Development of Nascar Engine

[The1]

Very Interesting!

[youtube]https://www.youtube.com/watch?v=rBZCnG1HwDM[/youtube]

[Charlescrown]

Very interesting video. I am amazed with the valve spring oscillating continually between openings. Can understand why they break.

[vlad01]

great stuff!

I bet ecotec springs do that with 1.9 or higher rockers. They break like clock work with high ratio rockers.

[delcowizzid]

thia is where the beehive spring comes into play the resonance is in the lower rounder coils not the skinney end by the valve stem to help control bounce off the seat like in that video.the downside is its 1 spring and if it breaks by by valve down the hole more often than a duel straight spring breakage have the 2nd spring keeping the valve up where it should be

[immortality]

It seems though that when beehive springs break they don't tend to drop the valves as quickly due to the taper of the spring.

Lots of V6 high ratio rockers out there, not really heard of that many breaking.

[The1]

ive seen 4 engines in various models that i recall with 1.9 rockers that have had stock valve spring failure, ive also seen dyno tunes where stock valve springs have cost power because of float, never seen or heard of any failures with 105 or higher springs and rockers.

[vlad01]

It seems though that when beehive springs break they don't tend to drop the valves as quickly due to the taper of the spring.

Lots of V6 high ratio rockers out there, not really heard of that many breaking.

close to 100% of ecotec owners I know of that installed 1.9 rockers broke the stock springs in short order.

here is a spare engine I have. mace 1.9 rockers on them.

[youtube]https://www.youtube.com/watch?v=FFyz4hKlBs0[/youtube]

[immortality]

Well now you know one that hasn't

Having sold these in the past, I didn't seem to get any complaints about broken valve springs from customers.

As I always said, if you fit 1.9 rockers with the intent to rev the engine then upgrade the valve springs. Ultimately, most folks fitting 1.9 rockers are doing some on fairly high mileage engines so the factory valve springs aren't going to be in the best condition.

[vlad01]

Well now you know one that hasn't

Having sold these in the past, I didn't seem to get any complaints about broken valve springs from customers.

As I always said, if you fit 1.9 rockers with the intent to rev the engine then upgrade the valve springs. Ultimately, most folks fitting 1.9 rockers are doing some on fairly high mileage engines so the factory valve springs aren't going to be in the best condition.

Exactly. I tell people whole intend to install them to replace the springs with good higher rated ones.

As far as I know crow make good springs where comp (the other common choice for v6) had a period where the springs where failing in plague proportion when they moved manufacturing to mexico. Not sure on poundage but 105 was the min recommended by mace?

[immortality]

Yep, MACE supply the Crow 105lbs springs but you need the retainers to suit. If you install with the stock retainers than you get a bit more seat pressure as the stock retainers have a lower installed height.