1.65 roller rocker dilemma

[Tabcon]

After putting my engine together and installing the new 1.65 ratio roller rockers from Good Parts, I noticed that the push rods are now pulled towards the inside wall of the push rod tubes to such an extent that I'm afraid they will collide with the tube wall. I talked to Richard Good about it and he said the arms have to be shortened to create the 1.65 ratio. I'm not doubting this at all, but I don't trust the clearance issue I'm having.

I've tried different sized rods, lifted the rocker pedestals, etc. all to no avail. Is there a way to correct this problem?

Thanks-

 

[dougie]

If the Triumph's head is like the big Healey's, you either need off-set rocker pedestals or you must mill the push rod "tubes" larger to accommodate the new ratio and thus the great angle of the push rods.

Dougie

 

[Hap Waldrop]

Here's the question I would have for you, when you increased your rocker ratio, did you do so with stock rocker pedestals. The reason I ask is because companies like Harland Sharp and some of their vendors offer higher rocker arm's ratio, but if the rocker arm ratio is changed by any significant amount then the pivot hole in the pedestal must change to reflect that ratio as well, if not then the geomentry will be greatly off kilter.

 

[Tabcon]

Thanks for the help. The pedestals I'm using are new block style aluminum ones I bought from Bastuck. They have a standard ratio I would think since they work fine with the stock rocker arms.

I think it's too late for me to be trying to make the push rod holes any larger, but it would have been a good idea when I was having the head done. I think the easiest solution would be to either buy different pedestals set up for the 1.65, if I can find any, or machine the ones I have, which would most likely not work.
Like Hap said, I don't want the geometry off kilter so I'll look for some pedestals.

Any hint on who may have the correct pedestals? I'd try and fabricate them, but it would most likely end up costing me more than buying a set.

The entire set up appears to be be off from stock by about 1/10", enough to angle the push rods. I played around with some sketches in cad and if if the ratio is derived from measuring from the center of the rocker shaft, then there isn't much I can do with the pedestal set I have.
I could move the entire set up over, including the shaft by moving the mounting holes in the pedestals, but then I would be moving the shaft as well and of course this would defeat the whole purpose. Is this correct?

 

[Hap Waldrop]

Tab I seen a few people over the years with 1.5 HS rocker arms on MG Midget motors (stock ratio is 1.25) use the stock pedestal and have a oversized hole bored into the pedestal , then make a offset bushing to put the pivot hole where they needed it to be. The other issue recently R&D greatly by Sean Brown at Flowspeed (he pretty much does MGB stuff, but this still applies) is that the pivot hole center line is too low on almost all the aftermarket higher ratio rocker arm offereings, so he made pedestal shims to get that right for the Titan and HS roller rocker arm set ups for MGBs. It's a good read, you can see it at www.flowspeed.com what happens alot fo the time is with greater rocker ratio the geomnetry is less than perfect, so the rocker arm loses alot of ratio thru arc, getting the pedestal height and pushrod length nailed helps you to get all or ost of that ratio. Nailing a roller rocker arm set up invloves alot more than most folks realize, which is something it sounds like you have fiquired out.

 

[Tabcon]

The sketch above shows the measurements I took with a micrometer. The difference of minus 0.160" between the stock and the Good Parts roller rocker seems to be too great to me.

No matter what I do, it seems as though the arm will either be short on the valve side or the push rod side.

?????

 

[Hap Waldrop]

Just out of curosity, have you try talking to Joe Siam at Checkered (he spells it differently) Motosports in SOCAL. Joe seem to be fairly knowledgable on putting roller rockers on Triumphs, I not sure how much he has worked with TR4s, but I would give him a call.

 

[Tabcon]

Thanks Hap.

The "Flowspeed" site was extremely helpful.

I've traded several emails with Richard @ Good Parts and I'm actually very surprised he hasn't addressed this issue on his site. I realize he mainly sells TR6 stuff and he does have the pedestals for the TR6 application, but not for the TR4.

Today I ditched the intellectual approach and called on the caveman within. I took a short length of pipe and 'gently' tapped each of the pedestal studs towards the push rods a bit, and voila...fits great!

 

[Hedgehog]

Tab, have you checked with Joe Alexander? He and his son race TR4s and Joe owns Alexander Racing. He's also good friends with Kas Kastner (Triumph factory support) and both are very knowledgable in racing TRs. They can also point you to who may have the pedestals available.

https://www.the-vintage-racer.com/

 

[Tabcon]

I found the pedestals I need at Cambridge Motorsports. They're made by Titan in the UK and they run about $80.00 each. With shipping, I'd be looking at almost $400.00 for just the stands and then I'd have to hope they work well with the rockers I have.

