roller rocker trouble

[trt74]

Hi guys,

 

As the rockers had been becoming increasingly noisy on the trip back from Malvern and the engine was running a bit rough, I finally found time to check the valve settings.

When I took the rocker cover off yesterday, I came across a nasty surprise. The roller of the No.1 inlet rocker arm had come off and was lying in the bottom. It seems the rollerpin had either broken or come loose and the valve stem cap has since been eating into the rocker arm.

I've been able to fish out some pieces of the debris but have not yet come across the rollerpin.

 

There are some questions I hope you can help me with:

 

As I have no info on the origin/supplier of the roller rockers, does anyone recognize the make/type, so I can order a replacement rocker?. ( I don't know the ratio)

 

Do I need to take the head off or can I get away with cleaning out de debris from the top( and hopefully finding the rollerpin)?

 

I would be very grateful for any ideas and suggestions,

 

Many thanks,

 

Cheers,

 

Tim

[rpurchon]

the only place it could go is down the pushrod side of the head.

it might be down one of the holes sat on the block or in one of the cam followers.

if not it will be in the sump.

dont remove the head for such a small amount of aluminium.

the bits will be small and chewed up and in the oil filter or in the sump.

youve been very very very lucky the collets on the valve didnt come undone and the valve drop out.

richard

Edited August 16, 2010 by rpurchon

[Alec Pringle]

Hi Tim,

 

please see PM

 

Cheers,

 

Alec

[john.r.davies]

I think that style was sold by Tony Lindsay-Dean at one time.

Kingstone Sports Cars

 

His bare, barebones website is here: http://www.kingstonsportscars.co.uk/

 

John

Edited August 16, 2010 by john.r.davies

[Tony Millward]

I think that style was sold by Tony Lindsay-Dean at one time.

Kingstone Sports Cars

 

His bare, barebones website is here: http://www.kingstonsportscars.co.uk/

 

John

 

 

 

You're right about it being a 'barebones' web site. John.. ...it doesn't work...

 

Tony

[RogerH]

...the clock and calender work.

 

Roger

[88V8]

I think that style was sold by Tony Lindsay-Dean at one time.

Kingston Sports Cars

His bare, barebones website is here: http://www.kingstonsportscars.co.uk/

 

Hope you can find them elsewhere. On another forum is a long thread complaining about a total lack of service from the aforesaid, including a comment from someone who says he had been waiting a year for TL-D to send a replacement roller rocker. Eventually TL-D himself chipped in on the thread, commenting inter alia that his ' roller rockers suffered from being made from the wrong spec of material & unauthorised modifications by the machine shop'. He didn't say whether he is still able to offer replacements.

 

I don't think it matter which rockers you have in there, so long as they fit the shaft and you can get some special spacers made if necessary, so as a stopgap until you can find an exact replacement just buy another roller rocker of any make that is the correct ratio and will fit, and has the same type of bearings (needle or plain). Or even a standard rocker if they're standard ratio.

 

Problem if you want a roller, may be buying a single one.

 

Ivor

[Stevie P]

Hi

 

They look like the Roller Rockers that Chris Witor does, have a look on his site.

 

Steve

[john.r.davies]

I SAID it was 'barebones'.

In fact I said it was bare, barebones.

How could I be clearer?

 

And if you have a website, you have an email address, in this case "@kingstonsportscars.co.uk"

Try "tony@kingstonsportscars.co.uk", though the last time I corresponded with Tony was in April last year.

 

John

Edited August 16, 2010 by john.r.davies

[Guest ntc]

Hi guys,

 

As the rockers had been becoming increasingly noisy on the trip back from Malvern and the engine was running a bit rough, I finally found time to check the valve settings.

When I took the rocker cover off yesterday, I came across a nasty surprise. The roller of the No.1 inlet rocker arm had come off and was lying in the bottom. It seems the rollerpin had either broken or come loose and the valve stem cap has since been eating into the rocker arm.

