NB8A blown head gasket

Postby **NitroDann** » Wed Mar 05, 2014 12:59 pm

Johnny... Just stop mate.. Please.

Its basic ignorance like this that has allowed someone to sell you a ffs supercharger

noobee · Postby **noobee** » Wed Mar 05, 2014 1:02 pm

the point is it will take it up all on the tensioner side,thus moving cam pulley by double the distance you have removed from the head.
Mick

johnnyreble · Postby **johnnyreble** » Wed Mar 05, 2014 1:07 pm

Well if you think shaving the head 20thou is going to make such an adverse difference .. Don't do it..

noobee · Postby **noobee** » Wed Mar 05, 2014 1:12 pm

noooo!,i'd go 35 or 40,lol.
Mick

Postby **NitroDann** » Wed Mar 05, 2014 1:43 pm

johnnyreble wrote:Well if you think shaving the head 20thou is going to make such an adverse difference .. Don't do it..

Did you even read my post, I explained that most shaves wont make enough of a difference and I even explain the cheap and easy way to fix it without resorting to buying adjustable cam gears.

Read man. This is why you have 180whp for $8000 not 250whp for 6.

Dann

Mr Morlock · Postby **Mr Morlock** » Wed Mar 05, 2014 1:57 pm

Everyone should know- if the car overheats i.e. boils then do not drive it. How do you baby it- you cannot - the engine just does what engines do- increases the heat and if the cooling system is failing it does damage. Unfortunately the right thing to do is get a flat top . PRR is right- get the thing checked by a competent professional.

wydra · Postby **wydra** » Wed Mar 05, 2014 2:12 pm

Mr Morlock,
As soon as the engine dropped all its coolant and overheated I shut it down straight away. After waiting on the side of the road for about an hour I managed to get the hose re-clamped and I got someone to bring me 6L of distilled water to get me running again.
From that point onwards I babied it so it got me home (which it did).

I have contacted a Head place here in the West and they are going to pressure check the coolant passages, valves etc and do a hardness test.
If it is in good enough condition they will surface the face (they said hopefully less than 10 thou) and get it back to me.

I am going to purchase a Genuine Mazda OEM head gasket.
The only thing I need to decide on is if it is worth going to studs, or getting new bolts.

wydra · Postby **wydra** » Wed Mar 05, 2014 4:09 pm

I have decided to get myself a set of ARP head studs.
I know there has been a lot of discussion on torque specs, it seems ARP say 80lbs where most people besides ARP recommend 65lbs. I was thinking 65lbs should be heaps as I am going with an OEM gasket, has anyone had a failure with either of these torques?

OurCognitiveSurplus · Postby **OurCognitiveSurplus** » Wed Mar 05, 2014 4:36 pm

10 thou? Like, $10k?

wydra · Postby **wydra** » Wed Mar 05, 2014 4:47 pm

hahaha nah,
I meant they will be shaving under 10 thousandth of an inch off the head.

Mr Morlock · Postby **Mr Morlock** » Wed Mar 05, 2014 5:17 pm

I completely agree that moving the car is so tempting- not sure if I would take my own advice but it's so easy to damage engines in modern cars. I had old rockets that you could boil regularly and it did not seem to matter but then they were low comp cast iron heads etc. wydra seems to have it under control - head specialists should know.

Aussie Stig · Postby **Aussie Stig** » Wed Mar 05, 2014 6:07 pm

wydra wrote:Mr Morlock,
As soon as the engine dropped all its coolant and overheated I shut it down straight away. After waiting on the side of the road for about an hour I managed to get the hose re-clamped and I got someone to bring me 6L of distilled water to get me running again.
From that point onwards I babied it so it got me home (which it did).

.

This is a little worriesome as I have inadvertantly overheated other cars (non mx5) with no issues. Maybe I was just lucky.

Good luck.

davekmoore · Postby **davekmoore** » Wed Mar 05, 2014 7:27 pm

When the head is checked it needs to be checked for straightness throughout and for the cam bearings not being overheated etc etc. If the cams and the rest of the head are out of true, skimming the bottom of the head won't make up for that.

Before you do only the top of the motor, out of interest, how do you know there's no damage to the bottom end?

wydra · Postby **wydra** » Wed Mar 05, 2014 8:48 pm

Yes I am dropping the head complete with all valves and cams to a head specialist to check it over and machine the face IF it checks out ok. If it doesn't check out ok I will have to find a replacement.

As for the bottom end it was in good condition before this issue. After the overheat there was no bottom end noises and oil pressure remained fine. Being an iron block as long as I don't see any marks/groves in the bores it "should" be fine. Again if it is bad then I will have to replace it but for now, I'll repair what is most likely.

davekmoore · Postby **davekmoore** » Wed Mar 05, 2014 9:18 pm

Seems you have all bases covered so good luck with the head repairs.

The overheating event(s) on my car (which also happened to cause or to be a result of a lot of other stuff) caused the BP4W head to be warped, twisted, out of true in three dimensions and to have bent cams and valves and scored cam journals. All good apart from that though.