98 replies to this topic

[Alberto]

I've always wanted to rebuild an engine.  Finding chunks of metal stuck on my magnetic oil drain bolt in the middle of this year presented me with an opportunity.  Thought I'd share the experience figuring some of you guys might enjoy watching my progress and hoping some will share advice.

 

Just for perspective - I'm not trying to build a motor to race Nationals / Majors.  Just a reliable, competitive motor and sealing it at 115 rwhp to run Sealed SM Regionally.  I'm currently running a low mileage motor from a 91 that I installed before the 2011 SCCA licensing school in preparation of my rookie season.  It has always been a bit weak dyno'ing at 107 rwhp after tuning.

 

Behold the original, 180k mile engine from my early 1990 Miata!  Ah, the aroma and feel of dried out oil and years of grunge.

 

 

It has been sitting forlorn in a corner of my garage since late 2010.  Occasionally, I hear it calling to me in the dark begging me to re-install it into the it's old home in the Miata - and complaining about the spiders.

 

The Plan

Assuming everything checks out, the plan is to do a budget freshening of the bottom end.  Still trying to work out what to do about the head.  Just got hit last week with some unexpected plumbing issues at the house we bought in Sept that are going to set me back a few thousand so not sure how the budget is going to work out... 

 

Current Status

Progress so far:

 

 

 

Next Steps

• Get some measuring tools - still need to buy these.  Any recommendations?
• Start measuring clearances before dismantling
• Dismantle
• Settle on a machine shop to clean up the block and maybe also confirm my measurements
• Buy parts

 

More to come... 

 

Advice always welcome! 

 

Thanks.

 

 

[Ron Alan]

Your pretty handy Alberto...why are you paying a plumber?? Plumbing is pretty simple stuff...pm me if you need expert advise

[Alberto]

Your pretty handy Alberto...why are you paying a plumber?? Plumbing is pretty simple stuff...pm me if you need expert advise

 

I'm handy with cars and some home stuff.  Never done anything with plumbing though.  The 40 year old Sewer pipe under the toilet might be leaking.  I'll shoot you an email.  Thanks Ron.

[Bench Racer]

Alberto, I have a similar chunk in the corner. Same thoughts over a couple years as you and will watch your progress.

[Alberto]

Thanks Bench.

 

 

Not much progress on my end.  Work keeps me way too busy during the week.  House has been keeping me busy on weekends when work doesn't bleed over.  Spent most of Sat Googling how plumbing works and what to troubleshoot and in the attic crawl spacing balancing between 2x6 crunched over inspecting pipes, vent tubes and exhaust fans.  Couldn't find anything obvious but I'm completely ignorant about plumbing.  Well, maybe not as ignorant as I was before Saturday anyway...

 

 

Back to the engine.  I'm up to this point as of today:

 

I'm stuck on the timing belt cog.  Having trouble removing it.  I went to O'Reilly's and rented a few different pullers.  None worked.  Between driving to different auto parts stores and trying to use them to remove the cog, I probably wasted 2-3 hours on this Sat afternoon/evening... 

 

How do you remove this frickin' thing? 

 

A semi-local guy is mailing me his home made "timing gear puller".  Hoping that works.

 

[Bench Racer]

Could a plate with a center hole for the puller jacking screw and 4 matching bolt holes be fabed to secure to the pulley. Then attach whatever puller to the plate.  Place a slug of steel over the end of the crank for the puller jacking screw to press against. Tighten the jacking screw for a load on the pulley and tap the jacking screw to help break the pulley from the crank.   

[dstevens]

If you are having the machine shop do most of the measurements you don't need to spend a bunch on equipment.  About 10-15 years ago I was using the cheap HF calipers and micrometer.  I've upgraded to Mitutoyo.  Enco has good deals and you can find them on ebay.  I find telescoping measure tees to be handy.  Besides torquing fasteners the most critical measurement will be bearing clearance.  I use Plastigauge though the guy who does my machining hates it for race engines.  The pullers I use I've gathered over the years from HF, ebay and the tool truck.   The valve spring compressor you can rent from the auto parts store though I got mine IIRC at Tooltopia.

 

That carbon should come right off (right off being a relative term, elbow grease required) with a brass wire wheel or brush and some Seafoam.

 

 

 

I did the short block, cleaned up the head.  If I ever get to racing it I'll just get a head from Drago or a known source.  My guy is good with the circle track and tuner/drifter car guys but doesn't do many heads for road race and for the price I can go to someone that does them all the time.

 

I went from this...

 

 

To this...

 

 

 

www.flickr.com/photos/dstevenslv/sets/72157625551344336/

[Keith Novak]

How do you remove this frickin' thing? 

 

A semi-local guy is mailing me his home made "timing gear puller".  Hoping that works.

 

 

Maybe a dumb question but you removed the rectangular key from the pulley, right?

 

One bit of advice I'd give is to form a good relationship with your machine shop.  Take the parts to them and have them take a look as well.  They might be able to identify problems that you don't.  I've had cylinders and cranks that looked good to me, but my machinist pointed out issues that could be fixed but not with a spec engine.

[fotostars]

Just went through that last summer (on a 1.8 though). Finally put the engine in the car a week ago, drove around the block! No smoke or bad noise, no leak.

Car is now waiting for break-in at the track , scheduled in 3 weeks. Then Dyno/tune to see what I've got.

 

Didn't do any headwork other than clean and manual lapping of the valves. Got the block cleaned and honed as well. 

Used all Mazda OEM parts from Mazdacomp, cost of ~$1000 (changed the oil pump as well as water pump and all seals, gaskets, bearings... ).

re-used pistons, rods, valves, etc,...

