Crank hard to turn with just 3 pistons installed

[Lil' Shaun]

I had the parts store give me the wrong rings once. It took all my weight to turn it over with just one piston instaled.

 

[bryanwheat]

I had the parts store give me the wrong rings once. It took all my weight to turn it over with just one piston instaled.

IF the rings fit the pistons and have the correct end gap i don't see how they could be the wrong rings.

 

[rlacasse1]

^^^ True that. And if it took all your weight to turn it over, how in the hell did you get the piston down the cylinder in the first place? Beat it in with a hammer?

 

[bryanwheat]

^^^ True that. And if it took all your weight to turn it over, how in the hell did you get the piston down the cylinder in the first place? Beat it in with a hammer?

That's what i want to know. You would know that something is wrong when you stick the ring in the cylinder to check the end gap.

 

[jmelocik]

I've always lubed the cylinder walls as well as oil the rings down thoroughly and never required much effort at all to turn over even a newly honed block with brand new rings. Not saying it's not possible just saying it didn't take anything more than my bare hands on every 4 cyl engine I've ever built.

Josh

 

[EagleTalonTim]

Ok, fresh morning and just tested the resistance of the crank with a 3/8" torque wrench. It only does IN lbs so what I got was 200 IN lbs which converts to 16.66 ft lb's of torque to turn the crank. I did read last night that if there was more than 25ft lbs of resistance, then something is binding. Guess I am still in the clear?

got all the pistons installed and the torque went up just a little but is under 25ft lb's. I have spun the engine over several times and it feels a little tight, but I think it is because the rings are new.

 

[NHerron]

Can you isolate where most the resistance is. That seems a little much but maybe thats because I never used a torque wrench on it. Can you push the counter weights down with your palms?

 

[EagleTalonTim]

I can turn the crank shaft by pushing on the counter weights now. Just had to spin the engine over about 10 times with the wrench to get everything moving. When I did that, the color of the cylinder walls changed a bit...they look a little more shiny than they were right after I honed it. I think everything is ok now.

 

[NHerron]

I dunk pistons in a bucket of fresh oil before install. My experiences with that turn out great, keeps a lot of oil even after being rotated so many times

 

[rlacasse1]

Good for you OP.

 

[donniekak]

Did you wash the block, and scrub the cylinders with a brush after honing? You may still have honing grit in he cylinders.

 

[EagleTalonTim]

I wiped them out before I coated them with oil. Never used a brush in the cylinders.

 

[JacksonAuto]

A fresh shortblock should take less than 15-20 ft/lbs of breakaway torque. It will vary depending on the type and thickness of rings.

How much side clearance do the rods have? If it's insufficient, the engine will be hard to turn over. If it's not corrected, oil will not be able to flow properly which will cause elevated oil temperatures and subsequent premature failure.

 

[EagleTalonTim]

I know it is not the rods since i can loosen all rod caps to where the caps are barely on and the tension is still the same. Right now, I am getting 17ft lb's of torque when I turn the crank. The tension is the same with the caps torqued down.

 

[JacksonAuto]

Please be aware that side clearance is different from vertical oil clearance. The side clearance is a measure of the clearance between the sides of the rod and the outer edges of the rod journal. If this is to tight, you wont notice until the rod cap is installed and the bolts are snugged. With the rods in place, this can be measured with a dial indicator or feeler gauges. Out of the block, you would measure the width of the rod and subtract that value from the width of the rod journal. Nearly every set of rods that I've installed, which is in the hundreds, had to be machined for clearance because out of the box they're too tight.

Are you measuring your break away torque with still only three pistons installed or have you installed the fourth?

 

[NHerron]

For yet another reference,

I tore down an engine that failed from a previous owner and they used Eagle rods. Upon reassembly, I measured side clearance and found it was way too close, I forget the measurement it might have been .002". My machinist was shocked it even ran for as long as it did. I dont know if that would have caused the problems I had, but the rods looked like they were never even touched compared to a brand new rod, just like JacksonAuto had mentioned

 

[EagleTalonTim]

Not sure what the side spacing is on the caps to the crank is. Anyone know what it is supposed to be?

