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MGA Race Engine - Resurection - Ghost Main :)-D

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MGA Race Engine - Resurection - Ghost Main :)-D

 
Old 03-01-2019, 04:11 AM
  #11  
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I think my crankshaft was the first (and only) MGA/MGB hybrid crankshaft that Marine Crankshaft has built. Thus, one disappointment was that the crankshaft conflicted with the oil pump.

Shortly after ordering the crankshaft, I anticipated an oil pump clearance conflict. I mocked up a spare block and crankshaft that demonstrated how tight the clearances were on a stock engine and sent these off to Marine Crankshaft with some measurements and a follow up call.














From the call, I had the impression that Marine had an off-site engineer who drew up the design for the crankshaft that was used in the manufacturing process. I'm not sure my email ever reached him. In any event, the crankshaft as delivered did, in fact, conflict with the oil pump.

Consequently the machine shop was confronted with the problem of modifying the crankshaft.

First, the oil pump boss casting on the block was damaged somewhat when the original crankshaft broke. The side towards the rear of the engine had a substantial gouge. So that needed to be cleaned up and the boss flattened anyway.

The shop (Carlquist Engines) modified the oil pump boss. At it's narrowest point, they reduced the boss from about 0.395" to 0.307" . Above the lower edge (below in the two pictures) the side of the triangle was also shaved a bit.








I also gave the shop a new oil pump. They shaved down the two sides of the oil pump itself.








The more critical modifications were to the crankshaft. The #6 and the #7 counterweights were shaved to clear the oil pump boss and the oil pump.

Although the outside edges of the counterweights came with a slight chamfer, the nominal thickness of the #6 counterweight appeared to be 0.546". This was ground down to approximately 0.226" on the very outside edge, 0.260" at the chamfer, and the grind extended approximately 0.529" deep.



The nominal thickness of the #7 counterweight appeared to be 0.556". This was ground down to approximately 0.275" on the outside edge, 0.396" at the chamfer, and the grind extended approximately 0.483" deep.





Future design modifications for the #7 would also need to factor in the adjustment to the oil pump boss, so perhaps the grind on #7 should be a bit greater if the oil pump boss is left alone.

Here are some pictures showing the resulting clearances.







And this photo demonstrates how even with the counterweight modifications made, the crankshaft still conflicts with a stock, unshaved oil pump.




The nominal thickness of the unmodified counter weights ran between .548" and .559".

The crankshaft was then rebalanced with weight being drilled out of the #8 and the #1 counter weight, although it looks like more meat was taken out of #8.



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Old 03-02-2019, 11:37 PM
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The oil holes in the crank look good. How is the balance of the whole assembly: crank, rods and pistons?
You must be running a flat tappet cam. What oil are you using?
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Old 03-03-2019, 03:35 PM
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Disappointed as I made no progress today - just some measurements.

But first to answer Richie's question. The rotating mass has not been dynamically balanced unless the machine shop did a partial without my knowledge. I'm pretty sure they had the weights of the rods and pistons, and they did rebalance the crank after all those modifications. But they did not have the front harmonic damper, the flywheel of the clutch. It is a flat tappet, pushrod engine. I usually run 30 weight Valvoline VR-1 Race Oil, but I just bought three cases of 20W50 weight on sale. I'm not sure what I might use for engine break in, perhaps just the VR-1 or perhaps some break-in oil. It has to be a "dinosaur" oil as opposed to a synthetic.

So the purpose of these measurements and photos is to demonstrate the modifications to the block.

The main crankshaft flange is 1.066" thick, but it has two details that perhaps exist or do not exist in an MGB crank.

First, there is a second, larger, internal diameter to the main flange. This photo demonstrates the what I'm referring to. It's at the back end, towards the inside of the engine.




There is also an additional detail on the internal surface where the flange meets the main journal.




It appears that the block and #3 Main Cap have been bored out to a 3.70" diameter with a depth of 0.56".


