By Joe Mondello
In this article, Joe Mondello is drawing from over 50 years of building performance engines.
Building a performance engine today is not easy! I’ve been in this business over 51 years and all of it has been in the high performance industry. It has been the best fifty-one of my seventy-four years on this planet. The difference between when I started and today is we are now spoiled with great computerized machining equipment; wet and dry flow benches, CWT balancing centers that balance front, rear, and the center of a crankshaft, plus we can balance the camshaft.
Here at the Mondello Tech Center (MTC), we like very efficient, trick high performance equipment and that’s why our shop is full of it! One of the hard parts of the engine building business today is getting good, reliable parts like we are used to; those that are made in the USA. We could order parts from any parts house, jobber, or warehouse distributor facility in the industry. We knew when you bored the block .030 over, ground the crank .010-.010; machine the line bore to middle spec and resize your rods to middle spec, you were pretty much assured when you check with plasti-gauge and/or micrometers everything would be very close to a proper fit and all specs would be good. Nearly all pistons were within match balance weights, 2-3 grams of each other. This seemed to be so, even as recent as five years ago. Well, think again everyone! Those days are over and long gone. The biggest reason is that more than fifty percent of our major manufacturers are leaving the USA because of higher profit margins, due to cheaper labor and inferior materials in China and many other countries. I must say however, I owe Ron at Hedman Headers a great big apology for previously stating in an earlier article that his products were made outside the USA. They are NOT; Hedman has kept operations here and uses high quality materials to produce his products… A great big thanks to Hedman Headers!!
Just because a company has had a previous reputation for high quality products, that is no reason not to check and double check specs and material content today. We all are used to dealing with certain companies and products and think they are the same today as in the past. Beware, the parts you think you are familiar with have almost certainly changed, especially in the past few years.
Today, the only way you can properly build a performance engine is to obtain a crank, rods, pistons, rings, and bearings first; then machine the block to match the sizes of the components you purchased.
Today, the only way you can properly build a performance engine is to obtain a crank, rods, pistons, rings, and bearings first; then machine the block to match the sizes of the components you purchased. YOU MUST FIRST check and re-check every part closely. Check the cam for straightness and correct timing on an Audie Cam Pro Plus. Mic the crank, check its stroke, be sure it is straight, and the keyway is indexed to the number one rod journal. Then spin it making sure the counter-weights are positioned correctly so it won’t fly off your balancer. Don’t laugh; this is becoming more and more common, especially with cast off shore cranks. The forged ones aren’t quite so bad, yet. While I’m discussing cranks and the importance of balancing, especially neutral-balance engines, you cannot neutral-balance a Chinese or American made crank and expect to sell a Chinese harmonic neutral balanced balancer and flexplate to your customer without spinning the assembly before it leaves your shop. I have seen “neutral balanced” Chinese flexplates that are .070 thick on one side and .095 on the other. I would say that flexplate has a built-in counter weight, wouldn’t you? Twenty-five years ago, you could go to GM or Pioneer for a flex plate (made in the USA) and just bolt it on your neutral balanced Chevy and it would run very smooth.
Today the difference is unbelievable. There are no specs on metal quality in developing countries nor do they check the material content for correct hardness when making our parts. They cannot control flatness when rolling out steel plate with their antiquated or inferior machines. This is the very reason your flexplates are not flat; making them out of balance from the start. Mondello has been making billet flexplates and fly wheels for over 40 years for all type engines; even the odd ball stuff using USA rolled steel stock.
Check the connecting rod center to center distances and measure the pin end to make sure you have .001 to .0015” press fit to pin or .008-.001” if it’s free-floating. Check the big end of the rod for concentricity and size. We have also found some discrepancies with Chinese rods that are warped and bent. Check all the pistons for correct compression heights on both sides and measure the piston skirts .250” below the oil ring groove, just above the bottom tang for correct taper. Weigh all the pistons making sure they can match weight for balancing. Do not sell an engine assembly, short or long block, without balancing all of today’s engine components.
If you are thinking about using a Chinese 350 Chevrolet block, do not! We have put them on our Sunnen RMC V-30 machining center and every one were all over the place; bore centers, lifter bores, cam tunnel, main line, even the decks are out of whack. As my friends from New York would say, “Forget aboud it!” The worst about them is the heat treatment numbers; top to bottom and end to end – they are horrible. If you decide to machine one; all I can say is good luck! They move around while machining like silly putty. I cryogenically froze and stress relieved and shook one, then bolted on the torque plates to machine it on my V-30. Guess what? It was still a piece of silly putty junk. AERA member Leo Croisetiere from R& L Engines in New Hampshire feels the same way I do; we have had it with Chinese engine parts.
