distributors

I have been following the posts that have been put out regarding engines not running up to the right speed and all the talk about the distributor and through this have learned that the on in my boat is wrong. Right now it has a vacume advance, I am looking to replace and at the moment I have been advised to look at Mallory or Pertronics. What would you guys advise? The engine is a SBC chevy which has a carb.

I have the Mallory Marine distributors in my 454 Crusader's and have never looked back. Simple drop in replacement and no worries in 12 years of service so far. Summit Racing had the best price for these distributors too and I have no connection to Summit. jmtc

The auto engine can take advantage of diaphragm vacuum advance during high manifold pressure....... but the Marine engine cannot!
An automotive diaphragm vacuum advance distributor is not only illegal when used in an enclosed engine bay, the advance curve and TA would be incorrect for a Marine engine!


I would consider most ignition systems with exception to the Pertronix Hall Effect units. (tiny plastic magnet embedded triggering wheel)

The companies who make EST typically use photo-eye triggering. (EST = electronic spark timing)
From what I read, Delco offers a good EST.

Mallory can be had in mechanical advance with either photo-eye or VR (variable reluctor) triggering.
Photo-eye uses an interrupted infrared beam to trigger the spark event.
VR uses a 4, 6 or 8 pointed magnetic reluctor wheel to trigger the spark event.

VR has been tried/proven since the early 70's, and would be my preference between the two.
For a Marine SBC in a Mallory VR..... this would a YLM 624 AV!
The same in photo-eye would be YLU 624 AV.

With EST, there is no mechanical advancing mechanism. All advancing is accomplished via the control module. As long as the control module functions, all is good!

With mechanical advancing, you will want to prevent water intrusion from within the flyweight and return spring area.
When these are well maintained, they'll go for years and years.



The Marine SBC ignition curve is fairly predictable since so many SBC exist in the Marine environment.
Non-quench build...... typically a TA of 26* to 27* @ 3.2k rpm.
A quench build....... typically a TA of 30* to 32* @ 3.2k rpm.
Best to use your OEM specs!


Which way are you learning towards, and why?
Just curious.


.

I am Looking more at the mallory as the folks I have spoken to have all had high praise for its reliability as well as it's peformance and ease of the change over. And of course I have been reading up on the options here on this site. I will be going from a points system to a electronic ignition which should improve reliability as well. Thanks for the advice guy's and have a good day.

Paul

Paul, you'll have a choice between the YLU and YLM in the 624 AV. The "U" is photo-eye, and the "M" is magnetic... or VR.
Of the two, and in my opinion only....... the YLM will not give you any trouble, whereas the photo-eye unit of the U may occasionally fail. Not real common, but they can fail.

Either will use the same housing, cap, mechanical advancing system, and will give you the same curve/limit, etc.


.

These guys at Michigan Motorz sell an awesome kit that has everything you need to convert to Delco EST distributors. I have a set sitting in my garage that I'm going to throw on my port engine as soon as I can get a weekend free.

http://www.michiganmotorz.com/delco-voyager-marine-electronic-distributor-p-119.html

If you like the idea of EST, the Delco Voyager would be a great choice.

I am looking at the YLM624AV Rick. I found what appears to be a replacement number for it, 18 5494-1. Does that make sense to you or am I miss reading things?

missnancy said:

I am looking at the YLM624AV Rick. I found what appears to be a replacement number for it, 18 5494-1. Does that make sense to you or am I miss reading things?

Click to expand...

You may want to have the seller qualify.
Many venders want to substitute the YLM for a YLU.

.... Replaces Mallory Electronic Distributor YLM624AV For Chevrolet all V8 includes 482, 502, 540 CID (Except 348, 409 ...

I have my suspicions that they may be selling a YLU!



.

Apparently, SeaStar acquired Mallory Marine in the past few years. Sierra, Teleflex, Morse Controls and Shields Hose are all subsidiaries of SeaStar. The part number in this case, 18-5494-1, is a Sierra part number (sorry, I don't know if it's YLM or YLU).

http://www.seastarsolutions.com/products/mallory-marine/

Thanks for the interesting discussion about distributors. I've bookmarked this thread.

DJR said:

Apparently, SeaStar acquired Mallory Marine in the past few years. Sierra, Teleflex, Morse Controls and Shields Hose are all subsidiaries of SeaStar. The part number in this case, 18-5494-1, is a Sierra part number (sorry, I don't know if it's YLM or YLU).

http://www.seastarsolutions.com/products/mallory-marine/

Thanks for the interesting discussion about distributors. I've bookmarked this thread.

Click to expand...

I just looked at a few more of these including the Go2Marine link for the

http://www.go2marine.com/product/83...olet-gm-v8-electronic-ignition-18-5494-1.html

They too list the 18-5494 as a YLM 624 AV replacement, and also show it for Std LH and Rev RH rotation engines.
Further down (line item 3) they correctly list the YLM 624 AV for Std LH rotation.

Due to the Rev RH engine camshaft rotation and gear cut and the downward thrust, the Rev RH engine requires the YLM 624 BV (not AV)!

Point being.........You'll want to ask your seller questions if you are looking for a VR unit, and you'll want to make sure that you ask for a YLM 624 BV for any Rev RH rotation engines.





These guys get it right re; the YLM 624 BV
http://tewarehouse.com/SM-18-5498-1



Here's a 18-5498-1 for $120! It is likely used.... but it sure looks clean.
http://bayshoremarineengines.com/18-5498-1mallorydistributor.aspx

Tag says YH (not sure about YH)

If this is a YLM 624 BV, change the gear and this one becomes an AV.
(we cannot go the other way)






.

If they are factory Crusaders blocks, the reverse rotation engine will take the "A" version too...

makomark said:

If they are factory Crusaders blocks, the reverse rotation engine will take the "A" version too...

Click to expand...

Ah....... good point!

If the camshaft is gear driven it will still rotate in the standard direction...... therefor the same driven gear will be used causing the same upwards shaft thrust.


.

Ok I have received my distributor from Go2marne and now have to wait until spring when I get her uncovered to install it. Will the coil I was useing work with the new unit or do I need a different coil?

Yes it should work, but why not replace it as well?
Mallory offers a coil p/n for use with their YML.

BTW... I'm curious..... did they ship a YLM to you...... or did they substitute the YLM for a YLU?

.

They shipped the YLM.