Building up a bare block

Hey everyone,

My current car seems to be running fine although I have very low oil pressure (it's a '70 so I need to check that the pressure gauge actually works). But I have been thinking about what to do when the engine finally gives out; it’s bound to happen sometime.

I am considering picking up a bare block and getting started on a replacement engine. I am wondering if it is something that is worth doing myself or should I farm it out to a trained mechanic. I want it bored out and will need to get it tanked which I would obviously pay someone for. What parts of the build could I do myself? What parts should I definitely pay a professional to do?

My concerns with rebuilding are not based on cost; it's something I would like to accomplish myself (if I wanted to just pay somebody to do everything I would have bought a miata and not had these concerns). What I am wondering is does it make sense for a person to try the rebuild them self or will there be a significant loss in quality compared to having a professional do it?

Also, I am still early in the stages of thinking about this so any advice on what to read up on, etc... would be appreciated

Thanks for your advice

Eric

Eric - rather than a bare block for which you would have to find items like a crank, timing cover, end plates, etc. I would look for a complete engine, strip it, fix what needed fixing, and rebuild. It is not hard to do if you have some mechanical skills - and can follow the diagrams and instructions in the manuals.

The best bit is driving behind an engine that YOU built!

Buy the new pistons in advance and pay someone to fit them to the block (bore and hone to fit) along with a crank regrind. They can probably check the rods for straightness and press fit the pistons as well. Maybe align bore the block if it needs it. The rest you can easily do yourself, with the right tools and a bit of help from the forum!

I'm in a similar position. Which book can I use to work through the rebuild?

You CAN strip down and rebuild a block yourself after a little education. In addition to the MG manual, I would buy a generic engine rebuilding book from Amazon. Though not specific to the MG, this type of book does a great job of explaining the step-by-step process of stripping and building up an engine in layman's terms. You obviously need a machine shop to hone the cylinders, grind the crank, and the check the head, but I would also let them install the camshaft and bearings. For a little more money, it's not worth the risk of damaging the cam bearings. The rest you can do yourself if you are mechanically inclined. While I have never done an MG engine, I have done them for a Mustang and Tbird and never had a problem.

You can start with THIS then use Bentley to fill in the details where necessary.

Like Jeff said - figure out your overbore, buy appropriate pistons THEN have it bored to the pistons. I would also recommend timing the cam properly, new timing chain, sprockets, tensioner, bearings, and an oil pump rebuild.

Other items are up to you, and may depend on the condition of the engine. For example, a new cam and lifters "may" not be needed if you are staying stock - but be sure to keep the parts such that they go back in the place they came from - lifters will wear to the cam and should not be moved (same with pushrods, rocker arms, and valves).

I got a copy of Dr. Doolan's engine rebuild of Ebay, not foolproof by any means but really shows whats involved, plus the guys pretty funny.

As Eric sugested, I'd look for a complete engine or at least a short block. Perhaps that's what you meant. As long as you aren't worried about numbers an 18v would work also. Plenty of them around but you'll want to stay local or the shipping will cost as much as the engine. If you can find one with a good head so much the better. I wouldn't pay more for one just cause it had a head though unless it was garranteed not to be cracked. This way you have all the extranious pieces that otherwise would have to come off your present engine. This is what I did and you can keep driveing the car while you build the new engine. One weekend to drop in the new bullet & your back on the road.

Building the engine yourself is very do-abe, if that's something you like to do, have a fairly good assortment of tools, and research and educate yourself in how to go about it. I always give the same advice for DIY engine builders, do it because you want to do it for the experience and the feeling of acomplishment, not because you're trying to save a buck. You want to use really, good parts so get better bearing, cams, lifters, gaskets, don't just opt for the cheaper entry level parts, there is a huge difference in quality. Fiquire about $2000 for a budget with good parts and extensive machine work, you'll probably spend less, but plan for the worse case anyway.

I don't know you personally or your capabilties, but assuming you are the average car guy with good basic wrenching skills, here a fair guideline for what you an probably do yourself, and what you will probably need to hire out.

Machine shop:

Cylinder boring/ final honing, once current bore size and desired over bore size is determined as mentioned above then you will need to purchase the piston set for the machinist have before boring, so piston to clyinder wall is clearence is correct, most repalcement MGB pistons for the street recommend .0025' piston to cylinder wall clearence.

