R

Rjc

Member
Hi I'm New on here ,top site☺.any way my problem is I have a top end tap on my 4.6 but only when warm does it on lpg and petrol.it's had a new high torque cam kit New rocker assemblies .got good compression hot and cold and good oil pressure. all plugs are nice even colour no water loss or overheating probs.coil packs have been changed aswell checked manifolds are tight . Any ideas anyone? Thanks in advance.
 
Welcome to the site mate, when you say new rocker assemblies new can I take it new can, hydrolic lifters and rockers ???? So did you have new rocker shafts as well ???
 
OK I suspect a faulty new rocker a search on here will find others with the same symptom, iv just renewed all of mine.
Which bank left or right can you use a long screw driver or similar to narrow it down a bit
 
biketeacherdave said:
OK I suspect a faulty new rocker a search on here will find others with the same symptom, iv just renewed all of mine.
Which bank left or right can you use a long screw driver or similar to narrow it down a bit
Click to expand...
At first it sounded like it was on number 2 went down rocker cover listening with screwdriver and it got quieter at number 8 so changed the whole assembly still taps when warm and same sound all the way with screwdriver .
 
Well as long as correct cam run in was done on first start up I'd still go for rockers did you load them with oil first ???
 
Yes mate I did.only changed cam,rockers etc as process of elimination to solve the tapping.
 
Yeah bit thin that 5w 30 as the older engine use to run 20w 50 I think, your running the reccomended stuf now have you tried an additive ??
 
Time to get the spanners out again then mate keep us posted on here mite help others in the future. Let's hope its not a slipping liner
 
Yea ,don't mind getting the spanners out as long as I know what I'm looking for! If it was a slipped liner wouldn't there be loss of water, overheating discolouring on the plug etc? Thanks for your time will keep you posted as to what I find.
 
its not always the case check.out the search function its pretty good but you have coverd all the usual suspects top end only valves left so unless one of then is letting go nothing else left
 
Just a thought - as you had new everything did you check the preload on the tappets? -Should be 0.20" to 0.60" from memory
 
No I didn't check preload but in my defence the push rods can still move as they did before. It only taps when up to temp will have the head off and see what's happening.
 
Rjc said:
Yea ,don't mind getting the spanners out as long as I know what I'm looking for! If it was a slipped liner wouldn't there be loss of water, overheating discolouring on the plug etc? Thanks for your time will keep you posted as to what I find.
Click to expand...

Not necessarily, I take it the 'tap' was present before you carried out the work?
A slipped liner noise will be at crankshaft speed, as opposed to valve gear which is half of that. Starting from stone cold the noise will usually become apparent as the engine begins to warm up. Out of interest did the 'tap' originally occur when running on LPG but not on petrol, but then could be heard with both fuels?
 
Yes it was there and getting louder was told it was the cam so had it replaced ,no change and a grand lighter! Parked it up for 12 months then started work on it again last week.'tap' was present when warming up on lpg or petrol top get liners it is.is there any other tweaks I can do as it's going to be a full rebuild?
 
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