aan engine. more revs??

[Thuppu]

Ok, note for myself: Never write posts in the middle of the night: The lighter one´s ARE CLAIMED to be usable up to 7800rpm. My opinion is, that this is risky, and they in fact should not be used like that. Sorry for that one
I know that the light ones are something for making money with, nothing else...the 8000rpm with the stock ones is something that I am a bit doubtfull on, I would have said "no way", but in if you say it works...hm. I dunno :-)

My point was just that the revvs is the one what stress the tappets, not the power itself. For example the 5cyl engine can make 700hp at 7500rpm's which is perfectly ok for hydro tappets. You just was thinking a lot more complicated at this. There is nothing wrong with that, and you are right that with a big turbo the powerband is quite short if using stock rpm limit.

[Quattronaut]

IMHO stock hydros are usable to 7500 rpm, some aftermarket lighter ones till 7800 with better springs- but in this rpm range their use is risky, and they will be worn out fast. And we are not speaking about a car that is used on street and driven normally all the time, and that is in real high revs from time to time. We are talking about a track and race car, that will be driven in high rev ranges most of the time. I for myself do not think that hydros are usable that way real safe.

You have a very strange way of thinking about this. I would never use lightweight tappets in a high revving engine, they hardly hold in a stock engine, so 8krpm with high lift cams and stiff valvespings and they collapse for sure.

Ok, note for myself: Never write posts in the middle of the night: The lighter one´s ARE CLAIMED to be usable up to 7800rpm. My opinion is, that this is risky, and they in fact should not be used like that. Sorry for that one
I know that the light ones are something for making money with, nothing else...the 8000rpm with the stock ones is something that I am a bit doubtfull on, I would have said "no way", but in if you say it works...hm. I dunno :-)

[varia]

an interesting read on the subject

http://theprojectpad.com/viewtopic.php?f=32&t=1263&p=61258&hilit=lifter#p61258

[repo]

Yea, btdt. I had a set, a friend tried two sets in his engine, before he swapped in to "heavy ones".

We had the faces to crack in high rev race engine. A friend had them going oval. I haven't used the lightweight ones since 2008 or so.

Lightweights are fine for stock engine and stock springs, but not for high revs or stiff springs.

[Thuppu]

How many people have collapsed lifters?

Ask Repo.

[terrybullwon]

How many people have collapsed lifters?

[Thuppu]

IMHO stock hydros are usable to 7500 rpm, some aftermarket lighter ones till 7800 with better springs- but in this rpm range their use is risky, and they will be worn out fast. And we are not speaking about a car that is used on street and driven normally all the time, and that is in real high revs from time to time. We are talking about a track and race car, that will be driven in high rev ranges most of the time. I for myself do not think that hydros are usable that way real safe.

I meant the 540hp that way, that peak powers up to around 540 hp are reachable with stock valvetrain, hydraulical tappets, no need of solids. Only when you go higher, you will need mechanical valvetrain. And I am not only speaking about damage, but also about sense- turbos, that are able to do 600hp, are that big, that boost will be at 5000rpm- when the rev limitter cuts it off at 7200, you are running into rev limitter at full boost, that can cause several damage; and the usable power range is senseless, only 2000 rpm range.

You have a very strange way of thinking about this. I would never use lightweight tappets in a high revving engine, they hardly hold in a stock engine, so 8krpm with high lift cams and stiff valvespings and they collapse for sure.

[Biturbo]

Head £1500+ Cat Cams + adjustable gears, £1000+, engine £5000+, dry sump £2500+... ish.

Schtick, DBillas, Cat Cams, Dahlback & various Swedish mentalists for cams.

This all you need if you rev till 10000 rpm Can't wait to see how is feels.On stock oil pump I rev till 7900rpm no problem at all

[Laaf]

I had lightweight hydros installed for about 30 min of engine running time before swapping back to OEM. They started making an awful noise and when taking them out 2 were soft, not almost stiff like they should. They are still lying on the shelf in the garage.

[elaw]

Oops... not down but I somehow managed to put a quotation mark at the beginning of the URL!

Should be fixed now.

[Albert]

404 for www.theprojectpad.com - webpage is down

[elaw]

Just FYI if you're thinking about switching to lighter hydro lifters, you might want to read this first: http://www.theprojectpad.com/viewtopic.php?f=32&t=1263

[Albert]

I some aftermarket lighter ones till 7800 with better springs

What hydros would you recommend for race car that can handle 7500-7800 rpm abuse ?

[Quattronaut]

IMHO stock hydros are usable to 7500 rpm, some aftermarket lighter ones till 7800 with better springs- but in this rpm range their use is risky, and they will be worn out fast. And we are not speaking about a car that is used on street and driven normally all the time, and that is in real high revs from time to time. We are talking about a track and race car, that will be driven in high rev ranges most of the time. I for myself do not think that hydros are usable that way real safe.

I meant the 540hp that way, that peak powers up to around 540 hp are reachable with stock valvetrain, hydraulical tappets, no need of solids. Only when you go higher, you will need mechanical valvetrain. And I am not only speaking about damage, but also about sense- turbos, that are able to do 600hp, are that big, that boost will be at 5000rpm- when the rev limitter cuts it off at 7200, you are running into rev limitter at full boost, that can cause several damage; and the usable power range is senseless, only 2000 rpm range.

[Thuppu]

Lehmann, Hohenester and others say, that 540hp is the limit of a 20vt with hydros.

How would the tappets know how much hp the engine have? I would say it's more like rpm related how much the hydro tappets can handle. 8000rpm have been proven to work fine with hydro tappets and stock oil pump. I would use stiffer valve springs though, especially if you use higher lift cams. But like told, there is no point in rising the rpm limit if the engine shokes badly at high rpm's