Main, Align boring/honing is not always necessary, but you need to have someone check it to be sure, and do it if needed. This a good extra item to do if you are unsure.

Caustic clean the block and head, make sure on your end you remove all the brass oil galley plugs and freeze plugs prior to taking it in for caustic cleaning. Remember a caustic cleaning is just the first step in cleaning your block, I also hot water wash and use a engine brush kit to get into all the orfices of the block after caustic washing and before assembly.

Size rod big ends and small ends if you have floating rods, replace rod bolts while you're there, cheap insurance, also you'll need the machine shop if you have press fit rods/pistons to remove the old pistons and install the new ones. This is a good time to have the machine shop R&R the cam bearings as well.

Crankshaft services: You need to magnaflux the crank, staright check it for run out, check the nose for wear, then more than likely, unless the old bearings looked almost new, turn the crank the undersize, if it's now standard/standard, more than likely if the crank is in good shape it will end up .010"/.010" undersized. here's the punch line on machine shops, alot of machine shop have a crank grinder, but not all machine shops do a large number of crank grinding, so not all shops do a great job here. What you want is crankshaft specailty shop most of the times, most big-medium cities have them. What you want from a good crank grinder is a genorous fliet radius at the journals, this is where cranks crack so a wimpy radius will cause a crack in the future. This is very important, check with local racers for thier recommendations on crankshaft services. If you do your home work with the machine shop and the crank shop, you can use a bearing book to set your rod and main clearences with the help of a bearing book, I build all my street engines at .0015" on both rods and mains clearences, feeding the crank shop your exact spec measurements for the journals withn the spec range will assure you the clearences you want, expect a working tolerance of +/-.0001". Blue printing sounds more difficult than it is, but really it's not tha big of deal, use this simple formula to set your crankshaft journal specs

Housing bore: the ID of the torqued mains, and the rod's big ends with no bearings.

Housing bore size - bearing shell thickness x 2 - journal size = clearence. All this information is available in the bearing book, checking it post machine work may be the tricky part for you, I use micrometors and bore gauges for this, but you can use plastigauge as a seldom or first time builder. I still use plastigauge as a secondary info from time to time myself.

Head work: The necessary stuff to service a cylinder head is not something most DIYers have lying around thier shop, so use the pros for this as well. First off pressure check it and then if it passes pressure check, after it dissasembled and cleaned up ( I bead blast my heads) check for cracks in the exhaust seat area, this may not show up on a pressure check if a water passage has not yet been breached, or if the combustion chamber is dirty with carbon, MGB heads are notorious for both exterior water jacket cracks and exhaust seat cracks, check your head very good, I know this one all too well from experience with MGB heads, they are not very durable heads, so check closely, leave nothing to chance. If all that checks out well then you may need to replace your exhaust valve seats with hardened inserts, you may need to replace some valves or the springs. Pay more money for a three angle valve job, it's worth it it. Tell them you want the valves and seats hand lapped, they will charge more for this, again, it's worth it. Don't let any of the pros tell you don't need hand lapping, I find a buttload of "quickie" valve jobs from machine shops and even fancy race shops where leakage is in the 20% range not long after thier work, extra care needs to taken here to have a efficent engine, all the go fast goodies in the world mean nothing if leakage is getting by the valves.

Head and block decking: both the head and block's deck need to be checked for starightness, and decked if needed. If the head is close to standard deck, then you can deck the head on a MGB for a nice yet still very conservative power boost, normally .020" is nothing for a MGB head, that's a good number to start with.

Rocker arm assembly, often times people over look this, check it out good, are the rocker bushings worn, does the shaft need replacing, don't over look this.

Things you can do yourself:

Disasemble the engine: Don't just take it apart mindlessly, this is a good time to check crank end float, cam shaft end float, check out bearing wear, check bore size. If you see alot of burned oil gunk, slime then assume it's where you can't see it as well, this is why you want to remove the oil galley plugs, so you can properly clean these areas, otherwise you be starting over with a already gunk up motor, and your newly turned crankshaft journals and new bearings will be the first items to be introduced to that left over oil gunk. The method I use for removing the factory brass plugs is drilling them on a mill or drill press, this assures the drilling is good and straight, you can do it by hand if you are VERY careful, but I don't recommed it.

