Board Logo

Motor Slap
mattie182 - September 24th, 2002 at 09:12 PM

I know this guy whohas a rebuilt 1600cc VW engine. Replaced everything, with new, but now when it runs, there is a motor 'slap'. This noise stops when the engine heats up, then starts, when you accelerate
Ant suggestuions

Matt

Menangler - September 24th, 2002 at 09:19 PM

Sounds like a loose or badly leaking cylinder head, It leaks when cold but when the engine warms up everything expands and it seals.

Che Castro - September 24th, 2002 at 09:48 PM

when i had a pulled head stud and was leaking from the cylinder head/cylinder joint it got worse as soon as it heated up because the sealing area would get hot enough to ignite the air/fuel mixture and would create the evil popping sound

Grey 57 - September 25th, 2002 at 09:20 AM

Same thing can happen with slightly loose exhaust manifolds. Small gap closes when the heads heat up. Just put a new exhaust on the 57 and this very thing happened. Make sure you use lock washers on the exhaust studs to prevent it happening again. :thumb

Zenjoe - October 10th, 2002 at 03:51 AM

check your cranck shaft end play. If you can pull on your pully and feel it move, you end play needs to be redone, FAST!
the end play should be at .003 to .005 (inch) more than that will kill your engine in short order.

vwrallycar - October 10th, 2002 at 09:44 PM

i personally know of this engine and the person building it and from what i know about it it seems to be a major mystery. havent heard the latest on it but will try to find out. everything has been checked several times, so it will be interesting to finally see what the cause is

mattie182 - October 11th, 2002 at 09:17 AM

Hmmmm, I guess you know its Rex and his rat...........
i told him that id post a message here to see what else people can come up with

The motor has been rebuilt twice!!!!!! and the slap is still there



matt

[Edited on 10-10-2002 by mattie182]

vwrallycar - October 12th, 2002 at 05:06 PM

hi mattie yeah i dont know what the problem is. maybe he needs to look at another motor, i know he has one there to rebuild

Zenjoe - December 3rd, 2002 at 02:03 AM

putting the rods in upside down will cause some engine noise as well. Might want to check that out.

vw54 - December 3rd, 2002 at 06:28 AM

You say they replaced everything

Does that include pistons and Barrels

Also the pistons could be in wrong way and also the conrods upside down.

Secoh - December 3rd, 2002 at 10:24 AM

Has he replaced the small end bushes? these, when worn or reamed to an incorrect size can make a knocking slapping kind of a sound.

sounds like a big end, but not as deep a sound and not a solid sounding knock like a big end makes.

Sure it's not something as simple as pinging? (just checking :D)

vw54 - December 3rd, 2002 at 05:52 PM

Adz

12, 15 and 1600 VW Conrods have an up and down built into them.

the up part is the notch on the center on the I section of the rod.

This means they are OFF SET same as pistons.