Engine evaluation
Discussion
Hi gents
When I strip my Merc M117 engine, is there anyone or a process used to see if components like the pistons, rods etc can be used for the power levels i'm aiming for?
I know that its revs that stresses rods and I dodn't intend to take the engine above standard revs, but the pistons i'm not sure on.
I'm happy to get all new rods and pistons but as the quality of these parts seems very high on these engines, if new parts aren't needed then i'm all for it.
Also, what are peoples opinions on ceramic coating, i've read a few articles on it but never anyone who has used it with good or bad results?
Dave!
When I strip my Merc M117 engine, is there anyone or a process used to see if components like the pistons, rods etc can be used for the power levels i'm aiming for?
I know that its revs that stresses rods and I dodn't intend to take the engine above standard revs, but the pistons i'm not sure on.
I'm happy to get all new rods and pistons but as the quality of these parts seems very high on these engines, if new parts aren't needed then i'm all for it.
Also, what are peoples opinions on ceramic coating, i've read a few articles on it but never anyone who has used it with good or bad results?
Dave!
Top Fuel Digger said:
Speaking in general terms, ceramic coatings (pistons specifically), doesn't tend to have a downside from what I've seen. It's standard practice on fuel and alky engines now, with a few of the quicker streetcars doing it aswell (Mr. Frost, that's you isn't it?). The coating will help the pistons in the event of severe detonation (you can get away with a lot compared to a standard non-coated piston). I'm not sure of price since mine were from Arias as a custom job.
If you've not sourced a coatings firm, then Balzers may be able to help. I've never dealt with them, but they've had involvement with all sorts upto Bob's AA/FC.
The modern (be it European or American) engines seem to have very strong bottom ends as standard (that's not to say they're great, but they're a very big improvement on a few years ago). As you mentioned, the valvetrain shouldn't have too many problems if the revs are kept around that of stock, though stainless steel valves are good for increased cylinder pressures.
ARP studs or bolts are a good investment IMO - be it for main caps or head fasteners.
The above is all general and not specific to the Merc lump, but still applies in most cases
Yes John,i use Calico coated main and big end bearings.It makes them very resistant to scuffing.I'm going to use ceramic coating on the piston skirts this year to try and stop the scuffing that i found on this years strip down...If you've not sourced a coatings firm, then Balzers may be able to help. I've never dealt with them, but they've had involvement with all sorts upto Bob's AA/FC.
The modern (be it European or American) engines seem to have very strong bottom ends as standard (that's not to say they're great, but they're a very big improvement on a few years ago). As you mentioned, the valvetrain shouldn't have too many problems if the revs are kept around that of stock, though stainless steel valves are good for increased cylinder pressures.
ARP studs or bolts are a good investment IMO - be it for main caps or head fasteners.
The above is all general and not specific to the Merc lump, but still applies in most cases
Top Fuel Digger said:
kestral said:
Does anyone recommend bead blasting the pistons.
I've not seen any on pistons before, but a few valvetrain folks (Jesel for example) use a similar technique on their rocker arms.As I understood it, the bead blasting/vibratory surface finishing was to assist in load spread on torsional or shear twist in parts (rockers arms being a prime example, but also rods). Pistons primarily have to fight against heat and mass cylinder pressure, so there's not so much twisting activity.
Andy, does that mean the current pistons are only coated above the rings? Dunk the whole thing in the khaki stuff
Bead blasting pistons skirts is usually done to 1/create pockets for oil retention,but most pistons come with grooves for that reason,and 2/ to give the surface a good key for coating in the old days of coatings.Apparently it's not needed now...
redvictor said:
As you mentioned, the valvetrain shouldn't have too many problems if the revs are kept around that of stock, though stainless steel valves are good for increased cylinder pressures.
ARP studs or bolts are a good investment IMO - be it for main caps or head fasteners.
The above is all general and not specific to the Merc lump, but still applies in most cases
Yes John,i use Calico coated main and big end bearings.It makes them very resistant to scuffing.I'm going to use ceramic coating on the piston skirts this year to try and stop the scuffing that i found on this years strip down...ARP studs or bolts are a good investment IMO - be it for main caps or head fasteners.
The above is all general and not specific to the Merc lump, but still applies in most cases
I've never heard of coating the bearings, are they specially prepped bearings for this or do you just send them a standard set as I was just going to use genuine Merc Parts in those areas?
Glad the ceramic coating is common place, will definitely be getting it done then.
Dave!
Howitzer said:
redvictor said:
As you mentioned, the valvetrain shouldn't have too many problems if the revs are kept around that of stock, though stainless steel valves are good for increased cylinder pressures.
ARP studs or bolts are a good investment IMO - be it for main caps or head fasteners.
The above is all general and not specific to the Merc lump, but still applies in most cases
Yes John,i use Calico coated main and big end bearings.It makes them very resistant to scuffing.I'm going to use ceramic coating on the piston skirts this year to try and stop the scuffing that i found on this years strip down...ARP studs or bolts are a good investment IMO - be it for main caps or head fasteners.
The above is all general and not specific to the Merc lump, but still applies in most cases
I've never heard of coating the bearings, are they specially prepped bearings for this or do you just send them a standard set as I was just going to use genuine Merc Parts in those areas?
Glad the ceramic coating is common place, will definitely be getting it done then.
Dave!
When i bought one of my old dragbikes the previous owner had teflon coated the pistons which according to him allowed him to run massive nitrous jets and more ignition than i wouldve risked all on pump gas.
When i stripped the engine there wasnt any signs of det on the pistons and they looked in pretty good shape but he had fallen into the old trap of putting 4 x 50hp nitrous jets in while using the smallest nos solenoids you can get which can only flow 60-80hp, so the engine wasnt as stressed as he or i first thought.
Probably easier to spot det on them as well when they are coated I personally didnt bother as i had bought Cosworth's entire stock of pistons so could treat them as consumables
I think most of the pro-stock guys coat their pistons but they also go in for this cyrogenics stuff as well which i am not convinced with
When i stripped the engine there wasnt any signs of det on the pistons and they looked in pretty good shape but he had fallen into the old trap of putting 4 x 50hp nitrous jets in while using the smallest nos solenoids you can get which can only flow 60-80hp, so the engine wasnt as stressed as he or i first thought.
Probably easier to spot det on them as well when they are coated I personally didnt bother as i had bought Cosworth's entire stock of pistons so could treat them as consumables
I think most of the pro-stock guys coat their pistons but they also go in for this cyrogenics stuff as well which i am not convinced with
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