c130vetret

I'm thinking I may have to swap motors at this point, but I'm still not sold.I just moved home after being medically retired from the Air Force. I bought an 86 Iroc-z (my dream car t tops and everything). The prior owner had rebuilt the engine 305 (bored .30 over, with a pretty mean cam from the sounds of it) and transmission, but it was having overheat issues. I started it and ran it and didn't notice anything too serious, but I can't be sure the gauge cluster wasn't hooked up.

After towing it back, and dropping it off at the local shop, it's like no one wants to break into it, they keep saying it needs a new motor or rebuild top end blah blah. I'm leaning towards doing a 350 swap, but I'd like to keep the 305 in there and take the time to build a 350 right. Obviously if the gauges aren't hooked up. whoever reinstalled that engine after the rebuild missed some things. I was hoping if I give you what happens you might be able to do a quick trouble shoot since everyone here seems to have pretty good knowledge, even on tpis.. I was a heavy aircraft mechanic in the Air Force but I'm lost on trying to figure out the car stuff.

The car cold starts pretty hard, but once it gets warmed up seems to run fine, but if you drive it just 2-3 miles away from the shop and back, it overheats like crazy and starts dumping anti-freeze into the overflow bottle with some extreme pressure. They have not looked into it too deep and I can't really get anyone willing to break into it. I'm hoping it was something as simple as a timing issue or something wrong with programming after the engine rebuild, or possibly something didn't get hooked up correctly, but like i said, noone is putting any effort into looking into it. I did notice one wire coming off the top of the block at the back just plugged with a bolt. They did tear out the heater core/ac unit as well. It also looked like (to my limited knowledge) what was the smog wire is just hanging out not attached to anything.

I do have to say after driving it the 2 miles, when I did a further inspection inside I did notice there was no fan hooked up to the radiator. I know this could be a huge issue if it was idling a long time but I literally started it and drove in all under 10 minutes. I know the fan doesn't help the over heating but I'm pretty sure this issue isn't that simple. The coolant was just boiling and had so much pressure
going into the overflow bottle.

I have looked it over and over and see no leaks of any kind anywhere. Other than when it runs and overflows into the bottle, no fluid leaks.
Before I scrap the motor and swap, do you know anything that could cause this issue that might be a simple fix or something overlooked when they reinstalled the rebuilt motor? I'm hoping it's something simple being overlooked, because I'm trying not to dump too much money into this car yet, as my wife and I closing on our first home back home right now.

Thanks a ton for any help!! I want to get this baby on the road,
I've ALWAYS wanted one.

c130vetret

Oh yeah, if I need to, I have a 350 out of a 89 suburban with only 79k miles that I can pick up for less than 600$. But after the install and anything needing to be swapped, I'd like to just keep the 305 if at all possible and build that 350 over time, rather than just slapping it in stock out of a burban.

gmstrong

Skip on that burban motor you wont be happy with it get a roller block you can drill tap it but i wouldnt.Hows your rad look?

c130vetret

You're the second person to tell me the burban motor would be bad. I guess low HP plus TBI = not worth the $$. I just want something with a little power and kinda loud.

The radiator looks brand new, and as far as what I was told from who I bought it from, it is new. Like I said the fan wasn't hooked up, but for the short amount of time I ran it I don't think that's the issue. The pressure/boiling anti-freeze dumping into the overflow was pretty extreme.

As far as I can tell I don't think it's a blow head/gasket, but I could be wrong. The oil dipstick showed full and there wasn't any other fluids in there that I could tell. The mech looking at it refuses to really "look" at it and just wants to engine swap.

gmstrong

Must be the water pump then.For 600 bucks you get a LT1.Ive had a tbi350 strong motor never left me on the side of the road had great torque but fall on its face after 3500 rpm.

TTOP350

iTrader: (8)

The 89 350 should be setup for roller. remove the valve cover and look down the pushrod slot and see if you can see the roller block machining.
I wouldnt use the cam or the heads.
your overheating can becaused by a bunch of little things.

c130vetret

this is on craigslist near me. But the post kinda scares me with the way it's worded, I don't want to drop $$ on something that's not going to run.

http://saginaw.craigslist.org/pts/2895093783.html

from looking at it in the pics, it looks like it would line up with my current tpi, but I'm not sure if that 95 lt1 would match. thoughts? I'd still honestly like to figure out whats wrong with the current 305, I mean it seems like it could be some simple fixes really. I'm just getting lost as far as what to do.

