9 replies to this topic

[bmarshall1]

I'm looking to get a bit of advice and guidance.  I have a spare 99 w/ 70k and a supposed 1 weekend crate motor (w/ very scored bores).

 

At this time I do not feel I would really be able to utilize the advantage of that last 1 or 2 HP that a Race Motor (RM) will generate and may spend my funds on something more helpful to improving lap times and skill, having said that, I have a few questions.

 

Horsepower.

 

What is the average HP of a RM, vs Fresh rebuild vs. Decent Junkyard motor.

How much HP loss does a restrictor cause.

Any idea HP vs Lap time example, 1 hp = .5 seconds per lap minute.

 

If I were to go to an engine builder, what do I even ask for, this is something I have not done before.

 

I assume find a reputable shop to bore/hone, then I take it from there?  What about working on the head, obviously a valve job is in order, but what else to do,(or not to do).

 

Would any shop worth their salt know what to do?

 

I am not asking for trade secrets, but are there any specific things I should be looking at (legal things) during a rebuild, any tips?

 

I have heard  go with over bore both yes and no

Mill the head  and block both yes and no

Don't mill the head but do 'deck' the block (and the opposite)

 

Which heads to use, which to avoid (e.g. 3-2 vs 4-4 etc...

 

More questions as i think of them.

 

[Tifosi27]

Give Chris Graham at Race Engineering a call.  He's local in Salisbury and can certainly work with what you need and give you all sorts of advise.

[Jim Drago]

bmarshall1, on 07 Dec 2020 - 03:04 AM, said:

I'm looking to get a bit of advice and guidance.  I have a spare 99 w/ 70k and a supposed 1 weekend crate motor (w/ very scored bores).

 

At this time I do not feel I would really be able to utilize the advantage of that last 1 or 2 HP that a Race Motor (RM) will generate and may spend my funds on something more helpful to improving lap times and skill, having said that, I have a few questions.

 

Horsepower.

 

What is the average HP of a RM, vs Fresh rebuild vs. Decent Junkyard motor.

How much HP loss does a restrictor cause.

Any idea HP vs Lap time example, 1 hp = .5 seconds per lap minute.

 

If I were to go to an engine builder, what do I even ask for, this is something I have not done before.

 

I assume find a reputable shop to bore/hone, then I take it from there?  What about working on the head, obviously a valve job is in order, but what else to do,(or not to do).

 

Would any shop worth their salt know what to do?

 

I am not asking for trade secrets, but are there any specific things I should be looking at (legal things) during a rebuild, any tips?

 

I have heard  go with over bore both yes and no

Mill the head  and block both yes and no

Don't mill the head but do 'deck' the block (and the opposite)

 

Which heads to use, which to avoid (e.g. 3-2 vs 4-4 etc...

 

More questions as i think of them.

I'm looking to get a bit of advice and guidance.  I have a spare 99 w/ 70k and a supposed 1 weekend crate motor (w/ very scored bores).

 

 

First thing to check is head, if bores are scored, it very well may have a warped head and in that case.. 

 

 

 

At this time I do not feel I would really be able to utilize the advantage of that last 1 or 2 HP that a Race Motor (RM) will generate and may spend my funds on something more helpful to improving lap times and skill, having said that, I have a few questions.

It better be more than 1-2 hp, despite expert opinions of "top Sm drivers' few of us have seat dynos that accurate. 

 

 

Horsepower.

 

What is the average HP of a RM, vs Fresh rebuild vs. Decent Junkyard motor. 

Dyno numbers are different every where. 

Fresh rebuild  depends on your definition?  Assuming you do nothing but valve job, hone, bearings and maximize compression and your fresh rebuild see below and just guesstimates as we have not done junk yard or rebuild like this in years..  

On my dyno

good race motor on 99 makes 127-130

fresh rebuild  122-123

good used  117-121

other can offer their opinion, that's mine

 

 

 

How much HP loss does a restrictor cause.

about 12 from memory , I have not tested this in many years

 

Any idea HP vs Lap time example, 1 hp = .5 seconds per lap minute.

pull your plate in practice, thats more than what a race motor will make and give you a better answer.. roughly 1 second depending on track 

 

If I were to go to an engine builder, what do I even ask for, this is something I have not done before.

Tell them you want a race engine for your Miata, despite popular opinions. All the reputable builders build every engine the same, the only difference being the actual head castings.

 

 

I assume find a reputable shop to bore/hone, then I take it from there?  What about working on the head, obviously a valve job is in order, but what else to do,(or not to do).

The problem is experience and tooling. Yes If given the rules and competent machine shoo can build you an engine that should be "competitive", will it be as good as the three or four builders that build 905 of the Sm engines, likely not.  Hard to just nail it on first 25-50 tries, let alone first

 

Would any shop worth their salt know what to do?

If you print off the rules and hand them to them, yes they should.. but how would you know?

