A4 Overhaul

[Dromo]

After months of prep work, I'm ready to put all the A4 parts, lying around my work shop, back together.
All the hard work is done.The cleaning, scraping, sanding, primer & paint. It's all down hill from here.
I thought I'd post some pic's as I went along to tap into the resources of the MMI forum and to offer what I can to this site .
Regards:Rick

[Mike Jenkins]

Looks great, I'm also in the process of a rebuild and hope to get the parts to a machine shop shortly for evaluation and cleaning. I need the order the parts from Moyer Marine depending on what the machine shop finds and hope to be in the same position as yourself in a month or so. Keep us posted with your progress and best wishes.

Mike

[Dromo]

Piston Rings

I'm ready to install the piston rings so I thought i would take the time and check the ring cap. From what I have read it should be .007" to 015"
I used the piston to push the ring into the cylinder bore and square it in place.
Using a feeler gauge I measured the ring cap. I found that removal of the ring is easier if you use the piston, from the underside of the cylinder to push the ring out, so you don't scatch the honing surface. So it's best to do this before the crank is in place.
I have included some text for the placement on the ring gap location ie. top comp. ring (12 o'clock), 2nd comp.ring (8 o'clock) and the oil ring (4 o'clock)
I didn't see this on any if the forum threads so I thought I would include it.

Regarding hasting rings direct from manufacturer. From: "Hess"

The original Atomic Four rings didn't have an oil ring backing spring, but the replacement Hasting rings do. It doesn't say in the instructions included with the Hastings rings, but the oil ring backing spring has to be installed with the gap in the spring over the slot in the piston at the bottom of the oil ring land. If you cover the slot with the backing spring the engine will usually burn oil after a rebuild.


p.s any comments/advice? feel free!

[lat 64]

Sleeves?

Your block looks like it has quite a history. it seems like it's been sleeved. is that right? I see head stud holes that look like they have repair inserts or Heli-coils. I read (in Don's manual I think) that these need special attention so they don't leak. Did you have any problem like that before the tear down?
I see a shiny surface on the valve seats. Did you get a single-angle or a three-angle grind?

Like Mike, I hope to be where you're at in a couple of weeks.

You go guy,
Russ

[Don Moyer]

Dromo,

Thank you for your detailed observations. If you continue throughout your rebuilding operation, you'll be leaving behind a valuable journal - as many others have done on this Forum before you. I'd like to add one item about ring gap if I might that I find very interesting from our own experience, as well as from the advice of our "usually reliable experts". Of the several things which affect compression, it turns out that ring gap is actually the least important.

The most important specification (so as not to keep you in suspense) is ring to ring groove clearance. It turns out that more compression is lost around the back side of loose rings than either ring gap or bore diameter (which sort of go hand in hand). I suspect this is why the maximum clearances for ring groove side clearances are so small, i.e., .0030" for the upper compression ring and .0025" for the lower compression and oil rings. You'll notice that we took no liberties with these specifications in preparing our own manual.

As bore diameter increases through normal wear (whether the engine started out standard, .010" or .020" oversize), ring gap will naturally increase above .015" for that particular engine. We've seen engines with compression ring gaps well in excess of .020" with no ill effects on compression.

For the purist: If your engine has such low operating hours that you're reusing your original pistons and you find your bore diameter approaching our .004" maximum after machine honing, you will probably only be able to retain the ring gap within the factory specifications by ordering the next size rings and filing the ends of the rings on each side of the gap until they fit into the bore with the appropriate gap. If you go to this trouble, I recommend having a machine shop do this work for you, because it takes a special tool and a bit of finesse to keep the ends of the rings nice and straight, and I would have them hold to the upper side of the specification (.015") so as not to risk the ring tightening up and seizing.

Don

[Dromo]

Regarding Sleeves

Russ, you're right - cylinders 1 & 2 were done. I had 2 of the head studs snap off. Guess I made a mess of things after that. On the stud between 1 & 2, I ended up with 3 hair line cracks, one of them going down the sleeve on 1 and the other in #2. If you look real close, you can see where it was repaired by a process called stitching. The repaired stud holes are not heli-coils, I'm not sure what they did.
I think the valve seats are a single angle grind. If I remember correctly, they should be done at 45 degrees, the valves and valve seats were done at the same time.
I let the pros take care of all that stuff for me. I was very fortunate to find a local machine shop that has said their doors are always open for any questions, help, or advice.

https://www.locknstitch.com

Regards Rick

[lat 64]

Ah yes, now I see the stitching. I am very familiar with this method. I fixed ton's (literally) of Chev 350 cylinder heads back in the '80s that way. It worked fine.

[67c&ccorv]

Don't you just love the look of the A4 hi-chromium content block and head after it has been machined?

