sancho

The initial break-in process on my freshly rebuilt L98 has been "fragmented", at best. Mainly, we were having issues with smoke comming off of the engine; I put a post here a while back on there, and everyone pretty much convinced me that it's the new paint cooking in. So I went back out today to do the rest of the break-in.

We ran it for mabye 8 to 10 minutes straight, and then my dad shut it off when he glanced at the temp-gauge (for the first time, apparently) and noticed that it was almost pegged at 260 degrees. The radiator was boiling over at that point (nothing leaked out, but you could hear it boiling). We immediately got a box fan and put it on top of the engine and set it on "hi" to help cool it down, as well as setting the key to the "igition" position (in my car, that turns on the driver's side fan).

I'm not just going to ask "why is it overheating", because I know that could be any number of different things. But, there's a couple of things I think it *could* be that I want to see if they make sense...

1. When my dad noticed that the car was overheating, before he turned it off, I could have sworn that the fans weren't on. To be honest, I'm not really even sure how the fans turn on in my car--the car can be cold at least one of the fans will be on with the key in the ignition position (with the engine off). But it's inconsistient about that--and sometimes it will only stay on for a few minutes and then just turn off (also with the engine off but the key in the ignition position). The wiring harness has oviously been hacked a bit up around the battery, which I guess could affect the fans. Either way, if the fans were in fact *not* running the whole time, could the engine overheat in only less than ten minutes just because the fans weren't on?

2. This is going to sound stupid... I can't tell how much oil I have in my engine. On a new engine where the oil is so clean, I can't really tell how high the oil is on the dipstick when I take it out. I know from memory that we put at least four quarts in it when we had the engine out to prime the new oil pump (and get oil to the lifters). I think that we might have put a half quart more after that, but I'm not sure. If the car had oil (which it definately has), but mabye not quite enough, could that cause it to overheat? I would just go ahead and put another quart in to be safe, but I don't know what the consequences of putting too much oil in are...

One other thing... in an ideal world, I always hear that on the *first* startup, you should be running your engine for a solid 20 to 30 minutes above 1,500 RPM. Well, between getting scared every time we saw smoke off of the engine, we have mabye a total of 18-min of running time on the engine across like six or seven different starts. I hope that doesn't hurt anything to have the engine cooled off (if only a little bit) between startups during the break-in period... does it?

I'm open to any suggestions at this point... thanks!

ede

check the timing, make sure the cooling system is topped off and no leaks, a fan blowing into the engine bay or through the grill helps when the car is sitting still.

AlkyIROC

Make sure the fans are working, make sure the water pump is working, check the timing, check to make sure the thermostat isn't stuck closed.

Check for vacuum leaks. I was breaking in my engine when I noticed the headers glowing red hot. The engine was running extreamly lean because I forgot to install the vacuum line for the power brakes on the rear of the carb.

89 TA

A couple years ago I was having the same problem, no matter what I checked it all seemed to be alright. It turned out to be the thermostat. For some reason it was defective and it wasn't opening. Just a thought.

sancho

Well, I'm done for the day, so I'll have to check the timing and see what the deal with the fans is later (that will probably be another post ).

I did start it up again, though. Started it cold--temp. gague was at the bottom at 100 degrees. Only exactly five minutes later, the temp gauge read 220 degrees. That's at varied (I varied it) engine speed of 1500RPMS to 2500RPMS. I made sure to keep an eye on the fans: the driver's side fan was on the whole time, but the passenger's was not. Theres more than enough coolant in the system. The water pump is new (actually, it's a high-flow pump). I don't have any reason to believe that I'm running lean (actually, the exhaust smells a little rich).

So, not only is it overheating, but it's heating up very fast.

Thanks for the replies--I'm still open to ideas.

IHI

iTrader: (1)

Sancho, I had your EXACT same problem when I started my new 355 few months back. Set back the timing to 28 degrees total, checked and changed thermostat, fans initally did'nt work re-wired for break-in. We shut it down 4 times in 30min cause it overheated that quick. Left the radiator cap off for a LONG time after starting for the 5th time, I truly believe there was a huge airlock inside the block or head somewhere, cause that time it did not overheat. I did put new radiator cap on after 5th start up was complete. Man, I was bummin big time cause I thought for sure the cam was gonna be smoked, I race it every weekend and the motor runs great.

sancho

IHI -- That's a thought. In fact, the engine rebuild book that I has been my rebuild Bible throughout this project recommended that, when putting the coolant in for the first time, that I take the thermostat out and fill from there to keep air bubbles from getting in the top of the block (or something like that). I read that, but then figured that "nah, that'd never happen"--pretty much because I didn't want to pull the thermostat out (I had put gasket sealant all around the thermostat housing and pulled it off once because we forgot to put the thermostat in the first time--was too lazy to pull it off a third time). I guess it couldn't hurt me to leave the cap off overnight; I'll go ahead and do that for tonight.

