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+--- Thread: Stronger OM606 headbolts? (/showthread.php?tid=8329)
Stronger OM606 headbolts? - AlanMcR - 04-05-2020
Looks like I've stretched out at least one head bolt again. Believe the last set was "VictorReinz". I haven't actually pulled the head off, but the last time, two bolts (between cylinders 1 & 2) were loose to the touch and had been stretched an extra 2-3mm in the threaded portion. The head was flat, in fact it was quite driveable (no leakage) as long as one didn't drive it hard.
This is in the G, which is a tad too heavy for the engine. On long loaded hill climbs it is continuously putting out max power.
Is there a stronger alternative? Other diagnoses? Maybe ease up on the throttle?
RE: Stronger OM606 headbolts? - baldur - 04-06-2020
If you have your head and block separated you can make some measurements and send an inquiry to ARP to assemble a set that will work. I did this for my OM602.
I have attached the measurement sheet that I made for the 602.
Get in touch with ARP at https://arp-bolts.com/p/contact.php
RE: Stronger OM606 headbolts? - zeeman - 04-06-2020
(04-06-2020, 07:37 AM)baldur If you have your head and block separated you can make some measurements and send an inquiry to ARP to assemble a set that will work. I did this for my OM602.
I have attached the measurement sheet that I made for the 602.
Get in touch with ARP at https://arp-bolts.com/p/contact.php
You need to spend the money and buy genuine Mercedes head bolts and torque them using the correct factory method. What kind of EGT temps are you pulling ?
RE: Stronger OM606 headbolts? - AlanMcR - 04-06-2020
(04-06-2020, 07:37 AM)baldur If you have your head and block separated you can make some measurements and send an inquiry to ARP to assemble a set that will work. I did this for my OM602.
I have attached the measurement sheet that I made for the 602.
Get in touch with ARP at https://arp-bolts.com/p/contact.php
Thanks, I'll look into that. Their site doesn't seem very well oriented towards mixing and matching parts for vehicles that they don't make kits for.
As far as buying genuine MB bolts, I'd need to be convinced that they were any better. MB has not always been the best source. Unsure of the EGT, but the first problems happened with stock power on a significantly opened up exhaust. I think the factory was betting on max power being used for passing, rather than 10 minutes of foot to the floor. Engine temp was reasonable 90C-ish until it suddenly jumped. I presume when the bolt(s) let go.
RE: Stronger OM606 headbolts? - baldur - 04-06-2020
(04-06-2020, 01:42 PM)AlanMcR(04-06-2020, 07:37 AM)baldur If you have your head and block separated you can make some measurements and send an inquiry to ARP to assemble a set that will work. I did this for my OM602.
I have attached the measurement sheet that I made for the 602.
Get in touch with ARP at https://arp-bolts.com/p/contact.php
Thanks, I'll look into that. Their site doesn't seem very well oriented towards mixing and matching parts for vehicles that they don't make kits for.
As far as buying genuine MB bolts, I'd need to be convinced that they were any better. MB has not always been the best source. Unsure of the EGT, but the first problems happened with stock power on a significantly opened up exhaust. I think the factory was betting on max power being used for passing, rather than 10 minutes of foot to the floor. Engine temp was reasonable 90C-ish until it suddenly jumped. I presume when the bolt(s) let go.
Yes the web site is not great for that, but if you send them the measurements they will assist you in finding the right parts from their catalogue.
RE: Stronger OM606 headbolts? - NZScott - 04-07-2020
(04-06-2020, 01:42 PM)AlanMcR Thanks, I'll look into that. Their site doesn't seem very well oriented towards mixing and matching parts for vehicles that they don't make kits for.
As far as buying genuine MB bolts, I'd need to be convinced that they were any better. MB has not always been the best source. Unsure of the EGT, but the first problems happened with stock power on a significantly opened up exhaust. I think the factory was betting on max power being used for passing, rather than 10 minutes of foot to the floor. Engine temp was reasonable 90C-ish until it suddenly jumped. I presume when the bolt(s) let go.
Seems strange. This forum is full of people running 2-3 if not more bars of boost with fuel to match on stock bolts and HGs....
RE: Stronger OM606 headbolts? - baldur - 04-07-2020
You should also look at your pump timing. Injection timing is critical for cylinder pressures, and it has to be tuned on a dyno, the only correct advance is the least amount of advance that still produces maximum power. Overadvancing the pump not only hurts power but hurts the engine as well. Injecting too early produces much increased cylinder pressures.
RE: Stronger OM606 headbolts? - AlanMcR - 04-08-2020
I will check it, thanks. It is getting a new chain when I open it up.
RE: Stronger OM606 headbolts? - Tobulus - 04-09-2020
(04-06-2020, 01:42 PM)AlanMcR(04-06-2020, 07:37 AM)baldur If you have your head and block separated you can make some measurements and send an inquiry to ARP to assemble a set that will work. I did this for my OM602.
I have attached the measurement sheet that I made for the 602.
Get in touch with ARP at https://arp-bolts.com/p/contact.php
Thanks, I'll look into that. Their site doesn't seem very well oriented towards mixing and matching parts for vehicles that they don't make kits for.
As far as buying genuine MB bolts, I'd need to be convinced that they were any better. MB has not always been the best source. Unsure of the EGT, but the first problems happened with stock power on a significantly opened up exhaust. I think the factory was betting on max power being used for passing, rather than 10 minutes of foot to the floor. Engine temp was reasonable 90C-ish until it suddenly jumped. I presume when the bolt(s) let go.
Factory set the engine up for the german market, which means that people drive it for hours at maximum speed on the autobahn or pull 3.5ton trailers with a G with this engine.
RE: Stronger OM606 headbolts? - AlanMcR - 04-09-2020
That sure wasn't the case with the G350. Driven hard or hot they didn't last to 100Kkm.
RE: Stronger OM606 headbolts? - Tobulus - 04-10-2020
(04-09-2020, 08:40 PM)AlanMcR That sure wasn't the case with the G350. Driven hard or hot they didn't last to 100Kkm.
Yes, the problem was even worse here in Germany. About 60% of the w140 S350 in the market got a new engine within the first four years.
RE: Stronger OM606 headbolts? - starynovy - 04-11-2020
Was chasing thing like this on bmv crapheap M51. Even developed my own 12.9 head studs. Turned out to be warped block and possibly weak threads in block. Had head off like 5 times and each time I torqued it felt like you are not torqueing at all. So kinda combination of both. Is your block flat? How does bolts feel when you tighten? There is no problem with factory bolts on this engine, save money on ARP studs. If you want you can buy genuine used 606 bolts from some breaker. Never seen used one from factory engine stretched by a bit, so perfectly fit for reuse.
RE: Stronger OM606 headbolts? - atypicalguy - 04-12-2020
Yeah it sounds like either the head or the block needs decking while you change the gasket.