Bent pushrod / damaged rocker
Discussion
Morning all,
I'm still struggling to get a reliable wedge I'm afraid, I've just had a new rad (the 2nd in 6 months) and cooling fan fitted, however when the garage started it up there was a terrible noise from the top of the engine and they suspect a bent pushrod or a damaged rocker. I've not seen the car since the nurburgring in may, but on the final lap the car developed what sounded like a misfire/flatspot that started at about 5,000rpm and ending up running lower at around 4,500rpm by the end of the lap, but it was possible to drive through it (above 5,500rpm it was fine).
So I've got two questions:
1) Is this misfire likely to be a sympton of the pushrod failing? I doubt it personnaly as it ran fine above 5,500rpm, but what are the thoughts of others?
2) Do pushrods become bent / rockers damaged on their own or are they likely to be a sympton of something more sinister?
3) Have I buggered it by driving through a flatspot/misfire?
Cheers,
Chris
I'm still struggling to get a reliable wedge I'm afraid, I've just had a new rad (the 2nd in 6 months) and cooling fan fitted, however when the garage started it up there was a terrible noise from the top of the engine and they suspect a bent pushrod or a damaged rocker. I've not seen the car since the nurburgring in may, but on the final lap the car developed what sounded like a misfire/flatspot that started at about 5,000rpm and ending up running lower at around 4,500rpm by the end of the lap, but it was possible to drive through it (above 5,500rpm it was fine).
So I've got two questions:
1) Is this misfire likely to be a sympton of the pushrod failing? I doubt it personnaly as it ran fine above 5,500rpm, but what are the thoughts of others?
2) Do pushrods become bent / rockers damaged on their own or are they likely to be a sympton of something more sinister?
3) Have I buggered it by driving through a flatspot/misfire?
Cheers,
Chris
It will be just like having a rounded cam lobe, it won't cause any other damage.
To diagnose it better before opening up the rocker covers try pulling off injector connectors one at a time, is he misfire goes then you've found the right cylinder. You can still drive it like that (injector off) just on reduced power (I did a thousand miles or so with a rounded cam lobe) and it won't be too expensive to fix anyway.
It might be the cam though, which is a little more expensive...
To diagnose it better before opening up the rocker covers try pulling off injector connectors one at a time, is he misfire goes then you've found the right cylinder. You can still drive it like that (injector off) just on reduced power (I did a thousand miles or so with a rounded cam lobe) and it won't be too expensive to fix anyway.
It might be the cam though, which is a little more expensive...
Hmmmm, pushrods and rockers are fine...
Last chance is that it's a hydraulic tappet that's given up the ghost, after the car has been left standing for a couple of months.
I suppose I should start googling for performance cams now.
Unfortunately it looks like I might be missing my track day in august. 
Last chance is that it's a hydraulic tappet that's given up the ghost, after the car has been left standing for a couple of months.
I suppose I should start googling for performance cams now.
Unfortunately it looks like I might be missing my track day in august. Okay after engine flushing, with flushing oil and new oil there's no love to be had.
So it'll be a new camshaft and lifters then, what else would other people consider whilst doing this? I'm not certain the engine is in the best of condition as the valley was covered in a lot of heavy gunk.
In my head I'm toying with everything from replacing with a real steel cam, to rebuilding a new engine from a 3.9 block with stage 1 heads and megasquirted, as obviously I have an oppurtunity to pursue a bit more power and the question is how much?
So it'll be a new camshaft and lifters then, what else would other people consider whilst doing this? I'm not certain the engine is in the best of condition as the valley was covered in a lot of heavy gunk.
In my head I'm toying with everything from replacing with a real steel cam, to rebuilding a new engine from a 3.9 block with stage 1 heads and megasquirted, as obviously I have an oppurtunity to pursue a bit more power and the question is how much?
wombat172a said:
Okay after engine flushing, with flushing oil and new oil there's no love to be had.
So it'll be a new camshaft and lifters then, what else would other people consider whilst doing this? I'm not certain the engine is in the best of condition as the valley was covered in a lot of heavy gunk.
In my head I'm toying with everything from replacing with a real steel cam, to rebuilding a new engine from a 3.9 block with stage 1 heads and megasquirted, as obviously I have an oppurtunity to pursue a bit more power and the question is how much?
Set yourself a budget out and see what you can get for your money reallySo it'll be a new camshaft and lifters then, what else would other people consider whilst doing this? I'm not certain the engine is in the best of condition as the valley was covered in a lot of heavy gunk.
