My s2 developed a bad missfire and a loud tapping coming from the 3rd cylinder a while back, since then Ive given the car a full service including plugs and leads etc but it continued, so, I decided to checked the tappets and cam. The exhaust tappet on the 3rd cylinder had a dished base instead of a nice flat one and after pulling the cam out, the lobe for this tappet was badly scored and worn.

I replaced the cam with a newman one and new hydraulic followers, applied plenty of lube and spun the cam once fitted to checked it moved freely and all the valves opened and closed with no probs. All fine there.

Bolted it all back together, fired it up to run it in and the loud tapping from the 3rd cylinder is still there!!! So turned it off to prevent any damage to the cam.

Im guessing my next step is to pull the head off to check the valve to see if its bent at all.

Would you do the same? Or have you got any other suggestions before I pull the head off?

Cheers

 

i thought all the newman cams used solid tappets and if the new tappets had not filled up in the time you gave them then maybe were still adjusting can take several minutes for them to sort them selves out i had one take 10 mins before going propper quiet how long did you keep it at 2000 revs for

 

Newman now do hydraulic followers for their RS cams, ordered the cam directly from them last week.

I ran it for about 5 mins, it was fine at first but got progressively worse. I left the tappets in oil over the weekend to make sure they were well lubed up but dont think that is an issue due to it coming from the 3rd cylinder only.

 

have you took the followers out since fitting them? mine did the same with kent products, it turned out that one of the followers got jammed due to the follower bore having a sight burr. You will know straight away if this is the case because the follower will not come out through the top, I had to slide the came out and pull the follower out form inside the cam chamber

hope this helps

 

I havent removed them just yet, I wanted to see what peoples suggestions were first. It just baffles me that its in exactly the same place as before and just cant think whats causing it to happen. I can understand that maybe it might quiet down once its been run in but dont want to run the risk of damaging the cam the way the old one was.

 

get em out now mate!!!! mine totally destroyed the cam within 10 miles, it was just mot'd and the car sounded a little tappety, drove home then took the followers out. When the can came out the lobe was completly worn down!!!!!

If you need any help in doing it pm me your number & i can talk you through it

 

It could be that the cam journal around number three is worn or has gone oval. This happens and all the oil pressure to that area will be lost.

Worth a check.

Have you checked the engine oil pressure? To ensure its not your pump that has gone? It is usually the case that the top half of the engine will fail first as this is the highest point for the pump to pump oil to.

 

I was thinking that maybe the oil feed to that particular tappet could be blocked somehow, anyway of checking this and clearing it? Im not sure how to check the pressure, im guessing I need some sort of gauge, where do I connect it?

 

There isnt a clear way of checking, but if you take the tappets out, you can see the oil journals, use a pipe cleaner to see that there is nothing blocked there.

I still think that if you try and get them out the problem will present itself

 

Generally if your Oil pressure is low enough to make the lifters tap then the oil light will be on, seeing as you have replaced the cam and lifters i would be thinking..... 'am i confusing a top end tap with a bottom end knock?'..... big end on No. 3 maybe? Just a thought!

 

get a garage to do a cylinder leakage test, if you have minimal leakage then its not your valve.... this is quick and easy and only involves taking the sparkplugs out to check.. also check your cam timing maybe...

 

Cheers fellas, thinking about the oil pressure, surely it would affect more than one tappet, am I wrong to think that? The missfire has stopped, im guessing that is due to the valve now moving fine as before the tappet was so worn it could not lift the rocker properly. When I first fired up the car after installing the cam there was no tapping (or knocking), it started gradually after 5 mins or so, also it was intermittent, not constant.

Do you mean a compression test? Or is a leakage test different? Ive double checked the timing and firing order and all is fine but the cam is set to standard timing (TDC) at the mo as I need to get it setup to be timed up properly.

Im thinking that the oil feed to that particular follower maybe blocked and causing it to lose lubrication, is it possible to crank the engine with the rocker cover off and tappet out to check the oil flow without getting covered in oil!!

 

I'd check for oil gallerys to that end of the head and if possible turn it over while the rocker cover is off to see if any oil comes out where it should!
check the rocker stud hasnt pulled out the head causing the noise (this happened to me! had to get a worth insert. fairly common on RST's)

 

what if you swap number three tapet with say number one, if you havnt already done it?
if the noise is still coming from no.3, you know the tappet is fine..ect

as for the leakage test or compression test- either would tell you if you have a bent valve but im preety sure its a leakage test you want as there is not much turning over of the engine involved, all you do is turn the engine over by hand tell the cam is off both lobes of the inlet and exhaust tappets, then you know both valves in that cylinder are closed. then wind in the tester in the sparkplug hole and force air into the bore, this will tell you the leakage, if any.. most if not all garages have this tool so it shouldnt be a prob for them to do.

 

Ill have a chat with a local garage to see if they can do a leakage test for me, but in the mean time ill check the oil flow, Cheers for all the advice, ill let you know the outcome.

 

hi , just been reading your thread ive got the same problem with mine . ive just put a kent 34 sport in mine with new followers and its knocking its ass off . ive swapped followers around still same . ive took it to loads off garages some say bottom end and piston slack so i took it back to garage were he s gonna strip it down but he seem s to think that its the shells around the cam . should have it back in the next couple days . if you get yours solved be for me get in contact ha tel 07716060507 cheers daz keep you updated

 

Sorry to hear that mate, im pretty sure mine aint that bad because when I started running the cam in, it sounded sweet, no taps, knocks or missfire. But after 5mins it started to tap slightly and got progressively worse so I turned it off. Just pulled the tappets back out and ex1 and ex3 have slight wear on them and had to be removed through the head, couldnt pull them out!! Plus, I cranked it over, didnt fire it up and no sign of any oil!?! So gona check the oil pressure to see if the pump has had it. If I solve anything Ill let you know.

 

Oh yeah, there is no oil light coming on or flickering so im a bit confused

 

It does sound like your new cam has knocked out the bottom end mate, happens quite often if it was on it's way anyway, big end shells are only good for about 60k and they are down to the brass!

If i were you i'd just whip the sump off and check No3 shells, you can at least eliminate it if it's not that!

 

What would I need to do to check them? Or would it be obvious when I saw them?

 

Take the sump of, then undo the end cap and remove the shells, you can check the condition of them, see if there are any visible signs of pick up/scoring. But you should be able to tell this just by the sound of it. Tap'y sound means head, a knock means bottom. (usually) its hard to explain but once youve heard both types (as i have :-( ) then you never forget

hope that helps mate

 

Right Ive pulled the sump off, checked the pick up pipe, which was clear, checked the shells, all were fine, they've only done 30k on a rebuilt engine. Ive ordered a new oil pump anyway while it was stripped so gona fit that tomorrow. Once thats together Ill get the leakage test sorted.