29 replies to this topic

[imaparana]

Hello All,

 

Just finished putting together my fast road 1330 with 1.5 ratio rockers

however have heard that 1.5 ratio can reduce the lifetime of your cam etc. and would obviously like the maximise the life of my engine

 

Has anyone has any experiences to add their 2 pence worth?

 

if it worth me putting the standard ones on to increase the life?

 

Cheers All

 

 

[nicklouse]

what cam?

roller tip or full rollers? (there is more than just cam wear to think about).

and yes a greater lever will put more force on the parts for the same spring.

[imaparana]

Ive got minispares 1.5 roller tip rockers and a claver RE13OT Cam, Ive got a fully worked head with double valve springs which are up to the job

[Ethel]

There's potential for less wear as the rockers most probably weigh less. Like Nick says (expressed in a different way), more lever ratio needs less stiff springs to keep the followers on the cam to the same rpm's.

 

But, of course, higher lift means compressing the springs more, so high lift can be an issue - however you get there.

[imaparana]

Soo they do cause more wear if using stronger springs?

[nicklouse]

Soo they do cause more wear if using stronger springs?

if you fit stronger springs the forces are greater so more wear can occur. (standard rockers)

but if you are considering 1:1,5 rockers you should already have stronger suitable springs. and then as you are increasing the lever ratio you are putting more force into the the drive train meaning you could have more wear.

wear is relative.

how many miles are you going to do?

[imaparana]

itll be a road car so maybe 4k a year

 

Cheers

[racingbob]

I read in one of the mags 1.5 rockers wear mpi cam out in 10000 to 50000

 

and it showed a photo of the flattened cam lobe

[hhhh]

I think that would depend on spring tension, lift, and even zinc content in the oil. The cam can't "know" what the rocker ratio is. It will have forces acting on it which can be equalized between 1.5 and 1.3 rockers by properly adjusting spring load. If springs designed for 1.3s are used on 1.5s, it will almost certainly increase cam wear.

[fwdracer]

I've used 1.5 ratio rockers on a standard cam with uprated head/valve valve springs. Engine did 100K and the cam was still in very good condition. I ran that motor on Semi synthetic, which as I I've gained more experience, I wouldn't repeat again. All the scaremongering on 1.5's is funny. Good 20w/50 with high zinc content and some decent double springs in a 1275+ engine with a 266/270 duration is a road car dream. You might have to rev the ******* out of anything with more duration when linked to 1.5's to reap the full benefits at high rpm.

 

I think that 1.5's work well when you've got compromised cylinder filling, which a short duration cam has.

[gazza82]

You've cheered me up... 1.5:1 and a 266 is my spec.

Tell us more about your oily experience ... maybe a new thread?

[Spider]

Soo they do cause more wear if using stronger springs?

 

Just think about it for a tick.

 

If we move the valve train more, then it's likely wear rate will increase.

 

If we load up the valve train more (with heavier springs) that too will likely increase the wear rate.

[nicklouse]

I think that would depend on spring tension, lift, and even zinc content in the oil. The cam can't "know" what the rocker ratio is. It will have forces acting on it which can be equalized between 1.5 and 1.3 rockers by properly adjusting spring load. If springs designed for 1.3s are used on 1.5s, it will almost certainly increase cam wear.

Springs are not designed for the rockers they are designed to control the valve so you don't get bounce. And so you don't get coil bind. That could be from a high lift cam and standard rockers or a short lift cam with high lift rockers. The Spring will be the same but the loads seen by the cam will be more.

[imaparana]

Thanks for the replys all

Nicklouse so you'd recomend for my use to stick with 1.3 ratio ?

[fwdracer]

You've cheered me up... 1.5:1 and a 266 is my spec.

Tell us more about your oily experience ... maybe a new thread?

 Oil - done to death. Basically Semi Synth doesn't protect the box as well, and finds every exit path. Good Mineral 20w/50 all the way - even in my race motor.

 

My road car is a 1293cc + MG metro cam (266 equiv), 1.5 ratio rockers, Rob Walker head and it gargles through a 45 DCOE!  Pulls like a train between 2-7k. That is exactly where you need the performance in a road engine.