23 replies to this topic

[chairchild]

If you want, PM me - I've got a set of sintered ones I was gonna chuck out today

Yours for the price of P+P :wink:




and out of curiosity, what benifits do you actually gain by seam-welding the tops of the pressed-steel rockers? Because I've got a set that I'm fitting to my engine I'm building, but would it be worth getting someone to weld them up?

[stormduck]

chairchild - Cheers fella, i've got a set so i'll work with that, but thanks for the offer. Welding the top of pressed steel helps to reduce the possibility of them splitting apart, effectively making them stronger (taken from David Vizard book). Only really needed for race engines, hard used fast road.

coxon - They're going in the bin! But i'll seperate the lot to get an idea of how it's all assembled. The set of sintered items I have have travelled 87k miles. I'm guessing that the shaft will be worn enough to warrant replacing? My other concern is the wear patch on the rockers where it hits the valve - i'd have to match this wear patch up to the valves - is this good pratice or should i be looking to replace them? And i'm assuming that the springs, washers etc. can all be re-used with no worries?

One last query as i haven't dissmantled the sintered rocker shaft so i don't know - Do these run with bushes? As on the minispares site they sell the sintered rockers: Here and state they run without bushes. If so i'd be looking at near on £100 for 8 new sintered items and a new shaft - worth it?

[stormduck]

This Seems a better bet than spending a hundred notes on a standard setup. I just have to make sure it matches with the new cam.

[The Matt]

Get the roller rockers :wink: ! What cam spec do you have? Also (out of curiosity, what head spec.)??

[stormduck]

The Minisport roller tip rockers seem the best bet? £160. I'm yet to choose the cam, i was going to have a read tonight and get a bit closer to choosing. The head will be a 12G295, double valve spring item with new guides and unleaded seats fitted. I assume i'll have to get new valves aswell - even if the old valves can be machined they're a bit rough looking! I'll get in touch with a decent engineering firm to do the work, along with some block work no doubt - nothing major, just ensuring everything's all good.

Any problems with machining push rods to make them shorter if needed?

[Dan]

Really 1.22? Ok I'll go with that. The Cooper S workshop manual I have is kind of type written and smudgy so I suppose it could say 1.22.

The reproduction ones are great but you need to be careful when picking them up (or getting them mailed to you). I got a set of 8 once and 4 of them didn't have the oil hole drilled through the bush! They went straight back.

[DaveCoxon]

this is a 998 were talking about isn't it???

Stick to small ratio rockers.

Regarding 'cheap' rocker assemblies - yer pays yer money............

£160 on a set of hi-lift rockers is NOT where money should be spent on a budget build. A SW5 cam will see ton's more gain than a slight increase in valve lift on a stock cam IMO.

[dklawson]

I went with the SW5. Swiftune's advice was prudent. They pointed out that the rocker gear could be added/changed later but anything done to the head and with the cam can't be done with the engine in place and should be considered at the time of the rebuild.

[stormduck]

oh no, i wouldn't substitute the cam for the rockers, the cam would come first, but i want to match the rockers to the cam. Been reading the des hammill book tuning the 998. So far the MG metro cam seems my favorite based on it's behaviour...matched to a set of 1.5:1 rockers it gives a valve lift of 9.8mm - i just need to check the best springs to fit.

ps. i may be getting a set of 1.5 roller rockers in exchange for my old vinyl off a friend