TOPIC: compression and cranking amps

Hi guys,
1957 Mark 55E. Had the starter rebuilt and got it back today. Now running compression test on motor. I have,
149 top hole
120 2nd hole
119 3rd hole
120 bottom hole.

The 149 seemed high to me so doing a little investigating I found the top hole had a good amount of clean, heavy oil in it. I was told by the previous owner he had oiled down the cylinders when he put the motor up many years ago. I'm letting that drain now and will recheck when it's all out. Are the 120 numbers acceptable? What would pristine numbers be for this motor.
Also, with a 460 cold cranking amp battery it hardly turns over. It's very labored. What Cranking amps are you guys using with these motors?

Thanks, Jeff

120 is fine those starters need cleaning and lube to work good if that does not do it have it rebuilt.

I just had the starter rebuilt. My question was about battery cranking amps to turn the motor over with the starter.

should be enough. make sure all connections are good

Hi Jeff,
Could be due to poor cable connections or not so good contacts in the starter solenoid.
Check both positive and neg cables the old insulation crumbles and then wires corrode.
Any weakness will limit amps and thus cranking performance. FYI batts I use are 650 Cold Cranking Amps.
Try directly jumping from battery to starter post and use a jumper for a good ground ,
make sure batt has full charge. If still weak pull plugs out and see if starter spins up if not then suspect
Starter even though it was rebuilt.
Randy

yep....bought one new and two rebuilt starters for a 1956 ford ht that I restored once...finally took an original to a starter shop and had it rebuilt before I had a good one

Jeff,

Who rebuilt the starter? Did they test it after rebuild?

Travis

Several years back I was working on a sixty something Merc1000 and couldn't get the starter to engage the flywheel. It would spin, but not hard enough to send the drive up to engage. I pulled the starter and sent it to our local rebuild shop.

The guy calls and tells me there's nothing wrong with the starter, come over and watch the stress test.... Turns out the battery cables (on the motor) were corroded inside the insulation where you couldn't see it, really restricting the "flow" of current.

Hope you get it sorted out Jeff, these really are engineering marvels once you learn the tricks. The gang here is always willing to help, as you can see!

63g3 wrote:

Hi Jeff,
Could be due to poor cable connections or not so good contacts in the starter solenoid.
Check both positive and neg cables the old insulation crumbles and then wires corrode.
Any weakness will limit amps and thus cranking performance. FYI batts I use are 650 Cold Cranking Amps.
Try directly jumping from battery to starter post and use a jumper for a good ground ,
make sure batt has full charge. If still weak pull plugs out and see if starter spins up if not then suspect
Starter even though it was rebuilt.
Randy

Yep, as that will tell you if bad wires are the problem.

The power head is off the motor. I hooked up the starter directly to the battery with jumper cables. The starter was rebuilt by a local shop I have been using for years, Kastner auto electric in Waukesha Wi. It spins ok with plugs out, but not great. I'm thinking the battery amps are not enough. 460 is not a lot of cranking amps. The battery is showing a full charge when I put it on the charger, but it's an 8 year old Walmart special. I'll try the battery from my ford F150 on it and see if the battery is my weak link. Thanks guys, I'll let you know how it turns out.

Travis, when you were rebuilding your Mark 55 did you replace the internal hardware on the upper mounts inside the leg? When I pulled mine apart the internal hardware is all rusted and rotted. I'm trying to find new stuff but none of the suppliers seem to have it. Do I need to improvise?

Mine were all good luckily. Do you have any pics of what your current setup? They were a pain in the butt to remove. I'll look up the part number on those so called rubber seals but they don't sell them any more. How I was taught on re assembly is to fill area with silicon well and it does the job. I've seen it done but it might take the craftsman in you find some rubber and make em'. Here are a few pics at disassembly. Bottom pick is reassembly this is where I fill opening completely
with silicon. Hope this helps


Travis [img] [img]http://www.fiberglassics.com/media/kunena/attachments/legacy/images/Upper_Motor_Mount_Mark_55_caps-20151219.JPG

Jeff, your 8 year old walmart battery is the problem or at least part of the problem. It may show full charge on the charger but it no longer has current delivery capability. Likely the battery has sulphated.

Yea, Your not kidding about being a PITA to remove. I was able to find new caps and the rubber rings for the other end. For the hardware I'll just take it all over to fastenall and match stuff up. For the spacer I should be able to drill out a big washer and tack weld a piece of tubing on it.
Where there's a will there's a way. Furgeson Poole has the rubber parts.
Thanks Travis.