Boxler1066

Thank you Joey Mack….what made me question all this was the diagram in my etech service manual…in the section on valve yoke installation it had brought up this issue with interchanging e7 and etech bridges….they had a diagram on how to differentiate the two but my bridges didn’t appear to match either bridge….my bridges aren’t rounded on the end like an e7 bridge nor are the underside of the button on same plane as the plane under the adjuster locknut….also my bridges don’t have .140” between them planes…more like .090 to .100” between the planes so I ask myself why don’t my bridges fit the profile of either the etech or e7 bridges as per the diagram…then I ask if my bridges not matching either profile are safe to use….thats what got me reaching out for help…. Thanks for the response!!

Oh and yes the intake valve yokes/bridges are pinless…no guides….only the exhaust valve yokes/bridges have guide pins

I had a AI-300A motor that needed an overhaul and decided to convert it to a E7460. The machine shop which sold me the PAI inframe kit and the PAI cam kit did the research along with PAI to tell me what would be required to convert it and I ordered the parts accordingly…..gave them as a reference the engine model and serial number off of a E7460 we have in one of our other trucks and also gave them the engine model and serial number off the AI-300A motor that I wanted to rebuild and convert into an E7460 I got an inframe kit, camshaft kit, injectors, oil pump, and different cylinder heads using the casting numbers that PAI said I would need for the conversion and had the machine shop go through them, I have yet to get the turbo and exhaust manifold The motor has no Jake or engine brake…I have both an E7 and also a ETEC service manual….the ETech manual says that using ETech exhaust valve yokes/bridges on an E7 can release the valve retainers and drop a valve….would AI-300A motor exhaust valve yokes/bridges cause the same potential failure of dropping a valve….I attached pictures of the exhaust valve yokes/bridges that were in the AI-300A that I can use if they are the proper ones and also I’d like to use the pushrods that were in the AI motor if they are the proper ones….can anyone tell me if these are correct ones to use on an E7460? I can provide the casting numbers of the heads that I’m using to convert it if needed….I just don’t have them with me right at the moment

Would anyone know if a model E7-460 Mack motor model year: 1999 with serial number: 11GBA4907P2 would have exhaust valve holes that are same or interchangeable with a 2003 model Mack: AI-300A motor with serial number: 11GBA15672YP1 I realize their are many differences between these motors….im just wondering specifically if Mack E7 and AI-300A have the same valve yokes and pushrods?

I noticed a couple people responded about putting a 460 in the truck…just to clarify…what I meant by AI-300A to E7-460 conversion was what it would take to make a AI-300A into a E7-460🙂

No boost leaks….I inspected all the piping and there is no issues with the piping and it has relatively new silicone hoses throughout the turbo piping and they all look good…no tears or abrasion damage to them…and the air to air cooler was pressure tested and that’s good…it had a new teflon lined hose from intake to air compressor inlet and that hose looks fine and II inspected the intake manifold gaskets all the way around each port with a good flashlight and seen no indication of a gasket being blown out and also sprayed ether around the intake ports while it was idling and no change in engine rpm so it doesn’t appear to have any leaks whatsoever and it had a new turbo put on it about a year ago and I pulled air cleaner pipe off recently to see if turbo felt like it had issues and it seems perfectly fine….If it’s getting too much fuel what would cause that? It has a mack reman computer put on it a couple years ago and the mack dealer programmed it given the trucks vin # and engine ID tag information….truck has a complete new wiring harness from front bumper to rear bumper… new cab, engine, transmission and chassis harness If It’s getting too much fuel what would cause that? the engine has considerably more blow by than normal I have oil pan off and all the lobes are nice and smooth… no indication of damage from a bad cam follower and same goes for eup lobes…I haven’t measured them yet with a dial indicator but I’m going to upon rebuild if I stick with keeping it a 300 to make sure it’s good

