Thread: Cams + Crank Timing Chain Question..Mating Marks..

See I just did my cams, When I check the timing i had to have it nearly retarded all the way to get 15 and it ran like shit. So I put it back to where it was, maybe I wasnt in full timing mode, but it was way advanced. Rechecking this today. My pins are exact counting 1 to 11 links dot to dot.

hmm, get a consult cable. Makes getting into timing mode a lot easier.

I tried it and i was pushing my valves onto pistons when I turned the engine over by hand. I took it back off again and put it back to where it was when I began, buttoned it up and the timing situation was finally solved and has not resurfaced since then.

I still think that is what happened.

If the chain jump one tooth on the crank gear, it's going to be 20 degrees. There's 18 teeth on the crank gear, so 360*/18 = 20 crank degrees per tooth.

If the chain jump one tooth on the camshaft gears, it will be 20 crank degrees.
There's 36 teeth on the cam gear, so 360*/36 X 2 = 20 crank degree per tooth. You times 2 because the crank spins twice as fast as the camshafts.

To the OP, without a degree wheel and dial indicator, your other alternative is to count the rollers between the mating marks on the crank and camshaft gears. Should be 56 rollers between the marks for the crank and intake side; 48 rollers for the exhaust to crank side.

Another way, and more complicated, you can get the S4 cam spec from JWT and ask them for the intake and exhaust valve left at TDC. Place a dial indicator on the intake retainer and rotate take the crank to TDC mark on the crank pulley. Take a reading and make sure it matches up with JWT spec. Do the same for the exhaust side. This is a sure fire thing, no more eyeballing.

Base of the pictures you provided, I suspect the chain may have jumped one link on the crank gear. The distrbutor should not be that advanced nor should there be that much slack in the timing chain. The distributor is advance so most likely the camshafts are retarded.

hate to raise this thread from the Dead,

Have an SR20VE on a B13 that we recently purchased, i knew the previous owners pulled the N1 Cams prior to the sale (give and take a few weeks,months ..maybe)

while checking timing, and i usually center the distributor prior to checking timing as this would most likely put you at or around 15 degrees (stock timing) IF everything was assembled right

i noticed with a centered distributor timing mark pointer was at the -5 degree marks = wrong assembly

pull vc, rotate the crank about 40 turns and eventually get the intake and exhaust, cant remember the number of links (its late around 11pm here and tired) have the intake and exhaust cam sprocket in the 10 intake and a little past 12 o clock exhaust positions, crank at tdc mark 2nd from left, the yellow marks on the chain are off, intake being retarded and exhaust sprocjet being advanced by a link.

do the usual safety measures, loosen the cam sprocket bolts, tie up the chain after releasing tensioner

match up the cam sprocket marks with the yellow marks on chain/zip tie em = with crank on tdc pointer at 2nd mark from left = 0

start the engine and has that strange intake sound, very peaky, sounds very advanced

take it out for a drive = almost no power on low, power starts from mid. and could hear the chain rattle (didnt do any high revs) just kept it below 3-4K rpm

suspect that now we are very advanced

check timing

all the marks are on the extreme end (very advanced)

I suspect that the crank sprocket is also in the wrong position in relation to the chain (Blue Mark),

we take down the oil pump cover, upper and lower oil pan to gain access to the crank sprocket and sure enough with the sprocket dowel at 12 o clock position lined up with the vertical mark on the block, dot on the sprocket in the 5 o clock position, blue chain link is behind by 2 teeth.

Just finished correcting everything, will post pics tomorrow and finish assembly

Tevs

hate to raise this thread from the Dead,

A Friend just bought a B13 with SR20VE, i knew the previous owners pulled the N1 Cams prior to the sale (give and take a few weeks,months ..maybe)

while checking timing, and i usually center the distributor prior to checking timing as this would most likely put you at or around 15 degrees (stock timing) IF everything was assembled right

i noticed with a centered distributor, timing mark pointer was at -5 degrees = wrong assembly

we pull vc and do around 40 turns on crank about 3 times just to make sure and get tdc on crank with yellow chain links not matching cam sprocket marks


do the usual safety measures, loosen the cam sprocket bolts, tie up the chain after releasing tensioner

match up the cam sprocket marks with the yellow marks on chain/zip tie em = with crank on tdc, pointer at 2nd mark from left = 0


start the engine and has that strange intake sound, very peaky, sounds very advanced

take it out for a drive = almost no power on low, and could hear the chain rattle (didnt do any high revs) just kept it below 3-4K rpm

suspect that now we are very advanced

check timing

timing marks are way off on the left side in relation to the pointer

I suspect that the crank sprocket is also in the wrong position in relation to the chain (Blue Mark),

we take down the oil pump cover, upper and lower oil pan to gain access to the crank sprocket and sure enough with the sprocket dowel at 12 o clock position lined up with the vertical mark on the block, dot on the sprocket in the 5 o clock position, blue chain link is behind by 2 teeth.

Just finished correcting everything



Will assemble everything tomorrow, very tired

Tevs