are there differences between black top and early silvertop heads

24th May 2010, 13:17

ive got a very low millage vtr blacktop spare engine, and an early silvertop 90bhp engine in my vtr which is coming to the end or in need of top end rebuild valve stem seals etc are leaking bad, now ive got huge plan looming which i shall reviel at later date (in case it doesnt happen for some reason) and what i wanna know is could i rebuild blacktop head as its already off with all new bits and put it on my early silvertop bottom end with all the silvertop inlet injection system etc, so basically are the BEAR heads the same? theyre both 90bhp but one black top and one silvertop, please dont get mixed up with silvertop 98bhp,

24th May 2010, 13:27

AFAIK the heads are physically the same ie port spacing.

As you will know already letr 98bhp silver tops had different port spacing and all silver tops have roller rockers.

24th May 2010, 17:20

Quote:

Originally Posted by dorsetsaxo

ive got a very low millage vtr blacktop spare engine, and an early silvertop 90bhp engine in my vtr which is coming to the end or in need of top end rebuild valve stem seals etc are leaking bad, now ive got huge plan looming which i shall reviel at later date (in case it doesnt happen for some reason) and what i wanna know is could i rebuild blacktop head as its already off with all new bits and put it on my early silvertop bottom end with all the silvertop inlet injection system etc, so basically are the BEAR heads the same? theyre both 90bhp but one black top and one silvertop, please dont get mixed up with silvertop 98bhp,

yes the bare heads are the same as far as i know, however theres a myth that the blacktop head has stiffer valve springs then the silvertop. also uses different running gear ie roller rockers and non-roller rockers.

something id like to know is in the haynes manual it says the non-rollers and rollers are interchangable between the two heads, so why when buying an uprated cam is there a choice between the two??

or is it purely based on the blacktop having stronger springs? if so wheres the proof?

24th May 2010, 17:51

yer i always got told about the valve springs being stiffer in blacktop head too, have never really looked into that though so not 100% sure if its true or not, but as pete said im sure you can swap the roller and no roller rockers over between the heads too
but if you look at cam specs, say newmans, the ph3 if you look at duration the blacktop has 280deg and silvertop 270 deg, so given that it does suggest that the blacktop would have stiffer springs plus due to it being non roller ou are able to run bigger cams through them safer, i dd have the reasons why yu can run bigger cams through non roller rockers explained and why hey are better but i really cant remember the reasons lol

24th May 2010, 17:57

Quote:

Originally Posted by vtr_chris90

yer i always got told about the valve springs being stiffer in blacktop head too, have never really looked into that though so not 100% sure if its true or not, but as pete said im sure you can swap the roller and no roller rockers over between the heads too
but if you look at cam specs, say newmans, the ph3 if you look at duration the blacktop has 280deg and silvertop 270 deg, so given that it does suggest that the blacktop would have stiffer springs plus due to it being non roller ou are able to run bigger cams through them safer, i dd have the reasons why yu can run bigger cams through non roller rockers explained and why hey are better but i really cant remember the reasons lol

comon chris we need to know!

surely tho if the springs are stiffer then using either roller-rocker or non roller wont really matter that much if at all when using a ph3?

also id like to add all the late silvertop roller rocker engines iv worked on have shown very little or no wear on the cam lobes or rollers, where as wear on the cam that had used non rollers was obvious.

24th May 2010, 18:04

lol ill ry to remember

hmmmm not sure on that one tbh i didnt wanna mix and match things around like that, i mean my build was mix and matched enough as it was and was a right pain in the arse lol but its just to do with the non rollers being able to take the tollerance o the higher duration cam and revving alot higher, ill have a word with my mate im sure it was him who told me about it all

yer thats because of the roller rockers not being as harsh on the cam, basically the non roller rockers are just a flat surface, so you think about it there is alot more fricion going to be caused between the cam ad rocker and the cam will be hitting that, where as on roller rockers the cam lobes will be more like gliding over it so there will be less frcition and wear in the cam lobes or rockers

lol i know what i mean and im thinking i just cant put it into words though haha so sorry if its a bit of a shit explanation

24th May 2010, 18:07

Solid and Hydraulic Lifters...

