Hello i'm new to this group, and i'm also only 16 yet on my 2nd IROC-Z i was wondering is there anything in the vin number that will tell me if my camaro has a true HO motor in it? Its an 86 5-speed, thanks!

 

Welcome and congrats on your 2nd IrocZ. I had to wait until I was 30!!!!!!

Regarding your VIN and engine . . . it will tell you exactly what engine your ride originally had. Look at the eighth digit. If it's an . . .
H - Then it's an LG4 305 (5.0L) 165hp/250trq 4bbl carbed engine.
G - Then it's an L69 HO 305 (5.0L) 190hp/240trq 4bbl carbed engine. (This was the engine that was referred to as the HO - High Output. It was available only with the manual tranny. However, only 74 were recorded made in '86. It was dropped due to poor reliability issues. Fuel boil problems being one of them).
F - Then it's an LB9 305 (5.0L) 190hp/285trq TPI engine.
There was also an 8, but that was for the L98 350 (5.7L) TPI of which there were only about 50 ever recorded made. You won't have that one. I just listed it for FYI's sake.

 

8th digit will be a G to be a true HO engine car. It should have a dual snorkle air cleaner, electric cooling fan, and 3.73 ratio rear axle.

Very few 5.0L HO cars were made in '86 due to the ongoing heat soak/vapor lock problems that engine had in the F-body. The option was put on hold very early in the model year and then eventually cancelled. The enginneers resorted to putting an electric helper pump in the gas tank, heat shields between the carb and intake, and a small vacuum cleaner motor blowing air on the carb by '86.

 

I think that is a bunch of Hooie, the Vapor lock problem may have been an issue but it was easily corrected by an in-tank Fuel pump pusher...

The true reason why the HO was cancelled was due to Emissions, almost ALL of the 1986's went to Canada (which had less restrictive regulations on emissions than the US) and most of those went to the Players series. I want to think 22 of the 26 Trans Am's were used in the Players Series, and 63 of the 74 Camaro Z28's went to the Players in Canada.

I always find it interesting to hear one thing or another, even things coming from GM which really do not make sence, especially when they had a fix for it...

John

 

GM should have just TBI'd the HO engines instead of trying to keep the CCC Q-Jet on them. 4.3 Caprices were TBI by 1985. That would have kept the L69 around longer and people wouldn't be complaining about the L03.

 

The vapor lock problem wasn't easily corrected by the fuel pump installation. The dealer installed the new in-tank fuel pump in my '83, and it still had the problem. It wasn't happening as consistently as it had been, but the problem wasn't completely corrected.

I'd agree, though, that the vapor lock problem probably wasn't the main reason the L69 was discontinued, that it was probably due to emissions reasons, mostly. But being unable to solve the vapor lock problem certainly gave GM more "fuel" for its decision to drop the engine.

 

My 83 had those heat soak problems as soon as I took delivery of the car. They changed out the carb. It codes out to be from a Monte Carlo, I believe, so it was probably a used one. Didn't help. (Now, I wish I still had the original one!)

Then, they installed the in-tank fuel pump, which also didn't help. Later, I bought the kit with parts for the bulletin that relocates the fuel pick ups in the carb. I never installed those parts as the problem seemed to go away on its own. It has 220,000 miles on it and on a very hot day I might get a hint of stumbling after letting it soak.

I'm glad I never installed the carburetor fan. Talk about a pound of cure!!!

Larry

 

I have a theory that the 5.0L HO engines heat soak problems were more caused by the electric cooling fan calibration The engineers spec'ed out the fan ON temperature at 238 degrees and the OFF around 220 degrees. I don't know why they ran it so hot when the early LG4 cars with the belt driven clutch fan run around 200-210 degrees and don't have vapor lock issues.

I don't think its a coincidence that a year after the LG4 gained the electric cooling fan, it also got the in-tank pusher fuel pump to prevent vapor lock issues.

 

Holy hijacked thread Batman...did Joshie_Love ever find out if he had a H.O. in his IROC?

I know he hasn't replied but I am sitting here punch drunk from exhaustion and thought it was funny how the topic went off on a tangent.

Mike

 

Went from History to Engine tech and no mods to be found!
Interesting topic though.

 

sorry for the long wait! my boot files crashd on my home computer and finding time to get on another has been hard but ill get back to you guys as soon as possible and let you know! thanks!

 

I know this getting further from the original subject, but where can I find a fan temp switch with a lower temperature setting? It's for my 83 L69.

It's been a while since I last looked, but it seemed that there was always a thread size or a connector style issue that prevented me from installing one. I don't want to modify anything to do this.

Larry

 

Well it is actually an H! The only reason i wondered was due to the "5.O High Output" badge on the back, but i just wanted to clear it up! Thanks

 

I have seen several cars where the original owner stated that the car came that way from the factory... I suspect that a dealership may have ordered the car and then when they got it or half way thru the order process it was cancelled, then someoen either on the line decided why not? its a sticker, or a dealer may have put it on the car.

John

 

Good thread! As far as incorrect badges / decals go, part of mine came off the line wrong. One side said 5.7 tuned port injection the other just tuned port injection. When I had her repainted I didn't think about that and the body shop arbitrarily put 5.7 on both sides. Placed the stripes upside down too - damnit.