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My engine build, please look over my shoulder [4 Banger]

Started by _Viper_ , Dec 03 2011 11:00 PM

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#26 _Viper_

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Posted 14 December 2011 - 11:38 PM

Cheers Ant

-Crank Fitting-

Time to fit the crank permanently...

First we need to give it a good clean.
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Use some carby cleaner and a rag...
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As well as some bottle brushes, Give all the oil holes a good clean out. look down each hole and make sure there is not grit or anything at all in the tunnels.
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So make sure the thing is spotless.
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Do the same for the main journals of the block, remember cleanliness is next godliness... or something like that.
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Give each bearing a wipe over with the carby cleaner and a rag and then wipe dry with a clean section of rag and fit the lower bearings to the block (ones with the holes)
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Rub some assembly lube onto the bearings (Engine oil is ok, but Assembly lube is better)
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Put some assembly lube on both sides of the thrust bearings and sit them in the block... Sorry I forgot to take a pic of where they sit but you will see in the next few pics... They are fitted with the slots facing towards the crank.
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Then put assembly lube on the mains and the faces where the thrust washers slide on the crank
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Drop the crank into the block... Carefully

Sometimes when you put the crank in the thrust washers will move around a little, Mine ended up like this
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Not a problem tho, just push them back down so they are flush with the block like this.
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Time to check end float (I should have done this when I first test fit the crank but forgot... tisk tisk)

End float is how much the crank can move forward or back and is controlled by the thrust bearings. There is 2 ways to check it... With a dial gauge or a simple feeler gauge. Ill show you the dial gauge first.

Setup the Dial Gauge onto the front of the block, making sure the gauge is straight and parallel to the crank and the pointer is either on the front of the crank or on one of the counterweights
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Lever the crank to the rear as far as possible
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Zero the gauge
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Lever the crank forward
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Then check how far the gauge has moved... in this case 0.004" (4 Thou) Acceptable range is 0.0024" to 0.0099"
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Or simply lever the crank either forward or back and then slide a feeler gauge between the thrust bearing and crank, 0.004" feeler gauge just fit.
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Then clean all the main caps using the same methods as above.
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Clean and fit the solid bearing halves.
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Apply some assembly lube onto the bearings
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Give the main bolts a good clean, make sure the threads are spotless.
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Apply engine oil to the threads and the underside of the bolt head.
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Sit the caps over the crank onto the block, Start the bolts into the thread a few turns and you will notice the caps are sitting up a little.
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Dont pull it down flush with the bolts, Give them a tap with the butt of a hammer.
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And make sure its sitting flush like this
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Cant remember if the G-series are the same but on the 4z's you need to apply a little bit of sealant to the areas with the blue box's on the very last main cap. Make sure you clean the faces and matching faces on the block first.
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Thread all the bolts in by hand, making sure you don't feel any resistance. They should go in easily, Then Torque them all in 3 stages. 30nm, 60nm and 100nm each time in the right sequence.

You should see some sealant ooze out from the rear main cap where you applied sealer.
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And done, Crank is now fitted... Give it a spin and it should rotate easily by hand and have no tight spots... If it feels tight at all then there is either some foreign material between the bearings or your clearances are not right.

If you did your earlier checks and kept everything clean there should be a problem. Job done
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Fitting Pistons/Rods is next, Stay tuned

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#27 _oldjohnno_

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Posted 15 December 2011 - 06:14 AM

Nice photos. Just one little detail I'd like to see added: the cap with the thrust bearings needs to be centred before it's pulled down tight or else it's likely that all the thrust loads will be taken on only one half of the bearing. Normally you'd pull the cap down tight then back it off just enough to let the cap move. Lever the crank back and forth (or tap it with a soft hammer) to centre the cap then tighten it fully. Checking the end float with no cap and again with the cap pulled down tight is one way you can verify that it's properly centred.

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#28 _Viper_

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Posted 15 December 2011 - 08:03 AM

Ahk Johno... would you recommend I redo that for my motor? I did actually happen to check the end play before and after Torquing as I was unsure if Torquing the bolts would effect the end play, But both times got the exact same reading on the dial so it seemed it didnt matter?

Could I simply loosen the 2 middle main cap bolts, tap the crank both ways then retorque... Or should I loosen all the main caps in reverse order and start again?

