SD7140 / JP 5618T timing set off by 7 degrees - is this typical?
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SD7140 / JP 5618T timing set off by 7 degrees - is this typical?
So back in July I bought a JP Performance 5618T timing chain set from Scoggin Dickey which is sold under the Scoggin Dickey p/n SD7140. I am using it on a STOCK 1998 cam, not an aftermarket cam.
Back in July I timed the stock cam with the stock timing chain, and made the thread below:
https://ls1tech.com/forums/generatio...-1998-cam.html
The stock cam has .050 specs of:
198/209, .500/.500 119.5 LSA
When I timed the cam with the stock timing chain, I got .050 lifter events on the intake lobe of 23 deg ATDC and 40 deg ABDC. So doing the math it's 180-23+40=197 deg duration at .050.
197/2=98.5
98.5+23=121.5 ICL.
On a 119.5 LSA a 121.5 ICL is retarded 2 degrees.
I did not time the exhaust events (it's a stock cam, why bother?).
So fast forward to last night. I've basically spent the last couple months doing fabrication work to complete the swap in my fox body and last night I got around to installing the SD7140 / JP 5618T timing chain. I installed the timing chain on the -2 setting (2 degrees retarded) and got the numbers below:
.050 intake lifter events 29.5 ATDC and 45.5 ABDC
the math
180-29.5+45.5=196 deg duration at .050.
196/2=98
98+29.5=127.5 ICL.
On a 119.5 LSA a 127.5 ICL is retarded 8 degrees, but it is only supposed to be retarded 2 degrees, which means the -2 timing marks are 6 degrees off.
I did this a couple more times after resetting my piston stop and resetting top dead center and re-zeroing the degree wheel, and basically came up with the same ICL number +/- .5 degrees each time.
Again, I did not time the exhaust events.
So since I knew the timing set is off by 6 degrees on the -2 setting, I figured I would try timing it on the +4 setting and see what I get.
Timing the cam with the timing set on +4 (4 degrees advanced) yielded:
.050 intake lifter events 24 ATDC and 41 ABDC
the math
180-24+41=197 deg duration at .050.
197/2=98.5
98.5+24=122.5 ICL.
On a 119.5 LSA a 122.5 ICL is retarded 3 degrees, but it is supposed to be ADVANCED 4 degrees, which means the +4 timing marks are 7 degrees off.
I was a little astonished at how far off the timing set is. I took some pictures of the chain slack and made a simplistic measurement of slack with the calipers. The chain slack was .310" from slack to tight.
So, all that being said. Is the JP Performance typically off by that much? I have not yet contacted Scoggin Dickey because frankly, it's 11 pm. I did plan to call them tomorrow, however, before I do, is this normal for a JP Performance 5618T or SD7140 timing set? Also, I am not quite sure what to expect given I bought the timing chain two months ago.
Thanks.
Back in July I timed the stock cam with the stock timing chain, and made the thread below:
https://ls1tech.com/forums/generatio...-1998-cam.html
The stock cam has .050 specs of:
198/209, .500/.500 119.5 LSA
When I timed the cam with the stock timing chain, I got .050 lifter events on the intake lobe of 23 deg ATDC and 40 deg ABDC. So doing the math it's 180-23+40=197 deg duration at .050.
197/2=98.5
98.5+23=121.5 ICL.
On a 119.5 LSA a 121.5 ICL is retarded 2 degrees.
I did not time the exhaust events (it's a stock cam, why bother?).
So fast forward to last night. I've basically spent the last couple months doing fabrication work to complete the swap in my fox body and last night I got around to installing the SD7140 / JP 5618T timing chain. I installed the timing chain on the -2 setting (2 degrees retarded) and got the numbers below:
.050 intake lifter events 29.5 ATDC and 45.5 ABDC
the math
180-29.5+45.5=196 deg duration at .050.
196/2=98
98+29.5=127.5 ICL.
On a 119.5 LSA a 127.5 ICL is retarded 8 degrees, but it is only supposed to be retarded 2 degrees, which means the -2 timing marks are 6 degrees off.
I did this a couple more times after resetting my piston stop and resetting top dead center and re-zeroing the degree wheel, and basically came up with the same ICL number +/- .5 degrees each time.
Again, I did not time the exhaust events.
So since I knew the timing set is off by 6 degrees on the -2 setting, I figured I would try timing it on the +4 setting and see what I get.
Timing the cam with the timing set on +4 (4 degrees advanced) yielded:
.050 intake lifter events 24 ATDC and 41 ABDC
the math
180-24+41=197 deg duration at .050.
197/2=98.5
98.5+24=122.5 ICL.
On a 119.5 LSA a 122.5 ICL is retarded 3 degrees, but it is supposed to be ADVANCED 4 degrees, which means the +4 timing marks are 7 degrees off.
I was a little astonished at how far off the timing set is. I took some pictures of the chain slack and made a simplistic measurement of slack with the calipers. The chain slack was .310" from slack to tight.
So, all that being said. Is the JP Performance typically off by that much? I have not yet contacted Scoggin Dickey because frankly, it's 11 pm. I did plan to call them tomorrow, however, before I do, is this normal for a JP Performance 5618T or SD7140 timing set? Also, I am not quite sure what to expect given I bought the timing chain two months ago.
Thanks.
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Spoke to the guy at SD this afternoon. I realized I am past the 90 day return policy and I mentioned that to him while we were speaking, he said pack it up and send it back anyway. He even emailed the invoice and invoice number for me to put on the return form.
Have to say, A+ customer service from Scoggin Dickey.
Not sure if I want to exchange it for another SD7140 or upgrade to the Cloyes. This is the first aftermarket timing chain I have purchased, which was NOT a Cloyes hex-adjust.
Have to say, A+ customer service from Scoggin Dickey.
Not sure if I want to exchange it for another SD7140 or upgrade to the Cloyes. This is the first aftermarket timing chain I have purchased, which was NOT a Cloyes hex-adjust.
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So I received the Cloyes 9-3153A last leek which I exchanged for at Scoggin Dickey, put it in this weekend, timed it straight up, and it was off by only 1 degree. Re-timed the cam by turning the hex to retard the cam 2 degrees, and it was nearly dead on, the cam timed within a half a degree.
I guess I got a bad timing set the first time. Good customer service at Scoggin Dickey though, I had not bought anything from them prior to this, but I will again.
I guess I got a bad timing set the first time. Good customer service at Scoggin Dickey though, I had not bought anything from them prior to this, but I will again.
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I forgot in my post last night. The slack on the SD7140 was .310" when I measured with calipers, the slack on the Cloyes was so little I didn't even bother measuring it. I estimated it was less than .150".
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I recently measured the slack in the Cloyes 9-3153 which replace the JP chain. The Cloyes chain had .117" slack with the calipers in roughly the same position as I had them when I measured the JP chain.
#13
Yep, mine is installed and runs great. Thanks for the thread. glad I just spent the extra $30 or so and got the cloyes. It was nice and tight and degreed in very easily. No t-bearing was a little bit of a bummer, but I am sure it's fine.