Prop recondition 370DA

jgoedd99

Active Member
Aug 10, 2008
204
Buffalo, NY
Boat Info
1998 370 DA
Engines
7.4 Mag MPI Horizon Inboards
Question regarding propeller reconditioning on a 370DA with 7.4 MPI Horizons (380 HP). Props are OEM i believe (18 by 22 1.5" shaft Nibral). Boat is new to me last year. Ran it all last season and no issues with props that i am aware of (no vibration, RPMs good). One prop looks like PO did some repair on it. I've read all the posts about reconditioning and learned a lot. It looks like PropScan is the way to go, but there does not appear to be a prop scan facility anywhere near where i boat (western NY), and none in New York state or Pennsylvania. So my choices are send them out or get the work done locally by a shop that does not have prop scan.

What is the the difference in end product from what a Prop Scan facility produces and a guy who doesn't have PropScan? I guess what i am asking, is the PropScan just a great documentation tool or does it make for a better end product?

Also in terms of the actual repair that the shop does, are they both doing the same thing? I.e. using pitch blocks and reshaping propeller, or does the PropScan tool also assist them in fixing the propeller.

Finally, on cost, i am seeing numbers like $200 a prop on this website for PropScan and reconditioning for similar sized props. I am being quoted $270 a prop for reconditioning with no PropScan, sight unseen. The part that bothers me about this, is that the props may be fine as they are (or close to it) and the quote is a hard quote.

Thoughts?

Thanks

JohnG
 
John,
I had my props done 2 years ago when I bought my boat. The boat was in Forked River, NJ and I am out on Long Island, NY. I used the PO's shop who did a nice job but, No PropScan. I paid about $350.00 for the pair. I just dropped my props off at a local shop because my slip can be shallow @ low tide and I just wanted to clean them up a bit. The woman at the shop said they don't have the "Propscan" system but do perform an MRI on the props and derive a report from it to guide them in their repair. She stated that ultimately it is still men reworking the metal to attain the expected/specified specs. She also stated that she will supply me with the report to see where my props were when they started. I don't have a cost on this yet and they just called me yesterday to tell me they are done. I should have got a quote but, I have used them before and was going to get the props done anyway so, since I was on the run that day I forgot to ask. I will let you know the cost when I pick them up next week if you wish.
 
Todd,

Thanks for response. Yeah i would be interested in knowing what you pay. Let me know your prop diameter and materials also as i think that affects price.

I think you confirmed what i suspected, that the reworking of a prop is the same regardless of whether or not they have PropScan. I am still unsure if the information provided by PropScan allows for a better finished product. Any experts on this ??

JohnG
 
It doesn't have to be Prop Scan, there are other companies that make MRI/Prop Scan type of computer mapping systems of props. The mapping is strictly an analysis of the surface area of a prop, and has nothing to do with shaping or balancing process. The reason today you want to use someone with one of these type systems is that they can precisely match your Starboard and Port props with each other, and not to mention they have a means of duplicating your specs in the event you damage a prop.
 
I've experienced a shop that used "Prop-View" and pitch blocks. After they were done, I took it to a "Prop-Scan" shop. There was a HUGH difference.

Prop-View apparently only measures half of the blade and assumes that the other half is the same, Prop-Scan reads each blade entirely.

Prop-View provides a data sheet that is a jumble of numbers that are difficult to understand. Prop-Scan provided data in various color coded bar graphs and it's easy to see if your props are setup properly.

Prop-View uses pitch blocks, while Prop-Scan does not. Their methods still involve striking the blades, but it is much more of an art (constantly measured and re-measured to check progress) rather than simply bashing the blade against a block.

After having my props done via Prop-View and then re-tested with Prop-Scan, the apparently "reconditioned" props were not even up to the sloppiest standards that they use. Also, the props showed evidence of being "polished" with a grinder (even in the wrong direction) which is a no-no, plus they still had numerous "pits" from electrolysis that were left untouched. According to the first shop - "You can't weld NiBral". Prop-Scan re-worked the props including that "impossible" welding and provided before and after documents for less cost than the first shop. Now, keep in mind that the first shop has been around for over 60yrs, so they really must know what they are doing - right? Wrong!

Now you know why I am sold on Prop-Scan shops. They seem to know more about props and apparently have a better system for getting the job done right. Needless to say - I did not pay the first shop's bill. They were truly embarassed when shown Prop-Scan's end product and the bill was actually lower - and they SHOULD have been embarassed!:wow:
 
Well, I haven't picked up my props yet but they are done. The total cost is $360.00, so they are inline with the shop in Jersey. I will let you know how the reports as well as the props look when I pick them up tomorrow.
 
The new measuring technology is an awesome improvement over ":heat and beat" and mechanical measuring. Shops now can precisely recon each blade to achieve the best "foil" for the bland and scribe on the blade exactly where to make adjustments and recheck. The process is much more costly than "eyeballing it". The consequence is a prop that will turn faster on the same fuel, supply more thrust and in the end save big bucks on fuel burn. Now if they could just make these things bottom resistant.
 
Unfortunately we have no one in the area, or this end of the state, for that matter that does PropScan or MRI. So while I am convinced of the value of it, I am not going to mess around with shipping props out of the area.

The good news is that i did find another propeller shop that will recondition them for $80 or $90 a propeller. So i feel a lot better that paying $270 a prop.

JohnG
 
I went to Holland Propeller in Michigan, a PropScan Facility. My wheels are 21 x 22.5's Nybral. While the first scans looked a mess. The real numbers worse case out o.068" of an inch. just over 1/16th and the diameters were out as well. The final scans put the props less than 0.004" in all aspects of each other. Cupping looks great. I had the opportunity to take a dial indicator on a grante layout table to compare. They were near to identical. They claim we will see a min. 15% better fuel economy from where we were at. Now hear was kicker cost was 500.00 each! We will splash next week and I'll reply w/ my inital input. Mike
 
Reply to Prop Scan Props. Noticable difference at 5 MPH. Going on plane was even better. Very smooth. And I thought it was smooth before! The shocker was top end 3K plus improvement. Felt like a lot more and great sound w/ engine sync running. Jury still out on pay back as it just got tougher at $4.42 / gallon.
 

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