Remedial Engine Building Questions

[Ovis]

I have finally accumulated all of the parts and pieces and the requisite machine work needed to start putting my motor back together.

As a disclaimer, I am by no means a mechanic, just the son of one. I have watched tons of YouTube videos and read a plethora of books, yet I have many basic questions that I want to make sure I find the correct answers for.

So, I'll start with something simple, engine case prep. I want to give myself the best possible chance to build a motor that doesn't leak. With that said, I received my case (Aluminum) back from the machine shop with the case studs still installed.

Should I remove and replace these case studs? The mating surface does have the occasional knick here and there. What is the best method of preparing the mating surfaces? I have seen a video where a builder takes 600 grit sandpaper with a block and slowly surfaces the flange, thoughts?

I have purchased the Supertec Sealant kit. What about assembly lube? It will likely be a considerable amount of time from when the engine is built to the first start. What is your preferred assembly lube?

Through bolts. I have cleaned mine up, but do these need to be treated or coated with anything? I have seen them plated, but if I chose not to do so, should I blue them, paint them, leave them. Thoughts?

Thank you in advance for any help. My goal is to put together a motor that will serve me the rest of my days and therefore want to do it right the first time. I am sure I will have many more questions and I welcome all unsolicited advice and ideas.

Thanks!

[Flat6pac]

Through bolts, just clean them as they are submerged in oil constantly.
Bruce

[Neil Harvey]

Building any engine comes down to patience and your own level of quality and acceptability. What I accept may not be what others do. Some may have less some more.

Here is how I approach what you are asking. Some are pre case machining and some are post machining.

The very first thing to be done is to check for any cracks. Crack checking is very important. Late aluminum cases crack. Typically around the unsupported bearing cap of the #7 main. There is no point doing anything else if the case is cracked.

I always remove all perimeter studs and the rear dowels. I can then see the integrity of the threaded bores and do any repair work required, This is always something required on magnesium cases more than the aluminum ones. Then we place a straight edge on the parting faces to see how "flat" the surfaces are. This includes the bearing caps. Deburr all edges to remove any burrs that may have appeared. If the surfaces are not flat, these need to be addressed. Lapping can help typically but in some cases( excuse the pun) a light skim is required. Before skimming, you need to find 4 places where the surfaces are the same height. What's called touching off in 4 corners. Once the parting faces are skimmed determined by how much they are out, the cases are flipped and the cylinder decks cut to the same heights and parallel. A lot of work that is probably beyond the DIY builder. But these are checks that can be done by the DIY and then requested to the machinist when the case is set out for repair work. Unfortunately, this level is often never under taken as it takes a lot of time and many machine shops have the "close enough" mentality. If you want it right, these are the processes that have to be done.

If the parting lines are flat and parallel, without divots, you will not need a lot of sealant. A few microns is all that is required. I have seen this stuff caked on so thick it oozes out on the outside. That also happens on the inside. The common sealant is the orange stuff sold by Locktite. I personally hate that stuff. When you are tasked to machine these cases and you have to remove that stuff first, its so hard it requires so much time and effort to remove. We see instances where this stuff is caked around the studs and never removed in repeat rebuilds.

You also ask about the through bolts. These are pretty much bullet proof. Check the threads, clean off any dirt and make sure the washers are in good shape and the nuts. Something to check are the contact faces on the case halves. Often these need spot facing to establish to good surface. Check that are all the same height. A good check is to install the bolt washers and nut to make sure the nut does not bottom out on the stud. If through bolt nuts are open ended, this is easier to see. Check in the through bolt bores that the surfaces are clean and in good condition. The little O ring seals around the outside (case) and the inside ( bolt). Make sure all of the washers are clean and flat. Its pretty much all common sense.

The above checks should always be done before any line bore checks are performed. Post line bore, deburr all edges and holes. Remove the main oil galley plugs ,clean out all oil passages and check the Piston oiling jets. This includes the ting galley plug on the top of the case half where the drilling is for the piston oiling jet. If additional machine work is to be done, do this before any cleaning. Do a final clean, assemble the case dry and remeasure the main housing bore. Make sure what you asked tom be done was done correctly. You would now fit the main bearing shells and reassemble the case and measure the clamped ID of the shells. Along with what you measure the crank main journals, this will give you the clearances you have. This is also the time to check the countershaft alignment. Fit the oil pump without the seals, bolt it down and fit the countershaft and coupler. Make sure the coupler is free and not bound up. This is to check the coupler is not bent or twisted. Remove the pump so you don't forget to fit the seals.