Once the engine is fully disassemble, clean and de-grease every item, a parts washer and bead blast cabinet come in very handy here, but if you don't have either, you can still do it with degreasers, solvents, and paint strippers. I totally clean and paint/grease strip every item in a motors, and them paint the paintable pieces separately for a detailed finished look, it's more work, but you will be happy with your results if you go this route. This will be a big part of the job, prep is everything, don't take it lightly. Prepping of all the parts is the more difficult job in a engine build, keep a good inventory of everything, keep everything that is prepped good, cleaned and protected awaiting assembly.

Once everthing is prepped, then the real fun begins which is the assembly, after doing this 20+ years and 100+ engines, a prepped assembly awaitng assembly still puts a smile on my face, assembly of the engine is the best part of this job. Check and double check everything during assembly, one little over looked item can cause a major PITA or damage to the motor, this forum is littered with these stories, use it for research, there's tons of info here, use the search format here to hone in on subjects. Get a good manual, I never seen the video that folks talk of here, but many swear by it, consider it a good investment, the advice of someone that has done this job many times is 24K gold for the first time builder, because there are so many things to account for in a engine build, that can easly be overlooked for the first timer, use as many resources as you can get your hands or eyes on, nothing beats experience when it comes to this type of job.

Bottom line is, this may not be cheap even doing yourself, depending on the condition of your engine core, this will be alot of work, but if you're up for it, do your homework and execute the job right, you will have alot of self pride in your acomplisment, and that will be worth every penny and hour you spent on the project. Hope this helps, good luck, and feel free to ask me anything you would like.

WOW Good answer Hap!
He just explained the entire process in a very concise manner.
I haven't built 100 engines, but I've built over a dozen, and the words about prep are the best advice there. Spending the money at a good machine shop is the best way to spend your money. Knowing that the bottom end is right will give you the peace of mind to hop off into a cross country trip with a real feeling of security.
Hap, why don't you write a manual for this process? Sales on this forum alone would make it economically worth while.
You guys listen to him, he knows what he's doing!
Have fun

I haven't read the above posts yet Eric but here are my two cents.

Doing this is one of the best things that any gear head or even a wannabe gear head can do. These engine are the perfect ones to learn on too. They are simple enough to not confuse yet sophisticated enough to present a bit of a challenge to a newbie.

By all means do it.

Go to Amazon and buy the Burgess book on B engines and the Vizard book on A series lumps and read until you can't see straight. There are others out there too but these will get you going and will keep you right in line as you go through the effort.

BTW: You are already on target. The most important part of a rebuild is done before the first wrench is lifted. Read up all you can and then make a plan based on what you want to end up with and what you can afford. Farm out what you think will take specialized tools and instruments and do the rest yourself.

It will be a great adventure!

Jack

alabbasi Wrote:

Hap,

That was fabulous!! Thank You!!

Jimmy

Thanks!

Yep, Hap is a winner!

Great presentation Hap!

Stick that thing in the library so you don't have to re-type it.

Jack

twigworker Wrote:

Hap pretty well sums up the requirements for doing the re-build.

I once saw a book with the tittle "I learned everything I need to know about life building race engines"

Never bought the book. Wish I had, cause I can believe it is true. It is a bit of a zen thing when you do it properly.

To rebuild an engine you need to buy some basic tools.

A good torque wrench.

A set of micrometers.

A dial indicator.

A degree wheel.

A good set of basic hand tools is probably already in your garage if you own an MG. You need to decide if it is worth the price of buying the above tools. They are roughly equal to the price of havein someone good assemble the engine for you.

Starting up a new engine always gives me a thrill.

Pete

Eric,

I just finished a build and it's real do-able if you think about the options, plan your build for the type of driving you do. It's important to have the necessary tools, read like crazy (Hap's post above is priceless). Find a great machinist explain your goal and listen to what he says.

Octarine-Services has some great pages on rebuilding an engine:

http://www.octarine-services.co.uk/engbuild.htm

http://www.octarine-services.co.uk/enginebuilding.htm

If you want to add some performance, then go to:

http://www.aptfast.com/

There are also several great suppliers on this forum, seek them out.

Steve

laws hap, now i gotta print this whole page out so i can have it for refence this winter.