Since I just got medically retired, and my wife and I are in the process of closing on a house, with the down payment and everything, I can really only afford 1300-1500$ into this right now. I could push to try to throw in 2000$, but either way I'm trying to leave myself room for expenses with the house that might pop up.

InfernalVortex

iTrader: (4)

If you get teh LT1 make sure it has the "5.7" stamp on the back of it. They made a 4.3L LT1.

Non-roller, 1pc RMS didnt get machining on the top of the lifter bores for the dog bones to sit on them. Im not sure how big of a deal this is in practice if you were to try to convert it but it's the reason I never messed with it.

grumpyvette

c130vetret, where are you located? that sounds like a fun problem to diagnose , if your close to loxahatchee fla, maybe I can help,obviously you need a working fan so thats the first area too get working, and ID replace the T-stat and verify the coolant flow thru the radiator, theres reverse flow water pumps available for chevy and you would certainly not be the first guy to install the wrong pump or have a defective t-stat either,if fixing that doesn,t fix the heat issue , if the fans not the only problem, ID start by doing a few tests like a compression test,test for vacuum leaks , verifying tdc and ignition timing and checking for exhaust gases in the engine coolant, because the most likely cause of your problems symptoms are related to bad timing or a leaking head gasket,or cracked head(s) or block, a few tests will let you know where to look further.
you can,t make reasonable plans with out knowing the FACTs and you won,t know the facts without testing and verifying.
a simple step back and check/ test, the function of each potential problem area ,in each engine related system logically before jumping to conclusions, approach will get you running in short order


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gmstrong

[quote=InfernalVortex;5210987]If you get teh LT1 make sure it has the "5.7" stamp on the back of it. They made a 4.3L LT1.


Very good point.I always forget those.

lemons racer

No offense intended but if you can't figure out an overheating problem, do you have the skills for an LT1 swap.

Get your fan working, have the rad checked at a rad shop, try the blue fluid (carbon dioxide test) ether at a shop or buy the kit from a parts store, if the blue fluid turns yellow you have a leak- head Gsk. or cracked head. Make sure you have the proper water pump, some people have mistakenly installed CW for CCW or visa versa, ether will bolt on. Make sure the thermostat isn't upside down which is another easy Bozo problem.

I didn't check any of the threads so you may already have this info, hope I helped.

305sbc

iTrader: (3)

#1 Take to a different shop that isn't planning to rape you.

TTOP350

iTrader: (8)

I've only pulled out 1 TBI truck motor that wasnt setup 4 a roller cam and it was a very early 87 350?? Every other one I've seen is machined for roller.
Maybe I got lucky but I doubt it, I've seen a ton of them in the junkyard machined also??

Skip the LT1. not worth the hassle.
I also vote to take it to a different shop.

305sbc

iTrader: (3)

Last 3 truck TBI engines (L03 & L05) I saw 88 - 91 were flat tappet cams, - unfortunately for me.

I could've used another roller block.

c130vetret

I'm definitely not planning on doing the swap myself lol. Like I said I'm a medically retired Aircraft mechanic. I know next to none about tearing apart or matching up correct years/parts on car motors. I'm definitely not dealing with that shop anymore, and I'm not keen on that 350 anyways.

I did check the oil like I said, and no discolor or anything. I know I should still get the rad flush and tested, but if it was cracked head/gasket would it not have coolant in the oil as well? I'll know more about the issue tomorrow after I bring the car home and have an experienced friend actually look further into the cooling issue.

He was unavailable last week when I got the car, and I thought that the shop would actually take a look into it instead of just saying swap it.

I was able to locate a pretty built 355 4 bolt, and my friend is doing some checking to see if we can make it fit. It's just a hair outta my price range, but it's definitely what I'd want in the long run. I was told if everything lines up and it will fit, that I don't want to stay with TPI though? They were saying this will severely limit the HP of that built 355, is that true? If i go this route, what all would I have to change?

this is the info of that motor.
"350 chevy 4 bolt main .030 over, machined block, trick flow heads with 64cc chambers/ 180cc runners, elderbrock intake, balanced rotating asembly with flattop pistons, 10:1 comp ratio, hevy duty flywheel, fluiddamper balancer, aluminum roller rockers, comp cams 270 magnun cam kit, high-vol high-pres oil pump, holley fuel pump, aluminum valve covers and timing cover, new k&n air filter.all arp bolts and studs. no carb, accel distributor and new 8.8 wires"
He want's 1300$ for it. I've talked to him, he seems pretty decent, might be able to talk him down.