I've been able to fish out some pieces of the debris but have not yet come across the rollerpin.

 

There are some questions I hope you can help me with:

 

As I have no info on the origin/supplier of the roller rockers, does anyone recognize the make/type, so I can order a replacement rocker?. ( I don't know the ratio)

 

Do I need to take the head off or can I get away with cleaning out de debris from the top( and hopefully finding the rollerpin)?

 

I would be very grateful for any ideas and suggestions,

 

Many thanks,

 

Cheers,

 

Tim

 

 

Hi Tim

Whoever's they are you must drop the sump first IMHO and find the parts and also look at them to see if they are intact

[PJM]

Hi Tim

Whoever's they are you must drop the sump first IMHO and find the parts and also look at them to see if they are intact

 

 

I would be looking for the parts too they could literally be anywhere, the sump is as good a place to start as any.

 

I suspect TLD is rewing the day he heard of roller rockers, appear to be nothing but trouble really.

[trt74]

Hi guys,

 

Thanks very much for your useful advice. I will get in touch with Cris Witor and the owner of Kingston Sportscars and see if they can supply me with a single replacement rocker. If not succesful, I'll try to get a temporary fix.

 

One roller rocker breaking like this gets me rather worried about the quality of the others though, especially since the engine has only done about 4000 miles....I'll certainly check the others very carefully!

 

I'm very glad it won't have to be a 'head off' job!

 

Cheers,

 

Tim

[PJM]

Think twice before running the engine if you dont find the parts, they must be in there somewhere! It's easy for people to say dont worry, its not their engine!

[88V8]

One roller rocker breaking like this gets me rather worried about the quality of the others though, especially since the engine has only done about 4000 miles

What valve clearances are you running?

 

Ivor

[trt74]

What valve clearances are you running?

 

Ivor

 

 

 

Hi Ivor,

 

0.014 inlet, 0.016 exhaust, cold. Gasflowed, ported head with a fast road cam ( detailed specs unknown).

 

Cheers,

 

Tim

[88V8]

0.014 inlet, 0.016 exhaust, cold. Gasflowed, ported head with a fast road cam ( detailed specs unknown).

 

I only ask because rollers don't like the impact of large clearances and agressive cams.

 

Oddly enough, I'm in exactly the same situation, fast road cam, spec not known and for that matter clearances not known, but I'm also running 14i 16e. I have a set of roller rockers and I'm dithering about putting them on because of the relatively large clearances. A topic for another thread I think.

 

Ivor

[TR 2100]

Hi Ivor,

0.014 inlet, 0.016 exhaust, cold. Gasflowed, ported head with a fast road cam ( detailed specs unknown).

Cheers,

Tim

 

I only ask because rollers don't like the impact of large clearances and agressive cams.

 

Oddly enough, I'm in exactly the same situation, fast road cam, spec not known and for that matter clearances not known, but I'm also running 14i 16e. I have a set of roller rockers and I'm dithering about putting them on because of the relatively large clearances. A topic for another thread I think.

 

Ivor

 

Usual clearances for fast road cams are usually more like 20-22 thou.

but that's not to say that yours is.

 

If the clearance is too small, the rocker arm will be hitting the valve

too hard.

The principle of camshaft design is that the clearance is taken up

gradually and then, when the clearance is taken up, the valve gets

whopped open.

On that basis, the actual clearance doesn't matter - what matters

is matching it to the design of the cam.

 

If I didn't know what spec the cam was, my approach would be to

slacken off the adjusters to give too great a clearance, then

gradually tighten them until the noise just disappears.

I would do this when hot, even with the engine running, though

that can get a bit messy.

 

I'm happy to take on board any comments from those in the know.

 

AlanR

[RogerH]

Hi Alan,

I think you have just answered a query I've had regarding fast cams - Why the large gaps?

 

It sort of now makes sense.

 

Roger

[john.r.davies]

I only ask because rollers don't like the impact of large clearances and agressive cams.

