Motor is roasty toasty.

Zeke · 07-24-2003, 05:08 PM

Yep, out to lunch. Pulled the spark plugs. Don't even need to consider a compression test. Three really white (too white) plugs and one ghostly grey with metal deposits and oil. The theory on the failure is now running towards fuel starvation. In reconstructiing the circumstances, it may be that the little Facet fuel pump (which I bought used and was going to replace and never did; you know that syndrome?) was not keeping up with the carbs. So, a combination of things, which never makes diagnosing easy, is what caused the piston to melt (no. 1)

The plan: New fuel pump, better and more filters, bigger jets (maybe that was not the real problem) and some new pistons.

The worry: Did the head(s) suffer in the meltdown and am I set up for a dropped valve seat? I guess I'll send them out and see if they can be analyzed for heat stress. That's the most expensive part of the engine, hope I can use them again.

And the ugly: Slight metal in oil. Will have to completely disassemble engine and clean and check all bearings, etc. The oil was clear before the last run and I shut down quickly, but the thing was up high on the RPM and threw out a plume of smoke when it went away, so the oil has been circulated some, I'm sure.

That's racing. I better get to work.

bernbomb914 · bernbomb914's Garage

tough luck Milt. I did the same thing to my motorhome in Colorado last month. should be able to pick it up next week. many dollors later. good luck on your motor.

Bernie

M. Hendrix · 07-24-2003, 06:24 PM

When you get it apart, take some pics?

I'd be interested in seeing what happend.

Sorry man.

M

Toast · 07-24-2003, 09:03 PM

Hope you have better luck than I have had with my 1776 VW engine. Have had to rebuild it twice since January!
Good Luck!

Toast · 07-24-2003, 09:04 PM

Toast's Roasty Toasty engines......

John Rogers · 07-24-2003, 09:07 PM

I was wondering what fuel you were using? If it was 91 octane that could be too low especially in the heat? Also what the compression ratio is since the head temp seems low for what you are running. We had that temp range (325 or so) with my big 4 and kept melting valves and pistons. I had 10.5 c/r and was running race gas(100) with 33 degrees advance total. The Union 76 tech guy and the dyno guys both said the timing was not advanced enough so we bumped it to 38 degrees total and the head temps went to 375 or so but we stopped melting things??!! Seems like the fuel was still burning as the exhaust valves were opening and causing a lean like mixture and resulting problems. We finally got the valve problems fixed for a couple races but tore the top of a rod off at full speed in Fontana and tore out the top of the crankcase! I decided to go with a six finally! Good luck

Zeke · 07-25-2003, 08:07 AM

John, sorry about YOUR motor! My fuel was a blend of leaded race gas and 91 (should have been near 100 octane by guesstimate). Timing was 30 degrees. C/R is 9.5:1. Head temp was 350 ( maybe you misread my other post). Oil was 260. I remember your valve issues, I hope I can dodge that bullet.

Anyway, I'm going to make this an opportunity to go thru the motor and do some things I didn't do the first time. Like insulated carb spacers, Crane ignition, the real deal J & E pistons and thoroughly sorted carbs.

mike mueller · 07-25-2003, 09:11 AM

Ouch... (double ouch in Johns case!!!!)

I hate to read these things, even more so now that my motor rebuild (2.0 /4) is getting even more expensive by the week...

(could have done I six...almost....)

John Rogers · 07-25-2003, 09:43 AM

I'd definately go with forged pistons such as J&E or other name brand. I's also recommend spending the time & $$$ to set things up on a dyno. It was well worth the money when I finally did it and we found that the exhaust temps dropped 150 degrees at the header connection and the temp at the plug went up and power went up 15 HP which was what we wanted. We also ran the rings loose for a little less fricton in the barrels since type 4s do not have oil squirters to help cool the pistons. Good luck

Tom Perso · 07-25-2003, 12:19 PM

Concerning the T4 not having oil squirters to cool the pistons, you can make some easy enough.... In fact, it's a factory bulletin. You just notch the rods at the 12 o'clock position and 'blamo - oil piston squirters.

Just have an oil pump to keep up with it. Consider a 26 or 30mm T1 modified pump to do it.

Later,
Tom

mike mueller · 07-25-2003, 12:26 PM

real oil squirters similar to the 911 motors can be installed as well....

John,

Do you plan on selling your upright fan assembly?

John Rogers · 07-25-2003, 06:07 PM

The big four was sold already for the parts, sorry as the new owner is putting a four back in the famous #22 Yellow IMSA 914. He got tired of big six's being too much for the light weight frame work I guess? The problem was when the engine was stroked, short rods were used which is most always the case with stoker type 4's. Even though they were a Pauter forged set they had 3 years of racing on them which when you squeeze 200 HP out of them was too much!

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Zeke, I would suggest going ahead and replacing all the seats. You're gonna have the heads worked anyway, right? So the extra expense should be worth it just to make sure you don't hole the motor shortly down the road. (Why do dropped seats always seem to happen shortly after a rebuild???)

--DD

Zeke · 07-27-2003, 07:29 AM

No, I wasn't planning on head work. They only have about 1/2 hour running time on them, so they are basically brand new rebuilt. I was just wondering if there was some kind of test to see how hot they got. Now, the temp sender was on the 3-4 side and the no 1 piston is the one that fried. 3-4 showed 350 degrees, no big deal. Who knows what the head on the 1-2 side saw in temp.