Engine Rebuild Time

[RTTTTed]

If you want a good, fast engine the best way to get it is to put rings and bearings into a 150-200,000km engine. Fuel injected engines that have been properly taken care of last as much as 350,000kms nowadays.

If you want a good, fast engine find one that has about 180,000kms on it and replace the gaskets, oil pump rings and bearings. You end up with a "seasoned block" that has proper wear for a race engine. I like the seasoned blocks because all new machined blocks need a lot of warm-up, cool down cycles to stress relieve the block - a lot! The machined block could be "seasoned/stress relieved by spending a week in an experts oven at thousands of degrees and being cooled slowly, but starting, warming to operating temp and cooling down again works best for me. A seasoned block is twice as strong as a machined block. When a machine shop does a "complete engine rebuild" it usually entails boring, new pistons, alignbore, hot tank, shaving heads, etc. etc. Sometimes they "blueprint" the engine as they assemble it, but usually "blueprint" means that they measured the clearances when they did the bore, decking, etc. I don't own a machine shop so I don't make $75/hr when my equipment is working so I don't understand why a proper engine builder would measure all the engine parts after doing the machine work. Why not measure the engine as you disassemble it and see what needs machining and replacing? Not enough money? Anyway, I pick a good slightly older engine that runs good and DOESN'T NEED rebuilding and Blueprint it. A couple thousands of an inch taper in the bore is perfect and not worth hundreds of dollars to bore the cylinder so that I can spend another thousand on pistons that were well within factory tolerances. A bit of wear on the engine is a good thing as too tight means too much friction and then you'd have to wait 100,000kms until the engine is loose enough to make really good power. Take the 180,000kms engine and replace the parts that are made to wear out (rings and bearings). Then replace gaskets, oil pump and water pump for reliability and put it back together. You'll have a new motor that will last 300,000kms except that this engine will be lots faster and a lot stronger.

When you pull a head off the block it usually is not completely flat, but that doesn't mean it needs to be decked, that depends on how far it is from flat. Machining the head when it's supposed to be slightly warped is a waste of time, and changes the compression and misaligns the intake manifold. If the crankshaft spins freely in the block why would anyone ever alignbore the block? Just to make more money? It changes the piston's deck clearance and compression.

On our engines it is a good idea to change the bearings once in awhile (200,000kms?) because that is the main cause of catastrophic engine failure in these engines. The rings are the main reason for rebuilding the engine as they are the first important part of the engine to wear out. Change these two engine parts and the engine will "Live long and prosper" It'll also make a lot more power and rebuilding costs are relatively cheap without machine work.

Save money, save hp and have a faster engine - what could be better?

Ted

[Marine Doctor]

So you are saying the cyl walls will not wear during this period...just the rings.
Or....pick one with minimal cyl wear?

Most times when we rebuild engines, we bore the cyls due to the wear...if we throw just rings at it...we are left with slightly better engine prior to the rebuild.

But I believe I get what you are saying...a slight bit of wear along with the new rings...gives you a broken in engine...sooner.

Now...by faster..what do you mean...more HP and torque?

TMD

[fou]

This is an argument that I don't want to get in, but for the hell of it...

The cylinder wall will wear, unevenly... specially at the bottom of the cylinder. The up and down of the piston is not a problem, the wear comes from the connecting rods pushing the pistons side to side (or I should say front to back).
And that is more noticeable in a 2 stroke engine! But still happens to a 4 stroke.

[RTTTTed]

I agree, the cylinder walls do wear unevenly. However it's only a few thousands. At 180,000kms the engine is just past it's peak of being the fastest of it's life. With new rings it gets the faster again, and since the rings are what wears the most the engine is better than new.

And yes, I mean more hp and torque because of the new rings and extra cylinder wall clearance. Hopefully, the bearings have another thousandth of an inch of clearance, but usually you're lucky if there's a half thous extra clearance. I'l try to buy .001" undersize beatrings to get .002" clearance. The extra clearances are how you build a bracket engine and makes extra power due to the reduced friction. What most people don't know is how much extra power - it's significant.

