Mark T Posted January 31 Share Posted January 31 The 690 poked the pin through the adjustment on one valve. 690s had power Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568199 Share on other sites More sharing options...
Joey Mack Posted January 31 Share Posted January 31 Yep, but still needed help to even act like an engine brake.. we used to drill and tap the housings to put top oil feed lines to them to increase oil volume to get better performance, we either drilled the valve cover spacers or bought updated ones, and had to tap into the oil filter stand to get the needed oil from the turbo oil line port... What a joke, and put in a high volume oil pump... Only after a road test for diagnosis with hand written specs on a form to submit to Mack for approval.. It was a crazy time in early 2000's... Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568201 Share on other sites More sharing options...
Mark T Posted January 31 Share Posted January 31 I never understood that. The 680s had lots of oil pressure issues on the top.....and some didn't. I don't remember 690 on the E Techs being like that. Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568202 Share on other sites More sharing options...
Joey Mack Posted January 31 Share Posted January 31 The 690 was weak. I did a bunch of these upgrades and they were still, just decent. Its been a long time bud.. Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568203 Share on other sites More sharing options...
BronsonA2150 Posted January 31 Author Share Posted January 31 It’s really a shame that Jacob’s didn’t release that 349 sooner and give them more time to perfect the wear issues. I think they only made them a couple years before Cat went to the E model so they scrapped it. But if you look at the diagram of the operations you could really tell why they were so much better. I’m betting something similar could have been done with Mack Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568204 Share on other sites More sharing options...
Mark T Posted January 31 Share Posted January 31 8 hours ago, BronsonA2150 said: It’s really a shame that Jacob’s didn’t release that 349 sooner and give them more time to perfect the wear issues. I think they only made them a couple years before Cat went to the E model so they scrapped it. But if you look at the diagram of the operations you could really tell why they were so much better. I’m betting something similar could have been done with Mack They could do a lot of things to make stuff work better. Problem is most manufacturers have this thing called a board of directors. They don't really care about anything but how much they can make off of the product. Engineering can only produce what budget allows. Stuff did get better as time went on though. Not many guys can complain about performance of a Powerleash. Then there's the lack of maintainance. I rember the 690 had 6 bolts that held them on to the rocker pedestals. If you read the Jacobs literature, they recomended changing them every 300,000 miles. Not many did, then wonder why they had issues with alignment and oil leaks. Or guys would continue driving the truck with the soft plugs out of the rocker shafts until the shafts were actually gouged out and never be able to keep oil in them like was needed. We're spoiled now with these newer engine brakes that exceed 400 horse of retarding power with relatively little maintainance. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568208 Share on other sites More sharing options...
fjh Posted January 31 Share Posted January 31 11 hours ago, Joey Mack said: Yep, but still needed help to even act like an engine brake.. we used to drill and tap the housings to put top oil feed lines to them to increase oil volume to get better performance, we either drilled the valve cover spacers or bought updated ones, and had to tap into the oil filter stand to get the needed oil from the turbo oil line port... What a joke, and put in a high volume oil pump... Only after a road test for diagnosis with hand written specs on a form to submit to Mack for approval.. It was a crazy time in early 2000's... Yup It was a bogus Time for sure! They were trying lots of different things to over come the lack of braking! My opinion again is they were shooting at the wrong issue! Needed to get rid of more compression !They weren't getting the valves open enough in my opinion! Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568211 Share on other sites More sharing options...
fjh Posted January 31 Share Posted January 31 Yup Mark that was another mistake! What they were thinking We will never know ! Why you would change from a 7/16 bolt the served you well over 30 years And change to an almost 3/8 bolt on the rockers is beyond me! And this was even before these Volvo turds got involved! They do equally stupid shit ! Wimpy bolts to hold the injectors , in wimpy bolts to hold the intake manifolds on, orings where gasket's should be an so on! BUT Who are we to say, were just low life bolt turners ! They did finally get it right with the power leash though ! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568214 Share on other sites More sharing options...
Mark T Posted January 31 Share Posted January 31 The valve doesn't have to open a lot, just bump it off the seat. It's the overcoming the cylinder pressure is the hard part. Open the lash on a 680 or 346 . Go about .100. be wowed about a week (lol) then watch stuff break like housings or solenoids turned to junk 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568216 Share on other sites More sharing options...
fjh Posted January 31 Share Posted January 31 2 minutes ago, Mark T said: The valve doesn't have to open a lot, just bump it off the seat. It's the overcoming the cylinder pressure is the hard part. Open the lash on a 680 or 346 . Go about .100. be wowed about a week (lol) then watch stuff break like housings or solenoids turned to junk Yup you don't want to go over board thats for sure ! You can only tweak so much before disaster is in the cards! Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568217 Share on other sites More sharing options...
The Heinz Posted January 31 Share Posted January 31 25 minutes ago, fjh said: Yup Mark that was another mistake! What they were thinking We will never know ! Why you would change from a 7/16 bolt the served you well over 30 years And change to an almost 3/8 bolt on the rockers is beyond me! And this was even before these Volvo turds got involved! They do equally stupid shit ! Wimpy bolts to hold the injectors , in wimpy bolts to hold the intake manifolds on, orings where gasket's should be an so on! BUT Who are we to say, were just low life bolt turners ! They did finally get it right with the power leash though ! We've had a rash of cam's wiping out on MP engines, and go figure they're on super mega backorder. I'm fairly certain the problem is Volvo wanting to reduce mass in moving parts for increased efficiency, because the cams are not made out of one piece of metal like they used to be. Now they're almost pressed together, so go figure it's going to come apart. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568219 Share on other sites More sharing options...
fjh Posted January 31 Share Posted January 31 3 minutes ago, The Heinz said: We've had a rash of cam's wiping out on MP engines, and go figure they're on super mega backorder. I'm fairly certain the problem is Volvo wanting to reduce mass in moving parts for increased efficiency, because the cams are not made out of one piece of metal like they used to be. Now they're almost pressed together, so go figure it's going to come apart. Yup I could see that coming a mile away! I just shook my head when I saw they were going to that set up! Another dumbass move! And what did we save here? Yet another non improvement! 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75063-what-engine-brake-do-i-have/page/2/#findComment-568220 Share on other sites More sharing options...
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