View Full Version : Engine Timing

06-07-2002, 06:29 PM

I run a JH engine that the distributor advances to 46 below TDC (6 below timing set, 14 vacuum advance and 26 mechanical advance). It is hard for me to get to 6200 rpm in 3rd or 6000 rpm in 4th. I have a buddy who limits his timing to 38 BTDC and he can get 6600 rpm in 3rd and 6400 or more in 4th.. how do you all run your timing with what results? thanks

Joe Craven
06-07-2002, 07:10 PM
disconnect the vacuum and advance the timing a couple of degrees.

Campbell, you want to blow your motor?

36 ITB Capri and


06-07-2002, 07:24 PM
46 degrees total ??? How the hell do you keep headgaskets in the thing ???

06-07-2002, 07:34 PM
I dis-connect the vacuum advance, and set my timing at 35 degrees @ around 4,500 RPM.

That works for me.

Tim Linerud
San Francisco Region SCCA
#95 ITB GTI, GP for 2002

06-07-2002, 09:36 PM
Guys -

The 46 degrees is the factory set up! the Bosch distributor moves 40 degrees (check the Bentley manual) and the and the stock setting is 6 below TDC. It does seem exteme doesn't it...

I may be the only one running factory! that may be my problem.

06-08-2002, 01:41 AM
I melted a head at 39 degrees last season. Learned my lesson right quick. And that was with 100 oct fuel.


87 ITB Scirocco
www.geocities.com/highspeedconnectionracing (http://www.geocities.com/highspeedconnectionracing)

06-08-2002, 08:00 AM
Check your timing belt to see if it is off a tooth, Had the same problem with my 240sx no top end, the timing chain was off one tooth. I sent a valve from the head to the oil pan. dave

Ryan Williams
06-08-2002, 12:45 PM
Have not timed an 1800, but on the HP 1600 engine, I use an adjustable timing light set to 34 degrees and bring the rpm's up to about 3500 to 4000 rpm's. The vacuum advance is disabled and the mechanical advance is fully open at this rpm range. I rotate the dizzy until I see the timing mark in the bellhousing of the tranny.

Have not researched the timing procedure for an 1800 but the vacuum advance should not have an affect at higher rpm's; only the mechanical advance should be controlling the amount of advance. Check your Bentley and it should indicate where the vacuum advance drops out.

If you are actually getting that much of advance, your EGT readings may be higher than they should be, and you may be getting some detonation. Regards, Ryan

06-08-2002, 02:23 PM
>>I melted a head at 39 degrees last season.

But that didn't melt your engine. It must have been lean. 100 oct fuel isn't needed.

Bill Sulouff - Bildon Motorsport (http://www.bildon.com)
Volkswagen Racing Equipment

Bill Miller
06-08-2002, 09:54 PM
I don't run the vacuum advance either, and set the timing at 38 deg. @ 4000 rpm.

MARRS #25 ITB Rabbit GTI

06-10-2002, 01:02 PM
Is it necessary to remove the vacuum 'thing' on the side of the dizzy, or can I just 'cap off' the nipples.

A friend who used to race Rabbits mentioned substituting a Chevy advance spring for the heavier VW spring, said you can get them cheap at race shops. Has anyone tried this? What advantages are there to doing this?


83 Rabbit GTI - future ITB

06-10-2002, 02:55 PM
It would probably bring the advance attributable to vacuum earlier in the curve.