5vz Rebuild First Timer Noobtastic Thread

Good catch - the Cylinder Head International company has been in business for like 40 years according to the BBB so I guess in this case quality is directly related to time in business. I work with a few teachers with whom I wish this was the case

 

Some times machinist would leave their previous job and start a business of their own. I'm cool with that but they still need to build their own rep though. Seeing as how they have hits on BBB and some neutral reviews on ebay I'd steer clear.

 

subbed.

I picked up a 5vz that is thought to be good, for I think 4 energy drinks.

Because of the low cost, and the fact the sparkplugs were taken out at some point, I plan to at least pull the heads and replace head gaskets while it is out. Glad to see I am not the only guy who knows it going to cost more in the long run, but enjoy the challenge and perceived reliability of a self rebuilt engine.

I just rolled over 273 so I am not to sure how much longer I have, but she sounds solid so here is to hoping.

 

more rebuild threads pls

 

? You have a rebuild thread?

 

LOL, I fixed it.

 

So I got through the first 50 pages of Championship Engine. Basically what I read covered engine basics and then increasing cylinder pressures.

This book is more about OHV pushrod engines rather than dual overhead camshaft engines like the 5vz. I bought it because I want more information about assembling the bottom end which is basically going to have most of the same concepts I assume.

Some interesting things I read that most car guys probably already know:

* Engine Timing is the time (referenced by angle of camshaft) before the cylinder reaches top dead center when the spark plug is sparked so that the fuel / air mix will be burned at the best time for the piston to turn the crankshaft on the power stroke (piston going down).

* Fuel / air mix actually does not explode, but is a short, controlled burn for about .0015 seconds. Detonation (explosion) causes pinging or knocking. Pinging and knocking can also be caused by pre-ignition where a glowing red bur in the cylinder ignites the fuel / air mix before the spark plug sparks. Detonation causes extreme wear (in relation to normal operating conditions) of engine components.

* An increased overlap of time when both the intake and the exhaust valves are open during the exhaust and intake strokes is what's responsible in racing engines for the chugging sound. Unused fuel gets sent out the exhaust valves and the chugging sounds are increased when there isn't enough vacuum pressure at low rpm's to push all of the fuel and air into the cylinder so the engine rejects some of the air / fuel mix. Basically racing engines are calibrated to run at high rpm's and therefore at idle they are less efficient and sound sloppy and / or beastly.

* Volumetric efficiency is the amount of fuel and air that an engine can get into each cylinder divided by the volume of the cylinder. I think most stock engines are at .85 so enough fuel and air to account for 85% of the volume of the cylinder are pushed into the cylinder during each cycle.

* Superchargers and other forced induction systems like turbo chargers can push enough air and fuel into the cylinder that the volumetric efficiency is greater than 100%. Basically the air is already compressed when it goes into the cylinder.

* As volumetric efficiency increases, the cooling system needs to be more effective.

The rest are cool facts about drag cars:

* A supercharger on a Top Fuel drag car can take 500 hp to run, but it increases the volumetric efficiency for a net gain in power.

* A methanol (alcohol) drag car doesn't need a radiator or cooling passages because the fuel being atomized and entering the cylinders absorbs enough heat to keep the engine cool.

* A nitromethane drag car burns 5 gallons of fuel in 5 seconds. A gas powered drag car burns 1 quart during burn out and the drag run.

 

Were they NOS energy drinks by any chance? lol

Sounds like you've got a couple years more on your current engine at least Hopefully enough guys start rebuilding these engines that the knowledge base gets as deep as in topics like suspension and camping mods!

 

Best way to find a good. Machinist is to goto a local race dirt track type, those guys get a lot of machine work done. Some even sponsor the cars, these are the beater cars from th 80s that look like back yard builds not the fancy desoda mods.

 

Awesome thread man, love the pics. Keep it up!

 

Sub'd!

 

Been awhile. So far I've looked at porting and polishing the heads and adding Doug Thorley headers. Here's my inspiration:



Also I bought this:

$58 Lisle 36050 Valve Keeper Remover and Installer Kit

https://www.amazon.com/gp/product/B0012S61IO/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Here's a video that shows how it works.



Took apart the passenger side head. The tool is really easy to use without a hammer by just putting a rag under the valve and pushing. I made a big mistake by putting my safety glasses up on my head while doing this. Got a warning shot when one of the keepers stayed in the retainer and released the spring after I removed the tool - shot the keeper, retainer, and the spring all over the place - luckily I found the retainer and the spring. Ended up short one keeper. I just took a pic with all of the valves numbered and bagged each valve assembly.



Upon inspection, I thought I might have found a crack. I'm pretty sure it's casting flash though - it doesn't transfer to either one of the valve seats. I'll still get it inspected if it looks like it's still there after starting my p&p job.

 

Well after inspecting the other head I found a crack in the cylinder that had caused the head gasket failure:



I traced it to the intake inlet and saw that it transfered through to it:



That made me take another look at the thing I thought might have been a crack in the other head and I'm pretty sure it is, but I couldn't find it transfer through to any other surfaces. Here's a hi-res pic:

 

Its been 5 months... What happened

 

Trying to save up for a new head. Not cheap.

 

If u are posting n publishing the heads do a maniflod cut march. And polis the intake. I used to do that on the wrx i used to race. It was illegal to do it on the thunder car i first eaced.

 

Well which side? Drivers or passengers? I have a 3.4 on the ground with a bag hg. I could pull apart the side you need and see if the head is good...

 

@Dalandser

 

any updates

 

So here's the real update:

https://www.tacomaworld.com/threads...ation-fresh-start.472706/page-4#post-15783421

TLDR: Found a fresher engine and transmission and am in the process of swapping them into my truck.

I bought some heads off of a guy that's now banned on here and he took a good month to ship them out after I had already paid him for them, and they got to me (not surprisingly) in a lot worse condition than he had described. He did text me after shipping them that he might refund some of my money since the valves had a little "corrosion," but basically everything is unusable - maybe just the cams and the head castings, that's it so I haven't even bothered with them.

If they had been fresh it would have been a good deal for $275 shipped from the east coast, but it turned out to be a wash. I figure I've still got the block, and if these heads turn out to be any good, they'll get the ol' port and polish, and when I get my supercharger, they'll actually be worth putting in. I might build the bottom end with a 3vz-fe forged crankshaft and some forged rods and pistons; make this the last engine I'll need in this truck. Until then, I'll enjoy my replacement engine that was clearly babied by its previous owner up until the day the truck got into a fender bender that actually tweaked the frame so it became a total loss.

When I get some time to tear down the heads I'll post some pics