Mesa Balancing Racing Engines Bottom ends from Inside out
 

As you would expect the blocks come from the manufacturers and they take even more work than the heads to get started.

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Checking all the thread bores chamfering all the deck surface bolt holes magnetic particle inspection sonic testing and press testing once all that passes inspection they will go into machining. Here's a couple started today. These are 1 MB1100csefi or procharger efi set up and the 2nd is a MB900scefi or an entry level screw blower with EFI as well. I'll show every step along the way in the next couple of days. Hope you guys enjoy.

Finishing the lifter bores from a reamer finish to a finish hone with the clearance we run. We have had new blocks come through with the lifter bore being out of round as much as .008 and have actually found this in the inspection before we machine the block. We have also had engines specially engines that are purchased as short blocks through the mail order houses come through with stuck lifters is the block and damaged lifters from scoring due to the bores not being debured internally. This is not a very long process and eliminates many issues . When looking for reliability you can't leave any stone unturned.

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We normally run .0020 clearance and also debur the internal oil gallery with a ball hone for eliminating the possibility of scoring the lifter body with any internal burs. At the end before it goes to assembly it all gets steel brushes for the final cleaning. Many complaints of lifter noises can be eliminated by inspecting and knowing what the lifter clearance actually is before assembly. Hope you guys enjoy. Sincerely Laz

laz,just about every dart block i have seen needed the lifter bores resized,they tell you in the paperwork that comes with the block that the builder needs to do so.i recently did two 525 engines that needed new blocks,i bought the gm over the counter blocks that come fully machined,everything was machined spot on but they did a chit job of deburring them.they had a really nice hone job and the rings seated quickly.under 2 grand for a fully machined gm block seemed like a fair deal to me.

Mike you know GM stuff is hard to beat sometimes and they'll hold some power too. I'll be honest what I like the best about the Dart and Merlin stuff is being able to machine it where we want it for clearance and finish . One thing I have never been a fan of the GM stuff is the deck surface finish but you know that's easy to fix too. Thanks for your reply that's also very good for the guys from OSO because sometimes when the budget is not there they have that option as well. The most important reason for these post is to inform the guys here so as to understand were some of these problems they have come from and to not let shops take them in the wrong direction . Sincerely Laz

Here's a picture of the cylinders being finished in a Dart block with a custom gasket from torque plate. Again finishing for clearance and surface finish for the rings we are using.

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This is the first of 4 finishing stones we use for the proper finish

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Here's the finished product not cleaned yet and also the deck surface machined .

Got the blocks preassembled and working on setting the final piston to head clearance and static compression by decking . Also something else to be said these blocks come through un finished new out of the box they have steps on the deck surface from the manufacturing process. This is an area which I have seen many mail order short blocks come through un finished which will cause head gasket sealing problems as well as temp issues and water and condensation in the oil all problems that arise on the forums all the time and guys pull their hair out trying to determine were it's coming from. Also GM blocks that come finished and ready to run if you ever pull a GEN V or VI apart you will see in the lower cylinderhead bolt holes between the two center bolts they all leak in the area they all need to be properly machine with the correct finish to avoid this.

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In the picture above you can see after a light skim cut two areas on either side of the water passage were the factory machining was not flat this particular case the coolant would leak out from the deck but there are also areas were you would not be as fortunate and can lead to condensation in the oil.

Hey guys today's bottom end update. I hope you're all well here are some pics of the bottom ends going together after checking bearing clearances .

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Here block needs rear seal installed to drop the crank in. Check out the bottom of the cylinders chamfered and also very important when you purchase a new Dart of Merlin block chamfer the freeze plug bores they come with a sharp edge and will scar the seal when installing it which will cause leaks or worse the plugs to blow out under high water press. These are two things which look insignificant but are very important. If you've ever had an engine built and saw scratches at the bottom of the bores most likely the edge at the bottom of the bore was never chamfered.

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After crankshaft install the very first thing check the thrust clearance or endplay . I personally set this by leaving the rear main cap torqued to 5 ft lbs. and tap the crankshaft with a heavy hammer by the snout using a machined bar to keep from damaging the front of the crank and then tighten the cap to the proper torque and checking. Make sure the indicator is always straight with the centerline of the crankshaft. If you don't have an indicator it's a bit more work but you can slip a feeler gauge between the crank and the bearing.

Awesome threads from you guys, thanks for sharing. Your attention to clearance detail is what separates "engine assemblers" from real blueprint and balancing shops. Surprising about the Dart blocks though. I run their 302 Iron Eagle blocks in my vintage race cars and they are the highest quality, most precisely cast blocks we have ever seen. Wonder why the difference, especially with the pushrod clearance...