 

I am not asking for trade secrets, but are there any specific things I should be looking at (legal things) during a rebuild, any tips?

No warpage in head, no scoring of cam journals in head.. no wear in key slot in crank

 

I have heard  go with over bore both yes and no

not neded if block is in good shape

 

Mill the head  and block both yes and no

preference

 

Don't mill the head but do 'deck' the block (and the opposite)

preference

 

Which heads to use, which to avoid (e.g. 3-2 vs 4-4 etc...

Definitely avoid the 4-4, as they would be non compliant  

 

More questions as i think of them.

 

 

From what I am reading, I have not seen your results.. I don't think a motor is the best use of funds if funds are tight right now. I don't know your budget either. Its a personal decision, but unless you are within 1-1.5 seconds of pole routinely, I don't think the engine is your primary issue.   Pull your plate in practice and see where you stack up. Maybe that will help in your decision. I will share this.. I bought a race engine before race three in Sm, with no prior racing experience, just DE    It was 2003 and it was $6000 then. I blew it up in 2 weekends, it was a 94 and the shop I used to install it used the wrong timing mark.. so instead of 15-16 degrees, we were running 25-26   The premiere shop at the time was Sunbelt, they gladly sold me another for $5500   That was 11500 that I never needed to spend and wished I hadn't. The engine was not my main problem at that time.  

 

Jim

[gerglmuff2]

id do a couple of years/seasons on a "stock" motor before i bought a pro motor. get your first money-shift out on a cheapo motor, instead of a nice race motor. 

but also, don't underestimate the power of a race motor. its 1+ second of lap time. its real. its a lot more than 1-2hp difference. also drago is giving good advice, its wiser i think to order a motor from an established builder, rather than a local engine shop. chances are good the local shop will do something not allowed, or not do something that is allowed, and while they might be in the ballpark of an Xfactor/ESR/etc engine, you are pretty well guaranteed to have a great and legal motor from them, and only cost a slight bit more. your motor not agreeing with you one weekend, more than covers than price difference. 

[LarryKing]

Especially since you are NC, visit Mike Rossini, Belewes Creek, NC (sorta between Winston-Salem and Greensboro, Kernersville exit off I-40) Rossini Racing Engines

 

I have no financial interest, just a very happy customer. Outstanding power, value priced, and service after the sale. You won't regret it.

[SaulSpeedwell]

Have you considered racing something superiorly and properly engineered, like a Porsche or a BMW, or even F1 World Champion Of Automatic Transmission-equipped vehicles going -10 mph in the "fast lane" while the driver manually shifts their smartphone into passing gear (Mercedes-Hitler-Limo-Maker-Benz)?  Do that for a year or two, and then revisit this question.  

This message was 33% sponsored by Tom Sager.

[Tom Sager]

SaulSpeedwell, on 07 Dec 2020 - 8:54 PM, said:

Have you considered racing something superiorly and properly engineered, like a Porsche or a BMW, or even F1 World Champion Of Automatic Transmission-equipped vehicles going -10 mph in the "fast lane" while the driver manually shifts their smartphone into passing gear (Mercedes-Hitler-Limo-Maker-Benz)?  Do that for a year or two, and then revisit this question.  

This message was 33% sponsored by Tom Sager.

Well that's proof right there that confinement due to Covid-19 is taking its toll on the mental health of those forced-to-work-from-home.

 

Or it's just residual anger that your British ancestors lost their auto industry to the Germans, but when your outdoor product sold to people on a large island doesn't work in moist climates it's tough to compete.

 

But I still love you. 

[bmarshall1]

Great answers, I'll have to re-read and digest the info prior to commenting

[SaulSpeedwell]

Tom Sager, on 07 Dec 2020 - 11:11 PM, said:

Well that's proof right there that confinement due to Covid-19 is taking its toll on the mental health of those forced-to-work-from-home.

 

Or it's just residual anger that your British ancestors lost their auto industry to the Germans, but when your outdoor product sold to people on a large island doesn't work in moist climates it's tough to compete.

 

But I still love you. 

My Dad's middle name was Herman, and his dad's first name was Herman, and that's not something Gomez Addams could ever say, plus one of the Hermans told me he was 1/16th Cherokee.  Plus, I've owned at least 10 vehicles with the word "Cherokee" in the model name.  You, on the other hand .... well ... 'How Dare You?!"  /satire /parody /except_for_the_true_parts 

[Tom Sager]

SaulSpeedwell, on 08 Dec 2020 - 3:50 PM, said:

My Dad's middle name was Herman, and his dad's first name was Herman, and that's not something Gomez Addams could ever say, plus one of the Hermans told me he was 1/16th Cherokee.  Plus, I've owned at least 10 vehicles with the word "Cherokee" in the model name.  You, on the other hand .... well ... 'How Dare You?!"  /satire /parody /except_for_the_true_parts 

Marshall said the answers were great, even yours!