Noisy Crossflow engine??

[Richard Gibson]

I recently purchased a '85 Caterham 1600 Sprint. While at the wheel, I can clearly hear the carb intake, engine, and exhaust. The motor seems to be noisy. It ticks, jingles, jangles and makes more noise than I am used to on a sports car. My previous lotus twincam engined cars seemed to have quieter motors. Everything on the motor is sound (compression, and timing, etc.) Is the crossflow just a noisy motor?? Also The exhaust always pops on deceleration, Is this normal as well? New to the 7, stupid questions. Thanks.

 

Richard Gibson Barcorebar@aol.com

[I.Mupferit]

Richard

Surely being able to hear the carb intake and the exhaust is half the point. I have this habit of changing down if I'm going through tunnels just to hear the noise it makes - quite orgasmic!

However the crossflow is a noisy motor generally but of course yours could have problems which require expert diagnosis. I used to have a crossflow and found the camshaft was prone to early wear causing noisy valve gear. Have you tried adjusting the valve clearances to the correct setting for your camshaft? The 1700 engine does not use standard Ford 1600 settings. The 'popping' on overrun could be something simple like mixture seting on one (or more) of the adjusting screws (I assume you have DCOE's).

I always found the crossflow noise to be very harsh, especially when compared to a modern 16v engine , which I now have fitted.

One last suggestion - Try wearing ear plugs and don't worry about the noise!

Brent

 

Edited by - BRENT CHISWICK on 23 Jun 2000 09:04:42

[Dave H]

As a long time crossflow driver (I've had mine 10 years) all I can say is, yes, they are noisy, induction and exhaust, the thing runs in and out of tune all the time. I have tried a number of things over the years and some work some don't. Slick 50, the oil additive made some difference, as does checking the tappets from time to time. make sure the alternator bolts are all present and correct, the lower front one seems to dislike being on the car and escapes at every opportunity. Apart form that, regular oil changes and top ups and it should last for a few tens of thousands of miles.

The main thing to not worry about it too much, and enjoy driving.

like Brent I enjoy changing down to get the full impact of the sound in a tunnel - but be careful, the sudden increase in noise can scare the c*** out of anyone else around, especially cyclists and pedestrians...smile.gif

[Eric McLoughlin]

ENJOY THE NOISE - sorry, am I shouting? I've just been down to Goodwood and back today in my 1600 Classic SE (Crossflow of course) and may be slightly deafened.

 

I know someone who has just spent over £2,000 to make his Elise noisier (it does go faster now too - but that's only a spin-off benefit).

[Roger King]

Firstly the induction noise. This is perfectly normal on any engine with a pair of DCOE carbs. You may have had the same sort of set-up on your previous twincam cars (assuming they weren't on Strombergs), but the carbs were probably under the bonnet rather than poking out. This makes a considerable difference to the perceived noise level.

 

Popping from the exhaust on the overrun is quite common and is usually worse with the 4 into 1 side exit system due to small air leaks at the joint. As a general rule, the better the engine is set up, the less this will happen.

 

Mechanically, the Crossflow is quite noisy. Although the Twincam is of similar vintage, it has much more sophisticated valve gear which helps; throw in the lack of hydraulic cam followers, relatively rigid engine mounts and several other factors and the extra noise becomes inevitable.

 

Bizarrely, the rocker cover often acts as a resonating chamber and changing to a different type can sometimes make the problem better/worse.

 

Exhaust noise is largely down to the silencer type. They do deteriorate over time and fitting a replacement (Techcraft make an excellent range) can transform matters.

 

Roger King rkingeng@aol.com

[John E]

Great replies here fellas, my newly built crossflow ( thanks Roger ) sounds great. Quite a head turner during the 7 trip to Le Mans last week. A nice level of induction noise, memories of Roger Clark in the works twin cam going through Clipstone forest, and a bit of popping from the rear exit exhaust. Its what 7's are all about. By the way Roger I may (will depending upon my wife) wish to talk about exhaust systems very soon and possibly electic fuel pumps.

[Richard Gibson]

Thank you for all of the replies. The answers I got were very well written and informative. I expected to hear what was written. Thanks. RIchard Gibson

[John E]

Richard, if you are still concerned and depending upon where you live get your car to Roger King. He's sorted mine and in fact tomorrow he's going to rolling road the car and I live in Manchester, he's North of London. Some trip but worth it.