Today's progress got short blocks together and ready for oil pans next.

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Here one short block finished and the second in the works.

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Back out of the engine assembly room for a quick quality control inspection of all thread bolt bores and installation of pan and head studs then back into the engine assembly room for cylinder heads and valve trane assembly. Camshaft already installed and degreed.

Great thread..Thanks for taking the time.

You ever run into a situation where the lifter bore diameter is larger the the clearance you like to run ( We normally run .0020 )

We also run .002 clearance and yes to answer your question , we actually go through the quality control before we start on the blocks because a situation we had several years back were we machined a block start to finish assuming as we all do sometimes (its new so it has to be right) were the lifter bores were actually out of round at the bottom by ,008. We normally see bores come through with .0012 to .0015 but every once in a while we have to send one back. As long as the block is unmachined it can be returned as defective but once you touch it its yours. We have taken the precaution to inspect every block ever since. This is exactly the reason I want guys to see these post there are so many things a customer can ask the engine builder to do before they spend money on repairing the engines that would eliminate problems such as low oil press noisy lifters damaged bearings and so on. Thank you for your reply sincerely Laz

Not only will they not take it back because you machined it, you wasted all that time and labor Machining an engine that you are now not going to get paid for.

Could you sleeve the lifter bores? Just asking.

Thanks for the informative posts. I enjoy reading and learning.

Yes we can and in many cases were the block is being used for all out competition we sleeve them even if they are new with the right clearance this is to insure the location and angle of the lifter to cam is correct . Also aluminum blocks suffer from wear more so than iron blocks. Being that aluminum grows more than iron the lifter bore clearance is ultra critical. This is one of our specialties we're one of the leading shops in Florida for machine work and serve the engine builders as well as the machine shops from Daytona to Florida city. This is what sets the standards in the building of any type of engine not just racing engines. Thanks Laz

Thank you

Nice i have darts also. I had issues with oil drain back. The blocks dont have the the large hole at front of lifter valley like the gm blocks have. I had to use Smith brothers pushrods with .040 holes in them to limit oil to the top. This winter I want add drain back holes and lines in the heads to go straight back to pan. What are your views??

so on the Dart blocks vs GM blocks how accurate do the lifter bores tend to be in relation to location and angle?

As far as what we see the most of is the GM blocks are very unpredictable as far as size and location the Dart and Merlin blocks rarely come out but I've had Merlin blocks be out and Dart blocks big on the bore size as well so it's a catch 22 . That's why the proper procedure is check everything no matter who's it is and this way the customer will benefit in the long run. This is so easy to do but yet so many people refuse to do so( just because the engine was fine when it came in for rebuild) as they say when there's a problem . I say to the folks that are having engines rebuilt to ask the engine builder to measure and pay close attention and even provide a written report before the work is authorized. Some would think that's a pain in the ass but in essence it's the proper way to approach a job . Best of luck and thanks for the reply Laz

Terrific thread..

Ok guys I hope everyone is doing good todays update is always a subject here on OSO as a matter of fact a couple of weeks ago it was being discussed. Oil pan to pick up clearance here are some pictures of how we do it there's more than one way like everything this way you don't need any special tools and anyone building their engine at home can do it.

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Install and torque pump and at the same time install the gasket you will run and seal it to the block.

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Install a piece of tape to the screen as to not get it contaminated with the clay you will need to transfer the clearance . Note set the clay all the way across the surface of the screen to make sure it sets flat across the bottom of the pan and it's not blocked on one side or the other. Set the pan over the top and tighten it as it will be on the engine. Remove the pan and measure the thickness of the clay. At this point you know what the clearance is we run 5/16 or .312 to 3/8 or .375 . Note on marine engines with 10 to 16 quart pans you can be a bit more but never more than 1/2 or .500 . Automotive small capacity pans you don't have that luxury you will eat up a motor in a NY minute . Never run the pick up in any application closer than 1/4 or .250 from the bottom of the pan because you will start to see oil press problems and inconsistencies below that under sustained RPM. I hope you guys like this post I know this gets asked so many times here and what's best is the simplicity of how we check it you can go crazy and pull out a dial caliper and measure the height of the pick up minus the height of the oil pan and add the thickness of the gasket which is crazy ,1drop the pan over the pick up 2 tighten and pull off 3 measure and you're done. Simple as 123 . Hope you enjoy Laz

Wouldn`t ARP studs only be a little more then the bolts?

Perhaps but we've tested these bolts in 1500Hp turbo engines for 200 hours of tuning and running and never seen as much as .001 stretch on a free length bolt and great bearing wear and no cap shift. This is a MB700 should make 720 to 750 single carb 91 oct. pump gas.