I can't think of any motor that looks so good after machining. Too bad they didn't use stainless nuts, bolt & studs etc., on the original assembly.

Re: 3 angle valve grind - I wouldn't go through the extra effort and expense on such a low-compression/stressed engine as the A4.

Cheers!

[Dromo]

ring groove clearance

Thanks Don for your technical expertize. I would have never thought about ring to ring groove clearance. After scratching my head staring at the pistons, wondering how to get these measurements, I hope I got it right!
This is what I have.
Pistons #1 #2 #3 #4 pistons
Top Comp .0015 .0015 .0015 .0015
2nd. comp .0015 .0015 .0015 .0015
oil ring .002 .002 .002 .002

The Good news is these pistons seem to be in Great Shape.
The bad news would be if I did this wrong and I'm back to scratching my head.
Hey its all in fun, that's why I do it.
Here is I pic of what I came up with.

Again any input is more than welcome

Thanks

Rick

[Don Moyer]

Rick,

You seem to be measuring the ring to ring groove clearance correctly, but .015" is really more than we recommend. Are you using new rings in these measurements?

In actual practice, in any engine where bore wear allows for re-use of the original pistons, the condition of the pistons themselves will usually be good enough that ring groove clearance would not normally be a disqualifying factor. In other words, it would be very unusual to have to replace pistons with the same size, based solely on the basis of excessive ring groove clearance.

Don

[Dromo]

Don

You are right. I meant to put .0015 and ended up with .015
Thanks for pointing that out.
Rick

[Dromo]

Oil Circulation?

After reading Warren Casey's thread about no oil pressure, after doing all the work he did, I can just imagine what he was feeling. Want to say the engine looks great.

I decided to bring my rebuilt to a halt until I could somehow find a simple way to test the oil pump. I came up with a crude makeshift, but effective, way to do so. I didn't get an oil pressure reading, but the oil is flowing to all the journals and gears.

So I am confident that I can continue on with my assembly of the engine with peace of mind knowing that the engine will have adequate oil flow on start-up.

Cost of material $3.00 at the dollar store; 15 minutes of (my) labour- a few Beers and if anybody finds my method amusing....priceless! :-)
Rick

[lat 64]

oil pressure

Yes, my sympathies go to Warren Casey hope the he got it fixed without too much undoing.
I am inspired by your setup. I think I'll do just that. I want to put on some kind of bypass oil filter and this would be a great way to test it.
On some auto motors you can do this by spinning the distributor drive with a drill motor.
I think I'll just set my engine on the oil pan and do like you did with the hand crank.

Yes it was a good to see your idea.

Russ

[Dromo]

Update!

After MacGyvering up some kind of oil pump test, I felt reassured that the oil pump was in good condition. I didn't have the pistons installed, so the crank was very easy to turn. I used tape to block the holes on the crank where the rod journals would go to get some kind of oil flow through the crank and to the bearing at the flywheel end.

My next step was to install a new oil pump gasket, but when I tightened the bolts on the pump, the crank started to bind. If I backed off on the bolts, it would run free again. I tried different sequences of tightening the bolts, but the crank would always bind. I thought about a thicker gasket but decided not to, for it could cause low oil pressure at the pump gears. I decided to trace the gasket onto a plain piece of writing paper and add it with the gasket "worked great!" bolts are nice and tight and the crank runs free. I think in this application it would be ok to do this.

Any pros and cons would be most welcome.

Next - I installed the rods and pistons. All numbers on rod journal facing the cam and piston arrows pointing towards the timing gear #1, being next to the flywheel end of the block.

Valve adjustments - I'm going to refer to a thread by "rispelt = valve clearance adjustment/image" ,http://www.moyermarine.com/forums/showthread.php?t=2927 along with the MMI manual.
I did do something a little different here. I read somewhere that when the timing marks are lined up, that #4 piston is at T.D.C. I went to the timing marks and adjusted in order 4,3,1,2 checked again, and again, same reading. With the head not installed yet, it was easier for me to find TDC of each piston starting at #4, No guesswork!
After setting the valves I decided to order 8 new stronger valve springs from MMI just to be safe ,so I will have to repeat this procedure.
Well, that's it for the rebuild for now. I'm going to leave the engine at a short block stage as it is in my basement and I have to get it back up the stairs!!

I've taken a mock up pic of the engine.

Head gasket - I have both sets of head gaskets, single and double. I'm leaning towards a single thicker gasket, but would like some input from the forum on this matter. I can do either.

Until Spring.........Rick

[Dromo]

Head Gaskets

I got two sets of head gaskets, A set of two with the Victor Reinz gasket set and the so called new thicker one from universal.
I noticed that all three gaskets were the same thickness