24th May 2010, 19:08

Quote:

Originally Posted by PETE-VTR

yes the bare heads are the same as far as i know, however theres a myth that the blacktop head has stiffer valve springs then the silvertop. also uses different running gear ie roller rockers and non-roller rockers.

something id like to know is in the haynes manual it says the non-rollers and rollers are interchangable between the two heads, so why when buying an uprated cam is there a choice between the two??

or is it purely based on the blacktop having stronger springs? if so wheres the proof?

the only myth here is that you know what you are talking about
any engine with roller tappets will have white springs --soft as shite ,black top engines have stronger springs,ther was a small period when they fitted silver rocker covers to what is really a black top engine
never use std springs from silver top engine with anything other than std cam + roller rocker gear .
once you start modifying dump roller gear and fit stronger springs ,
cam profiles are different for roller +early type engine even if lift is supposedly the same .
do not mix and match these components .
you want proof --then either believe me --or measure valve spring tension and calculate rocker arm ratio yourself--thats how you get "proof".
forum posts are the worst place you can get info ,unless you can trust the source --this is where your myths come from .

24th May 2010, 19:13

Quote:

Originally Posted by PETE-VTR

comon chris we need to know!

surely tho if the springs are stiffer then using either roller-rocker or non roller wont really matter that much if at all when using a ph3?

also id like to add all the late silvertop roller rocker engines iv worked on have shown very little or no wear on the cam lobes or rollers, where as wear on the cam that had used non rollers was obvious.

again --what a load of nonsense --been working on these engines for 20years and only thing that causes wear is lack of oil changes etc.
as for stregnth etc non roller rockers are lighter than roller ones --have bigger contact area on valve head --seen more wear on roller types -- so less valve train wieght is better .If i were tuning to any extent then non roller is type to go for and if using full race cam 12mm + lift then fitment of porsche ballend units to non roller type arms is the answer especially if revving over 8k+

24th May 2010, 21:11

but its the later 98bhp that has roller rockers isnt it? not the early ones as i had cam cover off on mine and looked identicle as the black top,

oh and its not cam im after ive bought a turbo conversion so going boosted, still have a few items to get but should be fun

24th May 2010, 21:26

ive run an early silver top head with roller rockers, piper springs and apiper 270 cam with boost for 10k driving it very hard and never had a problem

24th May 2010, 23:52

Quote:

Originally Posted by tweeqd

ive run an early silver top head with roller rockers, piper springs and apiper 270 cam with boost for 10k driving it very hard and never had a problem

yes and the piper springs for the roller engine are stronger than the std ones --I specced them with piper 6 months after the roller rocker engine was launched ,as soon as i relaised how soft they were .
the softer springs on that engine is one of the reasons it has more bhp --stronger springs take more power to lift them ,but at the lift spec+ rev limit of the std engine they are fine --increase lift +up rpm and you get vlave "float",casuing the power graph to flatten off at higher rpms,blcak top engine used same specsprings as the ax gti which revved higher and had more lift in cam --hnce it made 100bhp form a 1360cc --not 1600cc

24th May 2010, 23:54

Quote:

Originally Posted by axsaxoman

again --what a load of nonsense --been working on these engines for 20years and only thing that causes wear is lack of oil changes etc.
as for stregnth etc non roller rockers are lighter than roller ones --have bigger contact area on valve head --seen more wear on roller types -- so less valve train wieght is better .If i were tuning to any extent then non roller is type to go for and if using full race cam 12mm + lift then fitment of porsche ballend units to non roller type arms is the answer especially if revving over 8k+

what iv seen through my own findings and physical examination of camshaft and rockers is that non roller rockers show more signs of wear then roller-rockers do. as you say this could be due to a number of reasons such as irregular oil changes, manner of which car is driven such as being revved high. which in turn is hardly nonsense its apparent. what you find through your own findings is your own argument, which im not willing to engage.

as you say you carnt believe everything you read on forums as most of it is Myth and a load of bollocks!

25th May 2010, 15:06

I think 20+ years of repairing and tuning tu8v engines from ax,s through to current engines is more than enough experience to back up my findings .
all the non roller engines you have seen will be at least 12 years old --I am guessing you have not had any experience with the non roller type when they were a current engine.
so for you to see wear on them is not suprising considering the type of life most saxo,s will have had over the years

as for proving strength of springs --dead easy put one each springs end to end in a vice and wind up the vice about 30mm ,then messure the springs --the roller type will be shorter ,proving it is weaker