This next picture is looking down on the block which is upside down. The flange is occupying the area normally occupied by the MGA crankshaft scroll seal. The clearance from the outer diameter (edge) of the flange to the block is .025" to .028". You can also see the clearance from the back of the flange to the block and the bearing. There, we are looking at an original surface. Essentially, the machinist has bored into the oil collection cavity for the MGA oil scroll, essentially removing the metal on the outside of that cavity so it is now open to the world. The vertical hole next to the bolt is part of the scroll seal oil collection cavity.




This next picture shows the modified main cap. On either side where the cap meets the block, 0.27" to 0.28" of material remains. In the center, 0.163" of material remains. (this is at the very bottom of the engine next to shelf for the cork strip at the rear plate/oil pan interface).

This picture demonstrated what it looks like with the main cap installed. Note that the machine shop unexpectedly installed plugs for the oil galleries, but they are sticking out too far for the rear plate. I'll need to pull them out and see if I can find the set I planned to use when I cut the threads. I remember that I had them all fitting flush. I hope my oil gallery threads haven't been compromised by the wrong sized plugs.




The final picture shows what it should look like with the rear plate installed. Dave Headley made the plate for me and, recognizing incompetence when he sees it, he kindly laid out how the plate is supposed to be installed.


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Old 03-04-2019, 05:17 PM
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Originally Posted by blueosprey90 View Post
Joe,

Thanks for weighing in. Not left over from Hap. I think Bill Carlquist's son did most of my work. It looks very well done and I am quite pleased. I'll be documenting some of that work as I progress with the rebuild.

My project was nebulous since it started out as "check the block and camshaft for damage" and morphed over 18 months into a bigger project. Initially I planed to use a stock crankshaft. So I didn't expect them to work the bores since I was essentially reusing the same pistons. Basically, I just asked them to check the piston clearances and set the crankshaft and camshaft clearances.

So I hadn't paid any attention to the bores when I picked up the block and planned to hone them with the dingleberry hone before giving the block a final wash. But then I saw what they had done and wondered if I should leave well enough alone. I had used the dingleberry hone on another block last year and remembered it as having a somewhat rougher finish so I wasn't sure.

When I picked up my "project", I spoke to Bill about the S2000 engine and he indicated that he had done some work for you. From reading some of the "Under the Hood" threads, it seems the S2000 engines are not such good candidates for rebuilds. So I wonder if you were satisfied with the work that he did for you. I don't need any work on my S2000 today, but one never knows when I might make some bonehead move on track.
Jeff, I brought Bill a sleeved block that I had picked up as someone's unfinished project. I picked up some CP pistons and had Bill final bore and hone the cylinders to fit the pistons. Bill said that he can bore the OEM cylinders to an overbore, but I did not go that route. I have been very pleased with their work over the years.
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Old 03-04-2019, 06:36 PM
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Joe, Good to know there is someone local who can work on the S2000 engine if needed.

Tonight's task - Measuring:

Established the thrust bearing clearance: Essentially, with the thrust bearings installed and the center cap "finger tight", you center everything up with several wacks on either end of the crankshaft. I used a heavy hammer and a block of wood. Then tighten down the center cap to its 70 ft. lb. torque setting. I then wacked the crankshaft fore and aft several times with a dial gauge set up at the nose end of the crankshaft. Once I was satisfied with how it was set up, I wacked the crankshaft from the opposite side to obtain the reading. It took me several attempts, especially to find out that I should measure from the same spot on the crank.

Eventually, my readings became consistent at .002.5" of end float. Crankshaft spins easily.

I'm not sure I understand the factory spec for end float. Perhaps there is none. Hopefully I will be OK.

I used new thrust bearings marked "2056 BR Std KU". Glyco A23 - 1/4 std.Standard thrust washers are 0.0915 inch thick. By caliper, mine measured .091.0" except for one that measured .091.5".

The faces of my old thrust bearings appeared unevenly worn and their thickness was all over the place. Three dimensions ranged as follows: Bottom #1: .086.5" to .089.0"; Bottom #2: 0.086.5" to 0.087.0"; Top #1: .088.5"; Top #2: .088.5" to .091.5".


