Head disassembled: what valve springs to use?

[jrw21]

small_m, thanks for the info. The m42 head I am using is from a 95 m42 engine. So, it has 6mm valve stems. Just to make sure I just went out a put a caliper on the stem and it checked out to be just shy of 6mm.

Also, someone correct me if I am wrong but I believe the ARP head studs are basically the same as m50's. I had an ARP Master dealer contact their sales rep at ARP to cross reference the part number racetep.com sells and the rep said the part number did not exist in the ARP database. So, I am not sure what racetep.com has going on with that part number.

I am interested in the MLS headgasket. I have read online and heard from Metric Mechanic that they fail as often as a stock m44 headgasket. What I don't hear is if the MLS gasket actually blows out or if the head they are failing on is warped and leaks out. I was under the impression that MLS gaskets on a milled flat head was near impossible to blow out. I can't find enough data either way to make a decision. But, I am likely to take the stock m44 gasket route.

[small_m]

Originally Posted by xxxJohnBoyxxx

small_m

Thanks for the advise it's always good. If you don't mine me asking how many M44's turbo builds do you have on the road running 20psi?

Thanks, John S

John,
I have 0 M44 turbos with 20psi on the road. Does that matter? I have built 911 turbo motors, vw 1.8t, toyota 3sgte (my 91' mr2 that did have 22psi), and a few others. Plus countless indy, nascar and viper motors at work.

[xxxJohnBoyxxx]

Originally Posted by small_m

John,
I have 0 M44 turbos with 20psi on the road. Does that matter? I have built 911 turbo motors, vw 1.8t, toyota 3sgte (my 91' mr2 that did have 22psi), and a few others. Plus countless indy, nascar and viper motors at work.

No I'm not questioning you ability or knowledge. You have stated several times what you worked on so I'm sure it is much more then I have. I just know that there are a few things that work on these M44 engines with high boost from experience. I do not flame or try to be the right person, just try to give good information.

1. The MLS head gasket has failed on a few motors so we have changed to a different one that works with no failures. This is from experience from many motor that are on the road.

2. The stock valves & seats have been ground to add additional area to help with cooling as you suggested and have failed on my motor within 1,000 miles at high boost with a proper tune and that is why we took a different route. I'm only offering information from experience.

3. The Busa race springs are not rated at 15K on my motor obviously. They are just a much better valve spring for my application due to lift. They are better all around and some people like to install quality products that are light weight at minimal cost increase.

4. M3 head bolts cut to fit, torqued with the recomended head gasket has resulted in no head gasket failures. ARP bolts are great very true but more expensive. I agree use ARP where you can but save money where you can too. I'm not sure of the price difference for a set of ARP -vs- M3 head set.

I'm not bashing you I like to read and learn from people just like you. I just don't want to see someone install a head gasket that is know to fail on their boosted motor when I know there is a better solution from R&D.

Best, John S

[small_m]

John,
Its good to know that you have found some stronger parts and have learned from the expiriance of boosting your m44. I am surpirsed to see that a valve failed. How did the valve fail from heat? Normally I have only seen a valve fail due to exessive forces from an aggressive cam, poor timing or an over rev. I would agree that the busa spring would be made at a higher quality as they have to handle the rpm and hard work that a race engine does. I guess with the ARP stuff its just a fail safe and something that you just wouldnt have to worry about.
I didnt think you were bashing, as there are people on forums that give advise on things that other people have just told them but never seen or tried and that does really help. So its good to question peoples answer to find out if they are full of S#@T .

[xxxJohnBoyxxx]

On the stock valves when they are ground on the 45 for the wide seat they are prone to cracking. This is from Metric. I had stock valves ground on the 45 on my high boost motor and burned a exhaust valve in the first 1,000 miles. This was found when I bent a intake valve from a destroyed DISA valve metal rod getting stuck in the valve seat. Tune was good since I ran the same tune for 15K miles with no issues after we got the new volvo valves in there that were thicker and cut the wide 45 seat.

