Project: Rebuild!

[sabretooth]

Yup, I have the Haynes also - as well as a scan from some book (possibly Keith Tanner's?). They say the seals are different yet I wasn't able to measure any difference in valve stem thickness.

If it's for heat reasons then surely it'd be cheaper and more effective just to manufacture one seal to the required tolerance level instead of running two lines of parts.

Many miata.net posters have said they're different, Haynes says they're different and the workshop manual probably says the same (and I forgot to get a copy of it from kitkat! ). It's got me beat, anyway.

[JBT]

Have you tried to get one of each as OEM parts from Mazda to see what the difference is?

[sabretooth]

Nope. I have a post on miata.net to see if anyone knows the difference in seals, then I'll make a decision from there.

CT, the valve stem seals you gave me - what engine are you using yours on? Any oil burning issues?

[JBT]

I'd hate to see you go to all this trouble on the rebuild only to have an oil burn issue because of 8 valve seals mate.

[sabretooth]

I know, that's why I'm researching it.

[sabretooth]

No more progress on the valve stem seals front, and nothing to suggest that the same stem seals all around could even potentially cause an issue! Anyway...

More work commenced with the head on the dodgy card table - and then the tedium began. After a bit of hit and miss with the lifter rebuilds, I finally found a guaranteed way to get the lifter to stay solid, and also learnt a bit about how they work in the process. Here's how to get them apart



First, wrap the lifter up in a rag and give the flat side a few sharp hits with the hammer. This will dislodge the centre assembly from the lifter. Now, using a set of needle-nosed pliers, pull the centre part out.



You'll now have about 4 separate parts, as shown - the main lifter itself, the outer part of the piston, the inner part and the spring. The inner part can actually be broken down further another 3 parts (spring, ball valve and cap) - so with the pliers, I gently grabbed the tip and removed it from the body. Be careful here, as a ball and a spring have the potential to fall out and roll away into one of those dimensional voids where spare change and lost mobile phones end up.



What followed was a quick rinse in degreaser, a rinse with WD40 and drying with a rag. The WD40 is to rinse any degreaser out - if you don't get it all out then the innards of the lifter are going to go all gluggy when the oil mixes in.

Reassembly of the lifter involves putting the tiny spring (which holds down the ball valve) back inside the small metal piston cap and placing the ball on that. Then press the inner, big spring and outer parts of the piston together. Submerge this assembly upside-down (assuming the outer part is the top) in a shallow pool of oil. With a stiff bit of wire such as a paperclip, push down the centre of the inner part of the piston - that's actually the ball valve which makes sure that oil only flows one way. Pushing down on this should let some air out - slowly releasing pressure on this will let some oil in, therefore 'pumping' the centre up. The important thing here is to not fill the piston up -too- much. If you do this then the valve is going to be always held open just a little bit by the lifter. You don't want this! Err on the safe side and push the small part of the piston in a little before releasing the ball valve.

Next, put some oil into the cleaned main body of the lifter (make sure you clean the oil inlet hole on the body of hte lifter) and insert the piston assembly. Push it in and make sure that the piston appears to have gone in sufficiently. And you're done! One rebuilt lifter. Now, if you push on the centre piston it should barely move at all. If it is, then you're done.


So, after I'd done that process a further 15 times, I had it all done. Some of the lifters appeared to be quite tall - the consequence of that is that the valves never fully close - not good for compression! I'm going to have to go through and figure out what's going on - most likely it's the spring pushing the centre piston out too much and filling up with too much oil.



What are opinions on the best way to reduce the 'open' length of a spring? Chopping, or compressing more? Or is there another way?

[sabretooth]

We made some more good solid progress on Sunday! The Stig (sab2) came around again, and after I did a bit of tinkering with the head trying to get all of the lifters the same height (some were not allowing the valves to close properly), we did the block wash. I filled 2 buckets up with warm water with some diluted CT18 degreaser. The block wash was carried out in similar fashion to Spectral's - the block was first hosed with a moderate amount of pressure to remove any loose garbage that may be caught in the block., and then the bores and crankcase 'scrubbed' with the sponges. After doing each of the bores, we then quickly moved onto the journals and then after turning the block upside-down we moved onto the crankcase. All of this was done extremely quickly due to the tendency of cast iron to rust. In the bores, the rubbing was done in circular motions to ensure that the whole of the cylinder was cleaned - it's really important that none of the honing residue is left in the bores. I did the cleaning like how you see people cutting down a tree, with one person on each end of a long saw - but I had one hand in each end of the block pushing the sponge up and down the bore.

As soon as the rubbing with the sponge was done it was time to rinse. The block was angled so that the crankcase could let the water drain out, and the block quickly rinsed to displace all of the suds. With that done the water dispersant quickly came out and we commenced the spraying, starting with the bores and the journals. We sprayed as best and as quickly as possibly but still managed to get a little rust inside the crankcase area. I can't see it posing a problem but it really does give a good idea of just how fast iron will rust.

