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Block Filler & Piston Clearances

bobbiemartin

Author of The DB2 Conversion Guide
Messages
567
Reaction score
22
Location
Jacksonville, Florida
I'm rebuilding a GEP engine and have been reading about block fillers. I have read Bill Heath's post and some general info on the web. Has anyone done this to their engine or anyone running a filled block form Bill? I admit its intriguing, but not sure I really want to experiment with this block. From what I have read on other V8's, it does not change the water temp, but causes the oil temp to increase which causes the main bearings to run hotter.

I'm also wondering about piston clearances. Bill says 5 to 5½ thousands, which is about a thou or so from stock. That part is easy, but what about ring gaps? I could file down oversize rings for the compression rings, but not on the oil rings. Anyone increased their piston wall clearances?
 
Bill told me he fills his ithin 1" of the top of the block so freeze plugs are totally covered.

if you fill it that high (and I know bill knows what he is talking about) how do keep the piston bores cool?

don't need a coolant passage block heat ........ I much prefer the tank style heater I had on my Land Cruiser .... no choke (dual webbers) it would start down to 5*F...... Just took 30 min to warm up and I only had to drive 6 miles. use the tank style coolant heater and it would start I don't know .... the coldest I seen it here -15*F and it would start ...... plus it was instantly warm

think maybe a tank style heater and a pad on the oil pan and cold weather starting would be covered.... or that heater that goes into the lower hose ..... My SideKick has one of those ..... haven't used it yet.
 
Had not thought about the block heater, but that is a good point. I rarely ever use it in Florida but have a couple of times, once on vacation. As you point out, there are other options if I really need one.
 
I hate to sound dumb, but then why do the factories provide so much block cooling?
I don't know for sure but my best guess is that the block cooling is a pretty much standard design. But the IDI heads run much hotter than normal heads.
 
I would use rings for what ever over bore you have,to tight and the ends can butt when they get hot. I also talked to Bill about block fill I looked at my 6.5 on the engine stand with the heads off and couldn't figure out how to get water from the pump if it is block filled 1 inch from the top,maybe he drills the filler back out,for the water pump,my next one will probably get block filled,seems to be alot of cracked 6.2,6.5 blocks,my 6.5 has cracks. Can't imagine .005 causing piston slap.
 
Sounds good,may be I should pull my 6.2 now and do it before its to late,be alot of work, I could set it beside the wood stove to cure.
 
I would use rings for what ever over bore you have,to tight and the ends can butt when they get hot. I also talked to Bill about block fill I looked at my 6.5 on the engine stand with the heads off and couldn't figure out how to get water from the pump if it is block filled 1 inch from the top,maybe he drills the filler back out,for the water pump,my next one will probably get block filled,seems to be alot of cracked 6.2,6.5 blocks,my 6.5 has cracks. Can't imagine .005 causing piston slap.

I don't remember hearing it being 1" from the top. Here is a thread from another member from another site on a rebuild using a block filler. http://www.dieselplace.com/forum/showthread.php?t=239385

If it's not in this thread use search to find another, I know he had more than 1.
 
Bobbie - phone Bill and get the information straight from the horse's mouth. He will gladly talk to you about it!

No offense to the membership here, but in reality, the opinions you get here mean nothing unless they are coming from someone with some experience with the block filler.
 
Just got off the phone from a long conversation with Bill. A real nice guy. He basically said I wouldn't gain much filling the block in my application and to run stock piston clearances. He suggested 2-3 months for the block filler to cure if you really want to do it right. But if you are going all out, a filled 6.2 block would make sense. So, I'll leave the block fillers to the others and just build this one as is.
 
Clearances.

As for filing an oversized ring, you're out of luck there, as there isn't an oversized ring for these engines. The only way you'd get one would be to get a set of rings from Total Seal. I'd only use Total's Top and Second ring, their oil ring sucks and they are all file to fit.

The clearance will increase on the ring end gap, but not terribly. You will find that on STD bore the gap will still be in range if you open it up more.

.005" to .0055" is acceptable.

On a piston oil spray block you really want to be running .004" 1-5 and .0045" on cylinders 6-8, seriously. The piston oil spray really does help the pistons and their skirts from swelling. Many of the engines I've torn down that had the piston oil spray cooling have always been tight on the bore size. Even so that i was able to hone out one of them out to .004 and .0045, it was actually tighter from factory, no scuffing. It's the block that's in the drag truck, I like the piston oil cooling, still no scoring in the cylinders with excursions into the 1500*F EGT range for 1/4 mile times.
 
Fair enough!

I am sure you got more out of the conversation than just information about the block filler....he knows his stuff....
 
I would want as much cooling as possible. Although head temps may be the highest, cylinder wall temps are important too for proper ignition timing.
 
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