[Alberto]

Maybe a dumb question but you removed the rectangular key from the pulley, right?

 

 

 

Hmmm... The manual made it sound like you had to pull the timing gear off first.  Not sure if I'm a dumbass or just too distracted to have read that incorrectly....

 

How do you get the key out?  It is in there pretty tightly as well.

 

That is a shiny motor there DT

Bench, the removal tool looks like so:

 

Thanks for the advice all.  Good luck on the break-in Richard.

[Bench Racer]

As my profile says, Different Strokes For Different Folks. Same concept, different design, should work well. Make sure the small screws have as many threads engaged as possible even if you need to get longer screws. Hate to pull threads because those 4 bolts need to hold the V pulley tight. Place a steel slug over the end of the crank. Don't want to frik up the threads in the crank. 

[Alberto]

As my profile says, Different Strokes For Different Folks. Same concept, different design, should work well. Make sure the small screws have as many threads engaged as possible even if you need to get longer screws. Hate to pull threads because those 4 bolts need to hold the V pulley tight. Place a steel slug over the end of the crank. Don't want to frik up the threads in the crank. 

 

Got it.  Thanks.

[Alberto]

FSM says pulley comes off first

[Keith Novak]

It was a dumb question.  After looking at one I have apart  my 1.8 key sticks out of the gear at least 1/2" and looks quite a bit different than the 1.6. 

[Alberto]

It was a dumb question.  After looking at one I have apart  my 1.8 key sticks out of the gear at least 1/2" and looks quite a bit different than the 1.6. 

 

Not a dumb question.  I think that is how you do it on a 1.8.  At least you made me confirm that I was following the steps correctly.

[Bench Racer]

Alberto, did the pulley come off ok?
How many miles are on the engine?
Did the engine do any smoking at start up or at WOT?
When you remove the pistons I'm curious if any of the oil control rings are stuck in the pistons and how much gunk/varnish is within the oil control rings?

Get that home work finished so you may play. 

[Alberto]

Progress!

 

The fudging timing cog is finally off.  It fought me mm by mm until it finally came off. Of course, I chipped the frickin thing at the very end so it is garbage now but it is off.  Removing the timing cog has been the single most challenging part of the whole dis-assembly process.  I guess that is a good thing though.

 

Full details on the status of this project is on my blog: http://blog.miatarac...ebuild-has.html

 

Summary, timing cog is off and the bottom end is dis-assembled. 

 

Timing cog removal:

 

Timing cog off!

 

Crank cleaned up.  Keyway looks ok

 

My favorite word of the day is... Crankshaft!

 

Took measurements before dis-assembly as mentioned in the FSM and Enthusiast Manual.  Checking clearances on the connecting rods here.  Clearances were in spec.

 

Connecting rods and pistons removed after checking clearances.  I marked them with a punch prior to removal so that I could re-install in the same cylinder.  Brandon helped me out from here forward while we scratched our heads observing how this stuff worked.

 

Main caps had unique marks on each one so I noted the marks and took pics.  FSM says to not punch or mark these.  It is difficult to see but to the right (well to the left in this pic) of the 5Z is a barely legible mark that helps to make the cap's identification unique.  Hope that makes sense...

 

Main caps off!

 

and the Crankshaft is removed!

 

Going to take a close look at the pistons and bearings next weekend.

 

Going to contact a couple of machine shops to figure out which one I want to use to clean the block, take measurements and such.  I'll probably drop the crankshaft off also to have them measure it for straightness and balance and clean it up.

 

Thanks for following along.  Please share any advice if you have any to share.

[Bench Racer]

Within the blog pictures of your cam journels you mentioned the wear of the cam to the journels. Might
this be an indicator that either the cam bearing surfaces are not concentric to each other or the cam journals bore are not concentric to each other. I ask only because someone a long time ago made comment about line boring the cam journal diameters.

[Alberto]

Update

 

I dropped the parts off at a local machine shop last week.  Turns out they have done Miata engines before for some other locals so that was a good sign.   Everything measured within spec so they cleaned everything and honed the cylinder bores.  The head also checked out and the marks on the cam follower thingies were acceptable according to them so the head got a refresh and is going back in.  I don't have budget for a pro head right now so this is a good thing.

 

I just placed an order with Mazda Motorsports and ordered the gasket set, bunch of other gaskets, oil pump, piston rings, timing belt pulley/cog, crank pulley, woodruff key.  The Mazda Motorsports guys are awesome!  Thanks James!

 

Going to re-use the water pump and other pulleys from the TB job on the engine that is currently in the car since they are only 2 years old. 

 

Need to get some assembly lube and plastigauge, clean parts and start assembling.  Hope I can get this done in time for the first SCCA race on March 8th.

[Alberto]

Alberto, did the pulley come off ok?
How many miles are on the engine?
Did the engine do any smoking at start up or at WOT?
When you remove the pistons I'm curious if any of the oil control rings are stuck in the pistons and how much gunk/varnish is within the oil control rings?

Get that home work finished so you may play. 

 

Somehow, I totally missed your post. 

 

Engine had 180k street miles.  Never over heated.  Pretty regular oil changes when it was in use but sat in the car in a yard w/ infrequent use for 7 years then had been sitting in my garage here in CA for the last 3 years.

The smoking I noticed was at start up.  I never really checked at WOT but it was blue-ish in color.

I don't recall if I took pics of the pistons.  I meant to.  But the oil control rings were not filled with any gunk or varnish.  They looked pretty clean.  They did however look a bit 'stuck' in the piston.  The other rings readily expanded but the oil control rings looked quite comfy in their bores.