Aftermarket Timing Belts

[satan_srv]

For the cams I'll be running a super strong t-belt is defintely needed. I used a Power Enterprise on my H22a with great results so I was wondering if any has some NSX experience with the aftermarket belts

Power Enterpise about $190 shipped
- says C30A but also 90/9+ doesn't close the date range

Toda Racing $250
- says C32B only...why is that does the C30A have a different size timing gear on the crank? different teeth spacing?

anybody else make them? Greddy?

Anybody using them?

 

[sjs]

You might do better with this question in the racing forum, but even there response may be minimal. I think you'll find that most people stick with the OEM part for street use because they have no reason to do otherwise. Since it sounds like you plan on high lift cams and the stiffer springs that requires, along with higher compression and redline, then a better belt is certainly worth getting. Unfortunately there still aren’t many people on these forums who have gone that route so you may need to base the decision on experience with other cars or broaden your search for answers.

 

[satan_srv]

hehe I'll just do what I know best...which is break new ground

at least for street cars anyway.

Does the NSX use a manual t-belt tensioner or an automatic/hydraulic one?

 

[sjs]

hehe I'll just do what I know best...which is break new ground ...

I suggest that you get a factory shop manual before you start breaking things, ground or otherwise.

 

[satan_srv]

already ordered from helminc. Breaking things is my specialty.

 

[Yellow Rose]

Does the NSX use a manual t-belt tensioner or an automatic / hydraulic one?

The t-belt tensioner is nothing more than a simple spring assembly.

Beginning with the drive pulley on the crankshaft, the t-belt wraps around the tensioner pulley on the "back side" of the t-belt.

The tensioner pulley and the water pump pulley are smooth; whereas, all other pulleys are cogged.

After the tensioner pulley, the next sequence is:

rear cylinder bank exhaust cam pulley
rear cylinder bank intake cam pulley
water pump pulley
front cylinder bank intake cam pulley
front cylinder bank exhaust cam pulley
back to the crankshaft drive pulley

PS - "satan" vs "saint".....could be an interesting relationship

 

[satan_srv]

ahh so it's 'manual' then as in you tighten the tension yourself.

the H22a had this terrible design where a hydraulic tensioner would tighten to keep the belt tight all the time while driving...problem is it always fails they had to redesign the part finally in 2000.

Super strong belts and high lift cams were especially hard on the auto-tensioner because it would be used to the strength of the valvesprings and belt! We had to take parts of the Si H23 motor to eliminate the auto-tensioner.

 

[Yellow Rose]

ahh so it's 'manual' then as in you tighten the tension yourself.

No.

Wrap the t-belt around the pulleys, install the spring-tensioner and you're done. No tightening involved.

 

[Eddy]

FYI,
C30 and C32 timing belts are the same (length, width, part number).

Eddy

 

[satan_srv]

ahh so it's 'manual' then as in you tighten the tension yourself.

No.

Wrap the t-belt around the pulleys, install the spring-tensioner and you're done. No tightening involved.

umm no.

Do you actually advise people of this kind of stuff? Have you ever assembled a Honda 'engine'? Done a timing belt job?

Perhaps you should review page 6-22 of the helms manual where it shows you how to adjust the tension on the timing belt. with the adjustment bolt. It's number 12 in this pic

Thank you, have a nice day.


p.s. your quoting style is pretty darn annoying. edit: I await your latest cursing PM

 

[Yellow Rose]

To answer your question, yes, I have rebuilt an NSX engine and I have also done a t-belt on said engine.

You are VERY mistaken. Item #12 that you try to rub my nose into IS NOT the tensioning device. Look closely, and you will see item #10 as the spring assembly that I reference.

How much further do you wish to take this?

BTW - as I speak / type. I have an original NSX service manual in front of me.

 

[satan_srv]

To answer your question, yes, I have rebuilt an NSX engine and I have also done a t-belt on said engine.

You are VERY mistaken. Item #12 that you try to rub my nose into IS NOT the tensioning device. Look closely, and you will see item #10 as the spring assembly that I reference.

How much further do you wish to take this?

BTW - as I speak / type. I have an original NSX service manual in front of me.

Are you gonna make me scan page 6-22 to prove you wrong? I'm looking at the 91 PDF manual and indeed #12 is the adjustment bolt. If you have the manual in front of you I'm surprised you don't open it up once in awhile...I know the spring hodls the tension...the bolt adjusts it...meh

disclaimer: maybe you are dealing with the C32B1 and the tensioner is different..I'll give you the benefit of the doubt for now. But the C30A1 has an adjustment bolt and it's very obvious spelled out.

 

[satan_srv]

For my own amusement:

 

[satan_srv]

FYI,
C30 and C32 timing belts are the same (length, width, part number).

Eddy

Thanks Eddy...makes sense good to know there's at least 2 options.

 

[Yellow Rose]

My point is, Einstein, is that once installed, the t-belt tension is a constant and does not need to be adjusted.

Tell you what.....both of our hormones are out of control.

I stepped out of line initially, corrected myself, offered some help, but that was not to your liking.

You want to continue, let's go PM to avoid subjecting our public friends to our poison.

 

[satan_srv]

I agree with you on the tension should not need to be adjusted in stock form once installed.

But in the reality of high lift cams and stiff valvesprings which is the context of this topic a stock t-belt and tensioner will need to be adjusted before the service interval, or just replaced.

And we don't need to continue with the PMs because I am not 2 years old.

 

[mystican]

timing belts

The way I understand it...Factor X engineering has stated that their turbo NSX uses the STOCK OEM timing belt has tested the belt in the car's development in the past...

The Toda belt is stronger but not need according to Factor X...

Just my two cents...

 

[sjs]

Re: timing belts

The way I understand it...Factor X engineering has stated that their turbo NSX uses the STOCK OEM timing belt has tested the belt in the car's development in the past...

