Coils - ZR-1 Net Registry Forums

32valvZ · 11-29-2019

If you were going to pull the plenum, would you replace the coils while it was apart?

One gentleman on this site has a stock set with 4800 miles on them, very reasonable.... & I was thinking that would be a decent replacement to my 35000 mile set.

I know that Accel makes them, but I feel stock units are probably as good if not better?

What would your choice be?

Ccmano · 11-29-2019

Unless the car is an NCRS car I always recommend replacing the coils and wires when doing a first plenum pull or if they have never been done. Aside from mileage you have the issue of age. Our cars are 25-30 yrs old. Who knows how many start/stop cycles it gone through even on a low mile car. Why take the chance. AC Delco coils are still available and a new set of AC Delco replacement wires can be found as well, largely on ebay running about $75-$100 set. If you drive the car regularly it’s a minor investment in reliability.
H

A26B · 11-29-2019

If you decide to stay with ACDelco coils
https://www.jerrysgaskets.com/coil-i...lco-90-95-6b3/

These are made by the same manufacturer that made the original plug wires for the LT5. Same color & sheen, just without the Corvette LT5 silk screened lettering.
https://www.jerrysgaskets.com/wire-s...lug-90-95-9b2/

and plenum gaskets which you will need to replace coils & wires.
https://www.jerrysgaskets.com/gasket...2-90-95-7-5d2/

tgonyaw · 11-29-2019

When I purchased mine in July 2018 it needed injectors and a starter. I didn't want to do the job 2 or 3 times so Dempsy at Evolution in Fredricksburg replaced coils,spark plug wires,spark plugs, injectors,starter,alternator,PCV hose assembly,deleted secondary throttles,deleted throttle body coolant,ported intake.engine tune,powder coated intake/valve covers along with replacing all fluids in car. This car had 74,000 miles and was all stock in good condition. I have since added about 3500 miles and a new Corsa cat back exhaust. The car has been totally trouble free and is a very "happy car" going down the road.
I was worried about the almost 30 rear old maintenance parts and decided to do it all a once so I would know what was in the car. The only judging this car will see is cars and coffee along with the 10 foot,10 mile an hour drive thru! Hope this helps with the decision.

Paul Workman · 11-29-2019

Quote:

Originally Posted by 32valvZ

If you were going to pull the plenum, would you replace the coils while it was apart?

One gentleman on this site has a stock set with 4800 miles on them, very reasonable.... & I was thinking that would be a decent replacement to my 35000 mile set.

I know that Accel makes them, but I feel stock units are probably as good if not better?

What would your choice be?

Preventive maintenance: Age, and heat cycles plays a factor in the life of coils (of all sorts).

FWIW, one of my stock coils failed on the HI voltage side @ 42k. miles. I swapped them out for new AC Delcos & new plug wires, sans the silk screening: now @ 73k w/ no issues.

+2 for replacing them now. But, as long as the coils have continuity, (primary & secondary sides) and neither is shorted to ground and the car ran fine w/ the old coils, maybe keep one "in case"...as a spare.

XfireZ51 · 11-29-2019

When I pulled the plenum for the first time, I swapped coils and injectors. I could also suggest freshening up the starter motor contacts.

32valvZ · 11-30-2019

Ok, guess I should clear a few things up. The plenum was pulled a couple years back by the previous owner. New starter was installed, new wires and the coolant passages were blocked off to the intake. He did a good job on it, but I know he didnt replace the coils.....

I'm pulling the plenum only to ship out the injector housings and intake to Pete for a port job. Yea, I decided to leave it to a pro....

Paul Workman · 11-30-2019

Quote:

Originally Posted by 32valvZ

Ok, guess I should clear a few things up. The plenum was pulled a couple years back by the previous owner. New starter was installed, new wires and the coolant passages were blocked off to the intake. He did a good job on it, but I know he didnt replace the coils.....

I'm pulling the plenum only to ship out the injector housings and intake to Pete for a port job. Yea, I decided to leave it to a pro....

You'll love the improvement. Lotus really choked the potential of the LT5 with their initial porting scheme. Even with the very conservative "kiss" to the top end in the gen II (405 HP), no question they still left a lot of performance on the table. No question. AND, the best thing is, you'll not loose any mid-range torque, fuel mileage, or drivabilty: what's not to like!?

XfireZ51 · 11-30-2019

Quote:

Originally Posted by 32valvZ

Ok, guess I should clear a few things up. The plenum was pulled a couple years back by the previous owner. New starter was installed, new wires and the coolant passages were blocked off to the intake. He did a good job on it, but I know he didnt replace the coils.....

I'm pulling the plenum only to ship out the injector housings and intake to Pete for a port job. Yea, I decided to leave it to a pro....

Good move.