The current tranny in my car is a 700r4.

Thanks for any help on this guys. And I'm learning a ton already, this is why I bought the car, . So call me a noob if ya want, but everyone starts learning somewhere.

Edwardgp

I had a 350 in my third gen for awhile with the most rad cam and had the over heating problem. Checked the cam specs and she was good from 2000rpm to 8000rpm and yes it did sound good but was just for dragging. Pulled motor rebuilt it change cam no more overheating.

TTOP350

iTrader: (8)

Yeah the motors were flat tappet cams but were machined for roller. Atleast the ones I saw were..

Edwardgp

Yes Sir just thought I would tell of what happened to me.

c130vetret

Do you think they built the 305 that's in there too big? What would fix the over heat problem. Maybe it was just built for a drag style I'm not sure. (I know the kid I bought it from lived right next to a 1/4 mile speedway) We haven't pulled it apart but like I said the cam in there has to be large because this thing for the small amount of time it starts up and runs, sounds like a monster. Lol. and it cold starts just like any drag car I've seen at the tracks, takes a good 3-5 minutes to get it started and warmed up. and as far as I can tell it idles fine, but if you start to put it in gear unless its getting a lot of gas, wants to stall, and then after the 2 miles I drove it away and back to the mech shop it's at, it overheated like that.

EDIT : Thought, I wasn't getting on it at all during the 2 mile drive, just normal driving up to 55, then back to the shop. So it's overheating with very minimal stress/time running.

TreeFiddy

You can drop in all the 350's you like, but if you don't fix this it's going to continue to overheat. Without fans, mine will overheat from dead cold within 10 mins.

lemons racer

As far as getting coolant in your oil, a split fire ring (part of the head Gsk) or small crack in the chamber won't affect the oil, that would occur if the head Gsk was completely blown out filling the cyl after engine shutdown, which then would drain past the rings into the oil, also if that occurred the engine would hydra lock causing more serious problems like a bent rod or broken piston when you cranked it over.

Quit trying to guess your way through it & have your friend (hopefully a professional mechanic) check it out. Other wise find a reputable shop. Remember its just a car, nothing magical, just mechanical.

InfernalVortex

iTrader: (4)

Did you note the machining on top of the lifter bores? Have you actually converted one over before? I could never get an answer to how important that machining is. It gives teh dogbones a place to sit on top of the lifter bores.






See the difference?

TTOP350

iTrader: (8)

Yup, I know the difference. They were machined. I'm always looking for them.
Whats the date on that non machined block in the 2nd pic?

lemons racer

Don't forget to check the cam lock plate bolt holes also, not a big problem just another point to look at, on my current roller I'm putting together I had to file the block cam plate surface flat, it was slightly convex causing the plate to warp & bind up the cam. Always check the details. I also had to shim the crank gear forward .015 to line up with the cam gear, sloppy factory tolerances.

Fritomaster

When i got mine the heater core leaked bad and the car over heated in 2 to 3 miles....
I bypassed the heater core and had no thermostat in and it would run cool, I added a thermostat and it would get hot fast I fixed the fan and now it is low temp after a 2 hour drive.

naf

iTrader: (7)

Before doing anything else, replace the radiator cap. They're a common wear item and when they fail they will bypass coolant into the overflow below their rated pressure.

Fix your fan. It will overheat fairly quickly when driving below 45 with no fan.

If your TPI runs with your cam, it's not too big to cause overheating issues.

I'd recommend you take the time to fix, and figure out, what you've got now before trying a swap. You can't own one of these cars and expect mechanics to help you. Most won't have working knowledge of these older cars and it's not often worth their time to put in the troubleshooting hours necessary compared to the book rate they get on the newer stuff. Many are also hesitant to accept the work because of the high likelyhood of additional broken stuff on the vehicle that keeps bringing the customer back because it wasn't 'fixed'.

