New Problem with my FP Miata

H

HPMotors

Member
Just had a bad weekend at CMP - New engine3 tune, runs great, then the alternator/water pump belt jumps off. Checked it out, put belt back on and off she came again. This time I think I overheated the engine.

Stock pump, crank pulley and alternator - alignment looks perfect. All Mazda bits. The outlier, is that we were able to twist her up to 9k.

Anyone else seen this issue? Been running Miatas for quite a while, and this is a new one for me.
Henry
 
Check to make sure the crank pulley and water pump pulley run true. You really shouldn't be running those rpm's with any of that stock stuff fyi.
 
Not sure what caused it to come off, but alignment of pulleys does not appear to be the problem. Checked visually, with straight edge and small rope. All looks good. Ditto with the alternator - spins freely with no binding, noises or discernable abnormality.

Best plan now is to change to multi rib belt. No issue with the alternator or water pump pulleys as 1.8 pieces fit. Problem as I see it is getting a multirib pulley for my SNC harmonic balancer. Don't know if any off shore 1.6's had a multirib belt, but fairly certain there isn't one avalable for the SNC. Guess I will just bite the bullet and put a long nose in.

Any ideas on an electrically operated water pump? Convert alternator to dc motor and run a gilmer belt? This option seems to require a total discharge battery system which is another problem to design around. Mount electric motor directly on the water pump?

cheers
Henry
 
GT6 said:
Have you read pg. 460 of current GCR?
Click to expand...
m. Other Engine Components
1. The use of alternate engine components which are normally expendable and considered replacement
parts, such as fasteners, gaskets, seals, bearings, water pumps, etc., is permitted. Electrically
driven water pumps are prohibited.
 
I've got the November 2024 GCR in my hands, and (.1.5 Production Category starts on page 471, which is Level 1 Prep. Page 476 starts level 2.

However, the section m is what you quoted and despite looking for the mention of electric water pumps, i had missed it when I started this idea. Mea Culpa.

Good thing I don't have done anything other than research on the electric pump idea. Thanks for the heads up.

So, back to my problem. How do I put a multi rib pulley on my 1.6 with the short nose crank? Obviously, next engine will have the LNC but I've got this one in the car and the next event is in 3 weeks.

Other ideas as to keeping the v-belt on my engine are welcome. I am just guessing that the multi rib belt would better handle the high rpms.

Henry
 
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I don't see the November 2024 GCR.

How did you get that soo early?

There's always the option to make your own pulley.
Many people will create a 3D model for you and many quick-turn job shops will make the part for you.

Maybe you could add/bolt/weld guild washers to your existing pulleys? That way the belt has to stretch much further before it jumps off.
 
There's no way to install a serpentine style belt onto a short nose crank.
You're on borrowed time with that crank with a high rpm application. Maybe keep your revs down a bit for this last weekend for the year.
 
On the 2024 GCR - it was on the SCCA website under downloads. They have a 2024 GCR shown, then each month of an updated 2024 including the future "November 2024" version.

As far as Jesse stating that my SNC crank has been on "Borrowed Time". If that is the case, it has done so for the last 19 years. I have used these cranks specifically to prove there is nothing wrong with the crank itself. Every SNC car that we had in the shop with a damaged crank had improper repair procedure done previously when the timing belt was changed. Specifically installing the directional woodruff key backwards to create a false torque.

As further proof of the concept, my wife has a 1990 with the original SNC 1.6 engine - only showing 185,000 miles and no problems. My son also has a 1990 Miata - original SNC 1.6 engine but with a SuperCharger installed since we bought the car in 1995. It has over 261,000 miles on it with no issues. Also had we had an 02 Miata in the shop with a broken crank - pulley got loose. Clearly the 02 had a LNC

All that said, I did not realize the limited bits available for the SNC. Fortunately I have several 1.6 LNC - just none that have been prepped.

My machinist buddy is evaluating the possibility of making an adapter that will allow the LNC crank pulley to be installed on the SNC.

Hey Jesse, Last time we talked you said that you only sold your FP cams with a complete engine -Is that still the deal or can I get a set of cams from you? My current cams are Integral FP4 and FP3 cams that I bought back in 2005. My thinking is that cam development should have come a ways forward in the last 19 years.

cheers
Henry
 
Sounds like you're doing just fine. Excellent.
No, I don't sell just parts unless their inside of a complete engine.
Good luck!
 
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