Tyre rubber, methanol, and bore wear

Status
Not open for further replies.
Joined
Dec 12, 2002
Messages
43,886
Location
'Stralia
Was talking to a mate yesterday, one of Aussie's burnout champions. Blown Big Block, methanol and mechanical injection.

He was talking to his engine builder who has observed what he considers remarkably low (i.e. none visually) bore wear, on engines that have even run 5 years between freshen ups...just throw in new rings/bearings and off they go.

He had a theory (or throwawy line) that the burnout cars running methanol seemed to have a level of additional protection provided by the ingestion of copious amounts of tyre rubber, coupled with the methanol.

Now tyres contain lots of cross linked polymers, sulfur compounds and whatnot.

The engines are typically fitted with blower screens only, 3-4mm grid spacing, and they catch a LOT of rubber, so a lot must be getting through.

Started near cold, then run full noise for minutes at a time, they get a lot of fuel down in the sump, and clearly rubber must be going with it.

So more for Molakule and the chemists...is it possible that some EP type protection is being given to the upper ring area as a result of the interaction of tyre rubber and methanol ?
 
Originally Posted By: Shannow
Was talking to a mate yesterday, one of Aussie's burnout champions. Blown Big Block, methanol and mechanical injection.

He was talking to his engine builder who has observed what he considers remarkably low (i.e. none visually) bore wear, on engines that have even run 5 years between freshen ups...just throw in new rings/bearings and off they go.

He had a theory (or throwawy line) that the burnout cars running methanol seemed to have a level of additional protection provided by the ingestion of copious amounts of tyre rubber, coupled with the methanol.

Now tyres contain lots of cross linked polymers, sulfur compounds and whatnot.

The engines are typically fitted with blower screens only, 3-4mm grid spacing, and they catch a LOT of rubber, so a lot must be getting through.

Started near cold, then run full noise for minutes at a time, they get a lot of fuel down in the sump, and clearly rubber must be going with it.

So more for Molakule and the chemists...is it possible that some EP type protection is being given to the upper ring area as a result of the interaction of tyre rubber and methanol ?



PIB is a rubber like component, and in some form a big part of (more expensive) two-stroke oils. It's also used as a fuel additive to prevent deposits and wear. I don't know if the methanol has anything to do with it.
 
Shannow, do they take any protective steps against the methanol's corrosiveness itself, like put the pistons in the dishwasher after each run?
wink.gif
 
Garak,
I hate methanol, when I did my thesis the guy the year before had used methanol on the inlet manifold test rig...everything was covered in white powder, injectors and pipes were clagged with the stuff...

These guys find a reliable tune then run them until they refresh or break them...5 years was the one mentioned with new rings/bearings, no hone even...i think they change the oil then leave them till next meet.
 
Yeah, methanol motors are run, change oil, park (push in). You gotta change the oil after every session. That might be a day or two at the most... If they are going to idle around, it's on gasoline ...

Drag cars running methanol, change each run with my friends.

I think it's the Pennrite HPR50 and the rubber
smile.gif


My theory is that the mini-rubber balls are cleaning the surfaces of carbon build-up. Carbon can be hard (diamonds anyone...), and getting off every surface all the time is good
smile.gif


Sort of shot blasting with forgiving shot
laugh.gif


Would like to see the underside of the heads when torn down. Bet they are clean as pin too ...
 
Last edited:
After they change the oil, do they spin the engine, without spark, so as to get fresh oil all over?

Other than fuel dilution it seems they are run "always" with fresh oil.

Let's see: 5min at 7k rpm is 35,000 revolutions. This morning I drove to work; 60min x 1,500rpm is 90,000 revolutions. Granted the two operating conditions are polar opposites. However over the course of a month I will do an easy 4 million revolutions (again under easy conditions). While that methanol motor will do what, 35k? [I honestly don't know how often they go to meets.]

*

Actually, is it worst condition? High rpm but once those tires break loose, aren't the motors (mostly) spinning? I won't say it's a lazy spin but I'm wondering if loading is as bad as we think.
 
The only real way to get a handle on that is to look at the throttle position data during a run. If they can back off, yeah it's not the big number all the time. If the throttle is mostly open with minor variations for drift control, it
's making big power all the way.

Drag cars will start the motor on gasoline as part of refresh Q/C for a few seconds and that will splash fresh oil everywhere... Once at the line, they start on gasoline again, then switch over to methanol for burn-out and run ...
 
Status
Not open for further replies.
Back
Top