Some of the cranks and rods from K1 Company; Scat, Howards, and Ohio Cranks and some of Eagle’s components are okay for some applications, but I recommend the GM 350 replacement blocks. I like and use mostly Dart and some World iron blocks and also aluminum blocks. If you’re using a used GM block don’t go over 4.030” without sonic testing. Don’t try to run your Rottler 65 or 75 series or the Sunnen RMC V-30 on blueprint mode on a stock 350 Chevy because the bores will end up .040 to .075” oversize to correct the OEM production line block machining.
If you are not checking the lifter bore angles and location in stock and some aftermarket blocks when you are assembling an engine, in a lot of cases some will have camshaft failures. It’s easy to check the lifter bore angles. I have a Mondello lifter bank angle tool, PN LBT350 for you. We are now manufacturing this item due to popular demand. There are sometimes as many as 1 in 10 Chevy blocks that have bad lifter bores. It’s pretty amazing that 302-351W Fords and most Mopars are good in this area and I have only found two 455 Oldsmobile engines out of thousands that don’t have decent lifter bore angles. GM, I’m asking you, who’s making the Chevrolet blocks? Where? Where is quality control? Prior to 1998 they were made in the USA; now in Mexico and Canada supposedly using GM specs and our level of quality control. Hmmmm… questionable, I think.
The Siamese blocks, late OEM 460 Fords, some 350-403 Olds from 1977 and later, and all years 400 SB and BB Chevy blocks, early or late, all seem to have lifter bore issues. The reason the Siamese blocks have problems is there is not enough material between the deck and main saddle to eliminate the crank from flexing and pulling the cam tunnel down at RPM and overheating. Any light weight block has this problem. When there is no material between main line and cam tunnel, the crank will pull the cam tunnel downwards changing the lifter bore angle. Don’t take things for granted; jump out of the woods and see the trees! After all this checking is finished you are now ready to machine and blueprint your block at the same time you fit the components.
Take all the specs you have recorded and machine the block and rods to match your clearances. If you’re using a Chinese crank, make sure you check the intersecting drilled oil holes between rod and main journals because some may not go all the way through. Another very important thing many shops don’t do is check their torque wrench calibrations. I know builders who have five year old wrenches that have never been checked. This can be a major problem if your wrench is off even 5 pounds; some are off 15 and believe me, when we use our Goodson torque wrench checker you would be amazed at the inconsistencies we’ve discovered. Customers send us their torque wrenches to be calibrated and we had a one year old Mac Tool dial type wrench come in that was hardly used and it was off by twelve pounds on the high side! This is a big issue if you are trying to build a professional quality engine.
You know, I don’t understand why some builders call engines, motors. “Motor” is the correct classification of an electrically run mechanism. Engines run on some type of fuel, be it conventional, compressed gas, or an alternative liquid. Just a little pet peeve of mine! I love the phone calls on Monday after a big race weekend and I hear “everything was going great until I lost my motor”. A bad weekend is if you lose the motor in your blender while making Margaritas for everyone and the party is over!! Another thing that still bugs me is why engine builders do not check their micrometers with the correct standard. This instrument is not bullet proof and does not like to be dropped or over-tightened. It takes a very short time to check and re-calibrate your micrometers.
You should have standards for all your measuring devices in your shop. I believe the most overlooked of these devices is the level. How Level is Your Level? Goodson has a great write-up on how to level your level before you try to level your unlevel piece of equipment. Don’t laugh; it’s a very serious subject! Unlevel surfacers or your head center boring equipment can cause chatter, non-concentric valve seats; and heads, blocks, and manifolds not being flat or having the correct angle end to end. When you know your tools and equipment are calibrated correctly all your shop employees are on the same page. This allows you to professionally build that engine with confidence.
Cam bearing installation in a lot of shops is a joke. We’ve found very few builders check the cam tunnel specs with mics and/or the mics have not been re-calibrated to check before installation. Plus, adding to the horror, they use an old cam to check clearances and if it doesn’t fit they use a bearing scrapper to “solve” the problem! I have not heard many builders say they check cam to cam bearing clearances while blueprinting an engine. I like to see .001 – .003” on all cam journal bearing clearances. I have found that .004 – .010” is too much clearance causing an internal oil leak and lowering pressure. Another area of concern is rod and main bearing clearances. Smaller engines with small journal diameters and good oil pumps can usually get away with up to .0025 – .003” clearance without problems. Buick, Olds, Pontiac, and 460 Fords engines with 3” and larger mains, 2.500” rods, and so-so oil pumps .003” and over clearances are looking for a short life through premature failure especially when using aluminum bearings and no nitriding or heat treating of the iron or nodular cranks after a .010 – .010” or higher re-grind. I nitride and cross-drill my cranks plus use either the ACL Tri-Metal Race Series or Clevite’s new H-Series; Speed Pro Race Series bearings are also good. I have not had much success with Sealed Power aluminum bearings. I go .0022-.0026” rod bearing clearance and .0022-.0028” on the mains.