The fastest stock engine I ever owned was in a 69 GTX and when I took it apart to see what made it soooo fast ... it was completely worn out. It had .080" ring gap. I don't know why it didn't smoke, but it was a 12 sec car stock. The car had 180,000 MILES on it. The cam measured 13% less lobe, the cylinders needed to be bored and the pistons needed to be replaced. The bearings were all worn to the copper. That's what made it fast. It had too much wear to just fo rings and bearings so I threw it away. It does illustrate what I'm saying though. It would have been much faster with new bearings and rings, but had too much wear for my use as it wouldn't hav lasted much longer being that all the clearances were way past factory tolerances.

What I'm saying is get a good older motor and replace the rings and bearings and it'll last 300,000kms after that with more power than new.

Ted

[fou]

What I'm saying is get a good older motor and replace the rings and bearings and it'll last 300,000kms after that with more power than new.

Ted
I agree with you Ted, but there is a bit more then just rings and bearings.
Don't get me wrong here, my 4 bolt main had 78 000 miles on it. The guy that had the engine, had so many knocks, that the landing for the top ring was broken...on all 6 piston.

And to get back to rebuilding an engine, you can build them loose if you want. It all depends what specification you give to the machine shop.
Blue printing an engine, is not that great of and idea. The shop will build the engine to the manufacture specification (in short a new tight engine)
On the other and I got my engine machined for maximum performance, tight rings (for NO leak down, maximum compression) and good clearance on the bearings (for less frictions and maximum rotation). I almost go the crank windage, but didn't enough $ and could not justify it for a street car.
.

[WoodroweBones]

Good stuff. Thats basically exactly what I did.

[RTTTTed]

Blueprinting is actually only the measuring part of the engine and matching specs. Hopefully, the specs that you told them to do the machine work to. The factory lists a full range of specs for all their engines, at least Chrysler does. They give minimium to max. specs. Max means replace and the smallest numbers are for the new factory specs (the specs that the engine is supposed to be at when it leaves the dealership. Eg. Bearings are .001-.003", so new is .001" and time to replace them would be .003". A bracket motor would be .0015-.0025" depending on how close they came to getting what you asked for. There is variance of course. One thousandth of an inch is tiny and it takes the best equipment and operator to get within .0005".

I mentioned that I always Blueprint the engine when I build it, that means I measure all the specs listed in the Chassis Manual when I disassemble it so I know what needs replacing and what doesn't. Fuel Injected cars last a long time nowadays, expecially if you use synthetic oils. I've got 350,000kms on my Ford F150 and it's still going strong, but it does use a little oil and I wouldn't rebuild it - I'll take out the stereo, park it at the dump/junkyard and remove the tires. My White Stealth has 200,000kms on it and runs perfect - that's a candidate for my style rebuild - as long as the Blueprint job I do on it when I take it apart says the main parts are ok. Like you said, if the pistons are pitted from bad care/gas, it costs probably an extra $1,000 plus for a cylinder bore and new pistons. My way of rebuilding the costs (doing it myself) are $1,000 complete. The head gaskets are the most expensive parts.

I need to change the headgaskets (it overheats) and it was recommended by George (at GT Racing) that I pull the engine to change the headgaskets. So if I'm pulling the engine and I rebuild the short block while it's out, get the synchro changed in the tranny (3rd grinds), new clutch and port the heads while I'm doing the valves seals and checking clearances on the valve stems ... I've added 50-75hp and the entire driveline is new. The engine should last the life of the rings and bearings as they wear about twice as fast as the main parts (cylinder walls, pistons, cams, etc.). If the engine does get big miles on it you won't be able to do a simple rebuild like this one - second time you'd have to do a full rebuild. And that's not worth the $5,000 when the car has over 450,000kms on it.

Ted

[fou]

My stock engine had 285 000km on it, when rod #1 fuckup the crank and that was a 2 bolt main...So I drop it in a big blue bine and got $15 for it. :D