Rattle after rebuild?

[r_9ore]

Well finally got new cam and rockers fitted on my 325, set the clearances up etc, all ready to go. Went to start it today, struggled to get it going, then all of a sudden it fired into life! It was idling fine for a few minutes then it slowly developed a very loud rattle...

Dunno what it is, it sounded like the rockers slapping against the cam lobes, but i re checked the clearances and they are fine, everything up top is good...could it be big end? sounds really loud, too loud to be piston slap...then again, could it? Sounds like its coming from inside the rocker cover, but noise travels i know...

Anyone shed some light on it? im gonna remove the sump and check for big end play after xmas...

i just wanna now...

[E30Adam]

What profile is your cam?

If it's a high lift cam and you haven't uprated the springs then this could be the problem.

[r_9ore]

Nope standard cam from euro car parts, cost Ԛ£73...

[gcorky]

dry lobe.oil ways clear up top?

[r_9ore]

There didnt seem to be much oil getting up top,which i thought was strange, i thought there would be more.

the previous owner said he used 15w-40 oil in it, ive read 10w-40 is better, maybe even thinner, could this have blocked the oil ways?

How will i clear them? how can you check if they are blocked?

[Jimbob]

oil spray bar?

[Dan318-is]

oil spray bar?

My friends m20 had this once. it rattled like mad and the bar had come loose. possibly the easiest ever fix!

[Jimbob]

I meant that it might be blocked, good point though I hadn't considered it to come loose

[Dan318-is]

how would the block cause the rattle?

could a block cause a pressure failure do you think?

[r_9ore]

By oil spray bar, you mean the thin pipe running above the cam?

My oil pressure seems fine, the light goes off straight away when it starts up.

I will check that spray bar tomorrow, give it all a lubricate before rocker cover goes on and see what its like...

[Dan318-is]

By oil spray bar, you mean the thin pipe running above the cam?

My oil pressure seems fine, the light goes off straight away when it starts up.

I will check that spray bar tomorrow, give it all a lubricate before rocker cover goes on and see what its like...

yep thats the one!

[r_9ore]

Megs, will defo check that tomorrow. ill take it off and give it the degreaser treatment!

What about oil, is 15w-40 too thick for my engine? its done 114k...the previous owner said he ran with it, should i maybe use thinner stuff?

[Karan]

oil wouldnt cause this..... but use 10w40 neway.....


check cam timing...... and make sure it is spot on!!!!! u could have bent some valves...

unlikely to be bottom end unless u forgot to tighten something up completely!!!

[r_9ore]

it was only a top end rebuild, i havent touched the bottom end, so i dont know what condition it was in anyway!

checked timing numerous times before i built rest of engine it was fine, i then stripped it all down after i rebuilt it to have a final check and its fine.