Jump to content

GM 4.3L V6 care and feeding


The Arp

Recommended Posts

Yes I understand it is a terrible engine.  What does it take to keep on alive for endurance racing?  

 

I'm mainly concerned about oiling.  I plan on using a astro van steel pan as it is the best fit . Any oil pressure issues?  I was planning on running an oil cooler but there is a non trivial amount of cost and complexity associated with adding an accumulator.  I'm not super excited about trying to make my own oil pan trap door baffle.

 

Any other things you learned about the motor after running it?  

 

I won't be running it in a truck but a car because I am stupid... and i like building things

 

Thanks in advance. 

 

Edited by The Arp
Link to comment
Share on other sites

We ran an sbc for a few years.  Same engine with 2 extra cylinders in the middle.

 

Don't rev it too high.

 

Make sure there is plenty of oil in it.

 

Add oil pan baffles.  Add an oil cooler and accumulator if you can.

 

Talk to Tacoma on this board.  They have run one for a while with no issues.

Link to comment
Share on other sites

We ran our stock, balance shaft 4.3 motor for 5 races with no engine issues at all. The motor never let us down in any way.  We've never had an oiling issue that we've noticed.   Maybe we aren't pulling enough G's though.   Contrary to popular belief a 4.3 is NOT simply a SBC minus two cylinders.   We've learned that over the last 6 races.  There are MANY iterations and variations of the 4.3 down through the years.  The balance shaft and non-balance shaft engines are different lengths.  Timing sets are different, cams are different, no mech fuel pump boss on non-balance what block, etc  If we had it all to do over again we would run a non-balance shaft 4.3.

 

We've not performed a post mortem teardown since RA17 yet.  But preliminary investigation indicates a broken timing chain failure on Lap 6.  Several lessons learned in this area too.  It was a stamped link chain.  From our research, no one makes a true double roller chain for a balance shaft 4.3.  The chain that failed was the third one we've had in the motor.  The previous two were stretched quite a bit after extended track time.  We rolled the dice on it going into RA17 and lost.  

Edited by Turd Ferguson
Spelling
Link to comment
Share on other sites

Have you been using this set?

https://www.summitracing.com/int/parts/clo-c-3211/applications/

 

The main issue is that the good heads only came on the balance shaft engines, and you can't mix and match without taking points. That being said, porting will help the early swirl port heads quite a bit but it's not a job for someone new to porting.

Link to comment
Share on other sites

My plan is to run a non balance shaft block and I can get double roller timing sets for it.    How high do you rev the motor?  I plan on short shifting in the lower gears but I will be top speed limited if i can't rev it up to 5500 or so in top gear.

Link to comment
Share on other sites

 

 

No, we've used two stamped steel link chains by two different big name brand supplier (not an Advance Auto or Auto Shack brand.  Yes, I realize I dated myself with the Auto Shack reference).  At the time of purchase we couldn't find a true roller timing set.  Possibly we overlooked the unit in your link.  I know a Comp Cams double roller timing set for a SBC wouldn't work.  It wouldn't fit under the POS balance shaft timing cover and the cam bolt pattern was different. 

Link to comment
Share on other sites

Cloyes C-3211, for 92-06:

http://www.cloyes.com/Images/HP_AppPagesB.pdf

 

I'm pretty sure I used one on the balance shaft twin turbo 4.3 I did for a swap into a '95 Camaro for a guy, seems to me I also bought a fresh plastic timing cover for it instead of cleaning the old one. Sorry I can't be absolutely positive but it was about 10 years ago. By application it should fit.

 

That 4.3 made 268 hp and 312 ft.lbs of torque without boost and 469 hp/530 ft.lbs at 9 psi. :)

Link to comment
Share on other sites

 

 

Was the Cloyes C-3211 about the same thickness as a SBC double roller set?  IIRC, the SBC timing set I tried was way too thick to fit under the plastic cover....even if I had fit onto the camshaft (which it didn't).

Link to comment
Share on other sites

 

 

Was the Cloyes C-3211 about the same thickness as a SBC double roller set?  IIRC, the SBC timing set I tried was way too thick to fit under the plastic cover....even if I had fit onto the camshaft (which it didn't).

No, it's a single row roller specifically for the 4.3 balance shaft block with the plastic cover. Might be a good idea to call Cloyes and verify that but I'm pretty sure that's the one I used on the TT 4.3.

 

It has a 1/2" pitch, meaning the rollers are quite a bit bigger than a double row chain for better durability:

clo-c-3211_w_ml.jpg

 

  • Like 1
Link to comment
Share on other sites

While it is possible that a double roller timing chain would be better than what is readily available for the 4.3 you should check out SAE paper 962513. They did extensive testing of different camshaft drives and the double roller fared very poorly in the tests.

Link to comment
Share on other sites

And years later Roush was running belt drives on their clean-sheet FR9 engines. ;) I could only find Hy-Vo for the non-roller block SBC/4.3 application.

 

I run Cloyes double rollers in the road race SBCs that I build. Typically get 20-30 hours between freshening, moderate wear and zero chain failures despite 600 lb valvesprings and 7500 rpm. From my understanding a fair amount of the wear on a chain is from idle and low rpm because the power pulses cause torque reversal, with a V6 being worse than a V8.

Link to comment
Share on other sites

 

And years later Roush was running belt drives on their clean-sheet FR9 engines. ;) I could only find Hy-Vo for the non-roller block SBC/4.3 application.

 

I run Cloyes double rollers in the road race SBCs that I build. Typically get 20-30 hours between freshening, moderate wear and zero chain failures despite 600 lb valvesprings and 7500 rpm. From my understanding a fair amount of the wear on a chain is from idle and low rpm because the power pulses cause torque reversal, with a V6 being worse than a V8.

 

So you have to pull your motor every second race weekend? 

Link to comment
Share on other sites

 

 

So you have to pull your motor every second race weekend? 

No; as mentioned that's for the 650+ hp SBCs and is part of the seasonal refreshing.

 

I have about 70-80 hours of race time on my GM V6 so far and will be checking the timing chain stretch when I get a chance.

  • Like 1
Link to comment
Share on other sites

Checked the timing chain; as I suspected at the end of last year it's about ready for replacement. Not bad, about 3x the life span of the SBC stuff.

 

WIll check the bearings and do the clutch as well when I drop everything out, and it's all going into my DD Fiero. New drive train going into the race car.

Link to comment
Share on other sites

Our new Cloyes stamped link chain had like 1/2" of play in it ~16 hours of track time.  We replaced it with a like for like set and completed the December Chumpcar Barber race last year.  And it broke 6 laps in to Road Atlanta this past February. 

 

Well, we THINK it broke.  Still have yet to tear it down.  But the chicken bones point to broken timing chain.  

Edited by Turd Ferguson
Speling
Link to comment
Share on other sites

Mender, would you happen to know the differences between the two timing sets below?  Other than money....

 

I emailed Summit and of course they recommended the expensive one.  

 

https://m.summitracing.com/parts/clo-c-3211/none/images

 

https://m.summitracing.com/parts/clo-9-3654x3

 

I don't mind paying the extra money but I wanna get the one that fits.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...