racing cams

eEm · Post by **eEm** » Thu Aug 14, 2008 9:41 pm

Bosh! Not to scale obviously, took a while to triple check everything but its pretty accurate.

Updated after quadrupal checking lol

Ettore Bugatti · Post by **Ettore Bugatti** » Fri Aug 15, 2008 4:54 pm

Thanks!

But can you confirm that the ?=39,6mm

Dont want to push my luck, but do you have the B20F as well?

Guess its time too turn Solidworks or Invetor on...

BTW you can reconize the cams by dots that are printed (stamped) on the cam between the lobes.

There are two rings next to each other. The first ring can have five dots 1,2,3,4,5) the second ring only two (1,4).

Markings:
B18E: 1-3
B18EP/FP, B20F: 1-4
B18FT: 1-3-5
B18FT mkII: 2-3
B20F mkII: 2-5

eEm · Post by **eEm** » Fri Aug 15, 2008 11:23 pm

Got a bit confused with the dots but you mean that 1 and 3 are opposite the 5 on the belt end. Like so-

I thought I had a mk2 B20F for a second

Oh ?=33mm's

So what do you make of that?

Ettore Bugatti · Post by **Ettore Bugatti** » Sat Aug 16, 2008 1:35 pm

The lowest ring in the picture is the first ring and the holes are numbered from 1 till 5. The upper ring in the picture is the second ring and the two holes are numbered 1 and 4.
So if a B18E cam has the markings 1 and 3 then the 3 can be found in the first ring, but it is unclear where you can find nr 1. Is it on the first ring or on the second ring? My information isn't clear on that one.

So I suspect that this is a first B20F cam since I see a dot in the second hole on the second ring (the upper ring in the picture)aka 4 It also should have a dot in the first hole, but again my information is unclear in which ring...

About the question mark. If that's 33mm then the valve lift is 30,8-(33/2)=14,3mm and that is a bit too much for a B18E (book value is 10,49mm@0,5mm lift)

So the X should be according to you be 30,8+16,5=47,3mm?

eEm · Post by **eEm** » Mon Aug 18, 2008 1:22 am

Sorry, just to confuse things fyrther, heres the updated measurements taken when I wasn't stoned

Its definately a B18E as its from an 87' 480ES with no cat and an EGR system which, according to the workshop manual were only fitted to the B18E engines.

Ettore Bugatti · Post by **Ettore Bugatti** » Mon Aug 18, 2008 4:43 pm

Hmm, that looks more feasible

Is the picture with holes your B18E cam? Then it should have a centre punch in hole nr1.

eEm · Post by **eEm** » Mon Aug 18, 2008 8:14 pm

I'm getting a bit confused, so this is how I understand the cam id system to work:-

B18E 1-3

B18EP/FP mk1 B20F 1-4

B18FT 1-3-5

B18FT mk2 2-3

B20F mk2 2-5

Ettore Bugatti · Post by **Ettore Bugatti** » Mon Aug 18, 2008 9:30 pm

hmm, that is a way I didn't think off.

I will scan tomorrow the piece from the manual.

In the mean time check this out

: http://www.chevyhiperformance.com/techa ... index.html

So your cam is 240 degrees (2x120), not the book value of 260...

480_rocket · Post by **480_rocket** » Tue Sep 02, 2008 10:27 am

eEm wrote:I'm getting a bit confused, so this is how I understand the cam id system to work:-

B18E 1-3

My B18E has markings just like this. I think eEm has the right idea how the markings are done. None of the indentations have any markings inside them.

Ettore Bugatti · Post by **Ettore Bugatti** » Tue Sep 02, 2008 9:29 pm

I also think that eEm has a feasible explaination for the marking.

Ettore Bugatti · Post by **Ettore Bugatti** » Tue Sep 09, 2008 6:57 pm

Et voila:

This is a very rough indication. It seems that the cam only is 240 degrees, but that could be wear.

So anyone please measure your cam so then we can compare

480_rocket · Post by **480_rocket** » Wed Sep 10, 2008 10:47 am

Are the specs not given at 0.05" lift?

Ettore Bugatti · Post by **Ettore Bugatti** » Wed Sep 10, 2008 5:19 pm

My graph is with zero lift, but I know that Volvo used different lift values for the cam marking so perhaps you cannot compare the cams...
These values are in the 0,5 -0,7mm lift. So if the B18E would be 260 degrees @0,7mm (for example) then the cam timing would be longer at zero lift.

Also I wouldn't be suprised if the graph would 5 till 10 degrees unprecise.

480_rocket · Post by **480_rocket** » Mon Sep 15, 2008 11:10 am

This is data gathered from an old post on the forum.