Anthony Pllu 262 Posted October 29, 2014 hey guys. have 351c FMX. stock other than RPM Air gap intake and holley 650 and top breather air intake. i also have thermo fans with a Davis Craig thermo switch etc etc. When she sits on idle it the temp normally sits around the 3rd to 4 bar on the temp guage. XD/XE style. But when cruising down the highway at 110 the temp is at about 3/4 to hot with the thermos blassing and it wont cool down until i stop and idle for 5 mins or so. it sits at about 2500rpm at 110 was wondering if it could be timing and ported advance is advancing it to much when at cruise speeds casing it to heat up. Im not sure how the vac advance system works just find it weird how when at idle with no air it does not get hot but at 110 with almost no throttle it heats right up Any thoughts thanks Share this post Link to post Share on other sites
PRO250 1,506 Posted October 29, 2014 turn the timing up 10 degrees and go for another easy drive and see if it stopsanother thing you can look for is the brass restrictor plate under the thermostat if that's missing is will have the same issue 3 bear351c, Stevemack and Outback Jack reacted to this Share this post Link to post Share on other sites
Anthony Pllu 262 Posted October 29, 2014 pretty sure i dont have a thermostat is that a issue. i dont have a heater Share this post Link to post Share on other sites
gerg 10,871 Posted October 29, 2014 No thermostat = cavitation in your water pump. It needs a restriction to pump against (ie the thermostat) otherwise the flow is unregulated. Instead of pumping, the impeller spins around in a vacuum bubble and does nothing. Try putting a thermostat in and see how you go. 3 Outback Jack, XTREME KARTS XF and Stevemack reacted to this Share this post Link to post Share on other sites
bear351c 10,273 Posted October 29, 2014 Yes. You must run a thermostat, and the brass restrictor plate (under that). Coolant runs too fast through the radiator, and doesn't have time to cool down. The thermostat isn't there for the heater, it's to warm up the block to operating temperature. Opposite to that is running too cold, makes the oil sludgy. Ignition timing may be the issue, as pro250 stated. 4 Outback Jack, XTREME KARTS XF, Gaz and 1 other reacted to this Share this post Link to post Share on other sites
Anthony Pllu 262 Posted October 29, 2014 ok i will pop the housing off tomorrow and have a look Share this post Link to post Share on other sites
Trev Vaa 1,185 Posted October 30, 2014 you should see this once you take the housing off if you see this, you need to get one of these: http://www.ebay.com/itm/351C-Bypass-Restrictor-Plate-Solid-Brass-Pantera-Mustang-All-Other-Clevelands-/171476456933?pt=Motors_Car_Truck_Parts_Accessories&hash=item27eccb15e5&vxp=mtr thermostat should be a dayco DT66A 7 Stevemack, XTREME KARTS XF, Thom and 4 others reacted to this Share this post Link to post Share on other sites
bear351c 10,273 Posted October 30, 2014 Awesome XCsedan.! Photo with/without, and a link to a newie. That's gold. 1 XTREME KARTS XF reacted to this Share this post Link to post Share on other sites
Trev Vaa 1,185 Posted October 31, 2014 if your gunna do something... may as well do it right.... i learnt that the hard way haha 3 Thom, gerg and XTREME KARTS XF reacted to this Share this post Link to post Share on other sites
