39 replies to this topic

[Lmcgrew79]

New here my name is Luke McGrew purchased a 1994 miata and decided to build it towards spec miata with a goal of going racing in the next year or so. Been tracking/instructing and use to time trail since 2008 in various cars, mostly 2008 Dodge Viper with all ACR Mods and some suspension setup, a viper ta,  and a track prepped e46 m3. I ordered a new Viper ACR a few months ago and while waiting to get it, ive decided to build a miata. Co drove one sometimes autox and recently drove a friend of mines at ncm which was a blast. Funnest cars ive driving on track are an arial atom followed by a miata.

 

I Probably should have purchased a 99 but this one was close and cheap and im not looking to be a major contender just mainly for fun, it was smoking some from an over heat and i thought it was a stuck rings or valve seals. I replaced the seals and that didnt fix it, so i decided to pull the engine and found that cylinder 1 wall had some damage. Purchased another block and going reuse pistions and crank from this block as everything looks good. Got a long list of items as this car is stock. Learned alot already from the wealth of info on the forums. 

[Lmcgrew79]

Painted Trunk

2nd week of ownership

Power Steering Depowering

Hotsy Steam Clean

Prepping for Paint while motor is out.

[FTodaro]

Welcome to the addiction Luke, keep the pics coming.

[Diller]

Welcome. Sounds like you are setting some reasonable goals for a first time build and should have a blast. I also race a 94 and am always excited to see more people in the oddball year cars. I raced with NASA-SE all last season and I never saw another NA1.8. Start building a collection of spare parts as the 94 has some unique parts that nobody at the track will have.

 

Good Luck!

[Danny Steyn]

Welcome Luke - keep the pics coming!

[Jim Drago]

Welcome! Nice to see new drivers and new car builds going on!

Jim

[Ron Alan]

Its a good car...trust me! You say overheated...I hope you checked the head for any warp. Any serious overheat always bends the heads...making them pretty useless candidate for a nice rebuild! Have fun!

[speedengineer]

Welcome.  Looking forward to following your build progress!

[Lmcgrew79]

Its a good car...trust me! You say overheated...I hope you checked the head for any warp. Any serious overheat always bends the heads...making them pretty useless candidate for a nice rebuild! Have fun!

Shaving head down to allowable limit, block, crank and pistons are all getting micrometered as well.

[davew]

Check the cam journals for straightness. When heads warp they can cause binding of the cams.

 

Dave

[Steve Scheifler]

^ and do that with the head torqued to a block.

[Lmcgrew79]

Some more misc painting.

POR15 the under side.

Engine Bay Cleaned and Epoxied

[Lmcgrew79]

Check the cam journals for straightness. When heads warp they can cause binding of the cams.

 

Dave

The head was shaved from the reheat and seemed to be working properly. Im just having it shaved a bit more. Ive had the cams out twice now, if there was a problem would there be noticable heat or scaring signs?

[Steve Scheifler]

Shaving head down to allowable limit, block, crank and pistons are all getting micrometered as well.

When you say to the allowable limit it sounds like you mean minimal total "height" of the head. I have no experience with that particular engine but you want to be certain that combined with everything else that does not put you over on compression. Someone here will know.
In general, I would first calculate based on the minimum to get flat, and then look to deck the block so it is flat and level relative to the crank. Then to get to the compression limit, take off where you can "afford" to without ending up out of spec, or with piston hitting head, or having no margin left to shave again if needed. It's probably easier/cheaper to replace the block than an otherwise good head.

[Steve Scheifler]

The head was shaved from the reheat and seemed to be working properly. Im just having it shaved a bit more. Ive had the cams out twice now, if there was a problem would there be noticable heat or scaring signs?

Depends how tight and how long it has run. With the lifters out it should be very easy to spin the cams with two fingers. Any drag is wasted power and eventually wear or worse. Dave may have more to add from having seen so many.

[Ron Alan]

What others have said was my point with regard to an overheated head...warped. A head with a 12/1000 warp will/may be 12/1000 out on the cam side typical. Setting the cam in place on a warped head(no caps)...it will rock across the center journals when you apply gentle pressure on either end. So you can imagine what happens when you clamp down a straight piece of metal rod threw what is now not a straight line...

 

And as Steve said...you cant assume cutting a head to the minimum will not put you over on compession. Also, when cutting a warped head flat...relative to what they were...the volume in #1 and #4 chambers will decrease more than the center 2 chambers.

[dstevens]

Nice washer and dryer in the shop....    

 

 

Buy Wheeler's book.

http://www.advanced-...&products_id=42

 

I may have an NA 1.8 FSM in PDF, I'll have to look.  If not someone here will have one.

 

Here's a 95 FSM  https://s3-us-west-2...ervice 1995.pdf

 

I don't know if they are still in print but the Grainger book is a great companion to the FSM.  They're still out there. 

http://www.amazon.co...9/dp/1845840909

 

EDIT: add link to FSM

Edited by dstevens, 12-31-2015 04:33 PM.

[davew]

I am not an engine builder. My experience is that if a head is warped bad enough to loose compression it is not usable as a race head anymore. It may work fine for a street car, but will never be good enough for the abuse we put these cars through. I have also seen valve seats fall out shortly after overheats.

 

There are always exceptions, but we are talking "rules of thumbs" here.

 

dave

[davew]

For every newbie, do a google search and you will find most of the factory Shop manuals (FSM) to be available in a pdf form. For free.

 

The "Hayes" books and the "Enthusiasts" books are good references that you can get online pretty cheap.

 

And yes, my book is always available and hopefully it is helpfull.

 

Dave

[Lmcgrew79]

Got a little done today, ordered daves book, welded the pinion all the plugs and put the power steering back together.

 

 

Friend of mine tig welded 4 tacks then 4 more then solid weld with a cool down in between them all.

 

 

Never to much grease!