Once you get the fan fixed, do the regular tune up stuff: cap/rotor/plugs/wires and verify your timing. Change all of the fluids (rear end too). Treat it as if the previous owner did none of this. Do it yourself so you KNOW it's good.

Zaar

Ok,
ive had many overheat issues in the past with my tpi due to my earlier no experience days and not having many other friends around that had the knowledge about my iroc so lets go with my 15 years of trial and error ok first off the oil coolant lines from the oil cooler hoses near the oil filter if one is blocked or not circulating there is an issues also the plastic valve tee on the top of the engine is also another issue have your thermostat been replaced or removed temporarily to see if the overheating issue is cleared also replace that rad cap, if its dumping lots of antifreeze into the overflow tank then there is a lot of pressure?! is the water pump operating properly? this is all cheap easy stuff, hook the fan back up! these cars need to have a fan regardless of anything especially if its overheating dont cook your block! also check the relay to the fan to see if the fan is even working with the temp sensor to ecm i have no clue what this engine is. is it tpi or tbi ? i didnt read through all the posts but whatever the issue i doubt a rebuild or engine swap is necessary unless someone was tinkering around which i always hate playing with other peoples projects since you dont know what they did! ok so remember if this engine is computer controlled it needs to be in closed loop operation based on engine temp to operate properly dude i cant give you exactly the issue without diagnosis with the car in my hands but ill help you best i can once i get all the info shoot me a message if you still cant get this figured out ill tell you what i know...

c130vetret

Thanks so much guys, the last few posts were really informative, and I'm going to try just replacing everything cheap/simple as recommended. water pump, radiator cap, distrib cap, plugs/wires. My buddy that has the knowledge is going to be looking at it with me this evening, but just in case, does anyone know where to get diagram for the tpi?

Zaar it is TPI 305. The problem is that it was a project car when I got it. It's bored .30 over and has all after market heads, cam (sounds large, it's very loud when it runs), aluminum tappet covers. It looks clean, I just really think somewhere along the lines they messed it up. I'm not sure if it's something they did or didn't hook up right when reinstalling, timing or what. If you rebuild the engine with all that after market stuff, does the chip/comp need to be updated to reflect? Like I said as far as myself and a few other ppl that have looked at it, thinks it's something simple. The engine after warming up runs/sounds strong as hell.

I'll have more info hopefully tonight after playing around with it a bit with my more mechanically inclined friend, and replacing some easy stuff. That way It'll be noob proofed (sorry my first work/project car) so we can isolate if it's something more serious. I should have more info tonight/tomorrow, and I appreciate everyones help/input with the issue. I'm glad to even have this car running or not, it's the exact year/make I've always wanted, 86 iroc-z w/ t-tops .

InfernalVortex

iTrader: (4)

Do the simple stuff first! Thermostat, rad cap, water pump. Run the car up to temp, feel both radiator hoses... are both warm? Dont worry about the cam making it run hot, Im not sure I've ever heard of anything like that. Timing being off can make it run hot. MISSING AIR DAM can make it run hot. FAN BEING OFF can make it run hot. STUCK THERMOSTAT can make it run hot. WRONG WATER PUMP can make it run hot, etc. Make sure your fan(s) are working when it gets warm! Are you losing coolant or is the coolant level staying stable? Thesea re things you need to know. The coolant system is NOT complicated. Just, as grumpyvette says, be methodical and take care of things in a logical, thorough order and be done with it a lot sooner. Stop worrying about the cam or whatever. Worry about the coolant system.


I have no idea to be honest. It's the one in the car right now, but I never really cared what year it was. Now I wonder if it was a really early one.

If most of them come machined for dogbones, then the conversion would be pretty easy. I will look for more truck blocks in the future then, just gotta check the valley first!

c130vetret

Update! I towed it over to a REAL mechanic who has a passion for hot rods. He took a look over it, and says whoever installed the motor after the rebuild have the wires all the hell over the place. BUT, there is a missing sensor, that's especially important for idle/timing I guess. He said he's got a wiring diagram and he's going to completely rewire all the junk they did, throw in the sensor and install my dual radiator fan with a temp sensor + switch, just in case. So hopefully this fixes all the issues in one, if not, more troubleshooting to come :P. Thanks a ton guys sorry for all the