I've had a 2 litre laying around for a while,got it fromn a beetle wreck i bought the only thing i know about it is it's got a roller bearing crank,anyway i finally got around to putting it in a car to see what happens,fired up without to mutch trouble no smoke sounds smooth go for a drive,everythings good until i get to a hill and it makes a high pitch tapping sound(like a valve or rockers) when under load, so i back off change down a gear noise goes away until i give it a boot and the noise comes back,any ideas.

Sure you are not talking about "pinging"

You 100% the timing is set right?? Sounds like timing to me

agreed ^^

AFAIK roller bearing cranks don't like load,

they like revs.

Could be normal for those cranks, could be that the bearings are shot.

Sorry, can't be more helpful.

send the engine to me ,,,ill run it in my baja and when i get the chance ill let ya know whats wrong with it ,,,,lol

Pinging..............check timing and fuel quality.

it did have a bosch vj4 br8 dizzy in,but there was no condessor,rotor or cap on it,so i put a 009 i had in.

Would too mutch end play on the drive shaft cause it to ping?

I ran it on premium unleaded,could it be possible that the heads have been fly cut for higher compression? needing a higher octane fuel.

Thanks heaps for the info

keep the total ignition timing down!!!

Put a timing light on it and start around 26 to 28 degrees at maximum advance.
Your engine may like more but this is a good place to start.

If you keep allowing that your roller crank will be shot.

Yes use good fuel too, but pump fuel that is hi octane should be all you need,
unless it is a racing engine with more than 10 to 1 or some weird chamber or something.

Quote:

Originally posted by aussiebaja send the engine to me ,,,ill run it in my baja and when i get the chance ill let ya know whats wrong with it ,,,,lol [/quo any bigger then a 1200 and your baja would rattle to bits

nah ,,im a better car builder than that ,,,thanks

good on ya lol

Ok,I put a timing light on it and brought it down to 26 degrees at total advance,took it for a drive,was better but still pinging.

Drained the fuel tank,went and got 5 litres of bp ultimate 98 octane and a bottle of STP octane bust.They say to use the whole bottle to full tank of gas,so i put a third of the bottle(350ml) to my 5 litres.went for a drive,heaps better only got a tinny bit of ping,but still with the timming down so low and the octane boost it still pings,maybe i need some avgas

I thought i'd get some new points and plugs,i'ts got w8ac in at the moment so i went the cooler w7ac and see what happens, all gaps are set and the timing still at 26 degrees,went for a drive and no ping what so ever,sweet,but i can feel there's more power in this beast so i tried advanceing the timing a touch,no good it pings even this tiny adjustment,so i brought it back and all is good.

So what does all this tell me,is the engines compression is too high for pump gas,do i need to run it on avgas? or can i put shims in between the barrels and heads to bring the compression down so i can use pump gas.

any thoughts

OK - am guessing your compression is way to high??

But why??

BEST thing would be to actually check compression
Sadly that means a top end pull down.

if it comes out at say 10:1 - no worries. Shim it and all is well.

If it measures 8:1 - you got other problems

How do i work out what the compression is.

take the heads off and measure the deck height and the combustion chamber of the heads and compare that to the over all swept area

or click here

http://www.aircooled.net/gnrlsite/resource/specgeninfo/calcs.htm 

wouldnt it5 be easier too do a commpression test on it first ?

No = a compression test tells you if you have compression. ie if it is leaking
Not waht the ratio is.

the only way is to measure things.

From his previous post it seems like he has way too high of a compression ratio

oh ok i tought you may be able to do a compression test and work out what your ratio was by the amount of compression,,,,now i think about it more as i write i see what ya mean ,,,sorry my bad