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T-Series Bent Push Rods

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PAUL161

PAUL161

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Yesterday after a 150 mile trip, about 10 miles from home, I noticed a clicking/tapping sound above 3500 rpms, below 3500 no noise. Drove it home and pulled the valve cover to discover I had at least two bent push rods, maybe more. Looks like the re-builder used the original rods not new ones. Mind boggling why it ran perfectly for 4 years or more with no issues and now this happened. Running late, I did push it more than usual, but that shouldn't have bent the push rods. Maybe it was because I never pushed it up to 5000 rpms before. ?? Can stronger push rods be bought? PJ
 
OUCH! Tough luck, Paul.

Check with Crane Cams; I seem to remember that they offer hardened pushrods and they have cams for MGs.

Mickey
 
Thanks Mickey, I have a Crane cam in it now, but the push rods look original. I'll check with them. If the push rods were original and not perfectly true, I would believe that could have caused this issue. Reason I don't like using old push rods as they can get distorted by rough handling. Original style new rods would probably do the trick and since their an easy install I might just put a new std set in. Cars done for the winter, so no rush. PJ
 
With some aftermarket cams, it may be that you can't use the stock pushrods; maybe that's the cause?
 
Mickey Richaud said:
With some aftermarket cams, it may be that you can't use the stock pushrods; maybe that's the cause?
Click to expand...

Very possible because I never pushed it before. I'll check with Crane on their push rods. PJ
 
PAUL161 said:
Very possible because I never pushed it before. I'll check with Crane on their push rods. PJ
Click to expand...

Just heard from LaVerne and it might be caused by brass valve guides tightening up when hot. Ordered a bore scope to check inside the bore for anything unusual, but I have a feeling it's the valve guides. Strange as I've been running this car for 4 years with no problems and the day this happened was a very cool day so it wasn't overheating, actually it was running on the cool side. ???
 
He knows his stuff, for sure. It'll be interesting to hear what you find.
 
Well, here's a couple pics to ponder over. Have to pull the side cover off to check the followers and make sure their ok. Valve stem tops look like new, the damaged rocker didn't hurt it.
View attachment 60849View attachment 60850
 
Exhaust ports for cylinders 2 and 3. Siamesed. That would be an understandable argument for the guides being the issue.

Are there bronze guides available vs. brass?

OFF WITH IT'S HEAD!

ack.
 
The problem we have here Doc is, I lost the engine builders email address, retired MG dealer mechanic, I know where he lives and I'm trying to contact him to find out if the head does actually have brass guides in it or not. Looking through a pile of receipts, I haven't found anything pertaining to the head. I don't want to pull the head if I don't have to, but that doesn't look too promising. :frown-new:
Working on the engine on a TF doing anything major, it's best to pull the front of the car off, that in it's self is a royal pain.
 
I understand the pain, done it more than once. Not being able to determine guide metallurgy is kinda frustrating. If you can try a "scratch test" on a guide, brass is soft and will show a trace of damage where bronze is MUCH harder and is less likely to have evidence of minor damage.

Different color, too. Brass looks bright and shiny (almost like gold) with a scratch, bronze is darker and less likely to show evidence of damage.
 
Well Doc, after many discussions with some other guys, I think we have discovered the problem. Knowing the engine has run like a champ for 4 years without any issues, it had to be something very recent. Talking to a couple cam experts on Crane cams and and appropriate components I've decided that #4 & #5 valves momentarily stuck due to carbon build up on the base of the stems, #1 & #8 look good. Odd because I color tuned the plugs in the spring and they were a light tan in color, so for some reason the fuel mixture enriched and caused the heavy carbon issue. I pulled the manifolds off and looked inside the ports and that's how I saw the build up in 4 & 5. Carb cleaner seems to clean the carbon off the stems, but I need to collapse the springs more to look at the stems further up. New set of Crane push rods coming and 1 new rocker for #5. carbs adjustment needed also for a slightly leaner mixture, might be a sticking float?? As you can see, I don't want to pull the head if not needed! Glue it all back together and give it a go. :encouragement: PJ

Oh yeah, I pulled every cam follower and they look like new and a light swirl on the bottom shows they are rotating as they should. Another thing is, number 5 push rods cup wasn't polished as the other 7, kinda odd but??
 
Glad you're getting it sorted out!
 
Mickey Richaud said:
Glad you're getting it sorted out!
Click to expand...

Can't do much more Mickey til the parts come. Have to reach out to the fella who is supplying me with the Crane push rods and see if he has a #5 rocker arm also, if not I'll get one from the normal suppliers. Parts prices doesn't bother me, but it's amazing what it costs for shipping anymore!:rolleyes2:
 
New Crane push rods are in along with new #5 rocker. Odd, but not a problem, didn't realize it until all was back together and valves were adjusted that the new #5 rocker pushrod ball has a shorter thread area than the rest. Kinda makes the overall look a little odd. I wasn't about to pull the whole mess off to put one in from the original rocker just so it looks better! :rolleyes2: Now waiting for a set of new manifold flange studs, might be here today, so I can get this thing perking again!:encouragement:
Lower valve stems and ports have been cleaned of carbon while their open. Always a problem is getting parts in a short time, be nice if one could just run down to NAPA and buy what you need! Such is life.:peaceful:

View attachment 61013
 
With the cover on, nobody will know but us chickens. :wink:
 
Gave it a short test run on Saturday and everything seems normal, now I need to give it a longer run at 60/65 mph. Hopefully all will be as it should be. PJ
 
:thumbsup:
 
Well Doc, Len Fanelli (Roller Cam Guy) said my settings on valve lash are too close, Crane specifies .018 intake and .020 exhaust for those clearances on my cam and also talked with LaVerne and he said he sets his at .016 intake and .018 exhaust. Cranes settings might be a racing specification (?), but I think I'll use Laverne's settings as This car will never be raced, never knew it but this cam calls for a noisy valve train, nothing I can do about it. :grief: PJ

Oh, Maybe I can cover the engine with a moving blanket! :encouragement:
 
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