So the truck with the bad AI-300A engine has EUP’s and it is a 2003 Mack MR688S with an Allison…I forget now…I think it might be an HT4560…I’ll have to check to confirm that,…it has the computer located on the passenger side up higher…. kinda about the level of the intake and water manifolds…it has no cooler lines running to it where the computer on the E7-460 I believe is located down lower and if memory serves me right I believe it has cooler lines hooked to it and the 460 also has EUP’s So to fully explain what’s going on here is I’ve been referencing converting that AI-300A engine into an E7-460 for this reason…..we have 1999 mack RD688S with an E7-460 that we use on the farm and I decided to use the information from that E7-460 by using that trucks VIN and also engine ID tag as my reference to determine the difference between these 2 engines….I did this thinking this truck has always been good and reliable and has the extra power that I wanted our MR688 to have…..since the MR motor needs an overhaul I figured it would be a good time to convert to a higher horsepower level. As far as the Allison and driveshafts and power train goes I don’t think it’s anything to be concerned about in this particular situation….the truck stays in the farmyard all day and never has to go down the road….basically it never really exceeds 20mph and doesn’t have to deal with any major hills or rapid acceleration or takeoff on grades or anything like that….where the lack of power is my main issue on the AI-300A motor is has to deal with the load put on the motor to run the live hydrostatic pump and motor that runs the feed mixer on the back of the truck…..this mixer is mixing up to 35,000 pounds of corn silage, haylage and grains all at once in the mixer and that takes some power…..and to get the mixer to run the optimum speed to mix the feed ration adequately the math says the engine rpm should be 1600ish rpm range while the truck is being loaded with all the feed ingredients and also around that same 1600 rpm range offloads the mixer at about the right rate…. Problem is while mixing and offloading currently I generally can’t get the motor up much past 1100-1200 rpm range all the while the truck is laboring, throwing moderate to medium black smoke stream…. air cleaner is good… fuel filters good….air to air is good and pressure tested…. no air leaks from turbo compressor outlet to cylinder heads…has a new turbo on it…. has a new fuel transfer pump running proper pressure with a new hand primer pump on transfer pump and checked for air bubbles at transfer pump inlet with a clear glass sight glass to ensure transfer pump isn’t sucking air in fuel line from fuel tank to transfer pump inlet and see no indication of air…..I did all the above listed diagnostic about a year ago and it’s getting worse….i can tell the motor is just sick and it’s tired….its had a lot of hours put on it since we bought it used and I’m not certain of its history because I don’t know that the tach, odometer or computer are original when we bought it… but its got a fair amount of blow by,….coolant in oil and it’s always been sluggish but even more so now than when we got it…I think I would have considered looking for a complete descent E7-460 atec or E7-400 atec and then rebuilt that and put it in but when you weigh it all out I don’t know I’d be much farther ahead… far as I know if I bought a used one it may have needed a cam as well or the charger and injectors etc…etc… may have had needed to be replaced upon rebuild plus all the extra work of a complete engine swap and all the little differences you always seem to come across on a swap from one model to another vs an in frame rebuild of the sick AI motor so all that kinda got me to this point

Oh….one other thing…with a 460 being quite a bit more horsepower are the piston cooling jets the same size?

Can anyone tell me definitively if a model year 2003 Mack AI-300A motor with serial# 2SO814-11GBA15672YP1 can be converted into a Mack E7-460 with serial# 901373-11GBA4907P2…? The AI motor is in a truck we feed cows with and it’s real sick and needs a rebuild…..has coolant going in oil… pretty good blow by, sluggish, smokes black, not very responsive, doesn’t start as well as a decent motor would particularly when it’s colder outside and it’s got a lot of hours of use on it and in addition to that the motor was really not enough horsepower from the start….in addition this motor always seemed real luggish, not very snappy, tended to act like it’s always laboring and the turbo gets hot very quickly….all these issues in comparison to our other Mack e7 atecs that all seem more snappy and don’t always act like they are laboring more than what I’d consider normal Im told pistons and sleeves are same….it needs heads because ones on it have been milled beyond spec…so I’m told to get heads with either casting number 732GB5252M or casting number 732GB5341M….so what else would be different? I’m assuming injectors and turbo for sure but I’m not sure if EUP’s have to be changed or camshaft has to be changed because I’ve gotten different opinions on them from a few people I’m told the cam has to be changed because the AI cam is profiled so some exhaust goes back into cylinder for pollution???…Something about the AI motors have a different profiled cam to meet emissions and I’m also told there’s a bigger less restrictive exhaust manifold that should go on it and also computer would need to be reprogrammed or replaced??? I just want advice from someone who knows for certain if this is do able and if so what specifically has to be done Also can anyone tell me more about EUP’s…are they either good or bad or are there cases where they can have intermittent issues or they loose spec to where they don’t deliver proper fuel delivery and fuel rate in conjunction with proper timing? Lastly I’m putting a new oil pump in… which one should I get…aren’t there some pumps that pump more volume?? If I don’t have to replace EUP’s I’m planning on new alignment dowels for them and also check rollers and pins for wear or any other issues there….do they sell roller/pin kits for the EUP’s Any help would be much appreciated…I gotta get after this project because this is one of our feedtrucks that feeds our cows daily…with this truck being down if I come across a situation where our other feedtruck has any major issue I don’t have an ideal option for a backup truck to feed the cows with and they definitely have to get fed every day even if it means I got to use a pitchfork and a wheelbarrow and that would be tough seeing how there are close to 4000 head to feed every day😁🙂