Writing what to do often leaves out some important processes. Doing the work is more process as you see what is in front of you. If I have left anything out, I hope others will chime in any add.

Every good engine starts with a good foundation. Case, engine block, whatever, is the start. If you focus on this part and cover every required process, you will do the same with every other part of the engine. An engine is the sum of all of its parts. The case is now complete. Now give your attention to the Oil Pump. Same applies. Check check, measure and assemble with all parts checked and covered. Countershaft, same, crack check, straight measure, check all gears for wear, replace any that show wear, and remember to remove the front plug and clean the inside.

Crank is next, and in most DIY builds, this would have been sent out for work. It should be crack checked and straightened if required. Balance checked as well. When sending out the crank for work, the order of business is crack checking, straightening if required, Remove all galley plugs, measure all journals and cut as required. If the galley plugs are replaced with threaded set screws these should be fitted (not for good) for the balance check. Once the balance check is completed, you will remove the galley plugs to perform the final cleaning, then refit the galley plugs with some loctite. You need to remeasure the journals to make sure the require work was done correctly. You are the engine assembler and its your responsibility to check.

That covers the case and its parts. You will now assemble the case knowing every parts is checked and correct. You have all of the main bearing clearances noted, so that in the event you have an oil pressure issue you know that its not a clearance problem.

As for assembly lube, there are many to choose from. One is no better than another in my opinion. Most auto parts stores carry some brand or more.

The sealant kits sold by Henry cover everything you will need. My only change would be the case sealant. Its purely a personal choice based on what it takes to remove. I favor the Threebond stuff. They changed the "number" so may times I cannot keep up. This stuff is a lot easier to remove and clean.

Good luck. Go slow and be deliberate with everything to do. Take notes and record all measurements. If in doubt ask. Many on here are happy to advise. You may get all different opinions but take them all in and decide what you think is best you you. I'm in the business of building engines professionally. We do our own machine work. I often get told by some,

"That's not necessary. I've built thousands of engines and never had a problem. You are just making work to make more money".

I tell those people, as a professional we "have" to do this level of work. I tell them, I'm in the Rolex business not the Timex business. I read many times where a DIY gets into trouble and everyone comes to their aid with advice and support. "Sorry to hear this". etc etc. But when a pro does something wrong, those same people rip them apart.

The only way to do something is right, not close enough.

Remember, nothing will humble a man more than and engine or an angry wife!.

Hope this was helpful.

[Ovis]

Neil, that was a fantastic synopsis of case preparation and very helpful. I want to do it right, but as a do it yourselfer, as stated, many of the processes are probably beyond my ability. This is why these answers from the pro's such as yourself and Henry is so helpful. I've spent more money beyond my means to accumulate the parts for this build, so certainly I want to do it right the first and hopefully only time.

As to the build itself, I am working with an early Aluminum case. I have had the machine work done by a reputable shop, but the perimeter case studs remained installed, hence my questions as to removal. It did not require line boring, but the through bolt contact surfaces were spot faced. Per your advice, I am now wondering if I should purchase new washers. I cleaned up mine but they do seem a little rough on the outside with what appears a slight amount of surface corrosion on them.

Neil, thank you again for your response and any others who might chime in. I appreciate the help immensely and hope you don't mind if I shoot some more remedial questions your way as the build progresses.

thanks!

[PeteKz]

You should provide some info on your engine and your project car. That will save a lot of questions, such as: by "early aluminum case", do you mean 1960's, or SC 1977-1980? If the latter, chances are very good that you don't need case machine work. How many miles on it?

[Ovis]

Originally Posted by PeteKz

You should provide some info on your engine and your project car. That will save a lot of questions, such as: by "early aluminum case", do you mean 1960's, or SC 1977-1980? If the latter, chances are very good that you don't need case machine work. How many miles on it?

Late 65/Early 66 car. Case was cast in August 65. 70K miles on the clock.