 

[NHerron]

My FSM states .004" - .0098" and limit is .0154". In the manual it shows using feeler gauges to check this spec of connecting rod big end to crankshaft. They call it connecting rod big end thrust clearance. This was out of the 90-91' FSM for the 2.0L DOHC, I assume its the same for 93'. My 93-96' FSM's are incomplete

I believe on my Eagle rods, I set them to .007". Not really a reason why I set it to that spec though. Hopefully JacksonAuto can give a more educated recommendation for the ideal clearance

 

[EagleTalonTim]

My engine is from a 92 so it is a 6 bolt The clearance is .008 on 3 of them and .006 on the other 1. Not sure why that one is a little smaller. I am using the stock crank which is probably not precision ground like a $1500 - $2000 crank and it has quite a few miles on it as well.

 

[JacksonAuto]

.006-.008" is too tight, although that amount wont make the engine hard to turn. Factory specs are good for stock rebuilds, but if you're doing any mods you'll want to use them as a reference only.

Back to why the engine turns over hard- how much end play did the crank have before you installed the rods and pistons?

 

[EagleTalonTim]

I am not sure about the end play. I figured since I am going with a stock crank that purchasing stock size parts would match up right away. To me that is like buying an aftermarket water pump gasket and having to cut it down to size to make it fit.... I have already dumped over $3k in parts into this engine and my wife is not happy with me about that The more machining I have to get done, the more my wife gets mad at me. I have already been told to sell my car and get another one So .006 to .008 will not work at all? I will have to remove all the pistons again and have them machined?

 

[JacksonAuto]

The reason I asked about the crank endplay is because when you install the crank in a 6 bolt you must align the thrust bearing. If you don't, there will be no clearance which will make the crank tough to turn. Also, the lack of clearance will cause it to fail prematurely.

Your logic regarding new parts is flawed. New does not mean good. It just means that no one has figured out what's wrong with it yet. I've had plenty of "new" parts that had problems from new cranks with out-of-spec journals, pistons with improperly machined ring grooves, pin bores that are too tight, bearings that are the wrong thickness, rods have big ends that are too big or small, the list goes on and on. It happens a lot more frequently than you would think. Everything must be checked!

.006-.008 is insufficient. You will need to remove the rod/piston assemblies, remove the pistons from the rods and machine them so there is at LEAST .010-.012". Otherwise problems will arise that I described in one of my posts above. This will also give you a chance to set the endplay correctly Not really a big deal and should take around an hour. If you keep going ahead and ignoring these things the wife will be mad when you have to spend that $3k to do it all over a second time!! Do it right or do it twice.

 

[BogusSVO]

^^^^^^ This all of it.

I haven't said anything beacuse Jam has been telling you the truth.

Trust in what he has been telling you.

FWIW I have had some of the same issues that JAM talks about ofver the years also.

There us a huge differance between being an engine assembler and being an engine builder.
An assembler will assume that the parts are perfect right out the box.
A builder will check everyrhing twice to make sure they are.

 

[NHerron]

What does "too tight" mean on an engine meant to have higher power? I wanted to ask because I could not find much info on this until now, or it was conflicting info across other forums. My machinist recommended not to be too loose otherwise it may turn into an "oil burner" by slinging too much oil on the cylinder walls, so we went with the middle of the factory specs, .007". This engine will make decent power by next summer, upwards of 400, so would I need to open up the gaps before that?

So even though rod bearing clearance is much tighter than thrust side clearance, I will still run into elevated oil temps? Is that due to the resistance of exiting oil fast enough?

 

[BogusSVO]

Diffrent machinists and machine shops have diffrent knowlage bases they draw from, depending on schooling, experiance and there own R&D.

Some builders want a loose engine, some like them tight.

It comes down to what has been built and gone out the shop and stayed out.
Also what has gone out and come back that failed that the machinist/builder has torn back into to find what went wrong, and what they had come up as a cure/fix for that issue.

The factory stock specs become a guide line at that point.

If building a box stock engine the stock specs are fine.

But when taking an engine that was OE spec of 200 hp and going to 400 HP with it, the factory specs become a guideline, then add into that common sense, logic and experiance and new clearance specs are formed.

Now just beacuse you double the OE HP of an engine, dose not mean you need to double the OE clearance specs of that engine.