Miracle Cure!!!

[chassis 33]

Most of the time I've owned my Chimaera it rattled/ticked/clicked from the top end. After tightening the manifold bolts and praying it wasn't the cam I put the cause down to a cracked manifold, given the amount of exhaust paste wedged into the collector by a previous owner.

Anyway time has passed and as my engine is coming back from it's rebuild shortly I thought I'd clean up the manifold, take the plenum off etc etc, and guess what I have found...


...a loose trumpet, not just slightly out of the base, but totally out and rattling around (but still upright) inside the plenum, to the extent it has done a pretty good job of polishing the inside of the plenum roof. Judging by the amount of hymolar holding everything together a back street butcher has had a play at some point, despite the impressive main dealer history that came with the car.

I've also noticed a small capillary hole in some of the trumpet bases that runs from below the lip that seats the lower face of the trumpet up to the top face of the trumpet base...but only on the middle trumpets. Anyone any ideas why?

This brings me onto another point/can of worms to trumpet or not to trumpet? I seem to remember a couple of threads in the past six months or so that bascally ended up with the people who sell trumpets extolling the virtues of them and those who dont sell trumpets extolling the virues of blended trumpet bases. One of the things that was interesting in those thrads was the general opinion that a closing plate on the trumpet opening could be beneficially to the air flow/pulsing effects of the intake system; is there any percieved benefit in creating a false ceiling in the plenum if using shortened/no trumpets?

Regards
Iain

[GreenV8S]

I suspect that the capilliary holes were to prevent fluid from pooling in the trumpet base.

[chassis 33]

Ah, that would make sense! Cheers Peter, btw, ignore this morning's email, I've come to my senses and decided Ive bettner things to spend my money on that blowers...track time for a start.

Regards
Iain

[love machine]

Depends on the shape of the trumpet,eg:- exponential flares damp shock waves. I'd want my waves damped with that sort of cam/engine

[stevieturbo]

Strange. I think it was Tony or Ian over on the V8 Forum took theirs apart recently, to discover one of the trumpets had worked loosed also.

[steve_D]

The trumpets may well be there to compensate for an otherwise to short an inlet track.
My Chevy V8 produced much more power with a 1" spacer added under the carb.

Steve

[number 7]

Yeh, I've had two or three trumpets pop out, and sit at 45 degrees polishing the plenum roof. But typically, when I actually wanted to remove them, I had to resort to a blowtrorch and repeated beatings with a plastic mallet

I also assumed that the holes were drainage for any oil vapour which accumulated from the rocker breather.

7.