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#29 _oldjohnno_

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Posted 15 December 2011 - 12:07 PM

If you got the same reading with the cap on it sounds like you fluked it. I wouldn't worry about re-doing it.

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#30 _Viper_

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Posted 15 December 2011 - 03:03 PM

Cool altho im a little confused. Can you explain in more detail what's actually happening? What are you actually trying to center? Because pushing the crank all the way in one direction and then all the way in the other then tighten, wouldn't you be tightening it with it up against one of the thrust washers and a gap between the other?

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#31 ls2lxhatch

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Posted 15 December 2011 - 04:43 PM

I think Johno is saying that you lever the crank with the cap loose to align the thrust surface of the bearing in the cap with the thrust surface of the bearing in the block.

It is possible that the two halves are out of alignment so the thrust bearing in the cap takes the load one way and the thrust bearing in the block takes the load the other way.

Edited by ls2lxhatch, 15 December 2011 - 04:45 PM.

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#32 _Viper_

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Posted 15 December 2011 - 05:32 PM

Hmm my 4z block only has thrust washers in the block half, nothing in the cap? Are other motors different?

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#33 _oldjohnno_

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Posted 15 December 2011 - 06:23 PM

Most older style engines have thrust faces in both cap and block halves and obviously you'd want to keep them aligned. I didn't notice your engine only had thrust bearings on the block side so you can ignore all that cap alignment business.

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#34 _Bomber Watson_

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Posted 15 December 2011 - 08:39 PM

Something interesting i had a lad tell me, and i wouldnt mind mentioniong whilst we have everyones attention.

When running full floating rods he used to machine up nylon "plugs" to go into the pin bore of the piston over the spirolock.

The theory with this was if one come loose and the pin moved it would just push the nylon against the bore instead of the pin hitting the bore...

Thoughts??

Cheers.

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#35 _Viper_

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Posted 15 December 2011 - 09:34 PM

RE: thrust bearings..... Ahhk so thats why I was confused. make sense now... Cheers

Is it common at all that Wire locks come loose? I would hope not!!! How would nylon go with the heat inside the motor, and hydrocarbons? and the wear against the bores?

I fit one of the piston/rods tonight and checked the clearance with Plastigauge and got 1.5 thou.... Rechecked it and had the crank secured so it couldnt spin at all and got the exact same reading.... Is that ok? workshop manual says 1.2 thou to 2.3thou is "standard" with 4.7 thou being the limit. so its within specs but I would have thought it should be the same as the Main bearings (3thou)

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#36 _Viper_

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Posted 15 December 2011 - 11:46 PM

Oh also the side clearance between the rod and crank is 7thou... Manual says 8-14thou is acceptable? The 8thou feeler gauge does fit... But quite tight. Should the rods of been ground down a few thou on the sides?

Oh and why is there discrepancies with the clearances? Machine shop said we are aiming for about 2 - 2.5thou on all the crank bearings... So why isn't there? Is that just how it is and there are other variables that effect it and as long as it's withing the range it's ok... Or has the machine shop stuffed up and they should be able to get it to exactly the clearances you want? And should I be asking them to regrind the crank so it has 2 thou clearance on the mains and little ends...

Edited by Viper, 15 December 2011 - 11:54 PM.

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#37 _oldjohnno_

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Posted 16 December 2011 - 06:15 AM

Bomber, the nylon (or more usually teflon) buttons are very common in classes where quick teardown and assembly is very important, eg. TF, TA and N2O engines, or anywhere pistons are regarded as a consumable. Usually though the button is the only thing retaining the pin, there's no clip behind it. The advantage is being able to change pistons very quickly, the downside is extra weight and the buttons tend to go out of shape after a while so they aren't really for long term use.

Rod side clearance isn't very critical - so long as you have at least a few thou it'll be fine. What is important to check (especially if you have custom pistons and/or rods) is that when the piston/rod is fitted that there is some clearance between the side of the small end and the piston boss. It's possible especially with custom stuff to end up with a side load if the clearances aren't right.

I'd have preferred a bit more b/e clearance but in reality it'll be ok. You have to remember that you can't think about bearing clearances in isolation or as on factor on its own - instead you should be thinking about clearance, oil viscosity at running temp, and the running temperature as a group. So long as these three factors are compatible you'll be ok. There's a bit more about it here http://oldjohnno.id.au/page110.html but you don't have to overthink it for a street motor. Just stick with a light oil and you'll be ok, and go synthetic after the rings are bedded.