Thanks for the kind words, yes maybe one day I need to sit down and do something for the library. The second part of this would be to recommend the best parts, what items need to be upgraded and what items can be be bought normally.

Here's a short list of things I buy outside of the norm for one of my engine builds.

Rod and main bearings: there's alot of junk out there, AE glacier, standard County bearings, I would never use them in one of my engines. I prefer tri metal bearing, the current choices are ACL, County/King or Vandervell VP2.

Cam bearings: County and other cheap brands are of the split design, extremely hard to install, and for that single reason to keep the installer of the cam bearings a happy camper, get good non split cam bearing, ACL, Durabond and Vandervell all make non split cam bearings

Rod bolts: the standard repalcement rod bolts are more than fine for most rebuilds, but if performance or piece of mind is what you are looking for then ARP makes a much better rod bolts.

Cams and lifters: Here's a biggie, items overlooked by so many. alot folks out there are offering a reground cams, the problem is many are not rehardenng after regrinding, how important is rehardening you may ask, it's everything in my opinion, it was hardened from the factory and needs to be done again when a cam core is reground.
Some suppilers will tell you that cam has been parkerized and that, that is a type of rehardening, parkerizing will make the surface slightly harder but unfortunately does not penetrate the srface, so it will wear off quickly, more than often parkerizing is used as shelfing procedure to keep the part treated while sitting on the shelf, nitriting is the hardness treatment you want for a reground cam, nitriting penetrate the surface .030" and is a exactly what the factory use to begin with. One way to avoid all this rehrdening of a cam is to buy a billet, a billet is a brand new cam core than is already made of harder steel, this is becoming more and more the only reall good choice for re-camming a MGB, as not many folks out there anymore are able to find good useable cam cores for regrinding, a billet will cost you more, but it's worth it , if you cannot confirm nitriting to a reground cam. Lifters are another important purchase, the standard lifter being sold by all vendors are absolute junk, I don't use them in any motor I build, EVER. I did my Rockwell C testing of lifters a few years back and found the results of the standard lifter to be scary to say the least, I recommend the following lifter, CF-04 APT lifter, Mini Spares lightened lifters, and the Isky copies of the chilled Iron lifters, all of these choices checked ina t high 50s in Rockeweel C hardness testing. Remember the important thing with good cam and lifter to get near equal hardness, so mix matching cam and lifter hardness, like using a standard lifter with a billet cam can have bad results.

Gaskets, all gasket sets are not the same, so now the best choice is the Payen sets, both the thier head set and the conversion set is the way to go.

Timing chain sets: With most of the performance cam offerings you will need to advance the cam timing, this can be done with off set key ways, but because of thier poor fit quality as of late, I've gave up on them, I recommend a vernier timing gear set which allow you variable timing adjustment of aprox. 20 degrees and you can hit the timing number on the mark exactly, or if the vernier is too pricey for your taste then they make some multi key way units that will advance a set number of degrees, this is better tha offset keys in my opinion, but not as acurate as the vernier style. I often get asked what will happen if I just line up the dots on my performance cam and don't advance it as described, will the engine run ok, the answer for that question is YES, it will run ok, cam timing along with the cam grind itself sets the powerband of the engine, so if you just line up the dots on a standard timing set your engne it will run ok, but you have not taking full advantage of the performance cam you bought, and that's why you bought to begin with.

Flywheel bolts, ARP bolts are a good add on, you can get them anywhere for the MGB as they are the same thing as a small block Chevy or Ford. For ARP flywheel bolts, lose the MGB lock tab ring.

Head stud kit, ARP again is a very nice set, yes it's a extra 100+ dollars but it's a real nice set, if you don't spring for the ARP set, then look hard at replacing with a new standard set.

This is the jist of what I upgrade within a MGB engine rebuild, these above items will increase your engine rebuild parts budget possibly as much as $500+, or they worth it, you better believe it, if you have to open up the engine for any of the cheaper parts just one time, the good stuff more than pays for itself. There are tons more of performance offering out there, valves, valve springs, rings, pushrods, you can double your budget with the use of all of these items, but if all-out performace is what you are seeking then some of these items start looking pretty good. Here's a short list of the "fantasy" items I like and recommend for all out engine.

Tubular pushrods
Titan roller rocker sets
Total Seal gapless second ring set
Rimflow valves
Isky valve springs
Ported cylinder head