78SC ROW - Starter Problems (Heat soak) - steps to resolve

[acapella8]

Background:
78 SC, ROW with SSI's. 120k miles - original bosch starter/solenoid.

I never had issues with my starter until a few weeks ago when it topped 95F and I was on "staycation" wanting to make some good spirited drives.

Starter spins and engages fine every "cold" start (no problems)
Starter spins good each time after some runs, but after heatsoak does not engage (problem)
Did a voltage drop check and the starter is pulling a good load (my wiring is good)

I believe my issues are with the solenoid. - BUT -

See picture attached and you'll see where I'm going. . .as it looks the exchanger is just dumping the starter with nice humid dog days of summer heat...

A. I never had the "hoses" running from the top of the heat exchangers installed to the bottoms of the heater/flapper boxes... (I don't want to install them unless I determine I must) Do I need to have these installed?

B. Before replacing solenoid, I wanted to try some insulating "header tape" (rated to 1500+ deg F) to see if I could keep the starter solenoid running cooler. I will report results.

Questions:
1. Are there any write-ups on just replacing starter solenoid?
2. Looking for advice on using header tape to cool off starter and surrounding areas

Any other advice would be appreciated - thanks for reading guys.

(excuse the crappy pic/job of tin/heater tape but I didn't have the header-tape yet)

[Joe Bob]

Probably the solenoid.....needs a lube job or replacement. Dielectric grease tends to get sludgy after 32 years....go figure.

[acapella8]

Thanks - Do you guys have any input as to if running with NO hoses is OK? As stated, I plan to use the the hi-temp header tape to tape off the starter area and keep starter/solenoid cooler...

Question - would my blocking off the top of the exchanger create any unwanted effects?

[john walker's workshop]

silver heat blanket double wrapped around the whole unit and secured with zip ties may work.

[acapella8]

Thanks JW. Your posts have helped me a great deal with this SC. No harm in running the exchangers w/o the hoses you think?

[KNS]

The heat in those exchangers needs some place to go otherwise you've got unwanted heat trapped under the engine.

[acapella8]

Both JW and Kurt are correct...

Last night I started her up (cold) and no problems as expected in a test to get her good and warm to see if solenoid would fail to work when heatsoaked...

What I learned:
The exchangers cannot be covered the way I did with the "tin-tape". After about 5 minutes smoke started exiting the top of engine compartment, and specifically from the fan housing/alternator shaft area. It quit after 5 minutes, but I had a burn/tin smell.

Sure enough, I think it was burning the adhesive on the "tin-tape" that was created smoke and smell. I removed hoses from my back-dated heat and additonal smoke billowed out. (tough to see in pic, but it was thick...)

I have a hi-temp (2000F) blanket on order that I will wrap the starter/solenoid (per JW's post) and I will install hi-temp silicone hoses from HE to flapper-boxes per Kurt's thread.

(I know I could just get a new Hi-Torque starter, but I'm trying to avoid that at this time due to additional project expenses.)

[john walker's workshop]

yes indeed, gotta have air flow through the exchangers to minimize the oven effect.

[Eagledriver]

Just install the hoses that belong there. The way you have it now there is a massive amount of air flowing through the heat exchanger and onto the starter. If you hook up the hoses there will be a restricted flow out of the flapper valves. This will also give your cylinder heads more cooling flow. All of this may not help with your starter issues however. I think I'd just spring for a new/rebuilt unit, that one doesn't owe you much.

-Andy

[acapella8]

Well, I installed a double-wrap high-temp (2K+ F) wrap, and installed new hi-temp flapper-box hoses.

Took the 78SC-ROW for a VERY high spirited drive, got her to about 200F by the temp gauge, and shut her down. Started RIGHT back up. No issues. Waited 15 minutes, started right up. Waited another 15 started right up. I think I have the issue solved.

I strapped them with Zip wraps, but will use some stainless steel wraps this weekend, now that I know everything is working as expected.

I got VERY familiar with how to "bear-hug" my 915 trans....

And YES a hi-torque is only approx 150 + time to install, but this was a good fix for me...