Class 6 Off Road Race Truck D-50 build out. Chevy. 4.3L V6

[camoit]

Just picked up the new front end. It is off of a 2000 Nissan Xterra. The suspension kit is ordered and should have it by May. I was able to order it direct from the builder. They are meeting a group of Vorra Racers and handing it off to them then it will find it's way to me. No shipping charge As for the cost so far here is what I have. Compleat front spindles $400, frame $175, power steering box $200 long travel kit $3121. Total $3896

[camoit]

OK here is a rundown on the secret world of the machine shop. I just spent an hour or so here cleaning up some of my parts. Here are some things to keep in mind when talking to, and to looking for one to use. I’m using Rex Hutchison Race Engines.



Rex Hutchison has been building engines since the flat head was king.



One of the problems with a shop is the lack of time spent on an engine. When you take an engine to a shop take a look around



and see just what kind of money is sitting there.



I mean the type of engines and equipment. Is it just stock blocks or are there a 4 or 5 big money engines there under construction.



With Rex there are engines that range from stock to 11000 Horse Power costing around $80,000 bucks or more.
What are the steps your engine will go through. First thing that needs to happen after washing



is to magnaflux every thing. For most places this is a standard practice. The two main types of testing is Dye and Powder.



Now one big thing the shop must use is an ultra sound thickness gage. They will need to take at least 2 readings. two measure the bore. Top and bottom.



One problem with a block is there is no way to easily measure the wall thickness of a block. Before you bore a block you need to find out how thick the cylinder wall is. If you bore it over .030 you might have too thin of a wall and the engine can crack a cylinder or get hot spots when running. Once you use an ultra sound on the cylinder you can find the thinnest cylinder wall and rough size the bore accordingly. Making sure to have plenty of cylinder wall left.



Just because a block has never been rebuilt doesn’t ensure that it is a good block.



Next comes the line bore for the main bearings.
Now comes the wet hone



Normally they should be done in four steps. (NOTE the next picture has an adaptor bolted on to keep the fine hone in line with the bore so you can get the top edge honed correctly.)



This will put the cool little lines in the cylinder. These lines are very important. With out them the piston rings will never seat and will leak compression gas and oil. These lines must intersect at a 60-degree angle. During this hole process the cylinders must be repeatedly checked for taper and proper bore size. Bore size is determined by the new pistons that are going in and the ultra sound test. Here is one of my new pistons for my V6.



You must hone out to the final size. This takes quite some time to get it right. Every time you go to a finer stone you must take out less and less material and sneak up on the final bore diameter.



Onto the heads. Heads will always be checked for cracks. But if you are going for some power you will need the shop to port the heads. First they CC the combustion chamber then cut the deck or just check for twist depending on what compression ratio you want to get. Then we replace the valves and seats.



Then we perform a vacuum test to check our work.



Now they will work on porting and run them on a flow bench.



So now it’s time to work on the crank. They will polish it if possible,



if you had spun a bearing or lost oil pressure they must grind down the bad journal.



Now it can be rechecked for journal run out.



Last but not least of the fun stuff is the spin balance. In this step we must know a couple of things. First is the weight of connecting rod. This is combined with the weight of the piston and the rings. To simulate the pistons and connecting rods you clamp on these adjustable weights.



Now we can spin it up to speed.



During this test we can find out where the heavy spots are. There is a meter on the balancer that shows witch end of the crank is heavy and how high from center is the heavy spot. There is a strobe light that flashes on the crank so you can reference the crank to find the heavy spot to drill.



We must not forget about the flywheel and pressure plate. If this is out of balance then all the work done on the crank was a waste of time and money. So give them all of your parts.



One thing that they will do before starting to balance the flywheel and clutch is they should resurface the flywheel. Here is an 11-pound flywheel being ground. The small shiny circle about 1 inch wide is the surface for the clutch.



Well it’s time to put in the cam and start to work on the valve train. One of the biggest things a shade tree mechanic will do is go out and buy the biggest roller rockers they can find then wonder why the engine runs like crap. When setting up the valves you need to get the correct rockers. The rockers must match the cam profile you are using. I just saw a guy bring his car to Rex and asked them to look at it. First thing wrong was the engine had no breather. It was running under a vacuum. Next they has 36 degrees of advance. They put in a cam and rockers on stock compression and heads. I hope this helps to clear up what a machine shop does or does not do.

[camoit]

Well my block has been honed to the piston size.



The new pistons are .030 over sized flat top. This should give me a final compression ratio of 9.50 to 1.



Here is my new ceramic, 6 puck clutck disk. It took 2 weeks to build and ship in. It's a 10.5 inch 3.10 LBS

[TotallyBalistic]

pretty cool man...hope alot of people look at this to get a better idea of what goes on at a machine shop

[camoit]

I started burning wire tonight. The 2 X 4 box tubing is squared and tacked to the Extera front end. The roll cage will go fast.

[camoit]

My crank was balanced today. Or I should say they started on it today. I just happened to show up there when Mike, the crank and head guy was working on it. He was having a problem with the balance. He was trying to figure out why the balance was so far off. Apparently the 4.3 V6 even fire engines have a built in unbalance to them. The odd fire is not as bad. The crank is a total of 180 Grams under weight. 180 Grams under is nearly un heard of. But then again this is a Chevy V6. There known as the little shaker. They did not have the right weights to finish the balance. They need to order them in. 5 days. One weight is in LA and the other they need is in Minnesota. I can’t figure out for the life of me why GM or any other manufacture would have an engine so out of balance that they need to have a counter shaft. If they would just balance the engine to begin with they would not need the horsepower robbing balance shaft. But I can only guess that it must be cheaper for the manufacture to just drop in the shaft and keep production rates high VS spending the extra time to do the job right the first time.

If you look at the picture you can see the added weight simulators on the left and right of the crank. It’s a bolt with a copper weight on it locked between big counter weights.

[camoit]

It’s parts day. I picked up my rear trailing arms. They will go over to the strippers then get a new coat of paint some new bushings and new uniballs.




Here is the front end. I should be able to get about 14 inch of travel. It has uniballs with high misalignment spacers instead of ball joints.






My new Quick Time bell housing from D & D transmission was the wrong one. It’s was for a Ford. So they are going to send me another one. Hope it will be right this time. I will replace the pictures with better ones soon.

[Ramit]

Pardon my ignorance, but uniballs dont have rubber boots or grease?? How do they work? I dont see any grease fittings.

[camoit]

Now that is a good question.
A uniball is a chrome alloy ball and cup held in place by just a snap ring. The cup has a Teflon type material built into it, this works as liberation. No grease no boots. Just a really hard steel ball with a hard chromed finish. Just like a tractors hydraulic ram has. It works with the same principal that if you take two smooth finished surfaces and rub them together there is very little wearing to the two parts. This is because the tolerance is so tight. Unlike a crankshaft that has up to 0.002 of clearance between the bearing and the journal. There the space is filled with the oil and a hydrodynamic wedge is created. This keeps the two parts from coming in contact with each other. I hope this helps.

[Ramit]

Good answer. Makes perfect sense. I'm guessing they can handle alot of abuse.If one were to fail, I guess you could just remove the snap ring and replace the whole unit? By the way,I'm digging this build thread. Keep it up!