Another OHV M90 build

[Dono]

Couldn't help it. Trigger happy. seems like its free power. A smaller pulley has to take more horsepower, but something like this just increases efficiency. Just more labor to change it out.

 

[rocket 5979]

I wish I'd have seen this earlier:
http://gm-supercharger.com/m90-eaton-rotor-pac90.html
$50.00

The coated gm rotor pack fits the Ford M90 I have with the change of a locator pin. Apparently is good for a 1psi boost, and less heat. Too good to be true?

Rocket? Want to give it a go as you progress? I'd have tried it for that price.

No thanks. Even though it isn't expensive I will just spin the pulley a little faster if I want a little more boost out of it. It is definitely not optimal to do it this way but I am not going for anywhere close to a maximum setup.

 

[Dono]

I hear you Rocket. I don't have the toys you have to play with. If I did, I don't think I'd bother also.

 

[Dono]

Ok, exhaust and 2.7" pulley on.

Thinks I noticed are:
With the 10% pulley boost was max 10lbs. Now with exhaust, max boost is 7.
I just logged, and my iat's at wot, high rpm are down 35 degrees from where they were.
James has the logs to perform his magic with when he has a moment.

Now the bad:
Cabin drone, and no mandrel bends.
Obviously the mandrel bends dont matter at the Y pipe to 4" pipe going in to the high flow cat. From cat to muffler (flopro) it might a bit. Then the tail pipe has lots of bends. Im betting the non-mandrel bent pipe looses 1/2 inch at the bends. I probably effectively only have 2" pipe at the tail.
As far as the drone, I'm older and its a daily driver. I need to do something. Maybe another resonator, or another muffler? I'll work on that next week.

It was interesting (Not in a good way) that after the new exhaust was installed I had a leak at exhaust manifold to head. Im not sure what happened there, as I'm sure the shop didn't do anything to cause that other than move the pipes around a bit.

I pulled the manifold, and wen't to install a new gasket I thought I had laying around, and found they were old gaskets ****! I cleaned up the surfaces and gasket and re-installed. No leak so far.

So, It was interesting that a free flowing exhaust reduced boost by 3lbs and reduced the iats by 35 degrees (Thats comparing the iat's of the 3" pulley against the iat's of the 2.7" pulley). Exhaust definately made a huge difference performance wise (Fact, looking at preliminary numbers).

Can't say performance (accelleration) wise, as I couldnt really tell a difference with just the exhaust, but we all know that combined with the smaller pulley makes a faster truck.

My truck doesn't sound too loud from the outside (I kinda like it) when someone else is driving and I'm standing on the street. Its that cabin drone I need to reduce.

 

[rocket 5979]

Good to hear on the IAT drop even while going with a smaller pulley.

 

[jd4242]

Ok, exhaust and 2.7" pulley on.

Thinks I noticed are:
With the 10% pulley boost was max 10lbs. Now with exhaust, max boost is 7.
I just logged, and my iat's at wot, high rpm are down 35 degrees from where they were.
James has the logs to perform his magic with when he has a moment.

Now the bad:
Cabin drone, and no mandrel bends.
Obviously the mandrel bends dont matter at the Y pipe to 4" pipe going in to the high flow cat. From cat to muffler (flopro) it might a bit. Then the tail pipe has lots of bends. Im betting the non-mandrel bent pipe looses 1/2 inch at the bends. I probably effectively only have 2" pipe at the tail.
As far as the drone, I'm older and its a daily driver. I need to do something. Maybe another resonator, or another muffler? I'll work on that next week.

It was interesting (Not in a good way) that after the new exhaust was installed I had a leak at exhaust manifold to head. Im not sure what happened there, as I'm sure the shop didn't do anything to cause that other than move the pipes around a bit.

I pulled the manifold, and wen't to install a new gasket I thought I had laying around, and found they were old gaskets ****! I cleaned up the surfaces and gasket and re-installed. No leak so far.

So, It was interesting that a free flowing exhaust reduced boost by 3lbs and reduced the iats by 35 degrees (Thats comparing the iat's of the 3" pulley against the iat's of the 2.7" pulley). Exhaust definately made a huge difference performance wise (Fact, looking at preliminary numbers).

Can't say performance (accelleration) wise, as I couldnt really tell a difference with just the exhaust, but we all know that combined with the smaller pulley makes a faster truck.

My truck doesn't sound too loud from the outside (I kinda like it) when someone else is driving and I'm standing on the street. Its that cabin drone I need to reduce.

Are you saying you dropped 35* from what the smaller pulley was producing or from the 195* temps you was seeing with the larger pulley?if so what was the temps of the smaller pulley before the exhaust? If not then thats really hard to believe that with the smaller pulley (doubling the boost,witch i dont understand how a 3" gives you 4-5lbs and a 2.7" gives you 10lbs)just the exhaust dropped you 35* from the temp that you was seeing with the larger pulley.

