1641cc Engine pinging/ rattle noise.

[blue65]

Noise questions. There is a slight clatter when I start the engine and let it idle. Tinwear is all secure. I also get slight pinging or a rattle in the engine on 3rd and 4th gear when the revs are a bit low. On 3rd gear it noticeable only at low speed or at high speed when i reach the top of the hill. More noticeable in 4th gear when its under load and i try to pump extra gas. What could be the problem?

Ill be taking the beetle 1641cc engine to see my mechanic in the Monday morning.

[Q-Dog]

Your description sounds like "pinging" or pre-detonation. This can be improper timing, overheating, or too high compression for the fuel you are using (and maybe a couple other things) and can cause significant damage to the engine if not corrected.

I would take the mechanic for a ride to make sure the shop is aware of this issue before they get started on anything else.
_________________
Brian

'69 Dune Buggy
'69 Beetle Convertible
'70 Beetle

[andk5591]

And when was the last time the valves were adjusted? You will normally get some tapping when idling until the car warms up some and then it should get quieter. But totally agree that it sounds like detonation...Don't drive it more than absolutely needed until you get this corrected.
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[blue65]

The valves were adjusted 3000 miles back, or 4 months ago.

I blamed it on my driving style - pumping gas when the revs are not high enough.
But sometimes it can't be helped. I'm changed down to 2nd gear when going up a hill and it pings.

Its also noticable on 4th gear if I'm on a slight incline.

[blue65]

I sent it to my veteran vw mechanic this morning. He adjusted the carb jet by a bit to let in more fuel. But now the engine tends to stall when idle.

[andk5591]

The only thing he can "adjust" is the idle mixture. Otherwise they would have needed to replace the main and or idle jet with larger ones to let in more fuel.

You sure this person knows what they are doing?
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[Sharp64]

[Max Welton]

There's a lot of people taking money for working on these cars.

I think a lot of them ... really shouldn't.

Max
_________________
1967 Type-3 Fastback
Under the Knife https://shoptalkforums.com/viewtopic.php?f=24&t=151582
Home Stretch https://www.thesamba.com/vw/forum/viewtopic.php?t=767836

[blue65]

Hi all, works ok now. Mech fixed it.

To be fair to him, I'm probably translating his tech speak incorrectly.