Jump to content
Sign in to follow this  
bullzed

Rocker slipping

Recommended Posts

Matt,

 

It's spitting the number 5 and number 6 inlet valve lash pads. We had it running up at 5.5k and it was fine, we turned it off, went to take it out on a run and bam, starting it up fired the lash-pad off number 6.

 

These are the 2 rockers that started playing up when it had the bad setup (jumping off and whatnot). Could it be that these 2 springs were weakened quicker than they normally would have been?

 

Also, is it possible to get the springs off without removing the cam shaft or is that not an option?

Share this post


Link to post
Share on other sites

We've also noticed that there is a large amount for the lash pad to move sideways in the valve spring caps. This could be wear from the dodgy set up plus the rockers?

Share this post


Link to post
Share on other sites

zac,

 

Come round and pick up the other bits from me, sounds like the retainers, for want of a better description could also be worn, the lash pads should sit in the cap but shouldn't really have a lot of sideways movement, if there is more movement in 5 and 6 inlets compared to the other inlets then it would be fair to say that is the case.

 

Matt

 

Share this post


Link to post
Share on other sites

So, after different lash pads, different rockers, different valve springs and different spring retainers, it still jumps off.

 

Also, look what we found in cylinder 6.

168043_1648688190088_1623451284_1533830_1899706_n.jpg

 

As we pulled the nylon cord out, that snagged on it and came out of the cylinder. Possible valve and valve seat damage I guess.

Share this post


Link to post
Share on other sites

ZAC, a + karma for staying with it mate :)

  I keep getting a  -karma ....... :'(        so seems someone doesnt like me helping.....................W  T  F!!

so , that " metal" thingy?........... if thats IN the cylinder.... time to take off the head? :-[  not sure what that is?

you dont have a gremlin there.......... do U?....LOL

I have 3 head jobs about to get under way...........NO!!!! not that type of head job!!!

as I have blueprinted a n E 31 head ...... about .....hhhhhhmmmmmm...............................1974 :P

I may give a blo by blo account of the 3 heads as I go.

the heads are a P90, and 2 E88's... one has 260 valves... the other 280 valves... I also have a crow cam , but I tend to like a different cam grinder who gave me a grind,  180 RWHP @5000, L260 block,E31 head job..... back in 70's

damn Ive highjacked the thread :-[ :-X :'(

sorry Zac ............. :-[ :-[ :-[ :-[ :-[

 

You are fair dinkum out of your tree, Salty... ::)

That diatribe above has nothing to do with the topic! Go away & only return when you can post a sensible & ledgeable comment!!! >:(

Share this post


Link to post
Share on other sites

Zac,

 

Sorry to see you have found the problem, and it wasn't what you were hoping :'(

 

Never good to see things sitting in cylinders.

 

As Peter said it's time to pull the head off and see what's what in there. Hopefully no damage to piston or bore. If it's a simple fix of new valve, make use of the bits you have there where you can to save a few dollars.

 

If the bores are good, and block looks suitable to use for a 3mm overbore I'm sure we can work something out on a swap with my spare N42/N42 motor if you need to go down that path.

 

Stick with it, it will be worth it in the end..... :o

 

Share this post


Link to post
Share on other sites

LOL, salty, you're a funny one  ::) thanks mate

 

I'll be pulling the head off tomorrow and yeah hopefully no damage to the piston or bore. Thanks again for all the spare bits you've supplied me with, you've undoubtedly saved me money AND time.  ;D

 

You've helped me so much, we'll have to work something out, you're just too generous!  :P

 

I'll keep you updated with the condition of the bore and head tomorrow.

Share this post


Link to post
Share on other sites

So, after different lash pads, different rockers, different valve springs and different spring retainers, it still jumps off.

 

Also, look what we found in cylinder 6.

168043_1648688190088_1623451284_1533830_1899706_n.jpg

 

As we pulled the nylon cord out, that snagged on it and came out of the cylinder. Possible valve and valve seat damage I guess.

 

Well i doubt if that found it's way in there past the fuel filter.    :o

Share this post


Link to post
Share on other sites

what a wrap up , rope in the spark plug hole to remove valve springs, whats wrong with a straw, im outa here

Share this post


Link to post
Share on other sites

what a wrap up , rope in the spark plug hole to remove valve springs

Very true Daniel, considering that when rebuilding an engine you use a non lint rag/towel to clean the bores. Why oh why would you stuff a bit of  rope into the head, I'm sure that some fibres would come off and remain in the chamber somehwere.

But a simple explaination would suffice rather than a rant  :P

Share this post


Link to post
Share on other sites

Very true Daniel, considering that when rebuilding an engine you use a non lint rag/towel to clean the bores. Why oh why would you stuff a bit of  rope into the head, I'm sure that some fibres would come off and remain in the chamber somehwere.

But a simple explaination would suffice rather than a rant  :P

 

This is what I was told to do, nylon cord in the cylinder to hold the valve closed. Nylon cord doesn't shed and leaves no fibres in the bore.