Z51JEFF · 11-30-2019

Years ago when I replaced the injectors in my 91 I also replaced the coils with new AC DELCO coils only to have one of them fail with very little miles. I pulled the plenum and replaced the coils with a set of Accel coils.

11-29-2019	#1
32valvZ Join Date: Nov 2007 Location: Sunshine State Posts: 1,071	Coils If you were going to pull the plenum, would you replace the coils while it was apart? One gentleman on this site has a stock set with 4800 miles on them, very reasonable.... & I was thinking that would be a decent replacement to my 35000 mile set. I know that Accel makes them, but I feel stock units are probably as good if not better? What would your choice be? __________________ [B]1990 #2815[/B] [COLOR="Red"][B]Red/Red[/B][/COLOR] Ported Plenum & IH (by Pete) Haibeck Chip Rebuilt FPR (by Phil) FIC Injectors Watson LT Headers 3" Stainless Works exhaust Lingenfelter Open Air Lid Bill B Built Transmission Shifter & C Beam Plates [FONT=Impact][COLOR=red]1992 [COLOR=black]#[/COLOR] 091[/COLOR][/FONT] [FONT=Impact][COLOR=#ff0000]Red/[COLOR=silver]Gray[/COLOR][/COLOR][/FONT] [B]SOLD[/B]

11-29-2019	#2
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Coils Unless the car is an NCRS car I always recommend replacing the coils and wires when doing a first plenum pull or if they have never been done. Aside from mileage you have the issue of age. Our cars are 25-30 yrs old. Who knows how many start/stop cycles it gone through even on a low mile car. Why take the chance. AC Delco coils are still available and a new set of AC Delco replacement wires can be found as well, largely on ebay running about $75-$100 set. If you drive the car regularly it’s a minor investment in reliability. H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.

11-29-2019	#3
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,376	Re: Coils If you decide to stay with ACDelco coils https://www.jerrysgaskets.com/coil-i...lco-90-95-6b3/ These are made by the same manufacturer that made the original plug wires for the LT5. Same color & sheen, just without the Corvette LT5 silk screened lettering. https://www.jerrysgaskets.com/wire-s...lug-90-95-9b2/ and plenum gaskets which you will need to replace coils & wires. https://www.jerrysgaskets.com/gasket...2-90-95-7-5d2/ __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.

11-29-2019	#4
tgonyaw Join Date: May 2018 Location: VA Posts: 191	Re: Coils When I purchased mine in July 2018 it needed injectors and a starter. I didn't want to do the job 2 or 3 times so Dempsy at Evolution in Fredricksburg replaced coils,spark plug wires,spark plugs, injectors,starter,alternator,PCV hose assembly,deleted secondary throttles,deleted throttle body coolant,ported intake.engine tune,powder coated intake/valve covers along with replacing all fluids in car. This car had 74,000 miles and was all stock in good condition. I have since added about 3500 miles and a new Corsa cat back exhaust. The car has been totally trouble free and is a very "happy car" going down the road. I was worried about the almost 30 rear old maintenance parts and decided to do it all a once so I would know what was in the car. The only judging this car will see is cars and coffee along with the 10 foot,10 mile an hour drive thru! Hope this helps with the decision.

11-29-2019	#6
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,678	Re: Coils When I pulled the plenum for the first time, I swapped coils and injectors. I could also suggest freshening up the starter motor contacts. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

11-30-2019	#7
32valvZ Join Date: Nov 2007 Location: Sunshine State Posts: 1,071	Re: Coils Ok, guess I should clear a few things up. The plenum was pulled a couple years back by the previous owner. New starter was installed, new wires and the coolant passages were blocked off to the intake. He did a good job on it, but I know he didnt replace the coils..... I'm pulling the plenum only to ship out the injector housings and intake to Pete for a port job. Yea, I decided to leave it to a pro.... __________________ [B]1990 #2815[/B] [COLOR="Red"][B]Red/Red[/B][/COLOR] Ported Plenum & IH (by Pete) Haibeck Chip Rebuilt FPR (by Phil) FIC Injectors Watson LT Headers 3" Stainless Works exhaust Lingenfelter Open Air Lid Bill B Built Transmission Shifter & C Beam Plates [FONT=Impact][COLOR=red]1992 [COLOR=black]#[/COLOR] 091[/COLOR][/FONT] [FONT=Impact][COLOR=#ff0000]Red/[COLOR=silver]Gray[/COLOR][/COLOR][/FONT] [B]SOLD[/B]

11-30-2019	#10
Z51JEFF Join Date: Dec 2007 Location: Fremont,Ca Posts: 3,049	Re: Coils Years ago when I replaced the injectors in my 91 I also replaced the coils with new AC DELCO coils only to have one of them fail with very little miles. I pulled the plenum and replaced the coils with a set of Accel coils.