On the ARP head bolts the shank is smaller then the M3 bolts. I don't know about stretch and all that during torqueing but I go with what they tell me works from R&D. Metric has blown a few head gaskets on boosted motors to get it right. They swear by their head gasket and bolt combo and it has worked good for me so far.

Valve springs. The stock springs are good to 7,000 rpm but after 10K miles if you take them off and measure them they will have fatigue and slight different heights. The Busa springs have not shown this after 10K but we don't have any motors with high mileage yet for a test of like 50K. Everything is lighter with the busa springs which is good.

That is all I can offer.

John S

[jrw21]

This project is going rather slow due to lack of room in the garage.. But, I did do some more research/planning today. I am trying to determine the compression ratio so I decided to CC the head to determine the volume. I read online about 33cc, however, my tests were actually 36cc and 35cc (measured it twice.)


My plan is to shave about 4 - 4.5 mm off the s52 pistons, which will make the piston have a completely flat top. This picture shows the oem m42 piston in my overbored m42 block prepared with m44 crank, the piston sits 1mm over deck:


So, shaving 4-4.5mm off the piston will leave it sitting 3-3.5mm below deck, with a cc volume of 35.5cc, oem m44 HG that results in ~8.75:1 - 8.4:1.

[xxxJohnBoyxxx]

I was hoping someone would post on this but no one has. I was wondering if shaving the piston tops 4mm will have any effect on strength or cooling ability. I think it is better to have the rings lower from the crown on a turbo motor. I know nothing about this and was hoping for some education. Are you going to run squirters on the under side to cool the pistons?

John S

[jrw21]

the s52 pistons have a much larger "dome" than the m42 pistons, shaving them 4mm will essentially negate that dome edge. The top center portion of the piston will not be shaved so it should have the same strength as a non shaved s52 piston. You can somewhat see from this picture the edge that will be shaved.

[xxxJohnBoyxxx]

Yes I see now. Looks great. Lots of meat there before the top ring. Thanks for the information.

Best, John S

[ChItalian1027]

jrw21 if you need any help I can come over. How far is Dunlap from Glenview (northern suburbs of Chicago)

[ChrisM42Turbo]

I want to know how to install the hayabusa springs & retainers and what Volvo engine to take from it the valves and where to cut it from ?

[blowin 4]

Originally Posted by xxxJohnBoyxxx

On the stock valves when they are ground on the 45 for the wide seat they are prone to cracking. This is from Metric. I had stock valves ground on the 45 on my high boost motor and burned a exhaust valve in the first 1,000 miles. This was found when I bent a intake valve from a destroyed DISA valve metal rod getting stuck in the valve seat. Tune was good since I ran the same tune for 15K miles with no issues after we got the new volvo valves in there that were thicker and cut the wide 45 seat.

On the ARP head bolts the shank is smaller then the M3 bolts. I don't know about stretch and all that during torqueing but I go with what they tell me works from R&D. Metric has blown a few head gaskets on boosted motors to get it right. They swear by their head gasket and bolt combo and it has worked good for me so far.

Valve springs. The stock springs are good to 7,000 rpm but after 10K miles if you take them off and measure them they will have fatigue and slight different heights. The Busa springs have not shown this after 10K but we don't have any motors with high mileage yet for a test of like 50K. Everything is lighter with the busa springs which is good.

That is all I can offer.

John S

i dont know what to believe anymore last time i talk to jim i told him i blew my hg and ask him if i should change my valves to stainless steel he said no that they never had a problem he also said that the tips are harden and filled with something . what he told me was that alot of stainless steel valve tips mushroom out . im just going to learn from experience as i keep blowing **** up in the future until i perfect that motor...

[chzman]

Originally Posted by ChrisM42Turbo

I want to know how to install the hayabusa springs & retainers and what Volvo engine to take from it the valves and where to cut it from ?

I second this. I have the head off of my m44 now. I can either put the stock parts with 120k m on them or upgrade now. what Busa springs and Volvo valves do we use? I'm not financially ready to go the VAC route. Although they have made my fuel injector adapters to upgrade.

edit:
I never hear the timing chain discussed. i'm going to put a new one on since i have the head off. is there an upgrade to that or just an oem chain?