 

However, this is irrelevant as I'm taking the head off now and have the correct tool to compress the valve springs. I'll update as I find out the condition of the bore and valve/valve seats.

 

Zac

Share this post


Link to post
Share on other sites

Steve, I believe it was Matt who told me about the cord trick. I must say, it worked well. It even pulled that piece of metal out of the cylinder!  :P

Share this post


Link to post
Share on other sites

To quote an old diesel mechanic I knew from many years ago re: bits of debris in a engine cylinder other than metallic pieces etc. "Nothing lives in there!!" was his answer. Little pieces of nylon rope are the least of your worries; a 10mm spanner is another.

Share this post


Link to post
Share on other sites

Hello Bullzed,

                It seem to be an ongoing problem with your camshaft and head. Pulling the head and getting a reputable mechanic to check it out is the way to go. I would like to suggest a few points to bare in mind with the rebuild.

..Rockers, camshafts and lash pads have a run in period when new as they wear together. This creates a matching bond between the surfaces. If for example a secondhand replacement rocker was fitted it would have a different wear pattern to its surface and would not mate up to the camshaft lobe causing prematurewear. I know it's added expence but I would suggest getting a complete cam, rocker, lash pad and spring setup, and also getting a good head expert to set it up right. The other option is to buy a good complete secondhand hand head from one of the members.

.....I am in my 50's and as Salty suggested the rope in the combustion chamber is an old method to change springs when limited tools are available and you don't wish to remove the head.  (I have never tried it).

.....The other method of filling the cylinder with compressed air I have used. I made a fitting from a cut down sparkplug with an air attachment brazed to it. With the valves closed air is pumped int the cylinder with an air compressor. The air holds the valves closed and the springs can be removed with another tool made for the job. Care should be taken not to use too much pressure as this will force the piston down causing the crank and cam to rotate.

..... Anyway just a few things to think about. Good luck with the rebuild and hope you are on the road soon.

Regards

David. 

Share this post


Link to post
Share on other sites

Exactly, i don't see the problem with using a nylon cord  ???

 

We didn't want to have to take the head off just because of the cost of a new head gasket. One thing I may have no pointed out is that we have limited monetary resources and have to try to take the cheap option where ever possible. I know it's not desirable but it's the way it has to be.

 

If the head (or block for that matter) is ruined to such an extent that a full reco is needed, the next step will be saving for a new L28. If it comes to that the Z will be off the road for a long amount of time.

 

Thanks for everyones help.

Share this post


Link to post
Share on other sites

Very true Daniel, considering that when rebuilding an engine you use a non lint rag/towel to clean the bores. Why oh why would you stuff a bit of  rope into the head, I'm sure that some fibres would come off and remain in the chamber somehwere.

But a simple explaination would suffice rather than a rant  :P

the rope would have to shed a lot of fibres  a bit wont hurt, but i might go fishing in my bores , what u do on the weekend? buddy and i went to nissan lakes out past the heads threw a line in number 5 caught a few alloy flat heads , what bait were using? 8 mm manifold washers,

Share this post


Link to post
Share on other sites

This thread now has more pages than a lot of Build Threads on here. Jeepers!

 

Because of people making unnecessary and snarky comments. If people don't have anything useful (or even nice) to say, please refrain from posting in this thread.

Share this post


Link to post
Share on other sites

Okay people, the head is off! Bad news.

 

We found these in cylinder 5 and 6

 

165605_1651502220437_1623451284_1540311_6521114_n.jpg

 

Sounds like sabotage  :o

 

The damage in cylinder 6 is the worst

 

34816_1651502700449_1623451284_1540313_3937881_n.jpg

 

5 is pretty bad as well though

 

162802_1651502420442_1623451284_1540312_1703827_n.jpg

 

And that's not all, seems like the previous owner didn't even know how to set timing right, what's with the valve marks on all of the pistons?

 

I'm taking a guess and saying that little slot on the right side of all the pistons is cast in from the start. The valves in cylinder 5 & 6 are pretty bad, they took a beating from those screws and other little metal bits of crap.

 

All in all, what do you guys think is the next logical step? Are the pistons acceptable? The head should be fairly easy to work with, just needs a valve seat grind and a few new valves which Matt has already kindly donated to my cause.

 

And no more fishing jokes... please  :-X

 

Share this post


Link to post
Share on other sites

And that's not all, seems like the previous owner didn't even know how to set timing right, what's with the valve marks on all of the pistons?

 

Assuming there aren't valve marks in the front 4 cylinders, I'm going to take a guess at the valves being bent from the crap in the cylinders....

 

What the hell is that you found in there, anyway?

Share this post


Link to post
Share on other sites

The valve marks are on all 6 pistons. I wouldn't be surprised if they were bent though.

 

Well, there is a screw head for one, a piece of brass weld and 2 metal clips with "Australia" engraved into them.

 

What the hell did this guy do to this motor ?!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×