Very bad day...valve and piston sources needed

Looks like you need to get to the bottom of the trouble before worrying about pistons or valves.

 

Im not following how anyone could know the extent of damage without going into the engine a ways. You could jump a number of teeth on the belt and still be a long ways from mangling things up. The cam cover needs to come off to verify and/or correct valve timing, and a compression/leakdown test done to determine internal damage. Alternatively you could pull the cams, therby closing all valves and run a leakage test that way.

 

Sorry to hear about this, Blainewest. I hope it's not as bad as it seems.

 

I have a set of pistons being machined up for my engine (ROSS RACING) ... they should be ready fri it's taken them 5 weeks to complete they are STD size + 20 thou they cost me about $1200 the wait is killing me ...... valves i bought from fellow f/chatter louthancomp think he is located P/land origan haven't seen him on f/chat for a while he was pretty good with his prices st/steel 1mm oversize are you going to rebore the engine pm me if you want more info on them

 

How many teeth did the belt slip? Something similar happened to me, partly due to improper belt tensioning. my exhaust valves just kissed the pistons and bent enough to increase the cam-to-shim gap to 3-4 times the normal, but that was enough to take the compression to zero. There is just a slight dimpling on the otherwise smooth piston surface and a slight tilt to the valves. I got my replacements from T. Rutlands although Ricambi has them as well. I crashed the forward bank (5-8) so the engine had to come out. You may be able to get the 1-4 bank head off without pulling the engine. My guess is that the extent of piston contact will tell you how bad it is. You might get an early look with a boroscope, but I really couldn't tell until the head came off and I cleaned off the piston crowns. Good Luck.

George

 

If you only do 1 bank you'll want original pistons and valves, I have nice used pistons (1pc $40) and exhaust valves ($10) but I'm in Europe I'm sure many fchatters in the US have them if they didn't throw them away because many have changed pistons and exhaust valves.

 

And the reason why they have changed their exhaust valves is because they are the sodium-filled variety. They are not bad generally speaking, but if the valve guides wear, they are prone to bending and then shortly afterwards, breaking... In other words, not really a good idea to put those in, especially if the car in question is not equiped with the emissions system air-injection anymore (which the sodium-filled valves were needed for that, to withstand the extra heat generated).

Sorry to hear of your disaster Blaine. I am using Superformance's solid stainless steel exhaust valves. At the time when I installed them, they were very reasonable and no problems since.

 

Dave Helms has the replacement solid valves......

 

Pistons will be the bigger challenge as they are all gone OEM, but as noted tear into it maybe they are just nicked up, no large deal..

You break the set you'll have to rebalance/weigh them ALL......talk to Dave in Colorado.

 

Thanks for the post. Again it shows how frequent belt changing is not a cure to prevent all evils!

 

I was in a similar position with my 308 GT/4. No easy (or cheap) fix; nor would you want one. Mine was even a bit worse, with a bent crank. I ended up rebuilding all top to bottom, and the results were well worth it. Oversized water pump, new bearings, rods, seals, guides, and the works. I sent my heads out to Rob Louthan Engineering (address below). He installed new titanium valves and ported and polished the heads. Outstanding work. I will post pictures. Pistons are available or you can have some custom made. Finding all the right parts is a chore. Good luck in your project.

Robert Louthan.
Louthan Competition Cylinder Heads
6936 Labish Center Rd NE Salem, OR 97305
phone: 503 390 8875
www.PerformanceCylinderHeads.com

 

In those motors bending valves almost never damages the pistons to any meaningful degree. That does not mean it should not be checked. If the piston recieved any damage of the type that can happen in that scenario it will show as a cylinder sealing loss. Doing a leak down test with the head removed is easy and should be done in any event where the heads are off.

 

No but careful inspection of those lower drive bearings is part of a belt replacement job and when done properly eliminates failure in most cars. The lower drive bearings got a redesign during the prduction run to improve their reliabilty. Failures of them in the BB's, GT4's and early GTB/GTS was a known problem to those of us that have been working on them since they were new cars. The problem is bad enough on the BB's because of the 50% greater load they are under that I change them on most belt services on those cars. I do not how many miles were on those bearings and how many belt jobs that have passed but those cars are precisely the reason many of us that have been doing them a long time have long had the special tools to replace them in the car.

 

It sounds like you might get by just fixing the rear bank. Your pistons are probably okay. If you can fix the drive problem "in the car" and reinstall the rebuilt head, you could be back on the road soon.

 

Got your pistons and rods (a matched set) right cheer.

1978



Edwardo
Los Osos, , ,in CA
Image Unavailable, Please Login

 

Really? How do you do that? I have seen how it's done with the head on the block.



BTW I like your "New Avatar" with FNA.

 

Big piece of aluminum plate???

Rifledriver, it's really great to see you back!!!

Birdman

 

Good point.

 

http://www.superformance.co.uk/a-308/eg.htm

bought my Dino Pistons here a few years ago.

http://www.superformance.co.uk/a-308/ech.htm

valves too.

Not a specific referral as I didn't buy 308 stuff from them, but, I've had a ton of luck over the years with their parts for my Dino.

DM

 

I'm curious how many shops actually have these tools or ability . . . I encourage you all to ask this question specifically . .. I know when I droped about $6k on a major back in '96 I still had an oil leak coming out of one of the drive gears which upset me a lot after dropping that much dough . . was told there was no way to do the seal from the outside . . the motor needed pulling and tearing down to fix it so it's not like they could do it while they were in there (edit: I was staring at the drive pulley when he told me this with the engine in the car) . .. obviously BS but I didn't know any better at the time . . . and I trusted this guy 'cause he is/was the San Diego area guru . . . ask your mechanic if he can do this procedure with the motor in the car . . .some of you are gonna be in for a big surprise I think

 

Was it "B"?