1.9 Engine Tune

LaryHill · 06-20-2004

I hesitate to share this, but I must get an answer. While trying to set the dwell angle on my son's 1.9 without a guage, a gap attempt yielded an angle of 36 degrees. (We were shooting for 50 plus or minus 2) The engine roared more powerful unlike it had ever done before. We were both surprised and packed everything up and drove it 15 miles to my house to pick up the guages so that we could check the true point gap. Man, for that 30 mile RT, Father and Son were sily happy with how the engine was performing. After checking, we found that the gap was .029", which was a long way from the .018" we were trying for. We then followed the book, and went through all the proceedures to bring things back to spec. After nailing all of the numbers, we went for a test ride and immediately became disappointed. The performance was terrible.
Can someone explain why, will someone explain why? The obvious has been covered.

Larry

greensmurf20 · 06-20-2004

in my honest opinion, i woudlnt worry about the actual gap. dwell is what you should be more focused upon. on some guages, they dont really have dwell settings for 4 bangers. what you need to do is use the V8 readings and multiply it times 2. so if it says 25, it'd really be 50. just set it for the right dwell angle.

GTJIM · 06-20-2004

A wider points gap advances the ingintion timing so maybe you require a bit more advance when going back to the specified dwell/gap. So perhaps the distributor body itself needs to be turned a bit.

LaryHill · 06-20-2004

Thanks for the response info Jared and Jim. Jim, when you say turn the distributor body, do you mean bracket the gear position, or just change the timing? Do you think that there would be a problem if I went back to the 36 degree (by my instruments) which ran well?

Larry

GTJIM · 06-21-2004

Just change the timing back to where it ran well. 34 to 36 degrees is the maximum advance that Opel engines run well at (according to RallyBob).
No need to move the gear mesh as you should be able to just undo the clamp and turn the distributor a bit - after setting the points gap to specs. Then check the dwell and adjust gap and advance gain to get the best fit between dwell/points gap and maximum advance. At the least sign of detonation just back off the timing a bit.

06-20-2004	#1 (permalink)
LaryHill Opeler Join Date: Sep 2003 Posts: 14	Unanswered: 1.9 Engine Tune I hesitate to share this, but I must get an answer. While trying to set the dwell angle on my son's 1.9 without a guage, a gap attempt yielded an angle of 36 degrees. (We were shooting for 50 plus or minus 2) The engine roared more powerful unlike it had ever done before. We were both surprised and packed everything up and drove it 15 miles to my house to pick up the guages so that we could check the true point gap. Man, for that 30 mile RT, Father and Son were sily happy with how the engine was performing. After checking, we found that the gap was .029", which was a long way from the .018" we were trying for. We then followed the book, and went through all the proceedures to bring things back to spec. After nailing all of the numbers, we went for a test ride and immediately became disappointed. The performance was terrible. Can someone explain why, will someone explain why? The obvious has been covered. Larry

06-20-2004	#2 (permalink)
greensmurf20 OPEL-LESS!!! Join Date: Mar 2003 Location: Gobles michigan 49055 Posts: 2,112	in my honest opinion, i woudlnt worry about the actual gap. dwell is what you should be more focused upon. on some guages, they dont really have dwell settings for 4 bangers. what you need to do is use the V8 readings and multiply it times 2. so if it says 25, it'd really be 50. just set it for the right dwell angle. __________________ previousely owned 8 GTs and 1 manta. currently own 92 25th anniversary Z28. Ttop, 350, T56 swap, many upgrades, basically a complete restore. 67 chevy sportvan deluxe....next in line.

06-20-2004	#3 (permalink)
GTJIM Old Opeler Join Date: Jun 2003 Location: New Zealand Posts: 5,686 Provided Answers: 12	A wider points gap advances the ingintion timing so maybe you require a bit more advance when going back to the specified dwell/gap. So perhaps the distributor body itself needs to be turned a bit. __________________ GTJim Opel Owner since last Century! Copyright © 2000-2009 J D Henry All Rights Reserved

06-20-2004	#4 (permalink)
LaryHill Opeler Join Date: Sep 2003 Posts: 14	19 Freak Engine Tune Thanks for the response info Jared and Jim. Jim, when you say turn the distributor body, do you mean bracket the gear position, or just change the timing? Do you think that there would be a problem if I went back to the 36 degree (by my instruments) which ran well? Larry

06-21-2004	#5 (permalink)
GTJIM Old Opeler Join Date: Jun 2003 Location: New Zealand Posts: 5,686 Provided Answers: 12	Just change the timing back to where it ran well. 34 to 36 degrees is the maximum advance that Opel engines run well at (according to RallyBob). No need to move the gear mesh as you should be able to just undo the clamp and turn the distributor a bit - after setting the points gap to specs. Then check the dwell and adjust gap and advance gain to get the best fit between dwell/points gap and maximum advance. At the least sign of detonation just back off the timing a bit. __________________ GTJim Opel Owner since last Century! Copyright © 2000-2009 J D Henry All Rights Reserved

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