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Triumph TR6 - Rocker Spacers
|Any opinion on replacing the spacer springs with solid spacers on the rocker gear? I've noticed the springs tend to wear grooves in the rocker shaft. I'm thinking about getting a set of Jim Swarthout's bushed roller rockers and want to replace everything at once. Thanks.|
|I'm going to be interested in more feedback on those RR's. The one's I've seen on 6-pack seemed to hit about the same time and be just from those that got the freebies. A bit of Marketing, perhaps?|
Yeah - the rocker itself appeared to be bushed. The 1:55 RR's I have use needle bearings. They also use springs, not solid spacers. I've never had any issue with them, so I don't know what the benefit would be.
The loading on the stock camshaft might be a concern using 1.75 RR's. I stopped at 0.39" valve opening with a cam/RR combo to avoid a cam bearing installation. The 1.75:1 ratio gives a valve lift of about 0.41". New springs might be needed which will probably increase the force back on the cam. Just my opinion.
|I recently built a head using some 1.55:1 bushed roller rockers from Ted Schumacher. I found that I had do a little relief work on the #1 and #12 rockers that are retained by the pedestals. As for the spacers, I had a couple of sets of the type sold by TRF and Moss sitting in the tool box and found that they would not work with these roller rockers. I would up machining some of my own out of some aluminum rod stock, I had originally wanted to make it simple and keep the a constant OD on the spacers, but found that they needed to be relief cut to clear the studs used to hold down the rocker cover. For rocker alignment along the shaft, the final adjustments were made up by using some ,005" and .010" shimming washers. I started at #12 in the pedestal and determined what shimming it needed to sit nicely on the valve, then worked my way down to #1 fitting the pedestals, spacers and shims for each rocker/valve as I moved down the line. Alignment across valve with the swing of the rocker was not needed in my case, but if it had been required, we had a template for making up some spacers for the pedestals out of steel sheet stock.|
It will probably be a few months before the head is put to use, so can't really say how all of this will work out. We did some other stuff while in there (fly cut the guides and installed valve stem seals, some port work, different valve springs). Lift at valve works out to .412, no cam bearings installed. A friend has been running a TR250 with a lift at valve of .435 and has had no problems. I'll try and remeber to post back on it once it has been run for a while.
|Thanks Brent and Steve. Your expertise in this area is so much better than mine! I'll wait for some feedback to be posted on Swarthout's page before going further with this improvement. He can keep costs down by foregoing the needle bearings, making the conversion much more attractive.|
I appreciate the fact that he's sincerely interested and capable in manufacturing parts for our Triumphs (he's soliciting production orders for finned rocker box covers now).
|I have personally paid for a set of Jim's rockers. They look great but am awaiting new uprated valve springs before installing them. Will post results.|
|Am also very interested in any feedback from those of you actually install a PURCHASED set of RR's. All of the testimonials on Swarthout's site seem predicably biased, per Brent's earlier comments. In theory the concept makes a good deal of sense, and I'm always looking for ways to increase horsepower.|
Regarding valve springs, most of the justification for replacement I've seen and heard is basically predicated on the fact that the car is 30 years old, and the srings are BOUND to be tired. Do we really know this or is it truly just an assumption?
I'm inclined to think that arbitrary spring replacement has it's place in folklore. As long as the stresses don't reach the yield point of the metal the "strength" should be remain constant.
BUT - the ends of the spring can fret and wear over time, and I'm sure the coils can develop fatigue cracks if poorly made. Bottom line - if you are unsure about what is in there and you do a valve train/cam upgrade, it's best to replace the springs with something you KNOW will accept the new lift.
|I had this same question and a supplier talked me out of new springs (unless racing) saying all his personal cars had (not only TRs) original springs. So, being sceptical, had my buddy at the head shop test all my springs, and guess what - all the same length as each other and standing square, as original, inners and outers, all spring rates within specs INCLUDING the ones which had been in a compressed state for 10 years in a frozen engine. Draw your own conclusions. Will report later if this ever proves to have been a wrong decision. Peter|
|I would like to know the whole truth on this valve spring issue. I have also ordered a set of new valve springs to go with the r.r.s that I bought from Jim S. I just know for sure that replacing the rear springs on my car made it drive at least 50% better. If they wore out after 27 years, why wouldn't the valve springs?|
|I think the suspension springs are periodically subjected to much greater compression forces that likely enter the "yield" region - such as when a big pothole is hit and the wheel rebounds against the stop. Things like that have been known to break suspension springs. Valve springs on the other hand have a constant, smaller deflection and shouldn't deform.|
I think you're doing the smart thing by replacing your valve springs, BTW. The lift of those roller rockers is fairly radical - be sure and check whether you need to remove the stock inner spring spacer. You wouldn't want the inner springs to bind. Also - be sure and pull the valve cover after a couple hundred miles and check the inner springs. Especially on the exhaust valves which a a little "tighter" anyway.
This thread was discussed between 13/04/2003 and 21/04/2003
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