Questions for our master engine builders

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rx1jim

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OK master engine builders, I just ordered all the parts to rebuild my 2000 SRX engine. Everything: new pistons, rings, wrist pins, wrist pin bearings, gaskets, seals, reeds, etc.. right around $500 bucks!!!! I read the debate about whether to hone or not hone the cylinders and the type of hone to use if you do hone them. The engine has 12,000 miles on it and it's always been fed with Amsoil since the origianl tank of yamalube was used up. My questions are: what is the preferred way to measure the inside diameter of the cylinders: a snap gauge and an outside micrometer or an inside micrometer? 2. If the cylinders are out of spec. or at the upper end of the wear limit, I believe I can either buy new cylinders (about $900) or send them to a shop such as U.S. Chrome who can strip the nikasil coating and replate them. Who would you reccomend I send the cylinders to for stripping and plating? 3. Should I run at least one tanlk of conventional oil through the engine the switch back to Amsoil to allow proper seating of the rings?

Thanks guys!!!
 
I AM FARR FROM A MASTER ENGINE BUILDER, MORE LIKE GOOD COMON SENSE FOR ME BUT ANYWAYS I FIRST WOULD ASK YA YOU EVER BURN THIS ENGINE DOWN ? 3:16 (yammie tony)
 
Measuring should be done with a dial bore gauge, if you've never blown it up they will most likely be close to spec, with that many miles on it I'm sure they need to be honed the cross hatch is most likely worn off. Nikasil requies a diamond stone for the correct finish, I can hone them for you if necessary.

As far as oil goes, many engine manufacturers suggest running mineral oils for at least 500mi. before switching to synthetic oil to achieve proper break in.
 
As 800 mentioned, you will need to hone the cylinders in order to re-cross hatch them. If you do not, your new rings will not seat properly, and you will be down on performance. Do not use a ball hone. They are not hard enough to properly crosshatch nikasil. Use a honing tool such a Sunnen AN 112 or equivalent to do it properly.

As for oil, yes, run a mineral oil. DO NOT RUN SYNTHETIC for break-in. If you do, it will take 500 miles to seat the rings, if they seat at all. With hard running, using mineral oil, the rings should seat within 100 miles, but run the mineral oil longer to be sure they are seated.
 
Not to be argumentative but......
Nicasil can be honed with Silicon Carbide flex hones. A diamond honing machine would be my preferred choice if time and budgit allow. However I do use a 320 flex ball hone on my cylinders each season when I re-ring. They do look nice after honing with this type hone. Do a google search with the key words "Silicon Carbide and Nicasil".
http://www.enginehones.com/niapho.html
 
Thanks guys. The plan for rebuilding the engine is coming together. I have another question: will I need a wrist pin puller to remove and install the piston wrist pins? If so, no problem, I'll order one.
 
if i was you, i would order a wristpin puller. its like only $17 from parts unlimited. don't try and hammer them out. also, just curious why you are rebuilding it? i know of 2 srx's that have more miles on then yours and they are still running strong, with over 130lbs of compression.
 
Hello Mopar,

I am going to rebuild the engine due to the high mileage and the fact that I see a lot of discoloration on the piston below the rings as viewed from the exhaust port. This indicates there is a significant amount of "blow-by". Due to the mileage, I want to swap out the pistons, wrist pins, wrist pin bearings now, at 12,000 miles before they fail and cause major (and very expensive) damage. I am taking the engine out anyway to clean up the engine bay and change the tie rod end for the steering. I might as well change the crankcase seals so why not go completely through the engine. All of the parts, seals, gaskets, pistons, rings, etc., will cost about $500. I might even powder coat the outside of the crankcase halves, recoil starter case and cylinders to improve the appearance I'll do all the work myself so it fairly inexpensive to get full performance back while at the same time buying "insurance" on the engine. After this rebuild, I'll continue to feed the engine Amsoil injector oil so i should be able to get another 8-10 years out of the engine. I'll "freshen" up the top end at 4000 miles next time. I am in the process of gathering all the parts to go completely through the sled. replacing every worn part. I am putting a new predator style track, Simmons skis and improving the rear skid.

I ordered the wrist pin puller. Thanks.
 
Jim - Sounds to me like you have all the bases covered. 12K is long overdue for a performance sled. Don't wait 8-10 years before you change the rings this time. If you keep changing rings every 4-5k the pistons tolerances will hold up longer. Great choice predator track. My first one went 7500 miles or so. I'm now on a second with 1500. Enjoy
 
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