Unusually high EGTs after a full engine rebuild?

[Kimbo63]

Imo I would just do the lifters easy to do and valve set is not a big drama only because if you use hyd lifters you change the duration of the cam moving your power band up the rpm range also you will find there will be a loss in power and torque I could go into details on this but it will probably get to confusing

[SiberianPatrol]

Imo I would just do the lifters easy to do and valve set is not a big drama only because if you use hyd lifters you change the duration of the cam moving your power band up the rpm range also you will find there will be a loss in power and torque I could go into details on this but it will probably get to confusing

Thanks, Kimbo! From my research, the head and hyd lifters that were put on it are the same as are on the GQ RD28T, but the cam is mine from the GU RD28Ti. I assume the lifters should be interchangeable without any problems?

Can you give me some more details about the differences in the lifters causing the torque and power loss? I'm a shade-tree mechanic and know my way around a vehicle, but some of the details on how things exactly work are unknown to me.


1999 GU RD28Ti; mechanical injector pump, 5kBt Webasto circulation heater, 33" Yokohama Geolander I/T, SaaS boost & EGT gauges, 2" Ironman suspension...more to come

[Kimbo63]

Sure A solid-lifter cam has acceleration ramps that take up the valve clearance gradually, then start lifting the valve. By running the hydraulics, you've effectively increased the duration of the cam lobe by lifting the valves on the acceleration ramps.Due to it having 0 clearance this change in valve timing will make you lose power as it is also the same profile on the down ramp of the cam lobe so if your exhaust valves are open sooner and longer you will loose power out the exhaust hence the higher EGT hope this helps
Another point regarding boost it would not hurt to increase boost this will only help running your engine in however I would sort the lifter issue first as this can have serious consequences ie valve float
Hope this clears things up a bit
Cheers Kimbo

[SiberianPatrol]

Sure A solid-lifter cam has acceleration ramps that take up the valve clearance gradually, then start lifting the valve. By running the hydraulics, you've effectively increased the duration of the cam lobe by lifting the valves on the acceleration ramps.Due to it having 0 clearance this change in valve timing will make you lose power as it is also the same profile on the down ramp of the cam lobe so if your exhaust valves are open sooner and longer you will loose power out the exhaust hence the higher EGT hope this helps
Another point regarding boost it would not hurt to increase boost this will only help running your engine in however I would sort the lifter issue first as this can have serious consequences ie valve float
Hope this clears things up a bit
Cheers Kimbo

Makes sense. Thanks for the info. I'll take it back to the shop that did the rebuild and get them to replace the lifters. Is that the only thing that will need to be swapped out?

[Kimbo63]

I found this site read the section on cam profiles
http://www.enginebuildermag.com/2012...d-lifters-101/
Cheers Kimbo

[Kimbo63]

Let's start there mate and see how it goes as you have no dyno let's use that big hill of yours as the mobile dyno will be good enough for me to help you out
Cheers kimbo

[Kimbo63]

What sort of boost controller do you have?

[SiberianPatrol]

What sort of boost controller do you have?

Just a simple inline controller that I got from Mudski a while back

[Kimbo63]

That cool is it sort of like this
http://www.ebay.com.au/itm/New-Genui...-qExceapIWsVwg

[SiberianPatrol]

Same idea. This is the one I have http://m.ebay.com/itm/Dawes-Devices-...590?nav=SEARCH


1999 GU RD28Ti; mechanical injector pump, 5kBt Webasto circulation heater, 33" Yokohama Geolander I/T, SaaS boost & EGT gauges, 2" Ironman suspension...more to come