But, my dad had another thought that seems to make sense to me... when we replaced the water pump, the new one that we bought specifically said that it was a "high-output" pump. It certainly does put-out: with the radiator cap off, the coolant flow in the radiator was so turbulant that the coolant nearly came out of the cap hole! So, the thought is this: we're wondering if mabye the high-flow coolant pump flows so much coolant so fast through the radiator and engine that it does not have enough time in the radiator to actually be cooled off? Is that possible? And if so, why on earth would they still sell high-output water pumps like that (do you need a special radiator or something)?

If anyone has had experience with these "high-flow" water pumps, I'd be interested to hear about what your experience has been...

89formula#1

man i'm startin my 350 up for the first time tomorrow and i hope everythign is ok. i have one question. for timming how do i set it to just get the engine to start the first time? do i just line up the rotor with the number one cyclinder plug wires terminal on the cap? then whne i do crank it my book sayd raise the idle to 2000 rpm for 20 mins, now do i throw a timming light on it after the 20 mins or be4 i raise the idle?? thanks guys

AlkyIROC

Cap and rotor need to be off. You need to see the magnetic pickup pointer underneith.

Rotate the engine until the timing pointer is on your base timing. 10* etc. Rotate the distributor until the pickup pointers line up. That should be close enough for the timing to get the engine started and do the break-in without having to shut it off or let it idle. All your starting and stopping hasn't helped the break-in period but there's nothing you can do about it now.

From the sounds of it you either have an air lock or the thermostat isn't opening. Before you start the engine tomorrow drain the coolent out enough to remove the thermostat. Running without a thermostat won't hurt the engine during break-in. You could also drill two 1/8" holes through the thermostat to let any trapped air get through before the thermostat opens.

My race car runs without a thermostat because I want coolent flow through the block during cool downs between rounds. I use restrictor plates in place of the thermostat to slow the coolent flow down enough so it stays in the block long enough to absorb the heat.

High coolent flow has no problem releasing heat through the rad but has to stay in the block/heads long enough to be able to pick up the heat.

The main purpose of a thermostat is to keep the coolent in the block to speed up getting the engine warm. Once the engine is up to operating temperature the thermostat will stay open and has nothing to do with the operating temperature unless it sticks in a non open position. The engine temperature is then controlled by the rest of the cooling system.

89formula#1

ok wait how do i know wut my base timing should be? all i know is i put the engine at tcd and droped in the dist with the rotor facin the number 1plug terminal. now u are sayin take the cap and rotor off and turn the engien till its at 10* on the timing mark then look on the dist and do wut? wut is a pickup pointer? thanks man

ZZ28ZZ

Make sure the lower radiator hose isn't collapsing. That will overheat an eng real quick.
You may have cooked the intake gaskets with 260+ deg temps.
Check for vacuum leaks and white smoke out the tail pipe (after warm-up).
I cooked mine once. abt an hour of 260+ degs. (damn 305's are tough engs!) Abt 8 months later a chunk of gasket (along with most of my coolant) was sucked into the intake passage for #7 cyl. When I removed the intake, the gasket was extra chrunchy, and breaking into pieces.

For the dipstick reading problem;
wipe entire stick dry, install it, pull it back out and slide your finger down it till you see oil being pushed by your finger. There's your oil level.
A good bright light at just the right angle usually works. Look for the reflection.

Keep an eye on the oil. If it starts looking like a milk shake, you got problems.

sancho

Okay, I've read and thought about all of your good replies. However, after my experience tonight, I'm starting to think that the cooling issues are not related to the cooling system (at least not directly, anyway).

First off, I went out to put a timing light on the car for the first time tonight... disconnected the "Electronic Spark Timing" wire per the manual's instructions, and then I set the timing at idle to 6 degrees (per the label on the hood's instructions). Turned out that you guys were right to suggest that I check the timing--it was set so far off that the mark on the crank showed off like an inch off of the whole timing plate (mabye like 24 degrees or something).