I also like to coat bearings for performance use with Poly Dyne Calico and Tech Line coatings. I use Tech Line in-house with great results. Cylinder bore prep is one of the most important areas of your engine build. If you don’t have good ring seal, the vacuum is down and the carburetor powered engines are less responsive. Do it right by boring with .004-.005” left for honing. The use of torque plates is mandatory on all engines. Install torque plates in a temperature controlled room. We keep ours at 70°, using the same fasteners and head gaskets as final assembly. Take all your stock head bolts and gaskets that are worn out and toss them in the trash. Use ARP Ultra Lube on aftermarket fasteners like Milodon, Manley, ARP, etc. when you replace the originals making sure the fastener has reached its maximum stretch capability. Leave the torque plates on 3-4 hours before final honing. The use of the new ARP Ultra lube will save you time on old fashioned head, rod bolt, and stud torque cycling. We tested it and have used it now for over a year. A very important part of your final engine machine work is the proper way to finish the final cylinder block honing.
We rough hone to within .002” of final bore size with diamonds on our SV-10 Sunnen hone. If you have older equipment you can rough in the block to within .002” with a coarse 70 grit AN roughing stone. Then hone to final bore size using the SV-10 with a 220 AN stone grit. Let cool and recheck clearances. Come in and begin the plateau honing process with a 280 grit AN stone with three strokes using medium to light pressure at 30-32 degrees cross hatch angle, go back with a 400 grit AN stone with three strokes, same pressure and cross hatch angle. The final clean up hone is done with Goodson Ultra Finish plateau soft hone brush assembly. Wash thoroughly with lacquer thinner until all black is gone in the cylinder bores and then wipe with a white lint free cloth. Wash in hot water with Dawn Dish Soap and blow dry. If you are lucky enough to have a sonic cleaner use it before final assembly instead of the Dawn wash. At MTC we use an Omega Sonic cleaner with Goodson chemicals; you would be amazed how much black material is found at the bottom of the tank after this wash.
When preparing rings I like to use a little wider top and second ring end gap because a vacuum is created between the top and second ring with a pressure between the second and oil ring rails. On a 4 inch bore I like .020-.022” on the top plasma moly ductile or chromed steel ring and a .022-.024 Total Seal Napier or RBT series taper face ring for the second. The most dangerous ring in the engine is the stainless steel hard chromed face oil ring rail. You can always tell when an assembler takes rings right out of the box and installs them without deburring. The new one-piece oil ring from Mahle will not groove the cylinder bores because it has no gap. We lap all our rings at MTC with our Mondello RL400 ring lapping set with the exception of reverse taper second rings. I use a belt sander with180 grit, 1 inch wide belt and cut a 45° angle on the bore side of the oil rail so it cannot cut into the bore. All the straight vertical lines in a cylinder bore are caused from no end gapping or deburring the rings properly and not cutting the 45° angle on the oil rails. I make the RS103 which is a special half round very fine oil-filled stone 6” long for the deburring process. I prep all bearings, except ones coated by the manufacturer, with a debur knife on bearing edges, then use 600 grit wet and dry sand paper in a solvent bath on the bearing surface. Then go over them with ultrafine Scotch Brite in a light circular motion for a very smooth texture of the bearing surface. Once you remove the surface coating used to protect bearings during shelf life you will find imperfections that simply can’t be used in a professionally built engine. Always wipe cylinder bores clean with lacquer thinner, then use automatic transmission fluid to coat cylinder walls, then wash and clean up with hot water and Dawn dish soap, rinse, and blow dry. Wipe the bores with a white lint free cloth. If you see black on that cloth repeat the process from the lacquer thinner wipe until no more black is seen on the cloth. Use Techline’s Power Coat PKSX final cylinder bore assembly powder. Apply with white non-abrasive very fine Scotch Brite in a circular motion. Do not remove residue created by this process.
Do not install any camshaft in the engine without degreeing it in. Trying to line up the marks on a third world country timing chain set will be a disaster. The only chain set we have been able to line up on the marks is the Cloyes. Make sure everything is thoroughly checked, cleaned, fitted, and ready to go together. Remember, flat tappet engines need a lot of zinc on cam lifters and in the oil for break-in. I recommend Cam Shield’s break-in as used here at MTC. Have 2000 to 2500 PPM of ZDDP zinc in your oil for the first 500 to1000 miles.
I recommend the use of CMW’s totally new engine break-in oil for all engine types, flat tappet or roller, 10/40 weight. It has more zinc and phosphorus than any other available product. This is the “new generation of lubrications”.
Good luck on your well built engine!
Engine Professional 2011