tannerb

So heres the deal, I bought an 87 toyota pickup in feb of this year to build as a project after I graduated college. I just recently rebuilt the top end due to a blown headgasket when I bought it. I had the head decked to increase compression, 3 angle valve job, installed an lcengineering street cam, all new valves and seals, egr blockoff and a new timing chain. I also made a new intake but removed it seems to run too lean. I have gone through everything short of ripping the head back apart. The main issue is that it over heats and spark knocks

Things that have been checked:
radiator (new)
timing
plugs
fuel injectors
head gasket
timing chain
vacuum leaks
egr valve (removed)
coolant temp sensor
thermostat (new)

The only thing that I haven't checked is the knock sensor as it seems to spark knock at about 2500rpm.

iamsuperbleeder

TPS or AFM maybe?

Both have a little to do with timing and fuel curve


I noticed you didn't mention anything about the water pump; how old is it?

abecedarian

Detonation will cause high cylinder temps and overheating.
You said you've checked your timing... so what is it set at? Have you tried retarding the timing?
Have you tried a step or two colder plugs?
How much was the head decked?
Has the cam been degreed?
Valve adjustments are correct?
Any vacuum leaks?

tannerb

Thanks for the reply's guys. I checked the afm and tps. Valves are adjusted correctly and no vacuum leaks. The cam has not been degreed just put in according to the instructions from lcengineering. Now here the problem I forgot to mention that has me baffled, the timing was set at 5 degrees but I retarded it to 0 to try to get it to run cooler. I can't run it any mored retarded and if i advance it any more than 5 it starts to spark knock really bad. I tryed un hooking the coolant temp sensor again tonight and it didn't over heat although it came very close about 10 degrees away. Has anyone seen what temp is normal for this cam?

tannerb

Plugs are new and are the same as stock so I haven't tryed anything else, but it started doing this before i rebuilt it and that was the reason for the rebuild and it started doing it over night after I had driven it for a few weeks. The water pump is the original as far as I know but I had it off when doing the timing chain to clean it and install a new gasket and everything was still good, all fins were good and bearing was good.

TNRabbit

What's your compression ration? Also, I'd hope after all that you're running 93 octane fuel....

You MADE a new intake? Unless you have a wide-band O2 sensor to read your exhaust composition, the new intake was probably way lean. Did you do anything with the fuel injectors? Are they capable of keeping up with your modifications?

abecedarian

Not sure what "temp" is normal for your cam, but anywhere from 190F to 240F is pretty much normal for the engine.
And I will ask again...
...how much was the head "decked"?
...valve adjustments are correct?

tannerb

Valves are adjusted correctly. I'm unsure how much the head was decked. The timing chain had a head thickness spec for the chain and it was within that specification so I can't imagine it was decked as far as I though it was. As far as the intake is concerned it was just a cold air intake that I made from one that I had from a project car that I finished and is now forsale. I removed it and it is back to stock now.

deck height is just below stock, valves are adjusted correctly, .008 and .012. I just got home now and its 1:30am here and I am pretty sure its the fact that the fan clutch just can't seem to keep up with the engine. It checks out ok and has resistance but as soon as it gets warm it seems to free wheel to easily. My temp guage is running just below the red and it will go into the red and boil over if i let it. As soon as i turn the heat on it cools off.

tannerb

problem solved! The fan clutch was bad. It would be locked up when cold and once it got to a certain temp it would begin to free wheel once the car heated up so it was doing the opposite of what it was supposed to. next question, is anyone thats running a street cam have problems with loud valves, it sounds as if i have a valve float situation which I know is normal sound for some cams just wondering if everyones is like this with a cam.