new stroker?

moretoys · #1 (**permalink**) 10-04-2001, 07:13 PM

I have a new 351W stroked to 396c.i. The motor is built with all good parts, Scat crank, KB forged pistons, victor Jr heads, etc.. The motor was just installed in my car and it is running very hot, Headers are upto 600 F. at idle. and the oil temp stays around 110 C. Much higher than I or the builder like. Does anyone have any suggestions or have experience with similar problems?
Any input is appreciated.
Jason

dalola · #2 (**permalink**) 10-04-2001, 08:07 PM

Jason,
You may need to give more information before anyone can specifically help you. You say your oil temp STAYS at 110c(230F). Does this mean it has not gotten any hotter than that? If so, that is actually a good temp, so long as it stays in that range. What about water temp? There are many things to check, but more info is needed to go beyond the "normal" list of why an engine runs hot. Judging only from your initial post, those temps aren't totally out of line. You mention your engine builder. No one will know more about that engine than him. I would press him for information and acceptable specs for that engine.
Dave

marmmansa · #3 (**permalink**) 10-04-2001, 08:08 PM

My custom built 393 runs at 80C all the time if I am moving it is at 60-65C this time of the year. Today it was just that. Who did your build. Your fan must be constantly on. I have a edlebrock water pump.In the hot of the summer standing for 3-4 min. it will turn fans on but as soon as you move the temp goes right down.I have a 7lb. stant cap and expansion tank on it with catch can.

marmmansa · #4 (**permalink**) 10-04-2001, 08:11 PM

sorry oil temp 20-50 wgt. stays around 80-90 when warmed up with oil cooler hooked up! Even when new oil temp was same.

moretoys · #5 (**permalink**) 10-05-2001, 05:08 AM

I am comparing my temps to other spf cobra with similar engines. Most seem to run at around 80 c , 90 c max. Mine runs 20 to 30 degrees hotter. Water temp is also around 90, about 10 degrees hotter than others. The max temp was 110, but I really was only going up and down the block a few times, I can't imagine what it would be when I really git into the motor aggressively. We are talking to the engine builder, and checking the specs they want, However I have seen some very good info on this board and figured I would see what Ideas anyone had. This was the first drive, with engine in car, so we want to make sure things are fine before putting it on the road. The engine builder was RDI.
Thanks again
Jason

marmmansa · #6 (**permalink**) 10-05-2001, 06:21 AM

keep in mind these gauges are not the most acurate.

moretoys · #7 (**permalink**) 10-05-2001, 10:56 AM

These temps were measured with a hand held temp gauge. They corresponded to the gauge temps pretty well.

moretoys · #8 (**permalink**) 10-05-2001, 02:06 PM

Thank you for the feedback.
There is a problem with the engine and we are sending it back and having a new one built. I quess my new cobra will be spring toy instead of fall.
Thanks
Jason

wilf leek · #9 (**permalink**) 10-05-2001, 03:55 PM

Jason - would appreciate hearing what the problem was/is with your motor. My own Stroker 351W (396/408 depending how you calc it) is fine in "normal" street use, but get on it on the track and the oiltemp climbs and climbs until I have to back off and cool it down for a couple of laps. I have even tried electric fan assist to the oil cooler to try to help but to no avail. Up on the stands in my garage I have run the engine on no load but 2500 ish rpm and been surprised and a little concerned at how much heat goes into the oil. In all other respects the engine runs just fine and has given healthy BHP on the dyno. Water temps OK. I can only surmise that mechanical "shear" is heating the oil somewhere - maybe your own experiences could give me a lead.

At one time I measured temps of 130 degrees C in the sump using accurate thermocouple type electronic thermometer. Not so bad now I have increased the size of the oil cooler, but still a concern.

from a cool and wet UK

Wilf

Jeff Frigo · #10 (**permalink**) 10-05-2001, 06:19 PM

I assume the timming was set correctly? If it is set too low, this will cause the engine and exhaust to run extremly hot. Check to see if the piston is truly at TDC when the pointer says it is.

Jeff

427sharpe · #11 (**permalink**) 10-05-2001, 06:27 PM

Ck timing--may be too advanced. If you don't have a timing lite try the old way. TURN OFF MOTOR, loosen the dist holddown just enough that you can move the distributor with a little force, and make a small mark on the base of the dist where you can see it, and at least 1" away from the holddown. Start motor. Turn distributor counterclockwise until the engine starts to fumble and make a mark on the block @ the point where the dist is marked,than do the same in a clockwise rotation. Turn off the motor. Put the dist in the middle of the 2 marks on the block, and tighten the holddown. Ck and see if your problem is gone. Hope this helps!

Jeff Frigo · #12 (**permalink**) 10-05-2001, 07:18 PM

427sharpe:

Engines run hot if there is not enough timming, not too much. Also the only way to see if the timming marker is accurate to the harrmonic balancer line is to bring number one cylinder to TDC and see if they line up. Not to be critical, your method will not work to prove accuracy, and should not be used to set the timing either.

JJF

aeroace · #13 (**permalink**) 10-06-2001, 08:15 PM

Check your jetting and your idle mixture. Put 78-80s' in the primaries, 80's in the secondaries(if you have a holley double pumper, and you should)

If the tranny's input shaft is being shoved into the back of the crankshaft, the motor will have excessive thrust bearing load, wear, and heat buildup. Pull the tranny out of the bellhousing, measure the distance from the rear bellhousing flange (where the trans bolts on) ,to the pilot bearing, as installed on the motor. A straight edge and a piece of welding rod and a magic marker works fine. Compare this distance to the tranny's input shaft length. The input shaft needs to be inside the pilot bearing 1/2" but cannot be allowed to bottom out on the crankshft. 110 degree oil temp in a SPF is hot unless you're running at over 4500 rpm, with low speeds (no airflow thru cooler). The 500 hp 351 strokers (418 cid) usually run 80-100 with spirited driving.

If the motor is brand new, they do run hotter while breaking in. (But the water usually heats up before the oil. If the oil gets hot before the water: a problem. ) Just shut it down after the oil gets to 100, wait for it to cool, and heat cycle it twice more. By then the rings should have seated, and it should spin easier.