Setting the timing to 6 degrees lowered the idle quite a bit, and by the time we actually had the timing set, the engine had been running long enough to get up to 220 degrees--higher than I'd like to see it, but not high enough to make me want to shut the car off (I'm still shooting for a good solid 20+ minute run). At this point, the driver's side fan has been running the whole time, and the passenger's side fan has been off the whole time. My dad starts trying to rev it up in quick bursts at the throttle, and we notice that the engine has quite a bit of delay in actually pulling up with the new "correct" timing set.

Anyways, it's not running perfect at this point, but I've got something to work with. Of course, this is when the weird stuff starts happening... first of all, out of nowhere, the only running fan decides that it wants to shut *off* as the temperature hovers around 220. So I go to look at the temp gauge in the car as my dad tells me this and I notice that it slowly starts to climb up from 220. As if that wasn't enough, at the same time, the engine idle speed starts getting lower (actually, it goes into the proper idle range of ~700 RPM). Seemed odd, so we check the timing. For some reason, the timing decided to go way up to 12+ degrees. I have no idea why. So my dad starts trying to rev it up again, and surprisingly, it seems much more responsive (no delay like there was).

But, at this point, remember that the fan has shut off. So I check the temp gauge, and it's approaching the redline. That's when I decide to shut it off and put a box fan on the engine again and quit for the night.

So, I don't know what the heck just happend. All I want to do is get this engine to a point that I can work with it, but having it overheat in less than ten minutes is not very conducive to letting that happen. I do think that those of you who suggested that I check the timing were right in suggesting that. So in that regard (if that was causing it to heat up very quickly), me setting it to where it should be should have (theoretically) helped. But then again, I don't know what happened with the timing all-of-the-sudden deciding to change quite a bit on me in the middle of no where. I'm sure that it was probably just the computer doing some of it's magic, but I'd still like to know what was going on and if I did something wrong.

Also, even if the timing has been corrected and that is not contributing to heating issues anymore, the engine will still overheat if the fan keeps deciding that it wants to turn off as the engine gets hotter. That's probably a different issue, but it's still keeping me from getting this car on the road.

So, do any of you who are wise in the ways of engine timing/computer controlled engines know how to make sense of what just happened?

I really need some help here if possible, because I don't have the money after this expensive rebuild to take it somewhere and have it looked at so, as per usual, any and all suggestions are appreciated...

jimmy_mac

Sancho, this may sound way off but I have been breaking in my new engine this week and had similiar issues although not as bad. The engine was heating up quickly to 220 with a 160 stat and both fans running. I made sure timing was right and that the cooling system was working right but it still kept getting warm quick and staying there. I was also having weird idling issues. I read a couple of posts about adjusting valve lash while engine is running as opposed to the tdc method while it is not running. I took the valve covers off and put the shields on the rocker arms to block the oil and started adjusting. I was way off on at least five valves (to tight). I kept checking the temp to make sure it was not overheating as I adjusted and the temp which had gone up to 200 started dropping.

Just something to think about. Good luck.

sancho

jimmy_mac: I think I'll put that on my list of "last resort" items in case none of the other things that I should check don't work. I like the idea of doing that (as opposed to doing it with the engine off like I did), but I soooo don't want to have to take the valve covers off (mabye not so much the driver's side, but the passenger's side will surely be a PITA). I've actually seen posts about doing this, too, but I'm wondering if all of the guys that have tried that are probably using carbed engines--I wonder if mine would even run with all of the stuff that I'd have to take off just to get to the passenger's side valve cover.

When you did it, on what kind of engine did you adjust the valve lash on?

jimmy_mac

It is a carbed engine and the passenger side valve cover is a lot easier to get to now that it is that way. Even with a lot of that stuff not there it is still a pain to remove with the heater hoses and wiring to the alternator in the way.

If you feel confident with the lash adjustment you made with the engine out of the car then it may not be worth the pain. I can tell you where I went wrong. After initially setting the lash I double checked it on a few valves and tightened them down more. I'm betting bleed off occured causing me to think I had not tightened it enough. So I ended up about 2 full turns to tight.

Any way, if you don't feel 100% confident the lash is correct it will at least give you piece of mind. It feels good to here that smacking sound and tighten just enough to make it go away and then a half turn. It especially feels good if you where off like I was and suddenly your engine starts behaving.

I don't want to send you on a wild goose chase or anything, just want you to try and help out if I can. And some of the basic things that can cause those intial start-up problems are timing, incorrect spark plug wire location, air bubbles in the cooling system and incorrect valve lash. I'm sure there are many others but it sounds like you have checked quite a few. I know that feeling of putting all that work in and then having it not run right. But I also know that feeling when it finally does. It's worth it.