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Discussion Starter #1 (Edited)
What problems have you experienced with rebuilt engines?

We are working with Mountune USA to rebuild the 2ZZGE engines. We plan to offer rebuilds that range from mild to wild. Initially we will stay closer to 'mild' with engines that are a perfect swap for a stock car or supercharged car under 300hp. We are focused on reliability and longevity. I have spoken to countless clients over the years about the headaches of rebuilt engines. We used to sell engines and also learned first hand some of the problems - mainly caused from not running an engine on a dyno BEFORE shipping it out. We have corrected that with our Mountune partnership as they have the equipment and facilities to dyno engines before they ship.

1256762


Thanks for your feedback!
 

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Experiences that I've had, or have first hand knowledge of
-bearing tolerances not specified properly. Often in more 'wild' builds 'stock' specifications are not correct.
-Piston wall clearances not specified correctly. Same reason as above
-Piston rings not gapped correctly. same reason as above
--There needs to be some first hand knowledge of what the intended build will be and what that means for all the tolerances. If you put together an engine with parts meant to handle 700hp, the tolerances and specifications are wildly different than if you use the same exact parts but are building it to support 400hp. Same goes for what kind of induction, fuel, use of car, etc.
-I've seen issues with components not being balanced properly. 'Standard' balancing is used instead of the actual components, say CP piston specs are used when the final build uses Arias pistons
-If the final build is with head on, I've seen many issues with torque specs in relation to which studs, which head gasket, etc. They are all different and need to be treated individually.
-I've seen issues with freeze plugs. Not sure why but we've have freeze plugs blow out on a few builds. You can tell they were new, and a new one is simply put in after a blow, and it works fine. We never figure out how the builder screws that up.
-Final compression ratio. For some reason a lot of builders have a really hard time figuring out the compression ration when ALL aspects are figured in. Which headgasket, combustion chamber porting, piston design, head milling (even if it's just to make it true). This should be relatively simple math, and it makes a huge difference for tuning and power output.

I know there have been other issues over the years, but these are some things that apply to all engines. It pretty much boils down to how the variables are factored. Have all the variables been factored?
 

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Another feed-back, for stock rpm, maybe stock valve spring and better valves. The original valves are fragiles and may break at the top retaining clip recess.

The aluminum used on the engine block have a lot of silicium into it. The cylinder may move down. I saw few engine with that troubles. It look like you are going to this direction for the block. Nikasil is another option but the cylinder have tendency to crack, witch is really bad.

The oem conrod are good enough for 300hp, but race bearing are welcome.
 

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Acme Super Moderator ** The Enforcer **
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First of all, you shouldn't say "300hp." At the crank or whp? Big difference.

San
 

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Seems like a tough business model to make money on, when there are junkyard longblocks available for little money, and engine swap options available at a higher price point. Making rebuilds fit in kinda an uncomfortable middle ground.
 

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I think you should figure out one or two engine rebuilds which you support, and test the heck out of them, don't do improvised one offs. This way, you solve all the issues, and you can perfect the process to make good margins for yourself while also providing good value to your customers. Engine rebuilds suffer from a lot of teething issues when you didn't think about all the implications of your change, and it's hard to foresee everything.
 

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Discussion Starter #7
I think you should figure out one or two engine rebuilds which you support, and test the heck out of them, don't do improvised one offs. This way, you solve all the issues, and you can perfect the process to make good margins for yourself while also providing good value to your customers. Engine rebuilds suffer from a lot of teething issues when you didn't think about all the implications of your change, and it's hard to foresee everything.
Thanks and agreed. We have built engines in the past so have collected our own data/experiences. I wanted to see what other suggestions the market wanted to make. I've gotten good feedback from many of you on the phone as there is a need for built engines.

We intend to offer a couple of standard kits and then offer custom for those clients who demand it.
 
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