 

Ivor

 

 

Ivor,

And there's me thinking that rollers were for high lift camshafts and heavy springing, as the rollerexerted less side force on the valve stem.

 

Valve clearances I wot not of, in this respect.

 

John

Edited August 17, 2010 by john.r.davies

[TR 2100]

Hi Alan,

I think you have just answered a query I've had regarding fast

cams - Why the large gaps?

 

It sort of now makes sense.

 

Roger

 

Hi Roger,

 

I don't know 'why the large gaps', just that my fast road cam

requires 20-22 thou gaps. More than I would have expected, but

I don't know the reasoning behind the design of the cam, and it's

that that dictates the gaps.

 

I'm just guessing that other modified cams may also run with

larger clearances, but I don't know.

 

Running with gaps that are too small can/will burn out a valve,

and you probably won't find out until it happens, as there will

be no noise to alert you.

But - if you start out with gaps that are too large, you WILL

get an audible warning, then you can close the gaps until the

noise disappears (and play it a little bit safe - don't expect

to get rid of ALL the nise).

 

AlanR

 

AlanR

[88V8]

Ivor,

And there's me thinking that rollers were for high lift camshafts and heavy springing, as the roller exerted less side force on the valve stem.

 

 

And so they are.

 

But if the clearances are large the rocker will already have been accelerated before it hits the valve, at least that's my assumption because I have certainly read in more than one place that roller rockers can be damaged by large clearances. Perhaps that should read 'excessively large clearances'.

 

I'm using 14/16 because I know that I have an SAH cam and that's the clearance for the SAH fast road that Moss sell. OK for nearly 10,000 miles thus far, so I guess it's there or thereabouts.

Perhaps my rollers would be OK then.... and large clearances are probably not at the root of Time's woes.

 

Ivor

[TR 2100]

And so they are.

 

But if the clearances are large the rocker will already have been accelerated before it hits the valve, at least that's my assumption because I have certainly read in more than one place that roller rockers can be damaged by large clearances. Perhaps that should read 'excessively large clearances'.

 

I'm using 14/16 because I know that I have an SAH cam and that's the clearance for the SAH fast road that Moss sell. OK for nearly 10,000 miles thus far, so I guess it's there or thereabouts.

Perhaps my rollers would be OK then.... and large clearances are probably not at the root of Time's woes.

 

Ivor

 

Think of camshaft design in two stages.

 

The first stage is to take up the clearance slowly

so the valve stem is not hit hard.

Then, when the clearance is taken up, the lobe on

the cam whops the valve open.

 

The clearance required is based on the design of the

camshaft.

 

AlanR

[Tony Millward]

When you boil it all down, there are only two major reasons that could cause the roller to break off. Either the roller rockers are not of good quality or there is valve spring binding occurring...

 

Tony

[geofft]

this happened to me, roller pin held in with hex grub screw which had come loose, recovered srew/roller pin from cam follower with magnetic pick up tool. not much damage done to alloy roller body as few miles done. on checking other rockers they were loose. tigthtened with allen key,no problems since.

[Andy Moltu]

Some of the valve gaps settings are about getting the best from a cam profile.

 

Most of the after market profiles sold for the TRs were probably not designed with the TR engine in mind - they may be a Ford kent profile or whatever that has been ground onto a TR cam. These may have been designed to run with larger (or smaller clearances than the standard TR gap).

 

In use better performance may be gained by using different overall valve timings. More subtle chages can be achieved by increasing or decreasing the valve gap so that the valve opens slightly earlier or slightly later - for example widening the exhaust gaps may keep the valve closed for longer allowing more complete combustion befor the valve opens. Again there may be a balance between the ideal opening point for optimum performance yet that may increase the loading on the cam lobe/follower leading to premature failure.

Some roller rockers have a higher lift ratio which may well increase loading on the cam lobes as well as influence the opening/closing time of the valves as well as the lift. Increasing the lift on an already high lift cam may well not increase power signinficantly so the benefits of high lift roller rockers can be overstated.