The Toda belt is stronger but not need according to Factor X...

Just my two cents...

That's because they use stock cams and stock or only slightly stiffer valve springs. High lift and stiff springs are the concern with a built NA engine.

 

[satan_srv]

Re: Re: timing belts

That's because they use stock cams and stock or only slightly stiffer valve springs. High lift and stiff springs are the concern with a built NA engine.

Yeah that's my main concern, the vavlesprings are so stiff it causes a lot of pressure to be transmitted through the cams to the gears to the belt.

Even if an OEM belt would last long enough it's a question of insurance for me, because when a belt breaks that's a head job.

Same reason I'll put in an aftermarket oil pump gear, sure nothing will probably ever happen, but if it ever shatters at 8000 rpms and I ruin my crank and blow a rod I won't be too happy

 

[sjs]

Re: Re: Re: timing belts

...Same reason I'll put in an aftermarket oil pump gear, sure nothing will probably ever happen, but if it ever shatters at 8000 rpms and I ruin my crank and blow a rod I won't be too happy

Actually, the pump gear is probably the greater risk. They have been known to break, although I'm not sure the degree to which oil starvation from inadequate sump baffles may have contributed.

Surely you will be running more than 8K.

 

[AcuraNSX]

Slightly Confused.......

I thought all car manufacturers switched over starting the late 80's to engine types that can not suffer from bent valves or damage to the head as a result of a timing belt breakage. I believe they call it a noninterference engine? I may have the terminology wrong but the idea is the same, if timing belt breaks and the pistons go flying up, they do not go so far as to hit the valves and do the extensive damage to the valve train. correct me if I am wrong.......

 

[KulSecHskY]

Re: Slightly Confused.......

I thought all car manufacturers switched over starting the late 80's to engine types that can not suffer from bent valves or damage to the head as a result of a timing belt breakage. I believe they call it a noninterference engine? I may have the terminology wrong but the idea is the same, if timing belt breaks and the pistons go flying up, they do not go so far as to hit the valves and do the extensive damage to the valve train. correct me if I am wrong.......

sounds like a great idea haha. never heard of it before though, always been told that if your t-belt goes then so does ur head.

just found a thread where a guy totalled his head after his t-belt broke
here

 

[Ojas]

Re: Slightly Confused.......

I thought...

Your terminology is correct, but you're incorrect about manufacturers switching over to non-interference designs. The trend has been the opposite. Compression ratios have increased and engines with higher compression ratios generally require an interference design. Because I'm too lazy to explain, I'll just quote:

From http://members.shaw.ca/costall/1000Q/answers-terms.htm:
An 'interference' engine is an engine where the valves and pistons occupy the same space, but not at the same time. The other engine style is a 'non-interference' engine - this design provides enough room between the pistons and the valves so that they never occupy the same space. Non-interference engines are sometimes called 'free-running' designs.

Interference engines are a fairly common engine design. All diesel engines are interference designs, and many imports. Domestic engines have tended towards non-interference designs. Although all engines use timing belts, they are more crucial on interference engines; should the timing belt malfunction, the valves and pistons will likely collide.

While this may seem like a stupid engine design, there are reasons why an engine may be designed as an interference engine. Higher compression ratios are possible, leading to better fuel economy, power, and emissions quality.

 

[ncdogdoc]

Re: Re: Re: Re: timing belts

..........

Surely you will be running more than 8K.

Just curious as to why you would think this. He said he was looking at a street based setup, and the chances of big, expensive problems increase exponentially above 8000rpm. The above referenced engine by Comptech has a recommended tear down and rebuild once a year with an 8000rpm redline, but a once a quarter(or more often) tear down when the rev limiter is above 8500. They do not recommend above 9000rpm.

I have pondered this for the track car (increased rpm), but even with the oil pump gear, I am not sure the extra 500rpm would be worth the risk. Now if I had a higher R&P, hmmm.

With FI, I think it is really a risk due to such high cylinder pressures under boost the rods and walls are much more likely to fail above even 7000rpm. This is an email excerpt that I received from a friend late last year.

Just as a quick note. We calculated the rod stresses at various RPM and boost levels and determined that the rod loads increased over 90% as one ran past the 7200 RPM range

 

[satan_srv]

Re: Re: Re: Re: Re: timing belts

Just curious as to why you would think this. He said he was looking at a street based setup, and the chances of big, expensive problems increase exponentially above 8000rpm. The above referenced engine by Comptech has a recommended tear down and rebuild once a year with an 8000rpm redline, but a once a quarter(or more often) tear down when the rev limiter is above 8500. They do not recommend above 9000rpm.

I have pondered this for the track car (increased rpm), but even with the oil pump gear, I am not sure the extra 500rpm would be worth the risk. Now if I had a higher R&P, hmmm.

With FI, I think it is really a risk due to such high cylinder pressures under boost the rods and walls are much more likely to fail above even 7000rpm. This is an email excerpt that I received from a friend late last year.

Just as a quick note. We calculated the rod stresses at various RPM and boost levels and determined that the rod loads increased over 90% as one ran past the 7200 RPM range

In addition if I stroke the motor it's highly unlikely despite what cam I use my peak power will be above 8000 anyway.

For example using the same head and crower 3 cams on my h22a I have done 2 setups with similar compression

1. H22a block 90.7mm crank 11.9:1 CR
2. H23 stroker block 95mm crank 11.5:1 CR


the 90.7mm crank peaked at 7600rpms, the 95mm crank peaked at 7000rpms.

Same reason the new 'stroked' s2000 has a lower redline. I like high redline but I'd rather just have useable power everywhere, which you can do with compression, bore and stroke I like building race motors for the street, daily drivers with balls.