Hi everyone,

The ignition coil on my 1979 245DL is about to go out, and I need a replacement. I'm trying to decide between a Bosch stock coil (about $40), an MSD Blaster 2 (about $30), or a Summit stock coil (about $20). My interests here are reliability--I'm not looking for a performance upgrade. I don't want to destroy my ignition system, and from some of the posts I've seen here, there is a danger of that when changing the coil away from stock. Any thoughts? Is it worth the extra $10/$20 for a Bosch coil? Many thanks!

A Newbie

I agree with the previous caller...coils don't usually give a lot of warning.

A good junker will do. That said, I have an MSD coil on the 245Ti and it works great...and there was no smoke released.
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www.fidalgo.net/~brook4

Oh shit. No smoke? You musta hooked it up wrong.

- alex

'85 244 Turbo
'84 245 Turbo

First, what makes you think your coil is on its way out?

If you do need to replace the coil, just go to a junkyard and pull a coil out. Make sure it's got the same Bosch PN. You'll likely end up spending less than $20.

- alex

'85 244 Turbo
'84 245 Turbo

Thanks for the response; I appreciate your patience with a first-time Volvo owner (got it three weeks ago!). The engine hesitate/skips a bit a higher RPMs, leading a friend to believe that the coil isn't in great shape (not doing its job at higher engine speeds). We took it to AutoZone to have them test it, and the readings were low, about 25% below specs on the primary and 50% on the secondary. (low on voltage or resistance...I always get my electrical terms mixed up). Anyway, the fellow at AutoZone (a guy I trust) said a new coil would make a lot of difference; hence, the idea to get a new one.

This brings to mind a question: are coils either broken or not, or are there various levels of working, meaning, will an older coil perform as well as a new one? I gather from your post that it's critical to put the same kind of coil in...can you point me in the direction of an explanation as to why?

I like your idea of going to a yard; didn't even think of that goldmine! I got a set of front seats in great shape for $30 last week!

Bob

what about the basics:

wires
plugs
cap
rotor?

Do those first before the coil....in fact a new coil may make bad wires worse....and frustrate you more.
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www.fidalgo.net/~brook4

Thanks for the advice; we've replaced the coil, cap and plugs already, and the wires are pretty high quality, but we'll check it out--good advice.
Thanks,
Bob

Well maybe borrow a known good coil....or do the junkyard shopping....I'll bet it's a connection at on of the ignition wires...or maybe it's a fuel problem, not spark related at all.

What brand of new plugs?
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Paul's Amsoil and other lubricants

Paul:

If the coil measured out of spec, it may very well be bad. The question is, where was stuff measured? If you're not able to measure directly on the coil, your readings may have been influenced by poor wiring.

JenaBob:

The same coil may not be critical. My 84 and 85 have different coils (but same ICU part numbers.. hmm). When I swapped the ICU+coil from the 84 into the 85, I got some less than desireable results. Same Bosch part number isn't necesarily critical, but it's a very good idea.

I agree that the fuel system is probably a bigger suspect than the ignition one. Except.. if your car has a ballast resistor.. that could, in theory, be causing some problems.

Does your car behave better with a full tank of gas?

For ignition components, go for:

Bosch cap+rotor
Bougicord wires (or anything other than Bosch wires)
NGK plugs (BPR6ES or BPR7ES seem to work well for me)

- alex

'85 244 Turbo
'84 245 Turbo

Paul and Alex,

Thanks for the advice. I wouldn't be surprised at all if something is amiss with the fuel delivery system, so I guess it's time to let go of my dedication to carburetion and learn the mysteries of fuel injection. Time to spend some time studying that section of the Haynes manual...

In regards to the electrical side of things, thank you for all your advice. I've decided to go with the stock Bosch ignition coil (on it's way from AllOEM right now), and probably change the rotor, cap, and plugs pretty soon here, as they are all pretty cheap-o (the wires are Bougicord, I believe).

We'll see how much the new coil changes things, and then start to work on the fuel system. By the way, I haven't noticed if it behaves better on a full tank of gas, but I'll definitely keep that in mind as I go through my testing.

Again, many thanks for all of your help!
Bob

newly broke-in wrote:

"If the coil measured out of spec, it may very well be bad. The question is, where was stuff measured? If you're not able to measure directly on the coil, your readings may have been influenced by poor wiring."

Agreed - but I also think just hooging up the isolated coil to a $9.95 ohmage meter will give numbers that may be misleading.....he didn't say how he measured the coil though...I just think a few ohms between friends on a coil doesn't make a bad relationship...now if he got open or short on primary or secondary (or between the two!!) then we got problems.

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www.fidalgo.net/~brook4