Rabbit diesel missfires a little after warms up.. hmm

[rabbit_diesel]

When i first fire it up from being cold it bangs on all four cylinders just fine, but after it warms up a little i can notice a miss in one of the cylinders.. could it be that one of the valves are open? I hope it's nothing serious.  I don't want my poor rabbit to die.  Let me know what you think.  Thanks

[8v-of-fury]

On the cold start, does it smoke? if so what color? I think that if it were a valve sticking open, you might notice it more when cold..

Its a rabbit, but what year is it? engine original? if not what year is it?

[rabbit_diesel]

it's an 83, i'm pretty sure the engine is original because it's got the mechanical valves.  it doesn't smoke at all that i can see.  The only time i can notice this miss is when it's idling.  could the valves be out of adjustment? would that ever cause a miss?  i haven't adjusted them since i had it which was about 20k miles ago.

[Rabbit on Roids]

usually as valves wear, they get out of adjustment and get too much slack in the lifter assy, and then they tick.

the way your valves would be, they would have to be sticking open, as in not closing all the way, to make the miss, and that would be from not enough slack in the lifter, and the cam would be holding the valves open.

 i dont think this is one of those things where you adjust the valves and fix it. im thinking you have a messed up injector.. thats the only thing that makes sense to me.

[rabbit_diesel]

okay thanks.. yeah i was just thinking that maybe there wouldn't be enough space between the cam and the follower holding the valve open a tad bit at compression.  Then i thought when it warmed up it would expand making it stay open more.  But I im gonna agree with you on this one because i've never heard of that happening.   I think i'm gonna look into some new injectors.  Thank you for your opinions 

[Rabbit on Roids]

and if it was the valves sticking open, it would not be intermittent, that cylinder would just go dead when it warmed up, as in not fire at all, not just miss a little bit..

[rabbit_diesel]

1.6 n/a - VNT17, 20 psi, cold air intake, gov mod, 4A 4 speed

wow 20 psi to an N/A.. that rabbit IS on roids. what's the most the nonturbo motors can handle?

[Rabbit on Roids]

i start cracking blocks up around 37-40 psi. and that was on a stock engine with stock head bolts and stock head gasket.

that was a 1.5D block..

the 1.6TD block saw that much boost and did just fine, but it may have been that it was worn out with low compression..

if you used a set of head studs, and maybe a copper or MLS gasket, you could run more boost.

im not saying that all n/a diesel blocks will hold that kinda boost, but my personal experiences are that they will take 15-25 psi for the rest of time.. i would not expect one of these engines to live a long life pumpin out 40+ psi..

[rabbit_diesel]

is that 15-25 without an inter or oil cooler?

[Rabbit on Roids]

i think if you are not running head studs, oil and intercoolers are the least of your worries. they wont really allow you to run much more boost. but head studs and a metal gasket would.

also, dont get mad if you throw 25 psi at your engine and blow the head gasket. i would stick more towards the 15 psi side. these engines are very fun with 15 psi and moderate fueling.