 

[Dono]

JD, Your right. But, I looked at the logs myself before sensing to James.

I didn't log temps with the smaller pulley with stock exhaust. I should have.

I wen't thru all my logs before the new exhaust was installed, and all iat's at wot are reasonably consistant.

I am, without a doubt, seeing that a free flowing exhaust has a huge effect on iat's. At least on our motors.

I'll be making a few more logs to confirm my results.

Very interesting. Im extremely happy, as you can all imagine. I was worried about using the smaller pulley.

Still no where near the temps JD is seeing, but at least I have manageable temps.

An exhaust giving lower iat's, and dropping the boost by 3lbs is pretty good. So, maybe its worth the cash afterall.

 

[jd4242]

JD, Your right. But, I looked at the logs myself before sensing to James.

I didn't log temps with the smaller pulley with stock exhaust. I should have.

I wen't thru all my logs before the new exhaust was installed, and all iat's at wot are reasonably consistant.

I am, without a doubt, seeing that a free flowing exhaust has a huge effect on iat's. At least on our motors.

I'll be making a few more logs to confirm my results.

Very interesting. Im extremely happy, as you can all imagine. I was worried about using the smaller pulley.

Still no where near the temps JD is seeing, but at least I have manageable temps.

An exhaust giving lower iat's, and dropping the boost by 3lbs is pretty good. So, maybe its worth the cash afterall.

O definitely worth it

 

[Dono]

Well, latest annoyance. My M90 is getting louder and louder.

I'm guessing a bearing is failing. No idea for sure. Im going to have to get another rebuild kit before I take it apart.

I shimmed the pulley out about 1/4 inch to get my belt to align nicely. I wonder if that added enough stress on the snout bearings to cause this.

I might buy another M90 and rebuild the snout to stick on till I get the original sorted out. That way, no down time. Its definitely growling now. Seems to come and go, but starting to be more constant.

 

[Dono]

Well, I found my noise. It was the loose nut holding the wrench (Me).

The shimms (Metal Washers) I used to shim out the pulley were moving around in between the Pulley, and M90. Also, I don't think there was enough of the key holding the aluminum pulley in place.

Long story short, I now need a new pulley and key. The pulley key slot is probably an 1/8 inch wide causing the pulley to move around. The key is chewed and rounded.

The 10% pulley will be easy to find, but the key might be an issue. Education costs money. Shoot.

 

[Ronin8002]

I know you can get key stock from McMaster-Carr or other similar sites:

http://www.mcmaster.com/#

look under the "power transmission" section on the main page.

 

[jd4242]

I may have some key stock laying around my shop.ill check when i get home and post up the size if i do.of course its yours if i can find it

 

[Dono]

I think I'll be ok. A guy over at SCCoA has a spare hes sending me with a new 10% pulley.
I loved the aluminum one, but the one I am getting is steel. Apparently the aluminum ones don't fit the shaft as tight and rely too much on the key and that can cause issues.

I appreciate it guys.

The key thing concerned me (Not to mention me being pissed at myself for not being mare careful with what I was doing).

 

[phix-]

Hey Don, got any road video of that exhaust? I am curious if your high flow cats make it much louder or even what your cabin noise is like after reading your thoughts on it.

 

[Dono]

Nothing, but I'm sure I can record and post.
I added a small resonator between the cat and muffler.

The motor has a burble to it, and is a bit louder than stock, but not bad. I'd describe it as 'Throaty'. I'll get something up this weekend.

 

[Dono]

coated rotors

My 'used' coated rotors showed up. A bit more 'used' than I had hoped for, but maybe I was expecting too much.
I wonder what the best way to get this carbon off is? I tried a rag and isopropyl alcohol, but its slow and painful.

 

[jd4242]

My 'used' coated rotors showed up. A bit more 'used' than I had hoped for, but maybe I was expecting too much.
I wonder what the best way to get this carbon off is? I tried a rag and isopropyl alcohol, but its slow and painful.

You sure that's carbon and not the coating?i thought they were used blades that had been recoated .

 

[jd4242]

Or wait is that the old style grey coating on the tips?

 

[Dono]

Yes, the black is buildup, and the grey is the coating.
These are advertised as good used rotors, no rebuild.
The coating is nice and smooth as I get down to it, the coating is worn off the ends of the rotors. Too bad, as I would guess the closer the rotors are to the case, the better the seal making the M90 more efficient.

 

[Dono]

Here's an interesting read:
http://www.grandprixforums.net/i-rebuilt-my-m90-rotors-home-20356.html
The guy did this in Australia. I'd expect there to be a place that does the same thing in NorthAmerica. Interesting how he said rotor timing was not an issue for him during re-assembly. I'm not sure I'd be so brave.