So, I gave up on that idea and just ordered the entire 1.65 bolt on Titan set up. This way, I'll be assured everything fits as it should.

Sean Brown at Flowspeed has been a great help. His site has some great stuff on it for anyone considering going this route. I just wish I had known about all this before I bought the rockers from Good Parts. There is absoltely nothing at
all wrong with the GP roller rocker arms, as a matter of fact they are extremely well made, but trying to source everything individually is not the way to go with this.

I did all the calculations required as shown on the Flowspeed site, and I'm going to have to use shims under the rocker stands that are .2325" thick to get the full benefit of the 1.65 ratio. I'm making them out of some high strength aluminum 1/4" bar.

BTW, I ditched the caveman approach since I needed to use longer studs to compensate for the shims. Just as well, I don't think it was that great of an idea to begin with.

 

[Hap Waldrop]

Just a word fo caution, Harland Sharp rocker arms are designed to run on stock size sahft for a given engine, Titans are not, they are sold as complete assmeblies unlike HS, and use a unique shaft diameter to them, atleast this is waht we have found out on the MGBs and Midget, everythign on the Titan set up are unique to them, the sahft, pedestals, adjusting hardware. I try to only use Titan roller rocker arms on my race engines, I seen a few HS failures, and think Titan is a better product. On the Spridget we're able to get a really nice Titan 1.5 ratio roller tip assembly for well under $500, Mini Spares in London gets Titan to specially make these for them and orders them in quanity, on the oterh engine they only offer roller bearing on the shafts, which really isn't necessary, but that the only way they come, so they are much more expensive. Most palce in the US get around $1500-$1700 for the Titan set up for the MGB, wat we do is order from the UK, and get them for half that.

I've been told HS will make pedestals for you custom order.

 

[Tabcon]

I bought a Titan assembly from Cambridge Motorsports in the UK and it came out to about $750. I should receive it this week and I'll let you know how it works.

I've got the Good Parts set up for sale on Ebay if anyone is interested.

 

[Hap Waldrop]

We just ordered one for a MGB from Brown and Gammon in the UK, about the same money. I've used Titan stuff for years, it's real good stuff, you'll like it.

 

[Guest]

I'm wondering why on earth you want to fit roller rockers in the first place?

Why would you want to do that?

I have frequently found you get less power using them, and in any case there's not any heads out there (with one exception) can benefit from the extra flow (I've tested them all, so I should know)....

 

[Deleted member 8987]

I'm wondering why on earth you want to fit roller rockers in the first place?

Why would you want to do that?

I have frequently found you get less power using them, and in any case there's not any heads out there (with one exception) can benefit from the extra flow (I've tested them all, so I should know)....

Bragging Rights?

If you can't see it, all you can do is brag?

 

[Basil]

I'm wondering why on earth you want to fit roller rockers in the first place?

Why would you want to do that?

I have frequently found you get less power using them, and in any case there's not any heads out there (with one exception) can benefit from the extra flow (I've tested them all, so I should know)....

Goodbye! Don't let the door hit you in the A$$ on the way out!

 

[Deleted member 8987]

In the US V-8 market, most rockers are 1.5, but not roller.

Experience shows that they SHOULD be matched to a cam.....the issue being sometimes the lift is faster than the cam is designed for and you end up with some part-throttle driveability issues.
Not always, sometimes.

Oddly, the streetrodders find a 1.52 roller rocker is better than a 1.5, that's because the originals are advertised as 1.5, and a lot aren't even close.

Roller tips on LBC's could be a boon, I would think, in that it may remove some of the side load on the stem into the guide, and maybe reduce the frequency of guide replacement (and if I had a dollar for every LBC guide I've had to have replaced, I could have retired long ago) (joke).

But, stock spring coil bind is an issue that needs to be at least looked at when doing this.
I would like to hear how your mid-range and just off-throttle driveability is after you get it sorted.

Also, my particular LBC cannot use increased ratio rockers.....but cam replacement is a whole lot easier, too.

 

[Hap Waldrop]

I'm wondering why on earth you want to fit roller rockers in the first place?

Why would you want to do that?

Mostly for increased ratio, more so than the roller, well that's the HP reason anyway. On the MG A series race engines we could get more cam lift, which very much increased HP. In the case of the cam we were running in the race engines, we could acheive an extra .088" valve lift using the 1.5 ratio over the stock 1.26 ratio.

 

[RonMacPherson]

And they require less lube in a full pedal to the metal situation.. Remember the Porsche engine with full roller main and rod bearings? Good engine, sadly too comples(but it was German, whaddya expect?)