The round wire clips seem to be the most reliable way of retaining the pin and they are commonly used as OEM. Spirolocks look to be foolproof (they're almost impossible to remove without stabbing yourself in the hand and/or scarring the piston) but they've been known to come out. Different builders have different favourites but I'd always go with the wire clips and chamfered pin ends if only for the fact that they've been proven on millions of factory engines.

The variations in size stem from every item being made with a certain dimensional tolerance. The tolerance is there so that the parts can be made at a price that people like you and I can afford. If we look at main clearance for example, it'll be affected by the crank journal diameter, the main tunnel diameter and the bearing thickness. Each of these dimensions will have a tolerance or permissable variation and depending on how these stack up it dictates what the final clearance will be. They may cancel each other out or they may all go the same way, putting you at the extreme high or low side of the range.

The first thing you should do when building an engine - even just a street engine - is to prepare a build sheet. Record everything on it - main tunnel sizes, journal diameters, bearing clearances, bore and piston sizes, ring gaps, deck height, cam bearing sizes, the works. Anything that can and should be measured should be recorded. It'll help avoid overlooking things and can also be handy as a reference for future mods.

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#38 _Viper_

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Posted 16 December 2011 - 07:07 AM

Thanks again johno, I wonder how much postage is for a carton

I understand there is a tolerance for OEM parts but I had the mains line honed, crank reground and rods resized, the only off the shelf bit is the bearings. So is the tech not there that even custom machine shops can't get tolerances down to 0.0001"

Or are they spot on and it's just the bearings creating the slight difference? If so why don't they measure the bearings first and machine to suit?

And yea is that what they refer to as blue printing? I've got a pad where I've written down every measurement ive taken

did the same for the last motor I built for a guy in the club and gave it to him, so least he knows I checked everything.

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#39 _Viper_

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Posted 16 December 2011 - 07:16 AM

Wow nice link too, I'll have a read through the rest of the page later.

But that kinda what I was getting at also, if ive
Got 1.5tho on the little ends and 3thou on the big ends how do I choose a oil when there are 2 difference clearances at work?

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#40 _Ned Loh_

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Posted 16 December 2011 - 08:07 AM

So is the tech not there that even custom machine shops can't get tolerances down to 0.0001"

Or are they spot on and it's just the bearings creating the slight difference? If so why don't they measure the bearings first and machine to suit?

I'm told machining down to tenths of a thou it is part art and part science. I've had issues before. When you find a good machinist stick to them (& post their details here!).

Sometime bearing thickness will vary ever so slightly so you can juggle the bearings around to acheive your target clearance range.

EDIT: If it was me I'd at least be having a chat to the machinist to hear what they have to say.

Edited by Ned Loh, 16 December 2011 - 08:08 AM.

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#41 _oldjohnno_

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Posted 16 December 2011 - 11:51 AM

Machining to very close tolerances is entirely possible, diesel injection components are an example that comes to mind. But the closer the tolerances the higher the cost.

As for the big and little end clearances use the big end to work with. The pin end works at a much lower speed, relatively speaking.

What clearance have you got at the big ends? In one post you say 1.5 and in another it's 3?

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#42 _Viper_

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Posted 16 December 2011 - 11:51 AM

Spoke to machine shop, he has given me a spec to check the ID of the big end of the rod with no bearings fitted and if it's out he will open it up a touch.

Also told me to check the side clearance of the rods with a dial gauge rather then feeler gauges and same thing will shave a touch off the sides

So least he's happy to work out any problems

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#43 _Viper_

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Posted 16 December 2011 - 11:54 AM

Sorry I had my terms messed up, I thought big ends were the main journals and the littles were the big ends... Don't ask me why, now i think about it I feel stupid.

Ok so on the main journals I have 3 thou and on the big end of the rods I have 1.5 thou

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#44 _oldjohnno_

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Posted 16 December 2011 - 06:05 PM

It'd be nice if you could pick up another 0.5 to 1 thou big end clearance just by honing the rod. A quick linish of the rod journals is another easy option.

Machinists will generally machine components to whatever size you specify to produce whatever clearance you want. But if you don't tell them what you want they'll normally make any hole to the smaller end of the range and any shaft or journal to the larger end. This way it's relatively easy to make further size adjustments easily without having to change any parts like bearings or pistons etc.

