Engine tapping after rebuild?! Slipped liner?

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nicka2804

New Member
Posts
47
Location
Bradford, West Yorkshire
Hello,
I have recently rebuilt my dads 4.0 gems p38 engine. It appeared to have either ran out of oil or lost pressure as it wrecked the bottom end. Span the mains and the big ends were pretty much non existant.
So new block needed. Bought a second hand block with crank cam and pistons in which was guaranteed to be fine and only stripped because somebody needed a pair of heads. I then stripped that and replaced all bottom end bearings and seals, new piston rings and rebuilt it.
The cylinder heads were skimmed and i relapped the valve seats and replaced the stem seals. Put the engine in the car it starts and runs sweet until it gets warm and then starts to tap!
Initial thoughts were a stuck lifter perhaps but after running for a few hours and a short drive its still the same. I have also ran a oil flush through it and changed oil grade from 10W40 to 15W40 and no change.

My concern now is whether i am dealing with a slipping liner? Is there a concrete was of proving this?
Dont know what to do for the best as i guess im close to stripping the heads of again to find out what on earth is wrong.
Any assistance would be greatly appreciated.
Located in keighley, west yorkshire
 
when my old engine slipped a liner it would overheat but only after a run of around 10 miles from cold would tick over for a few hours before overheating.when you rebuilt the motor did you replace all the lifters and push rods with new items? if so did you soak the lifters in engine oil for a few hours before fitting?if not it will tap,did you rebuild the rocker shafts check to see if all the pads are on the rocker arms.
 
Thanks for your reply, the lifters and pushrods and rockers are all the original ones. Admittedly i didnt do anything with the lifters when i should have done!
However the car did still run before i stripped it just had heavy bottom end knock which was the big ends on the back two cylinders. I had no reason to believe there was anything wrong with them. Only different component in the valve gear is the cam is not the original one to the lifters etc. would that make such a difference?
Cheers
Nick
 
nicka2804 said:
Thanks for your reply, the lifters and pushrods and rockers are all the original ones. Admittedly i didnt do anything with the lifters when i should have done!
However the car did still run before i stripped it just had heavy bottom end knock which was the big ends on the back two cylinders. I had no reason to believe there was anything wrong with them. Only different component in the valve gear is the cam is not the original one to the lifters etc. would that make such a difference?
Cheers
Nick
Click to expand...

Yes.
 
Could this be it?
 

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nicka2804 said:
It isnt a new cam though its the one that came with the engine bought. Surely the lifters should account for the difference in wear between them?
Nick
Click to expand...

You should NEVER run lifters from one cam on another one. Even if you strip an engine and use the same cam and lifters, they MUST be marked and put back on the same lobe they came from. Standard practice. Did you measure the lobe sizes and check for wear on the cam and tappets. Or just throw them in hoping for the best?
 
No i didnt measure them. Wasnt a case of throwing it together ive rebuilt many engines but i havent worked on one of these prior to this one. Also why should it only happen once its hot. When cold its quiet as a mouse and runs perfectly. Valve clearences are there to allow for expansion as things heat up so surely if the tap is valve clearance related it should be there when cold?
I hope i dont come across as telling you how to suck eggs im really not just trying to understand it better. I appreciate your advice
Nick
 
nicka2804 said:
No i didnt measure them. Wasnt a case of throwing it together ive rebuilt many engines but i havent worked on one of these prior to this one. Also why should it only happen once its hot. When cold its quiet as a mouse and runs perfectly. Valve clearences are there to allow for expansion as things heat up so surely if the tap is valve clearance related it should be there when cold?
I hope i dont come across as telling you how to suck eggs im really not just trying to understand it better. I appreciate your advice
Nick
Click to expand...

Could be a few things. Maybe a tappet that is leaking with a bit of ****e on the ball valve. Leaks quicker when oil is hot, could take some finding. Sticky tappets sometimes go quiet and seal with extended high RPM but not always. You need a stethoscope on it to find out just where the tap is coming from. At least narrow it down. There are no valve clearances on hydraulic tappets.
 
wammers said:
Could be a few things. Maybe a tappet that is leaking with a bit of ****e on the ball valve. Leaks quicker when oil is hot, could take some finding. Sticky tappets sometimes go quiet and seal with extended high RPM but not always. You need a stethoscope on it to find out just where the tap is coming from. At least narrow it down. There are no valve clearances on hydraulic tappets.
Click to expand...

Yeah i do need to try narrow it down. Will try having a listen with a stethoscope tomorrow, got one at work i can borrow. i did have a few spare tappets that came with the engine but not a full set. they are fairly easy to get apart and clean out. bearing this in mind what would you do next? i know theres no valve clearences but if a tappet is leaking then if will give clearence and that is the noise you hear is it not?
 
nicka2804 said:
Yeah i do need to try narrow it down. Will try having a listen with a stethoscope tomorrow, got one at work i can borrow. i did have a few spare tappets that came with the engine but not a full set. they are fairly easy to get apart and clean out. bearing this in mind what would you do next? i know theres no valve clearences but if a tappet is leaking then if will give clearence and that is the noise you hear is it not?
Click to expand...

