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Rebuilding a GEP Engine

Spent some time today cleaning up the block and smoothing out the rough cast edges. I'll be taking the block out to the machine shop in the morning.

GEPWPPlate.jpg

GWPWPPlate2.jpg

Here is the water pump backing plate. Its like new.

GEPoilpump2.jpg

Even though this is an oil squirter block, the oil pump does not have a sandwich plate. Anyone know if the changed the design to a deeper one piece pump?


GEPOilPump1.jpg

I'm not sure if this pickup will fit a truck oil pan. I bought a new oil pan off eBay for a good price, should be here this week. Once the block gets back, I'll see how the pump fits.
 
When I swapped mine, I used the old pump. The tolerances were good, and I wasn't about to try to swap the pick ups. The pick up and pump did not work with my existing pan in my suburban. My "new" motor with the "old" pump make plenty of PSI.
 
bobbiemartin said:
I took the engine apart today. I'm convinced this engine has never been run, except maybe on a test stand when built. Everything is basically as new. The only problem I see is one of the cylinders that had the rust from the water intrusion may be pitted beyond what honing will clean up. I just cannot tell. I will be taking the block over to the machine shop on Monday and see what they say. Other than that, I really believe I could reuse everything in the engine. I spent some time removing the casting flash from the oil drainback areas of the block, still have a bit more to do. There is also some down by the lifter bores so I'm going to try and get that tomorrow. Also had to grind down one of the mounting lugs under the motor mount. Mine hit one of the extra lugs there, it must be for a HMMWV or something.

GEPMainsaddes.jpg

No cracks and not much dirt, it looks real clean. You can just see the casting flash between the back two cylinders.
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Yup i totally agree with it not being ran much at all, i dont think all the piston tops were even black!! Everything i saw looked new or nearly new, kinds odd though about the oil pump as that's the one it came with. Looks just like i remember it looking, hope the machine shop give ya good news. :eek:)
Don
 
After thinking about this, I'm wondering if because it was a non-turbo they figured the standard pump would be OK with the squirters? I guess I should install a high capacity oil pump as I'm adding a turbo.
 
bobbiemartin said:
BTW, I ordered a set of ARP head studs yesterday. Can someone verify, I think the main & rod bolts are reusable, not TTYs?
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You'll regret the head studs. I don't think there is a way to reliably seal these things long-term.

As for the verification, you can reuse the main bolts, no problem. You can use the rod bolts, no reason not to use them if the engine is low mile or just a test run.

About your oil pump. I noticed yours had the standard volume pump in it, very odd. My train of thought was any block that had the squirters should have the high volume pump.

Check the main bearings to see if they have the holes in them to allow the squirters to be used. I know for a while you could use the 6.2 main bearings without the holes for the squiters to block off the holes. It's possible AMG still does or did this in their N/A engines.

Compare the oil pump pressure regulator springs in your AMG pump to one out of your original 95 engine (or other 6.2 or 6.2 standard volume pump). Maybe it's calibrated for more pressure.
 
Was thinking one of Bigley's threads elsewhere said the NA GEP blocks didn't have oil squirters for the front cylinders?

Does your block have squirts just on the rear cylinders?
 
chevydiesel said:
Check the main bearings to see if they have the holes in them to allow the squirters to be used. I know for a while you could use the 6.2 main bearings without the holes for the squiters to block off the holes. It's possible AMG still does or did this in their N/A engines.
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That is a good point, I'll look at the bearings.
 
Just got the call from the machine shop, it had to be bored 20 over. I'm not sure if it has to be decked yet. Regardless, I ordered a set of pistons that are 10 thou less deck height, so I'm hoping I will keep the standard deck. That will give me around 20.5:1 compression. That should help a little bit. If anyone needs any like new standard pistons & rings, let me know! I also ordered a new oil pump for oil squirter blocks. Crank was fine though, so will go back with standard bearings. And my new truck oil pan I bought a on eBay for cheap came today.
 
chevydiesel said:
Still curious about the bearings...

Had to be bored? Was is rusty?

J
Click to expand...

First on the bore, yes it was rusty in one cylinder. It could have been sleeved and the rest would have been OK, but I thought a bore to 20 over was the best route.

On the bearings, you were right about the oil holes. I spoke to Jamie at Diesel Depot and he told me the same thing, the main bearings do not have holes for the oil squirters except the rear bearing. It does allow oil, I guess because they run hotter than the others. So that explains the standard oil pump. Incidentally, one main bearing (just one shell, not both halves) is .013" undersized. In speaking to Peninsular, I was told this is quite common, in fact he said that they almost never see all the same size mains. At the factory they mix and match bearing shells on every journal to get them as close as possible. He also said the number stamped on the block on the main bearing webs has something to do with the bearing size.
 
As I expect you'll be running this engine turbo'd, do you plan on swapping in bearings that allow squirter feed/function on the remaining cylinders?

Trying to think if there's any disadvantage of doing so, when you'll have the higher volume pump anyway? As the squirter cuts are already there, I'd think the only advantage in not using them would be going w/ the lower volume pump & saving the difference in power required to drive the larger pump.

btw - my mains also had the mix-n-match select fit using std & the 0.013 shells
 
SmithvilleD said:
As I expect you'll be running this engine turbo'd, do you plan on swapping in bearings that allow squirter feed/function on the remaining cylinders?

Trying to think if there's any disadvantage of doing so, when you'll have the higher volume pump anyway? As the squirter cuts are already there, I'd think the only advantage in not using them would be going w/ the lower volume pump & saving the difference in power required to drive the larger pump.

btw - my mains also had the mix-n-match select fit using std & the 0.013 shells
Click to expand...

Yes going turbo, so switching to oil squirter bearings & HD oil pump.
 
Anubis said:
so how do you size replacement bearings?
Click to expand...

The easy way is you tell Peninsular what you have and let them do the work. The hard way is you (double) check them when you assemble the engine. Since the crank is basically new and I have the old bearing sizes, it should be as close as it was from the factory - at least in theory! We'll see if that plays out.
 
I picked from a set of std & 0.001" (if memory serves) main bearing sets.

With the help of a friend that owns a race engine building & machine shop, we torque things together, measure the ID's. Then measure the crank OD's. Calculate the clearances & pick bearings as necessary to get as close to the target/desired clearance as possible.

I don't do this stuff that often, I always end up confirming w/ plastigage also.

My crank's rod journals were pretty consistent (within 0.0002" which is near the limit of measurement error)

2.3985 (0.1264) 2.3985 (0.1264) 2.3987 (0.1262) 2.3987 (0.1262) 2.3986 (0.1263) 2.3986 (0.1263) 2.3986 (0.1263) 2.3987 (0.1263)

So resized the rod's big end & std bearings made for very consistent clearances across all 8.
 
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