Knocking At 190* ?!!

[JayLashua]

I Don't know what is with this.. ok my turbo seal is a little leaky, my plugs have oil on them.. anyhow, the car runs great until it gets to that 185-190+ range.. and i can HEAR it detonate its ridiculous because the boost isnt even kicking in at this point..

At night the car runs about 180-190

in the daytime that goes up to like 190-200 at most

I have a robertshaw 160* tstat, a stock 84 3-core radiator.. stock fan... what gives? I konw that's not even close to being over heated...

 

[Nocooler]

Sounds like its on the warm side to me.......Mine always ran less than 170* w/ a 160 stat in it.

 

[JayLashua]

bah, noone else replied to this yet!?

I just changed the fan on it and it STILL runs at 195-200 .. BAH..

even if it was STOCK wit a STOCK thermostat it would run like that, so why is it detonating?!

i dont have a knock gauge but i know it shouldnt sound like that... its not very loud but still.

 

[TurboBuickSix]

Maybe you have carbon or oil deposits in the combustion chamber that is causing pre-ignition?? My car runs no hotter than 185-190 on a 85+ day and the power is wayyy down and if I were to get on it with 94 in the tank I know it would knock.When it's a little cooler outside it's fine and pulls super hard without knock.These cars hate high ambient temps it would seem.I suggest you try a different chip,if that don't help try some race gas.Also you might want to check your fuel pressure while the problem is happening,maybe it is the fuel system causing trouble when it is hot for some reason.I would drive it very gently in the heat for now.good luck

 

[JayLashua]

oil?! yes well my turbo does leak and i was thinking about that...

 

[Chuck Leeper]

KNOK KNOK???

Jay, it's likely the oil leak from the turbo is getting to a point, that when the engine is HOT and the oil is thinning out, your leak is feeding enough oil to the cylinders to reduce the octane to low enuf levels to cause knok.. boost or not... Engine oil does not have a very good octane rating!!
I bet the intake is also full of the stuff......
How old is the rebuild on the rad?? It's NOT the original, is it??

The knok can/is contributing to the overheating too..
IF the system/engine is in good shape, the temps should be close to the stat....

 

[JayLashua]

yea well radiator is stock, dave told me it was clogged as **** the only way to clean it good would be to unsolder the tank and ..well, couldnt really do that there. we flushed it out and that helped, as well as put an electric fan in, so it runs 175 now steady.

I would be looking for a good used radiator though

a good stock turbo

and this weekend I have to take care of a front seal leak so hmmm all my money is down the drain before i get it! lol

 

[Chuck Leeper]

USED RAD?

Jay, do yourself a favor and have it recored.. Not expensive compared to getting a used 1 and then having to have it cleaned..
A bit of "sage advice" from the old geezer!!..

 

[JayLashua]

Really? figured it would be more, i'll do that then as well on the weekend - thanks for the help

 

[Men in Black]

Fix the oil leak, oil in cylinders causes detonation.

 

[JayLashua]

irst things first i need to fix the front main seal I think that's the worst leak, I'll have to wait another 2 weeks to fix or replace my turbo unless you're selling a good hotair turbo for not alot of money..?? I cant think of any places around here which rebuild them.. =/

 

[JayLashua]

Update:

I have installed a huge radiator electric fan etc. and converted to an 87 ECM..

Only chips I have are a stock and a thrasher 92 ..but thats for 36# injectors.. =/

IF i retard my cam sensor will that possibly reduce knock?

atleast I havent lost compression, still starts up perfectly etc except when its hot ht takes a copule extra cranks=/

Oh yea, I also have a transmission cooler. Temps around 175-180 in hot traffic, since i just got my a/c fixed, when its running it goes to about 185.

 

[FJM568]

New radiators can be bought for about $120...When you buy one, get one for the 86-7 Regal with the V8 motor...The radiator will be about 4 inches wider than the stock 84/5 radiator and will have greater cooling capacity...Then hit the salvage yards and pick up the upper radiator core support for the wider radiator...You can get it basically out of any g-body car that had the V8 in it...Since you switched over to the electric fan, the 84/5 V6 fan shroud does no good but take up a lot of space...Also, go to O'Reilly's or Autozone and pick up a new upper radiator hose...BUT do not cut it to fit like you normally would with the shorter radiator...The extra length is needed due to the wider radiator...As with any radiator change, flush your system out and with your new wider radiator in there, you shouldn't go over 170* A/C off or 180* with A/C on...

 

[Buick From Hell]

Jay, you say it's harder to start when it's hot? Does the starter sound "labored" at all?

Could be your cam sensor IS adjusted too far advanced! Mine got that way after a timing chain change, and it DID knock with no boost!

After about 2 weeks of this, I retarded the cam sensor, and PRESTO!

Also, I did a little experimenting, I found that (with MY car anyway) that the engine WILL START and run with the cam sensor advanced too far. However, with it RETARDED too far, it wouldn't even TRY to start, and I even got a couple of half-assed backfires. I was also using a timing light to see if slight variances in the cam sensor setting had any effect on timing while running...NOPE. No matter where the sensor was set, as long as it was in the correct range to locate the number 1 cylinder, (and there's quite a bit of ''correct range" BTW), ignition timing was always the same at the various RPM's I checked...

 

[JayLashua]

yea the new rad. is already in its a huge mofo, it definitely runs much cooler, it stays like 165ish but runs about 180-185 with the a/c and the heat beating down which isnt bad i suppose

i will retard the cam sensor a bit and see if it helps at all .. thanks for the input guys.

BFH: Do you make huge like window sized banners? for front/rear windows or just small stuff? Id like a nice white buick logo with the solid turbo 6, the kind they had at the nats, could you make those?? ;P i pay!

 

[FJM568]

Actually, as a correction to BFH, the cam sensor locates cyl #6, as the initial reference used is 25* AfterTDC of cyl #1...#6 is the next cyl in the firing order of the engine...1, 6, 5, 4, 3, 2

Some cars run or idle better with a few minor tweaks from the factory setting of the cam sensor...If you advance it too far, fuel will puddle on the back of the valve until the next time it opens...if you retard it, it will still puddle a little, but still get some atomization into the cyl if the inj is still spraying when the intakde valve opens...It also depends too on whether you still have the stock cam or an aftermarket cam...The start point of the intake valve opening may be sooner and the duration longer on the aftermarket cams, so it is possible that tweaking the cam sensor *MAY* correct some idle or driveability problems...

And then there is always the "every engine, even though built identical, will run a little different from the next one" type of thing...You just need to tune your engine to itself and not to how someone else tunes theirs...They are all different...