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#45 _Viper_

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Posted 16 December 2011 - 06:16 PM

Yeh sounds good. He helped me plan my motor and recommended parts for me and choose comp ratio etc and said we were aiming for 2.5thou all round, which is why i was confused that we didn't get it. But sounds like he is happy
To sort it out so stay tuned

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#46 _Bomber Watson_

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Posted 16 December 2011 - 09:08 PM

Cheers oldjohnno.

And sounds good Viper.

Cheers.

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#47 _Ned Loh_

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Posted 20 December 2011 - 08:14 AM

Machining to very close tolerances is entirely possible, diesel injection components are an example that comes to mind. But the closer the tolerances the higher the cost.

A bit off topic but...Once I started measuring things to tenths of a thou I found my reasonably well reputed performance engine shop couldn't machine to the tolerances I was asking for. nice helpful guy but just couldn't seem to give accurate and consistant results. I've tried someone late last year and was pretty happy so will stick to them for now.

Niether of the shops do diesel work as far as I am aware but that is something I'll keep in mind if I'm looking for a new machinist in the future.

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#48 _oldjohnno_

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Posted 20 December 2011 - 07:12 PM

A bit off topic but...Once I started measuring things to tenths of a thou I found my reasonably well reputed performance engine shop couldn't machine to the tolerances I was asking for. nice helpful guy but just couldn't seem to give accurate and consistant results. I've tried someone late last year and was pretty happy so will stick to them for now.

Niether of the shops do diesel work as far as I am aware but that is something I'll keep in mind if I'm looking for a new machinist in the future.

Grinding or honing to within a tenth or two is almost trivially easy for any competent operator of fit-for-purpose equipment. The word that caught my eye when you mentioned "performance engine shop" was "performance" - no doubt there are plenty of "performance" businesses that turn out first rate work and products. But I'm also certain that there are a hell of a lot of guys in the "performance" industry that are turning out 2nd or 3rd rate junk.

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#49 _Viper_

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Posted 20 December 2011 - 10:40 PM

Well I checked my rod side clearance with the Dial gauge as the machinist asked and got 7.7 thou (0.0077")

Took the rods back to the machine shop, told him about the side clearance and said it is on the tight side but since there is only one rod per Journal it will be ok. (workshop manual says minimum is 8thou so it is RIIGHT on the limit)

I had one of the rods fitted with bearings and Torqued down and he measured with his Internal Mike (I didnt have one small enough) and with his measurement he came up with 2.4thou clearance between the Rod and Crank... hmm so hopefully he didn't just make up a measurement right in front of me (I couldnt get a good look at the mike, Thinking now I shoulda asked to do it myself)

2.4thou would be ok, but why did I only get 1.5 thou reading with the flexigauge... I used the same rod and same bearings both times (flexi gauge and him with the mike), Had the crank tied down so it couldn't spin and did it twice (with the flexigauge)

Only thing I can think of is because my Rods and rod-caps are the exact same shape so there is nothing sticking out of the rod cap for me to hit with a punch to get the cap off and I sorta have to hit it on the sides and flick the hammer upwards to remove the cap and alternate side to side and possible the flexigauge strip is getting squished more somehow?

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#50 _oldjohnno_

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Posted 21 December 2011 - 06:12 AM

I'd believe him. But if you aren't 100% confident there's an old school (very old school) method you could use to verify it - all you need is some outside mikes or verniers.
Basically all you do is cut a small piece of material of the desired thickness just a bit narrower than the bearing and about an inch long and fit it all up like you would with plastigage. Paper is good because it won't mark the bearing and you can use a couple of layers if necessary. But I've seen brass shim stock used too. So in your case you'd find something about 2 thou thick and fit it up (dry). It should still move freely on the journal if the clearance is more than 2 thou. Then you might try one thats 2.5 thou thick. If the clearance really is 2.4 thou you'll feel some resistance to movement and all the play will be gone. Ideally you'd check it just with a bare rod (no piston, or at least the piston not in the bore) so you can get a good feel.
One thing to keep in mind when doing this or even just when measuring bearings normally is that the bearing bores aren't round; the shells are thinner at the parting line than in the centre. So if you measure the clearance at 6 and 12 oclock as you normally would and again at say the 8 and 2 oclock positions you'll find the second measurement will be a couple of thou bigger.