Crankshaft:

Crank Main Journal sizes: Standard: #1 - 2.0006"; #2 - 2.0004"; #3 - 2.007"
Bearing clearances: #1 .0018"; #2 .0020"; #3 .0015" (verified by Plastigauge - all within spec.)
King tri-metal bearings #MB 312CP

False Mains have a diameter of 2.256" +/-
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Old 03-06-2019, 04:56 AM
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I lost a lot of time last night searching for a second set of Pauter rods that didn't exist. From when I pulled the engine, I remember that rods 1-3 were good, but rod 3 seemed to be missing. Two rods did not have builder's markings indicating their location in the block. After much searching, I finally remembered that I had sent my old rods off to be refurbished as opposed to ordering 5 new rods. Pauter must have shaved off the missing marking during its refurbishment.

I double checked the rod bearing clearances. All were within .015" to .020", so within spec. Side clearances (assuming I did it correctly) measured from .011" to .016". The side clearances are larger than the shop manual spec of .008" to .012". I'm presuming that this is not an issue as oil will escape from the bearing more quickly, thereby lowering oil tempratures..


On the rods, the main beam that runs between the big and little ends seems to be offset slightly from the centerline. Also one side of the cap has a "notch", presumably for oil to drain off.

When I pulled the engine apart, I was not aware of the subtle difference until too late, although I do know that the notch in the cap on #4 faced towards the front of the engine.

My plan is to install the rods with the notches in the caps facing each other as in the attached photos. This would mean that the beam offsets are opposite to each other. Hope this is correct.




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Old 03-06-2019, 11:22 PM
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Originally Posted by blueosprey90 View Post
I lost a lot of time last night searching for a second set of Pauter rods that didn't exist. From when I pulled the engine, I remember that rods 1-3 were good, but rod 3 seemed to be missing. Two rods did not have builder's markings indicating their location in the block. After much searching, I finally remembered that I had sent my old rods off to be refurbished as opposed to ordering 5 new rods. Pauter must have shaved off the missing marking during its refurbishment.

I double checked the rod bearing clearances. All were within .015" to .020", so within spec. Side clearances (assuming I did it correctly) measured from .011" to .016". The side clearances are larger than the shop manual spec of .008" to .012". I'm presuming that this is not an issue as oil will escape from the bearing more quickly, thereby lowering oil tempratures..


On the rods, the main beam that runs between the big and little ends seems to be offset slightly from the centerline. Also one side of the cap has a "notch", presumably for oil to drain off.

When I pulled the engine apart, I was not aware of the subtle difference until too late, although I do know that the notch in the cap on #4 faced towards the front of the engine.

My plan is to install the rods with the notches in the caps facing each other as in the attached photos. This would mean that the beam offsets are opposite to each other. Hope this is correct.
Do more research. Know you are right with the rod arrangement. Who builds these engines? Ask someone, get some extra advice from an experienced builder.
Are you using the old rod bolts? Maybe new ARP hardware. Just a little insurance when you have done so much work.

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Old 03-07-2019, 04:40 AM
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On the MG boards, one of the respected builders advised: "Look down the bores to see which way the crank journals are offset to the bore center. This will indicate how the offset rods get installed. All B series 3-main engines have offset rod journals and require offset rod big ends."

I did a quick look and found the offset to be so subtle that I might need to dig out my old plumb bob.

[COLOR=left=#000000]On the stock engine, there is a different part number for the rods (i.e., two types of rods). I'll study that as well. [/COLOR]
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Old 03-07-2019, 04:50 AM
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You seem to be covering all the options and doing a lot of research. Nice work. I hope someday to view the MGA in person
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Old 03-07-2019, 06:54 AM
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Regarding the orientation of the conrods, I did look down the bores again, splitting my view with a thin piece of metal sheet. It's a very subtle difference in how the crankshaft journals are off set, but I think the layout of my rods was correct. But I'll double check when I've had less to
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