Preparing cylinder heads for marine application

11-28-2018 | 11:15 AM

#11

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Quote:

Originally Posted by Camalot

The heads are Flotek I've used on street engines before and been happy with them, sure they are not high end name brand heads but the casting are good and they use good components. Part of my business is a small but skilled engineering facility. We have no problem doing the machining work but Like you have pointed out we do lack knowledge between street and marine.
The guides are Manganese Bronze and the seat are also Powder Metal which gives me good bones to start with.

I've just purchased a Rottler 3 angle cutting tool I'm not sure what valve seat width we will have until I cut a test piece, but I think I'm going to shoot for 5% of the valve diameter. We do have engine builders here in Nova Scotia but they are more reman stock engines, plus I like to keep as much work inhouse as I can and learn from the process. Thanks for all the pointers to date

I'd suggest contacting adk61 here on OSO. Top notch marine engine guy up in your neck of the woods.

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11-28-2018 | 07:11 PM

#12

mira boater

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A&j automotive Alyn Armstrong in Kingston NS has done some marine engines as well as Sussex engines in NB

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11-29-2018 | 12:30 AM

#13

picklenjim

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Quote:

Originally Posted by Camalot

I've been trying to find a valve seat face ratio but can't find one anywhere.

The Mercury Manual for high performance big blocks calls for a seat width of 1/32"-1/16" for intakes and 1/16"-3/32" for exhaust.

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11-29-2018 | 06:53 AM

#14

dunnitagain

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Ive always cut my seat widths to .040 on intake , .060 Exhaust . I also hit them real lightly with a lap stick and fine compound.
The powdered metal seats when cut that narrow with a dead pilot cutter , tends to not have real sharp defined angles .
With the good powdered metal seats they will spread .010 to .015 each after a few hours hard running , and seat in very well.

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11-29-2018 | 07:32 AM

#15

Full Force

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Quote:

Originally Posted by Ryan00TJ

Fully understand why you want the above in a big hp endurance marine build. Where is the line that it becomes mandatory? Look how many hours on stock 454/502 mpi and 496 setups. These are stock GM heads, same as in auto use.

The heads are not going to be the same off shelf heads as cars/trucks. merc sets them up for marine use, casting is the same sure... not the rest.

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11-29-2018 | 09:32 AM

#16

ICDEDPPL

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I wonder if it`s different with closed cooling vs. raw water. First one, the block stays cold and doesn`t grow with the rest of the internals. (need larger clearances)
The other is closer to a auto application as the coolant gets hot and block expands with internals?
I have no idea what temps closed cooling runs. Does it get up to automotive temps (180*+?)

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11-29-2018 | 09:56 AM

#17

Full Force

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Probably makes some difference, I think closed cooling runs 145-150 if I recall, I see 110 most... so it may play a role but I think a tad loose .0017.0020 still would be wise

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11-29-2018 | 10:03 AM

#18

getrdunn

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Quote:

Originally Posted by ICDEDPPL

That's a good point. I'm just guessing as well but you'd think the closed cooling temps would be very similar to auto. Might be completely different clearances, specs, etc all together.

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11-29-2018 | 10:06 AM

#19

getrdunn

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Anybody with stock merc closed cooling reading thread could post water and oil temps.

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11-29-2018 | 11:51 AM

#20

underpsi68

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