Shvhd

Has any one out there ever mounted a electric pusher cooling fan on a 65 BB vette. There are 2 cross bars welded to the radiator support & the fan would have to be mounted a couple inches away. Reason for this is I want to keep engine bay stock but it runs hot if I get stuck in traffic or on line to get into a show.

Nowhere Man

Have you checked with a IR gun to make sure it is getting hot. The gauges were never known to be right 100% of the time. Do you have the timing and vacumn advance set correctly? How new is your rad and or coolant

Shvhd

Rad. is a fairly new alum. Harrison, Electronic ign. no vac. adv. timing is good.car runs at 195 all day except when I'm stuck in traffic. It will go up to 215-225 & start pissing out the overflow hose. Correct BB fan blade & new clutch. I have a pusher fan & electronic thermostat for it & was just wondering if someone has mounted one in front before.

Bluestripe67

I don't think Harrison has made a rad in three decades. Is your NOS or used or a DeWitts correct reproduction rad. Running a distributor without vacuum advance can contribute to over heating at idle/slow movement. Address that, and you may not need to install a fan. Dennis

JohnZ

Your timing CAN'T be good with no vacuum advance, which is contributing to your low-speed/traffic heating issues. Read these two articles so you understand how your advance systems and your cooling system works so you can diagnose and maintain them properly.

http://www.camaros.org/pdf/timing101.pdf

Mike7061

If everything is set up properly there would not be a overheat problem. I have a 67 with 540ci ultrastreet and 650 hp, BB 7 blade fan and HD clutch and it runs cool as a cucumber. listen to John Z and learn.

G

Nowhere Man

there is a reason GM spent the extra dollars for all that stuff. and spent count less hours engineering and testing everything.

DansYellow66

Another vote for vacuum advance. Made a huge difference on my 427 operating temps. Night and day difference.

0Tom@Dewitt

John is dead on correct. Ebay that distributor

Shvhd

Base timing is set at 12degrees 38 at 2500. Distributor uses mech. adv. only. Not the original motor 71 402 mild hyd. cam idles at 800 rpm no problem. Vac. adv. is not going to change my base timing at idle & this is the only time I see a problem. I've read where a mixture of water & coolant should be used instead of pure coolant. Maybe a 180 stat instead of the 195. I'll hit it this weekend with a IR gun all over the radiator & motor to get a correct reading. Thank you all for your input.

Vet65te

Vacuum advance won't 'change' your base timing but will at least 'add' to it at idle and that's what the previous suggestions were leading to. Add in say 15 degrees to your base 12 and at idle your engine is now seeing 27 degrees, give or take. Might help. Also, with a strictly mechanical advance distributor, is there any chance that your springs are soft and the weights are already moving out at 800 rpm, meaning your base 12 degrees might actually be affected by the mechanical advance? If you were to try to drop the idle rpm to 650 is there any change in the 12 degrees you're seeing?
Mike T.

Shvhd

I'll check that out Mike. Correct me if I'm wrong I've never seen a 60s car using manifold vac. they were all using ported vac. to the adv. unit. Not until the 70s did I see a change. I put a vac pump to the adv. unit & its no good. I'm going to replace it & try it. Thanks Mike

wmf62

yes, you can add a pusher for extra air flow at low speed. just space out the fan mount so that you clear the x-brace and allow ambient air to flow around the side and into the radiator when the fan is not running/needed.

the pic is the way i spaced out my a/c condenser but it will give you an idea how you might go about spacing the fan out.

a word of caution size the overall diameter of the fan acording to how low you can mount it and still be able to fully open the hood. mount it too high and i may hit the front edge of the hood when fully raised.
Bill

wmf62

ported vacuum is mainly for emissions purposes and definitely hurts an engine's performance. 'can it' (pun intended...)
Bill

JohnZ

You haven't read either article I posted, have you? The "Ported Vacuum" aberration is covered in great detail in the second-to-last paragraph in the "Timing 101" article, entitled "Ported Vacuum". Vacuum advance was controlled by full manifold vacuum for decades until "ported" vacuum became an emissions "band-aid" in the very late 60's, when A.I.R. systems tried to do what catalytic converters did later in the 70's.

I hope you're not running straight anti-freeze (unless you bought it pre-mixed); anti-freeze should always be mixed 50-50 with distilled water (that's in the other article on Corvette cooling systems, on page 2).

ghostrider20

You should have around 30 degrees of advance at idle (with vacuum advance hooked to a full vacuum source). Your symptoms are classic of not having a vacuum advance can.

Your current setup is fine for a race car, which gets trailered to the track, per-heated, raced, and trailered back home.

Read the articles JohnZ posted and then send him 10% of the money you would have wasted over the next two years trying to fix ths problem.

Shvhd

Going to dump the coolant next week & repair vac adv. I'll let you know. Going to read that article now. Thanks

0Tom@Dewitt

John,
I find it odd when people are looking for answers that they will never leave the forum website to read links that are posted. So often I post a link that answers someones question only to have the thread continue as if I never posted anything. I guess that comes from half the posts being out in left field and trying to sort out the facts and BS.

BTW, we now have added a downloads feature to our new website and your articles are there for all to reference

http://www.dewitts.com/pages/downloads

And I have a running blog going with some of the FAQ
http://www.dewitts.com/blogs/news

Shvhd

I just finished the article, thank you. Back to basics sometimes you look so deep into things & its the simple things you overlook. Working 2 jobs & owning a shop there's not enough time in the day. Built & owned lots of cars in my time but this is the first C2 I've ever owned. Thank you all I do appreciate everyone's input. I think I need a vacation.

Nowhere Man

that article is just not for mid years. you can use it for any older car and it will hold true