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MG Midget and Sprite Technical - 1500 Noisy Rollers

Have a set of Harland Sharp 1.5 ratio roller rockers on a freshly rebuilt 1500. They are noisy once the engine begins to warm up.

Oil pressure is 80lbs cold, 40-60lbs hot, 30lbs idle. Running a SAE30 weight Zinc Break-in oil. Took off valve cover, theres oil up there on every valve. Valve lash set correctly, done it several times to double-check. Not running an external oil feed line as per Deborah Evans. I do have a Mocal 13 row oil cooler and oil-stat. Oil temp is never HOT HOT, just above normal temp. Rockershaft is a hardened one. Checked for bent pushrods, none bent.

I can't figure out why, any explainations are welcomed.
Ron Koenig

Ron,
You have probably done all of these checks, but l would look for:

1. Scuffing inside of the valve cover by the front or rear rocker. Although I don't see why that would only happen when warm.

2. Contact between the underside of the rocker arms and the spring caps. Can happen if you are using standard rocker shaft pedestals and no packing pieces. Difficult to see the tell-tale bright marks without removing the rockers to inspect. But may show with a small mirror and good lighting.

3. Binding valve spring coils on full lift. I think this is the one most likely to change as it warms up.
Guy Weller

Are they noisier because they run with a larger points gap than standard rockers?
Daniel Stapleton

Daniel - Points gap do you mean tappet lash?

They are currently .012 and .014" adjusted cold.


Guy - Coil bind at full lift, that is one I've never thought of. How do you check to see if they are binding?
Ron Koenig

Hi Ron,
Remove the valve cover and turn the engine until a valve is fully open, at maximum lift, on the point of the cam lobe. Then check visually that there is space between the coils of the valve spring. To allow for a little "bounce" you should have visual clearance but this could be checked by using a feeler gauge between the spring coils. I am not sure how much one would need to allow for, but I would try something like a 15 thou feeler. If the gap is more than that you are certainly OK, if less, then you may need to get more advice.
To be thorough, check each valve in turn, and do them when the engine is well warmed up
Guy Weller

The current springs are factory double valve springs as used on home market cars (N. American market cars used single). I guess if they are binding, I should look for different springs.
Ron Koenig

Ron,
Well, yes, different springs would be the solution, assuming that is the problem! But don't just take my word for it! It was only a suggestion and it is an easy enough thing to check out. Really you are just looking for daylight clearance between the spring coils when they are in their fully compressed state.

When I tried some 1.5 ratio roller rockers I did find them significantly more noisy than standard. And in fact I took them off again, although this was more to do with the changed power curve which didn't really suit my type of driving.

Your gaps seem to me to be tight, from what I recall being the settings I was advised to use. But logic would make one believe that would make it quieter, not more noisy! Sorry, I am not being much help here; I have run out of relevant experience to offer on this!
Guy Weller

Coil bind was the culprit. My cam and rollers gave much more lift than expected, and binding occurred. I've since purchased TT1703 high lift springs with hope these will do the trick. If not, it's off with those troublesome rollers.
Ron Koenig

Well, this is a pain that won't go away! So... I've reactivated this thread.

After replacing the valve springs with the high lift ones to eliminate coil bind, and removing the rollers and going back to standard rockers just for percaution, i'm still puzzled.

I'm adjusting the lash, but it won't stay. Keeps on getting looser even though the nuts are tight!!! For example, I set the lash to .012" and then run engine and eventually it will loose adjustment and go out to .014" and even 0.015"! I adjusted them over and over. And yes I do it when cold back to base setting. I can't imagine why they would change. These are solid lifters!!! The lifters get really loud as the engine warms. Piper 270 cam with hardened lifters, stock pushrods (checked, none are bent).
Ron Koenig

Ron,

Was the Piper cam new as part of the engine build, did you use new followers and did you complete the 'new cam' break in cycle immediately after starting the engine for the first time?

My 'horrible' thought is the cams lobes are wearing away - had it happen on a new Piper 270 in our 1380, even though it have been through the 20 minute run in cycle, new oil and filter etc. etc. Piper replaced cam and followers FOC.

With 1.5 rockers, shouldn't the tappet clearances should be 0.014" and 0.016" - will not help the noise though.
Richard Wale

Cam and lifters new as part of rebuild with flat tappet cam lube, 30w break-in oil with extra ZDDP. For break-in, ran idle about 2,000 rpm for first 15min of operation. After that, varied driving.
Ron Koenig

What is most alarming the adjustments won't stay. Everytime they go out of whack after running the engine and checking after cooldown. I had two other car guys there as i was doing adjusting just to be sure I wasn't going crazy haha.
Ron Koenig

This thread was discussed between 18/03/2013 and 29/04/2013

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