With that complete, I grabbed a clean rag and put some oil on it. With the oily part of the rag, I rubbed around each of the cylinders looking for any traces of discolouration. Black means that there's still some honing residue in the bores. The only cylinder that showed any signs of this was #2, so I set off I went cleaning number 2 again with the sponge, water and water dispersant.

After having done the bores, I took another look at the crankcase and stuck a rag in it. Black still. Once again the cleaning commenced and I got the water and the degreaser-filled sponge out. It was at this point that the injuries started - right now I wear about 6 different cuts on my hands from cleaning out the crankcase - all of the journals have some unpleasant and sharp edges on them. Once again this was followed with a rinse and some water dispersant.

With that all done I gave the engine a rotation to ensure that the water was indeed out of the block, sprayed it some more and then brought it inside. And here's how it turned out:



Looks shmick!

So then the interesting stuff started. I grabbed the packet of bearings and had a look at them. The set is comprised of two different bearings - one for the block side which contains the oil hole and channel, and one for the cap side - which look pretty plain in comparison.



And it's fairly obvious which bearings go where:

[sabretooth]

So, anyway - ensuring that the oil holes line up, insert the bearing into the journal, making sure that the tang on the bearing lines up with the cutout in the journal, and that the oil hole lines up. Make sure that the bearing is straight and that the top edges of the bearing are flush with the top of the journal. And that's it - you just repeat that a further 4 times (this is a 4cyl engine - so 5 journals) and that part's done:



Note in that last pic - some of the dreaded rust! It seems almost inevitable in places - thankfully that's the only place that it's appeared. Nothing on the surfaces that count. I'm not sure how I could possibly get rid of it to be honest.

And because I had to, here is a pic of the crank sitting in the engine.



What followed was a clean of the crank - the crank followed mostly the same procedure as the block - water spray, sponge, WD spray and

So, from here the next step is to get the pipe cleaner out (that was used on the head) and run it through the oil passages in both the crank and the block. It'll involve running copious amounts of degreaser and water dispersant through - and then a blast with an air compressor. And will be followed by more WD - the last thing I want is filings and whatever else (from machining) to go into the bearings and screw the whole lot up. I've heard of it happening to a friend of a friend - it screwed that engine royally and I don't want to make the same mistake.

So when that's done and my studs arrive, I'll be finally able to insert the bearings into the caps, clearance the crank with some plastigauge and make sure everything there is happy and bolt the mains down! With the mains down I can then install pistons (which I'll need a ring compressor for) and then be able to clearance those And when that happens, I'll have a complete bottom end!

For now though - the crank, head and block are all separate - the head is protected with the Familia cam cover, and the block and crank are individually wrapped once again.

[OMY005]

What are opinions on the best way to reduce the 'open' length of a spring? Chopping, or compressing more? Or is there another way?

Compressing more I would say. The whole idea is to let the oil pressure push the piston out thus taking up the clearance. But it would be very rattly on start up until they pumped up which they should do very quickly now they are all cleaned up inside.

I can then install pistons (which I'll need a ring compressor for)

I think I have one you can borrow if you want.

clearance the crank with some plastigauge and make sure everything there is happy

Did you have the crank ground, the block line bored or the caps closed and honed? If not then plastigauge should be OK. The best way is to measure the journals and bearing bores because you cannot check for out of round with plastigauge.

I have measuring gear as well if you want to do it that way.

Andrew.

[sabretooth]

Is there anything that you don't have, Andrew? Borrowing the ring compressor would be great! I'll let you know sometime! I just have to source the rods first (sigh). Although, silly me forgot to send the mains caps to the machine shop so it'd probably be wise to use whatever thingamy you've got to check the caps out.

Line boring was not done, but the crank was machined and bored to the next undersize (it's in the post where I report what was done).

[OMY005]

Line boring was not done, but the crank was machined and bored to the next undersize (it's in the post where I report what was done).

D'oh!, Knew I should have looked.

Although, silly me forgot to send the mains caps to the machine shop so it'd probably be wise to use whatever thingamy you've got to check the caps out.

They would only need the caps if you are going to line bore, which you aren't doing so that's OK. Just assemble the caps on the block with the bearings in and then measure the bores for eccentricity and also compare the the crank journal sizes to double check your clearances. Also need to check the end float of the crank now that the journals have been ground. Do you have a feeler gauge and dial indicator?

Andrew.

[sabretooth]

Feeler gauges yes, dial gauge no.

I assume with the eccentricity check you mean the eccentricity of the bearing surfaces of the mains. What have you got that can check that?

I was intending to just measure endplay with the feelers once the thrust bearings have been inserted. Is a dial gauge meant to be better for this?

[OMY005]

I assume with the eccentricity check you mean the eccentricity of the bearing surfaces of the mains. What have you got that can check that?

I have bore micromters.

I was intending to just measure endplay with the feelers once the thrust bearings have been inserted. Is a dial gauge meant to be better for this?

Feelers are OK, dial indicator is a bit easier to use and slightly more accurate. Plus I have one as well.

Andrew.

[jules]

Do you have a bicycle pump, or toaster per chance?

Jules

[Uncle Arthur]

Do you have a bicycle pump, or toaster per chance?

Jules

How about a left handed screwdriver?