I didn't believe the rod thing 'til I saw multiple return failures after reusing them. And yes, that is the way Cummins has you do the job, with sticks.. You will also need to remove the pump gear to get things back together, it can be pulled down, with some difficulty, with the gear on, but it will not go back together.

 

[Mos68x]

Dang John, you really don’t have anything to do, do you? Lol seems like every time I check my email to see if anyone has replied to the thread, you’ve already been in here and liked posts lol


Will, thanks for the tips! So one end of the 1/2” dowel is radius’d and split? Or is it just split? Are you referring to the oil pump or the coolant pump? (I think both sit inside the timing/accessory gear housing)

A quick search on the web yielded some expensive costs for a replacement head, about $1600/$1900 bare/populated. Anyone have any better prices? Granted those prices were for reman/new heads. I’m hoping used would be considerably cheaper since I’d still have my local shop mag them and rebuild them if they aren’t cracked.

 

[74M35A2]

I have 2 RFQ's (Request For Quote) out for a used 8.3L cylinder head right now for you. Should have prices for you tomorrow. Check the website I posted also if you have not already. The price should be much less than what you posted. Few members here had genuine rebuild kits for $1,000, which is generic white box type pricing. That, plus a used head for $500, gasket set, and bearings, you should have new life into it for $2,000.

 

[74M35A2]

PM sent to you, guy that buys rebuildable diesel engine cores. I bought a Jake brake setup for a Cummins ISL from him, unbeatable price, and included every single nut/bolt/washer/solenoid/wire/valve cover/etc that was needed to make it work.

In several seconds, I found several used heads for you from the $250-up price range on http://www.heavytruckparts.net