It is indeed. You could take the rocker covers off and see if you can find one with play that would find it quicker if you are convinced it is a tappet.
 
I can't compete with all the advice you are getting about lifters etc. but I can tell you about liners! In the first place a liner 'tap' will occur at piston speed (not valve gear which is half that) & the sound will start quite suddenly as the block warms up.
 
stopover said:
Skimmed heads (how much?) tappet pre-load?

Agree, it was a bad move not to have put in a new camshaft and new lifters. Did you also fit a new (tight) timming chain?
Click to expand...

Hi,
cant remember whether it was 2 or 20 thou that was skimmed from them it was a couple of weeks ago. will check what it was. cant see why a new cam would be needed. although if the one that came with the engine is more worn than my original one then i can understand it.
it still has original timing chain on. wasnt aware there was a difference with chains? i prosume a newer modified chain? i remember seeing one listed on island 4x4.
going to take rocker covers of this weekend and see if i can find any slack in the rockers/pushrods
also debating just pulling the heads back off as if im doing the lifters your almost there anyway. can check the liners this way also.
cheers
nick
 
norseman said:
I can't compete with all the advice you are getting about lifters etc. but I can tell you about liners! In the first place a liner 'tap' will occur at piston speed (not valve gear which is half that) & the sound will start quite suddenly as the block warms up.
Click to expand...

it does exactly as you describe, as soon as its hot it starts. dont know what to do for the best if it turns out that is the case i have to admit
cheers
nick
 
nicka2804 said:
it does exactly as you describe, as soon as its hot it starts. dont know what to do for the best if it turns out that is the case i have to admit
cheers
nick
Click to expand...

Must be a pain to listen to all this stuff, we are all trying to give good advice. Hope you can get to a solution. Some of us have rebuilt these engines many times so we should be able to help. Keep faith.


ps: timing chain if you decide to put in a new cam and new lifters (plenty of cam lube) should be a stiff one. Strangely the part number is the same as a loose new chain! Always specify a stiff one. When you come to look at your existing old chain it will be as loose as hell, well it's a bit like a loose new chain( just not as bad), get a stiff one and it fits precicely and no slack both ways. - just a tip.

On the skim, When I rebuilt the top end of my existing engine I had the max removed so there was no way the push rods would give the required pre-load on the lifters (Tappets) and had to use adjustable push rods in preference to putting shims under the rocker shafts to allow the adjustment. Don't worry about this at the moment as this may not apply to your engine. Did you use steel head gaskets or composite?
 
Last edited:
stopover said:
Must be a pain to listen to all this stuff, we are all trying to give good advice. Hope you can get to a solution. Some of us have rebuilt these engines many times so we should be able to help. Keep faith.


ps: timing chain if you decide to put in a new cam and new lifters (plenty of cam lube) should be a stiff one. Strangely the part number is the same as a loose new chain! Always specify a stiff one. When you come to look at your existing old chain it will be as loose as hell, well it's a bit like a loose new chain( just not as bad), get a stiff one and it fits precicely and no slack both ways. - just a tip.

On the skim, When I rebuilt the top end of my existing engine I had the max removed so there was no way the push rods would give the required pre-load on the lifters (Tappets) and had to use adjustable push rods in preference to putting shims under the rocker shafts to allow the adjustment. Don't worry about this at the moment as this may not apply to your engine. Did you use steel head gaskets or composite?
Click to expand...


Good job its a family motor, shame its not a paid job however but nevermind!
I bought all the bits from island 4x4 and ordered the britpart gasket set. Which are composite i believe.
Probably opened a can of worms now around part quality however taking into consideration the value of the car against repair costs most would have scrapped it. Was hoping to keep costs reasonable on the job as its almost like throwing good money after bad. However here we are:(
Only reason it got the repair is due to the ammount of repairs ive already completed in the last couple of years
Appreciate the feedback and advice lads
Cheers
Nick
 
nicka2804 said:
it does exactly as you describe, as soon as its hot it starts. dont know what to do for the best if it turns out that is the case i have to admit
cheers
nick
Click to expand...

Sorry to hear that, a lot of effort for 'nought. Hopefully you will have some redress against the supplier of the block, as it would appear to be 'not as described' :mad:
 
norseman said:
Sorry to hear that, a lot of effort for 'nought. Hopefully you will have some redress against the supplier of the block, as it would appear to be 'not as described' :mad:
Click to expand...

Well i bought it outside of ebay. It was listed on there but did a cash collected deal. I guess its time to stop guessing and get stuck in at the weekend.
Nick
 
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