In my head I'm toying with everything from replacing with a real steel cam, to rebuilding a new engine from a 3.9 block with stage 1 heads and megasquirted, as obviously I have an oppurtunity to pursue a bit more power and the question is how much?
wombat172a said:
Okay after engine flushing, with flushing oil and new oil there's no love to be had.
So it'll be a new camshaft and lifters then, what else would other people consider whilst doing this? I'm not certain the engine is in the best of condition as the valley was covered in a lot of heavy gunk.
In my head I'm toying with everything from replacing with a real steel cam, to rebuilding a new engine from a 3.9 block with stage 1 heads and megasquirted, as obviously I have an oppurtunity to pursue a bit more power and the question is how much?
If you going to do a re-build, then 3.9 are dirt cheap, so better off re-building one if these.So it'll be a new camshaft and lifters then, what else would other people consider whilst doing this? I'm not certain the engine is in the best of condition as the valley was covered in a lot of heavy gunk.
In my head I'm toying with everything from replacing with a real steel cam, to rebuilding a new engine from a 3.9 block with stage 1 heads and megasquirted, as obviously I have an oppurtunity to pursue a bit more power and the question is how much?
Also this way you can just swap them, when you have the 3.9 sorted.
AFAIK all 3.5 was standard SD1 engines, so a 3.9 with a re-fresh and fast road camshaft, will be nice upgrade, plus your be going from 190 BHP to 230 BHP. more if you get some better heads.
Also if you get a 3.9 that's complete or semi complete it will be hotwire, so easier to MS or Emerald.
If you want to go Emerald, and get a JE 214 camshaft then I can give you an emerald map. that will be 90-95% right.
Check the cam by taking off rocker covers and looking at the rockers moving first. If one or more only moves a little that confirms your problem.
Start with the easy one on the driver's side. As I said you can put this off (till the autumn) by removing the corresponding injector wire and carry on driving on 7 cylinders quite happily (I had to do this because I had lost an exhaust lobe and it was front-firing).
If you decide to stick with the same block then you may as well do the head gaskets if they haven't been done recently, while you are at it.
Start with the easy one on the driver's side. As I said you can put this off (till the autumn) by removing the corresponding injector wire and carry on driving on 7 cylinders quite happily (I had to do this because I had lost an exhaust lobe and it was front-firing).
If you decide to stick with the same block then you may as well do the head gaskets if they haven't been done recently, while you are at it.
adam quantrill said:
Check the cam by taking off rocker covers and looking at the rockers moving first. If one or more only moves a little that confirms your problem.
Start with the easy one on the driver's side. As I said you can put this off (till the autumn) by removing the corresponding injector wire and carry on driving on 7 cylinders quite happily (I had to do this because I had lost an exhaust lobe and it was front-firing).
If you decide to stick with the same block then you may as well do the head gaskets if they haven't been done recently, while you are at it.
That will not work most of the time, as it will only work if both the lobe and off lobe are worn more then the pre-load, that could be upto 100 thou, and seeing as he only has a slight problem at 5000 RPM + it sounds like it not that worn.Start with the easy one on the driver's side. As I said you can put this off (till the autumn) by removing the corresponding injector wire and carry on driving on 7 cylinders quite happily (I had to do this because I had lost an exhaust lobe and it was front-firing).
If you decide to stick with the same block then you may as well do the head gaskets if they haven't been done recently, while you are at it.
best to rotate the engine and measure how far they move, but if the lifters have pumped down, you may not get a full reading either.
TVRleigh_BBWR said:
adam quantrill said:
Check the cam by taking off rocker covers and looking at the rockers moving first. If one or more only moves a little that confirms your problem.
Start with the easy one on the driver's side. As I said you can put this off (till the autumn) by removing the corresponding injector wire and carry on driving on 7 cylinders quite happily (I had to do this because I had lost an exhaust lobe and it was front-firing).
If you decide to stick with the same block then you may as well do the head gaskets if they haven't been done recently, while you are at it.
That will not work most of the time, as it will only work if both the lobe and off lobe are worn more then the pre-load, that could be upto 100 thou, and seeing as he only has a slight problem at 5000 RPM + it sounds like it not that worn.Start with the easy one on the driver's side. As I said you can put this off (till the autumn) by removing the corresponding injector wire and carry on driving on 7 cylinders quite happily (I had to do this because I had lost an exhaust lobe and it was front-firing).
If you decide to stick with the same block then you may as well do the head gaskets if they haven't been done recently, while you are at it.
best to rotate the engine and measure how far they move, but if the lifters have pumped down, you may not get a full reading either.
Gassing Station | Wedges | Top of Page | What's New | My Stuff