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MG Midget and Sprite Technical - Jonspeed 1.5 Rockers?

Anybody had experience with the Jonspeed Billet 1.5 rockers, if so whats your opinion?
Graham.
Graham P

No experience with the rockers, but generally their stuff tends to fall at the lower end of the price/quality range.

My view for what its worth - stick with standard rockers unless you can afford a set of Titan roller rockers. Rocker failure can prove terminal...

Regards

J
James B

This link is to the appropriate page:http://www.jonspeedracing.co.uk/index.php?webpage=product_detail.php&product_id=14544&cID=13895
Graham
Graham P

As James said - get the Titan ones - they are awesome
rachmacb

James B is right 'rocker failure can prove terminal'. I know to my cost!!! And the reason was because I retained the standard pressed steel rockers. I'm sure these were OK on their day but after 40 years it is likely that something will fail (and on mine they did). I'd steer clear of the standard rockers and go for Minispares forged hi-lift rockers. See:

http://www.minispares.com/Product.aspx?ty=pb&pid=34870&title=

They don't look as impressive as roller-rockers but they do the same job at half the price. Visard recommended them although whether they are the same product today as way back when he wrote that book I don't know.

Chris
Chris H (1970 Midget 1275)

I would go with roller tip rockers if you can afford them, they do reduce a lot of the lateral load and at a lot lower cost than full roller rockers. But they are more expensive than either of those options, although not by as much as I thought: http://www.minispares.com/Product.aspx?ty=pb&pid=37972&title=. For that price I'd be just going with those.

Also they're purple and look cool.

I've got 1.5:1 alloy roller tip rockers on my 1440 Metro, and they go very well. Be aware though, with the fast road cam I am running (~0.320" peak lift at the lobe I think - if Dad puts his nose in he can correct me) I needed to got to uprated springs to avoid coil-bind with 1.5:1, so whatever you get check the bind point.
Andy Walbran

Chris,

I've used the pressed steel rockers with the top welded as recommended in Vizard and not had any problems in 70k miles in a 1420 with a 286 cam and revved to 7k+. They had been rebushed and refaced. What were you using with yours and what was the failure. IIRC Vizard mentioned they usually fail safe by bending.
David Billington

I've had one pressed steel rocker break, but it was on a race engine (not welded).

For a (fairly standard) road engine they are fine.
Dave O'Neill2

The pressed steel rockers were not welded. The problem I had was the thread stripped on one of the adjuster screws which 'popped up' out of the rocker arm leading to a permanently closed exhaust valve - followed a few seconds later by a blown head gasket (the exhaust gasses having nowhere to go!!!). There was a thread on this BB last year on this. Dave O'Neil called round to help so he will remember this.

I am using 200lb valve springs and was rather over-reving it at the time (and it had just undergone a track day at Donington prior to failure so I was pushing it perhaps). Mini Spares forged rockers now and it seems happy.
Chris H (1970 Midget 1275)

With any high lift rocker you need modern valve springs.
These usualy do the trick.
http://www.minispares.com/Product.aspx?ty=pb&pid=33655&title=
Onno K

COOL purple - if only they did them for V8s - I've seen the perfect engine that they would go with!

http://www.ebay.co.uk/itm/290708005991?_trksid=p5197.c0.m619
rachmacb

This thread was discussed between 02/05/2012 and 09/05/2012

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