spun rod bearing engine #4

[cheaterparts]

Hows your cheater beater, beater engine build going?

slowly but it should be ready before yours - going on your track record , lol.

[2.6_sigma_skidder]

hi guys interesting reading iv had the same problem in my new scorpy skid car iv done two bottom ends in two meets spun bearings all good tips il be trying out on my next build

[81GL]

M8 or 9 are both closed chambers

Picture of the M8 in the Gal


Not sue what determines whether an M8 will be kidney or hemi... no doubt a year model thing (emissions?)

[Rallyant]

You got any pics of the M8 casting marks? and the Gen3 marks. I cant see from the pic.

[81GL]

Please excuse the dust ...goes with living in a rural area.

Not sure what your meaning by "3rd gen marks" ??

Nick.

[Rallyant]

dust is fine
Defiantly an M8, be interesting to see if it has the gen3 marks also. I doubt it.
Im guessing they must have cast both gen2 and gen 3 M8 heads.
The gen markings are in 2 places, but the main one is on the front exhaust side of the head they have a II cast onto it in for the gen 2 and a III on the gen 3 (kidney chambers)
Ill post up some pics when im back on my computer.

[22dodge]

what would really help me is the actual part number for the head. Mitsubishi number would start M with a about 6 numbers. If I could get a part number, then maybe I can get a supplier over here in the the US to get me the part.

[Redzone]

PM sent to redzone


as for M8, I keep getting conflicting stories about them being open or closed chamber. but the consensus is all m9's are.

Did you get my email 22dodge? havnt heard back..

[astronturbo77]

I reckon your big end bearing crush tolerances are incorrect. Has the crank journals been ground/polished? Are you using flexigauge on assembly to check clearances?

[genius]

There is plenty of Information here to assist you in a reliable engine. The issue with the bearings is common. I would use the better pump and the best competition bearings possible. There would be some slight mods to the crank holes with polished chamfers and a mod to the leading and trailing edge of the holes in the crank. A huge cooler is a must and drain back from the head must be an area to address also. Use Shell Ultra Synthetic Racing Oil. Also be super fussy about all the galeries and passages that the oil pass through that they are cleaned and aligned. Use ARP or SPS rod bolts for that extra Insurance that the caps dont walk.

[cheaterparts]

A huge cooler is a must and drain back from the head must be an area to address also. Use Shell Ultra Synthetic Racing Oil.

before using an oil cooler check if the oil is getting to hot, oil below its best temp is just as bad as to high
if you run a good oil scaper the oil will be cooler
and I dont see the need for synthetic oil unless its to make more money for shell

running bearings in an astron is more to do with the sump - not enough oil and badly baffled

as for the drain back my next engine I was going to restrict the rear return so as the oil would not drop onto the crank at the rear of the engine - the reason less oil droping on the crank for less drag and less heat put into the oil
droping oil onto a crank that we use a custom made scraper to try to remove it does not make sence
and if the head fulls any way at high revs the oil must run down the timing cover
so theres plenty of return but about 1.5 lts is filled in the head at high revs restricing the rear return would have this amount of oil in the head all the time while running
with the sump filled to the full mark and the head full of oil to the timing cover it wouldnt drop the level of the sump at high revs

anyway thats what I intend to try - not that I've had any issues with bearings 10 years of racing with an astron ,1 run bearing due to a faulty pump

[22dodge]

my background in engine building is quite satisfactory. I have a large home shop (10,000 sq feet) well equipped . these 2.6 engines have been giving me fits, the last engine made 4 nights racing... but I built another 1qt to the sump and ran 10w30 synthetic. the pan I had came with a lot of baffling all around the pickup, i have a crank scraper, oil restrictor to the head, removed the fuel pump and installed oil return line to the pan and blocked off the rear oil return line.

my other race car is a 1985 dodge shelby charger 2.2 non turbo. it's a top 3 car every week same engine untouched for 2 years. the 1980 dodge challenger 2.6 is a full second off. 5 engines this year. I've put tons of money into this car, including $2000 USD into custom cam profile. I'm 45hp down from the 2.2.